TEE ATISE 
 
 OK 
 
 PHOTOGRAPHY, 
 
 BY 
 
 CHARLES WA LDACK. 
 
 FOURTH E D I T i 0 H - 
 
 C I N C I/N N A T t : 
 HJ W;t punier, No. 60 West Thiku Street. 
 1865. 
 
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Digitized by the Internet Archive 
 in 2014 
 
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WILLARD & CO. 
 
 PHOTOGRAPHIC WAREHOUSE, 
 
 No. 522 Idfcvositl way , 
 
 NEW YORK. 
 
 §toufactwm& Jmpavtcts, and grains. 
 
 AGENT8 FOR 
 
 REYNOLDS' PATENT CAMERA ATTACHMENT, 
 
 For Making the Celebrated Porcelain Piotnr^s; 
 
 ALSO, FOE THE BEST QUALITY OF 
 
 PORCELAIN G-3L.A.SS- 
 
 MANUFACTURERS OF 
 
 DAGUERREOTYPE CASES 
 
 IN GREAT VABIE T Y • 
 
 lyillard's Opal Varuish, 
 
 }Villard>s Union Gilding, 
 
 Willard's Union Collodion, 
 
 Willard's Gem Cameras, 
 
 Willard's Focussing Glasses. 
 
 GILT AND ROSEWOOD FRAMES OF EVERT DESCRIPTION. 
 
 Cameras, Apparatus, Mattings, Preservers, Pure Chemicals, eta. 
 
 pur Stock is always large, and will be sold at all times at the lowest 
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 WILLARD & CO., 
 
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EDW. AND H. T. ANTHONY & CO. 
 
 JVb. 501 Broadivay, New York, 
 
 MATERIALS OF EVERY DESCRIPTION. 
 
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 Photographic Backgrounds, Fancy, Plain, or Landscape. 
 
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 Nl®, 5Qf Broadway* 
 MANUFACTURERS OF PHOTOGRAPHIC ALBUMS. 
 
THCE CELEBRATED 
 
 HELION COTTON. 
 
 The Helion Cotton is made by the DAGUERRE MANUFACTURING 
 COMPANY exclusively, from the best Sea Island staple, by a process unknown 
 to all other chemists in the world. 
 
 The Helion Cotton is adapted to every structure of light and condition 
 of circumstances, and is exclusively used by all first-class Photographers in 
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 the present mode of making it. 
 
 The Helion Cotton is made with three distinct grades of intensity, 
 numbering 1, 2, and 3. No. 1 indicates the greatest degree of intensity, and 
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 results. 
 
 FORMULA FOR MAKING COLLODION WITH THE HELION COTTON. 
 
 95 per cent. Alcohol and Con. Ether, equal parts. 
 
 5 grains to the ounce Iodide of Ammonium or Cadmium. 
 
 2% grains to the ounce Bromide of Cadmium or Potassium. 
 
 5 to 6 grains to the ounce Helion Cotton. 
 N. B. — Iodize before adding the Cotton. Before flowing, add to each ounce of 
 Collodion three to five drops of full strength Tincture of Iodine. Tincture of Iodine 
 ia made by dissolving Crystals of Dry Iodine in Alcohol. 
 
 PRICE OF HELION COTTON. 
 
 No. 1 $1 00 per ounce. No. 2 $1 00 per ounce. No. 3 75 cts. per oz. 
 
 FOR SALE AT THE FOLLOWING ESTABLISHMENTS. 
 
 Willard & Co., Holmes, Booth & Hayden, Scovill Manufacturing Co., Will- 
 cox, Rogers & Graves, R. V. Harnett, W. H. Mountfort, Genert Bros., J. F. 
 Luhme & Co., George A. Chapman, New York; Benjamin French, John Saw- 
 yer, Boston, Mass. ; Parsons & Green, Albany, N. Y. ; L. C. Everett, Troy, 
 N. Y. ; J. A. Hall & Co., Utica, N. Y. ; F. Hendricks, Syracuse, N. Y. ; R. B. 
 Appleby, Rochester, N. Y. ; R. O. Benton, Buffalo, N. Y. ; C. C. Kelsey, Cin- 
 cinnati, O. ; R. B. Appleby, Chicago, 111. ; E. M. Osborn, Washington, D. C. ; 
 William Shew, San Francisco, Cal. ; George Dabbs & Co., Philadelphia, Pa. ; 
 W. H. Tilford, St. Louis, Mo. 
 
 SPECIALTY*— We desire to call the attention of Photographers and Dealers in 
 photographic cotton to this fact, that Helion Cotton, Collodion, and Chloride of Gold, are 
 specialities with us. We make but those three articles, all of which we know are as 
 good and as cheap as the market affords. 
 
 Beware of impositions. The unprecedented popularity of the Helion Cotton has in- 
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 get the genuine article. 
 
 READ THE FOLLOWING RECOMMENDATIONS. 
 
 Dear Sir: Your No. 1 Helion Cotton is No. 1 in every respect. Send us a few mor« 
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 Dear Sir: Something more than one year ago we commenced using your Helion Cotton, 
 and have used it ever since, with the most gratifying results. We have no hesitation in 
 recommending it to all, as the most reliable photographic cotton in the market. 
 
 J. GURNEY & SON, New York. 
 
 Dear Sir: We have used your Helion Cotton for a long time, and have found it uni- 
 formly good. We have no hesitation in recommending it as the best photographic cotton 
 we have used. C. D. FREDERICKS & CO., New York. 
 
 Dear Sir: We have used your Helion Cotton long enough to satisfy us that it is uni- 
 formly good. M. B. BRADY, New York. 
 
 Dear Sir : Your No. 3 Helion Cotton is most admirably adapted to our structure of light. 
 It gives sufficient strength to our negatives without redeveloping, and is, in all respects, 
 the most uniform and the best we have ever used. A. BOGARDUS, New York. 
 
 DAGUERRE MANUFACTURING CO. 
 
 P, D, T, DAVIE, Chemist. 93 Crosby Street, New York. 
 
THE "OLD RELIABLE" 
 
 P. SMITH & CO. 
 
 ( LATE PETER SMITH,) 
 
 JVb. 36 West Fifth Street, Cincinnati, Ohio, 
 Now keep on hand a full and complete assortment of Goods in our line, comprising 
 
 CAMERAS, APPARATUS, MATTINGS, 
 
 Preservers, Plates, fancy Frames, Cases, etc, Photographic Paper, Chemicals, 
 
 AND MATERIALS OF EVERY DESCRIPTION FOR 
 
 mw km 
 
 Our Assortment is Large, and will be kept up. 
 
 THE CHEMICALS 
 
 ARE FROM THE BEST LABORATORIES, AND ARE SELECTED WITH THE GREATEST CASE. 
 
 ALL ORDERS WILL BE PROMPTLY FILLED, 
 
 — AND — 
 
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 OUR TERMS ARE CASH, OR COLLECT ON DELIVERY. 
 
 Your Orders are kindly solicited, and satisfaction guaranteed. Orders 
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 given. All orders should be addressed 
 
 P. SMITH & CO., 
 
 No. 36 West Fifth Street, 
 
 CINCINNATI, OHIO. 
 
CINCINNATI STOCK DEPOT. 
 
 C. C. KELSEY, 
 
 WHOLESALE DEALER IN 
 
 PHOTOGRAPHIC GOODS, 
 
 MANUFACTUKEE OF THE CELEBRATED 
 
 B&aaer doIMtoa, Baaaer f&ratsa, 
 
 ALBUMENIZEO PAPER, CHLORIDE OF GOLD, ETC., 
 
 No. 137 West Fourth Street, Cincinnati, Ohio. 
 
 ARTISTS AND AMATEURS IN PHOTOGRAPHY 
 
 WILL FIND AT THIS ESTABLISHMENT THE LARGEST AND M08T COMPLETE ASSOttT- 
 
 MENT IN THE WEST, COMPRISING 
 
 Cameras of every make, 
 
 Apparatus of all kinds, 
 
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 Superior French and 
 
 English Negative Glass, 
 
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 Pure Photographic Chemicals, 
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 Solar Cameras, 
 AND ALL OTHEK ARTICLES USED IN THE ART. 
 
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 OYAL FRAMES 
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 Special attention given to refining Artists' Wastes. 
 
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 Address Orders 
 
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C. S. RUSSELL, 
 
 SUCCESSOR TO 
 
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 Comer Fifth and Olive Streets, 
 ST. LOUIS. 
 
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 PHOTOGRAPHIC ARTISTS 
 
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 NECTED WITH THIS BUSINESS FOR MORE THAN TWENTY YEARS 
 PAST, AN EXPERIENCE WHICH ENABLES IT TO 
 
 FURNISH THE OPERATOR WITH THE BEST QUALITY OF 
 
 CAMERAS, 
 
 APPARATUS, 
 
 CHEMICALS, 
 
 FRAMES, 
 
 PLATES, 
 
 CASES, 
 
 GLASS, 
 
 Etc., Etc. 
 
 AT THE LOWEST MARKET PRICES. 
 
 ^The reputation which this House has already earned 
 itself in the past, for the prompt and honest man- 
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 will, it is hoped, recommend it to those who may not 
 have yet favored it with their patronage. 
 
TILFORD'S 
 
 ST. LOUIS JIOTOGRAWJTOCK DEPOT. 
 
 ESTABLISHED 1848. 
 
 "W. H. TILFOBD, 
 
 IMPORTER OF AND DEALER IN 
 
 CHEMICALS, APPARATUS, CAMERAS, CASES, FRAMES, ETC., PHOTOGRAPH ALBUMS, AND, 
 ALL ARTICLES AND APPARATUS APPERTAINING TO 
 
 STTN" PIOTUEES, 
 
 Bo. 17 North Fourth Street, Opposite Oourt-House, St. Louis, 
 
 Having just completed and removed to my new building, especially arranged 
 and adapted to Photographic Materials, I am now prepared to offer the most 
 extensive and varied assortment of the above-named Goods out of New York. 
 My practical and long experience, together with advantages of purchasing i$ 
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 customers with reliable Goods, at low rates, and with promptness. 
 
 W. DEC. TILFOBD, 
 No. 17 North Fourth Street, Opposite Court-House, St. £oui», Mo ; 
 
TEEATISE 
 
 ON 
 
 PHOTOGRAPHY. 
 
 BY 
 
 CHARLES WALDAOK. 
 
 POURTH EDITION. 
 
 CINCINNATI: 
 H. Watkin, Printer, No. 60 Third St., kbar Walnut. 
 1865. 
 
Entered according to Act of Congress, in the year 1865, by 
 CHAS. WALDACK, 
 In the Clerk's Office of the District Court of the United States for the Soitthen 
 District of Ohio. 
 
PREFACE 
 
 Numerous changes have been made in this edition. 
 Matters become obsolete have been suppressed, and 
 improvements in the processes generally practiced have 
 been described. We have not noticed, however, any 
 of the new processes in printing, which have lately 
 made their appearance. The processes of carbon print- 
 ing we consider not yet sufficiently practical to be of 
 use to the professional photographer. We thought of 
 being able to give a method superior to the ordinary 
 printing process, and even, on this account, retarded 
 the publication of this edition; but the process in 
 question turned out to have been greatly overrated. 
 We refer here to the Wothlotype process, the appear- 
 ance of which created such an excitement in the pho- 
 tographic community. The results obtained by this 
 process do not meet the anticipation of photographers. 
 Prints made by it possess no advantage over those 
 made in the ordinary way, neither in quality, facility 
 of manipulation, cost, nor permanency. Our aim being 
 to bring forth a guide for practical photographers, we 
 have thus omitted a description of it, and devoted our 
 space to objects of more direct value. 
 
1 
 
 CONTENTS. 
 
 CHAPTER pagk 
 
 I. History of Photography 9 
 
 II. Philosophy of Light — Decomposition of Light — 
 Its Illuminating, Heat-producing, and Actin- 
 ic Properties — Invisible Rays — Refraction — 
 
 Lenses — The Photographic Camera 16 
 
 III. General Theory of the Collodion Process 23 
 
 IV. On the different Compounds used in the produc- 
 
 tion of Collodion Pictures 26 
 
 V. On positive Collodion Pictures 27 
 
 VI. On Collodion 29 
 
 VII. The Silver Solution for Positives 59 
 
 VIII. Developing Solution for Positives 69 
 
 IX. The Fixing Solution 73 
 
 X. Cleaning the Plate 75 
 
 XI. Formation of the Film of Collodio-Iodide of 
 
 Silver 78 
 
 XII. Exposure in the Camera 190 
 
 XIII. Development of the Picture 192 
 
 XIV. Fixing the Picture 197 
 
 XV. Mounting the Picture 198 
 
 XVI. On Collodion Negatives 101 
 
 XVII. Collodion for Negatives 103 
 
 XVIII. The Silver Solution for Negatives 107 
 
 XIX. The Developing Solution for Negatives 109 
 
 XX. The Fixing Solution Ill 
 
 XXI. Practical Details of the Negative Process 112 
 
 XXII. Strengthening of the Negative 117 
 
 XXIII. Alcoholic Collodion 122 
 
 XXIV. Imperfections in Collodion Photographs 123 
 
Vi CONTENTS. 
 
 CHAPTER pag* 
 
 XXV. Positives on Paper 134 
 
 XXVI. Direct Positive Process 136 
 
 XXVII. Preparation of the Sensitive Paper 140 
 
 XXVIII. The Printing 153 
 
 XXIX. Toning, Fixing, Washing, and Mounting of the 
 
 Prints ,.....«: 156 
 
 XXX. On the Fading of Positive Prints 168 
 
 XXXI. Instruments Used for Making Enlarged Prints 
 
 from Collodion Negatives — The Solar Camera 172 
 XXXII. Enlarged Prints by the Direct Positive Process... 177 
 
 XXXIII. Enlarged Prints by the Developing Process 179 
 
 XXXIV. Preserved and Dry Collodion Processes 193 
 
 XXXV. The Tannin Process 196 
 
 XXXVI. The Tannin and Honey Process 208 
 
 XXXVII. The Collodio-Albumen Process 210 
 
 XXXVIII. On Rapid Dry Collodion Plates 213 
 
 XXXIX. On Copying 215 
 
 XL. Out-door Photography 222 
 
 XLI. Instantaneous Photography 231 
 
 XLII. Photography on Painter's Canvas 235 
 
 XLIII. Binocular Vision — the Stereoscope — How to take 
 
 Stereoscopic Pictures 242 
 
 XLIV. Transparent Positives— The Opaltype — Enlarg- 
 ing Negatives 247 
 
 XLV. Recovery of Silver from old Solutions, Paper 
 
 Clippings, Washings, etc 251 
 
 XLVI. Removing Stains from the Skin, Linen, etc 256 
 
TREATISE ON PHOTOGRAPHY. 
 
 CHAPTER I. 
 
 History of Photography. 
 
 The art of photography (from the Greek 
 light, and print,) includes all pro- 
 
 cesses by which images or impressions are 
 obtained through the agency of light. The 
 application of the action of light to this pur- 
 pose is but of recent introduction. 
 
 The ancients do not seem to have directed 
 their attention to the modifications brought on 
 by light, in the physical and chemical condi- 
 tions of certain bodies. The only phenomenon 
 recorded by them is the loss of brilliancy of 
 certain precious stones, such as opal and 
 amethyst, by a prolonged exposure to the 
 sun's rays. In the middle ages some of the 
 alchemists noticed the fact that the fused chlo- 
 ride of silver, called by them horn silver or 
 horn moon, blackened under the influence of 
 light. 
 
 In 1722, Petit remarked that certain salts, 
 such as the nitre and sal ammonia, crystal- 
 ized easier being exposed to -the light. 
 
 In 1765, the celebrated German chemist, 
 Scheele, made a more scientific examination of 
 the action of light on the silver compounds, 
 and discovered that the chloride of silver black- 
 
8 
 
 ens more rapidly in the violet, than in the red 
 ray of the spectrum. 
 
 The first attempt at photographing was 
 made by Wedgewood, in 1802. He succeeded 
 in making silhouettes by projecting the shadow 
 of the object on paper dipped into a solution of 
 nitrate of silver ; the part on which the shadow 
 fell remained white, while the one exposed 
 to the light blackened. The image thus ob- 
 tained was immersed in water, which dissolved 
 the unreduced nitrate of silver. Wedgewood 
 and Humphrey Davy tried to copy landscapes 
 in the camera obscura by the same process, but 
 did not find it sensitive enough. Davy, how- 
 ever, succeeded in copying the enlarged images 
 obtained with the solar microscope. 
 
 Joseph Nicephore Niepce of Chalons, France, 
 is the first one who succeeded in fixing the im- 
 age of the camera obscura. His process was 
 based on the property of the bitumen of Judea, 
 or asphaltum, to become insoluble in certain 
 essential oils under the influence of , light. 
 Niepce dissolved the asphaltum in lavender 
 essence, and spread it on the surface of a sil- 
 vered copper plate ; when dried, the plate was 
 exposed in the camera obscura for several 
 hours, and then washed with a mixture of petrol 
 oil and lavender essence, which had the effect 
 of dissolving the unalted asphaltum. In the 
 image thus obtained, the lights were formed by 
 the undissolved bitumen, and the shades by 
 the silver. 
 
9 
 
 In 1829 Niepce associated with Daguerre, 
 who had labored to attain the same object, but 
 their combined efforts did not result in improv- 
 ing the bitumen process so as to make it prac- 
 ticable. 
 
 In one of their experiments, they used the va- 
 por of iodine to darken the shades of their 
 bitumen pictures, and observed that the iodide 
 of silver thus formed was altered in color by the 
 light. It is this fact, which is said to have 
 changed the direction of Daguerre's investiga- 
 tions, and to have been the first step towards 
 the discovery of the Daguerreotype. 
 
 It was only after the death of Niepce, that 
 Daguerre, continuing hik experiments, discov- 
 ered the process which bears his name. Da- 
 guerre's sensitive iodide of silver was prepar- 
 ed by exposing a well polished silver plate to 
 the vapor of iodine. The plate was exposed 
 in the camera obscura for a relatively short 
 time, and then was submitted to the vapor of 
 mercury, which brought out the latent image. 
 The mercury combining with the parts affect- 
 ed by the light, formed the lights, while the 
 black appearance of the burnished silver, which 
 had not been impressed, constituted the shades. 
 The unaltered iodide of silver was then ren- 
 dered insensitive by washing the plate with 
 a solution of common salt. 
 
 The publication of Daguerre's process in 
 1839, produced an immense sensation. At no 
 time and on no occasion before was a greater 
 
10 
 
 interest manifested by the lovers of art and 
 science. Men of science and artists of reputa- 
 tion embraced the new art with enthusiasm, 
 and in a short time, the Daguerreotype became 
 the beautiful process as it is now practiced. — 
 Daguerre himself did but little to perfect it. — 
 Baron Seguier, Foueault, etc., perfected the 
 apparatus. Herschel substituted hyposul- 
 phite of soda for the common salt used for 
 fixing the image. Fizeau discovered the 
 means of gilding the image and in this 
 way gave it more brilliancy and durability. — 
 Claudet discovered the first accelerating sub- 
 stance used, the chloride of iodine, and Fizeau 
 again used the vapor of bromine to the same 
 purpose, and thus reduced the time of exposure 
 in the camera to a few seconds. After that 
 followed the discovery of the dry accelerating 
 substances, bromide of lime and chloro-bro- 
 mide of lime (improperly called), the numerous 
 improvements in the apparatus, by which the 
 tedious process as described by Daguerre was 
 reduced to its utmost simplicity, etc. 
 
 Thus, in a few years, the process of Photo- 
 graphy on silver plates became the simple and 
 practical process which to this day has not had 
 its superior in sharpness, definition and brilli- 
 ancy. 
 
 While Daguerre was prosecuting his re- 
 searches in France, Fox Talbot was continu- 
 ing in England the researches of Wedgwood 
 and Davy. In January 1839, seven months be- 
 
11 
 
 fore the publication of Daguerre's process, Mr. 
 Talbot made his first communication to the 
 Royal Society of London. In this communi- 
 cation, he made known his process of copying 
 by application. A sheet of paper is firstly 
 brushed over with a solution of chloride of so- 
 dium (common salt) and then with a solution 
 of nitrate of silver. In this way is formed in 
 the texture of the paper a white precipitate of 
 chloride of silver, a compound much more sen- 
 sitive than the nitrate of silver employed by 
 Wedgwood and Davy. The object to be copied 
 is laid on the prepared paper and exposed to 
 the light. The light passes through the trans- 
 parent parts, and blackens the paper, leaving 
 unaltered the parts through which it cannot 
 penetrate. In this way an image is obtained 
 with the lights and shades reversed, which 
 Talbot called a Negative. This negative be- 
 ing laid on a .second sheet of paper, prepared 
 in the same way as the first, and the same 
 operation being gone through, a natural repre- 
 sentation of the object is obtained, which is 
 called Positive. 
 
 In February 1841, Talbot took his patent 
 for the Talbotype or Calotype process. In this 
 process, the paper is first brushed over with 
 nitrate of silver, then with iodide of potassium 
 and finally with gallo-nitrate of silver, (a solu- 
 tion of gallic acid and nitrate of silver.) It is 
 then exposed in the camera, developed with 
 a fresh solution of gallo-nitrate, and fixed in 
 
12 
 
 a solution of bromide of potassium. The im- 
 age produced is negative, and positives are 
 copied from it by means of the chloride of sil- 
 ver paper spoken of above. The Talbotype 
 process was modified and perfected by Blan- 
 quart Evrard, Humbert de Molar d, Baldus, 
 Legray, etc. It is a modification of the Talbo- 
 type process, which is now generally used 
 in printing enlarged pictures. 
 
 We will not in this work enter into the 
 many details of the Calotype process. The 
 different negative paper processes are more 
 suited to monumental photography than to the 
 reproduction of natural scenery. Our modern 
 public edifices, the elegant and tasteful dwell- 
 ings of our wealthy citizens, the luxuriant veg- 
 etation of our landscapes are bad subjects to be 
 photographed. Their reproduction presents dif- 
 ficulties which can only be overcome by means 
 of the collodion process. The processes of Le- 
 gray, Baldus and others, present thus too little 
 interest to our American photographers to speak 
 at length of them in this work. 
 
 Fox Talbot must be considered as the inven- 
 tor of what is commonly called photography, 
 which comprises the different processes on pa- 
 per and on glass. The waxed paper, the albu- 
 men and the collodion processes rest on the 
 same basis as the process he patented in Febru- 
 ary, 1841, viz: formation in paper, albumen or 
 collodion of iodide of silver with presence of 
 nitrate of silver, moleculary alteration or partial 
 
13 
 
 reduction of the sensitive surface by the light, 
 development or bringing out of the latent im- 
 age by means of gallic acid, pyrogallic acid or 
 protosulphate of iron, finally desensitizing or 
 dissolution of the unaltered iodide by means 
 of bromide of potassium, hyposulphite of soda, 
 cyanide of potassium, etc. 
 
 The prints made from paper negatives, ow- 
 ing to the coarse and irregular texture of the 
 paper, being very inferior in sharpness and 
 definition to the daguerreotypes, Sir John 
 Herschel suggested the use of glass plates.— 
 Soon after Mepce de St. Victor, the nephew 
 of John Mcephore Mepce discovered the Al- 
 bumen process, in which the iodide of silver 
 is retained on the plate by means of a layer of 
 white of egg. This beautiful process, most 
 simple in theory, but the most difficult in prac- 
 tice was perfected by Messrs. Bayard, Hum- 
 bert de Molard, Martens, Lemoynne, Whipple, 
 etc. The objections to this process are the 
 difficulty to avoid dust and the length of ex- 
 posure that is required. 
 
 In 1850 Legray suggested the use of collo- 
 dion instead of albumen, but Archer was the 
 first who carried out the idea so as to present 
 to the photographic world a well defined pro- 
 cess. 
 
 The discovery of the collodion process is 
 the most important that has been made in 
 photography since the discovery of the Da- 
 guerreotype. It has given an immense im- 
 
14 
 
 pulse to the art. It is certainly the simplest 
 and most successful process in use, and is 
 suited to almost any condition of light and 
 temperature. 
 
 % From the time the collodion process first 
 came into use attempts have been made to 
 preserve the sensitiveness of the film, so as to 
 be able to leave a certain time between the 
 preparation of the plate and the exposure, and 
 between the exposure and the development. 
 Mr. Shadbolt first succeeded in this by cover- 
 ing the sensitized plate with diluted honey, 
 thus keeping it moist. This process is now 
 abandoned, and processes in which the plate is 
 washed and dried have come into general use. 
 Amongst these we will cite Taupenot's collodio- 
 albumen process, Hill Norris' gelatine pro- 
 cess, Fothergill's, Sutton's, Major Russell's 
 and others. Major Russell's process, in which 
 tannin is used as a preservative, is the most 
 popular, and very successful. By some modi- 
 fications introduced in its practice, good results 
 have been obtained with an exposure not much 
 longer than that which is generally given for 
 wet collodion. 
 
 The attention of scientific photographers has 
 been directed, for the last few years, to the 
 means of preventing the fading of photographic 
 prints. The researches of Messrs. Barreswil 
 and Davanne, Hardwich and others, have 
 shown the real causes of the fading. , 
 
 Now that the old processes of toning and fix- 
 
15 
 
 ing together have been abandoned, and the 
 separate toning and fixing has been generally 
 adopted, prints are made more permanent than 
 they used to be. Many photographers, how- 
 ever, use their fixing bath so injudiciously 
 that the prints they produce are little better 
 than those by the old method. 
 
 Some experimenters have discovered pro- 
 cesses in which the salts of silver are not used. 
 The most noted one is the carbon process, but 
 the prints obtained by it cannot compete for 
 beauty with those obtained by the ordinary 
 processes. In our opinion the true progress of 
 photography lays in another direction. We 
 refer to the production of the print in printer's 
 ink. The process of photo-zincography used 
 at the ordnance survey office in Southampton, 
 and which is the invention of Col. H. James 
 and Capt. A. De C. Scott, gives, in the hands 
 of these gentlemen, very promising results. 
 The same may be said of Mr. Osborne's photo- 
 lithographic process, which is used in the sur- 
 vey office in Melbourne, (Australia.) Both 
 processes are nearly the same, and are subject 
 to the same objection, the difficulty in obtain- 
 ing half tone. 
 
16 
 
 CHAPTER II. 
 
 Philosophy of Light — Decomposition of Light — Its 
 Illuminating, Heat Producing and Actinic Proper- 
 ties — Invisible Eays — Refraction — Lenses — The 
 Photographic Camera. 
 
 When a pencil of sunlight is made to fall 
 upon one angle of a, prism, it is decomposed and 
 forms on a screen placed at a distance an image 
 of the seven primitive colors in the following 
 order: Violet, Indigo, Blue, Green, Yellow, 
 Orange and Red. This image is called the 
 Solar Spectrum. This experiment which was 
 first made by Newton, proves that the light 
 of the sun is composed of seven different rays 
 each producing a different illumination. Some 
 Philosophers admit only of three primitive 
 colors, blue, yellow and red, and contend that 
 the violet, indigo, green and orange are form- 
 ed by two or more of these overlapping each 
 other, red and yellow forming orange, yellow 
 and blue forming green, etc. 
 
 When white light falls on opaque bodies, 
 some of the rays are absorbed, others are re- 
 flected. A red surface thus reflects the red 
 ray and absorbs the others, a blue surface re- 
 flects the blue ray, white surfaces reflect the 
 light without decomposing it, while black 
 ones absorb all the rays. 
 
 The same phenomenon takes place when 
 white light is transmitted through transparent 
 or translucid bodies. While white glass will 
 
17 
 
 thus transmit the light without decomposition, 
 orange glass will only transmit the orange 
 ray, blue glass only the blue ray. 
 
 The compound light produces three effects : 
 it illuminates, it produces heat, and it has a 
 * chemical power commonly called actinism. 
 
 The power of illuminating resides mainly 
 in the yellow ray, the part of the spectrum 
 occupied by that ray being the brightest. The 
 heating properties are predominant in the red 
 ray ; a thermometer held in that part of the 
 spectrum indicates an increase of temperature. 
 
 The most intense actinic power is to be 
 found in the blue, indigo and violet rays. Thus, 
 when a sheet of sensitized paper is exposed 
 to the decomposed light in the spectrum, the 
 action will be found to be the most energetic in 
 the space occupied by these rays. But this 
 action is not confined within the limits of the 
 spectrum, for the paper will be impressed also 
 beyond the violet where the eye perceives no 
 light. The actinic rays which produce this 
 &re called invisible, or dark rays. 
 
 When the light passes from one medium 
 into another, one part of it is reflected, the 
 other part entering the new medium is bended, 
 Bef Taction is the property which light possess- 
 es of deviating from its primitive direction, on 
 passing from a medium of a certain density 
 into another of different density. The effects 
 of refraction are illustrated by some very sim- 
 ple experiments. If a stick be put into the wa- 
 
 2 
 
18 
 
 ter it will seem to be broken in two. If a 
 coin be dropped into a tub of water, it will ap- 
 pear much nearer the observer than it really 
 is. By the effect of refraction, a fish will ap- 
 pear nearer the surface, a basin or a river will 
 not appear as deep as it really is. We 
 see the stars at their rising, before the mo- 
 ment the rays emanating from them can 
 arrive in a straight line within the reach of 
 our vision, because these rays are refracted 
 by entering the atmosphere which surrounds 
 the globe. 
 
 When a ray of light falls upon a lens, the 
 phenomenon of refraction takes place. The 
 ray bends on entering the lens and bends 
 again on leaving it. The form of the lens de- 
 termines the direction of the refracted rays. 
 
 Convergent lenses are those which refract 
 the rays so as to condense them to a point, 
 divergent lenses are those which scatter them. 
 
 A biconvex lens is one which is convex on 
 both sides. A biconcave lens is concave on 
 both sides. A meniscus lens is convex on one 
 side and concave on the other, but more con- 
 vex than concave. A plano-convex lens is 
 plane on one side and convex on the other. — 
 The bi-convex, meniscus and plano-convex len- 
 ses condense the light to a point and are thus 
 convergent, the bi-concave and plano-con- 
 cave lenses scatter it and are therefore diver- 
 gent. 
 
 The point at which rays of light are brought 
 
19 
 
 together by convergent lenses is called the 
 focus. 
 
 When rays of light proceed from very distant 
 objects, they are parallel, or may be considered 
 so. Parallel rays, entering a convergent lens, 
 are brought to a focus at a point nearer the 
 lens than rays which proceed from a small dis- 
 tance and are divergent. The nearer the ob- 
 ject from which the rays proceed the farther the 
 focus is from the lens. The sun's rays which 
 are parallel, condense to a point which is called 
 the principal focus. It is to this point that 
 reference is made in speaking of the focal 
 length of a lens. 
 
 When a ray of light proceeds from a near 
 point, and passing through a lens, comes to a 
 focus at another point, these two points asso- 
 ciated are termed conjugate foci. 
 
 The nearer the object is to the lens, the far- 
 ther its focus will be removed from it, and 
 the larger the image will be. 
 
 The more convex the lens is, the shorter the 
 focus, and the smaller the image it gives. 
 
 The Photographic Camera, in its most simple 
 form, is a box composed of two compartments, 
 the one sliding into the other, one compart- 
 ment having a lens adapted to it, the other 
 being furnished with a ground glass, which can 
 be removed and a tablet holding the sensitive 
 plate put in its place. When this camera is 
 pointed towards an object the focus is found 
 by sliding the compartment to which the 
 
20 
 
 ground glass is adapted, forwards and back 
 wards, till the point is found where the image 
 is the most distinct. 
 
 The image formed on the ground glass is 
 more or less flat or curved, sharp or indistinct. 
 This depends on the construction of the lenses 
 or object-glasses. An object-glass, which gives 
 an image of which nearly all the parts can be 
 brought to a focus at the same point, is said to 
 have a flat field. Object-glasses giving very 
 sharp images, have generally a curved field, 
 so that when the center of the image is in 
 focus, the extremities are not. Flat fields, on 
 the other side, are obtained at the expense of 
 sharpness. 
 
 The want of definition of one part of the 
 image, when the other is sharp and distinct, 
 is due to two causes. The first one is the un- 
 equal refraction of the rays of light, resulting 
 from the spherical form of the lenses, and is 
 called spherical aberration. The second cause, 
 is the obliquity of some rays proceeding from 
 the object. This indistinctness of the edges 
 of the image, can be corrected by covering the 
 edges of the lens, in which the spherical aber- 
 ration mainly resides, and admitting the light 
 only through the center. This is done by fix- 
 ing in front of the lens a disc of metal or card- 
 board with a circular or square opening in the 
 center. This disc is called stop or diaphragm. 
 The effect of a stop is also to make the field 
 flatter, by intercepting a portion of the oblique 
 
21 
 
 rays, and thus lengthening out the focus of the 
 remainder. These effects are produced to a 
 greater extent in proportion as the diaphragm 
 is smaller. But in the same time, the quan- 
 tity of light admitted into the camera, being 
 diminished, the image is less illuminated, and 
 the sensitive plate requires a longer exposure. 
 
 In such conditions, when the use of dia- 
 phragms is not practicable, it is necessary to 
 use lenses, with the least possible spherical 
 aberration. The manufacture of such lenses is 
 a work of great skill and difficulty, and re- 
 quires extraordinary care. 
 
 Ordinary lenses refracting the light, decom- 
 pose it, and give images fringed with color. 
 This effect is called chromatic aberration, and is 
 corrected by the combination of two lenses of 
 different density ; a bi-concave flint, and a bi- 
 convex crown, sealed together, so that they 
 form a meniscus, which is called achromatic. 
 
 The achromatic meniscus, in order to give 
 the desired sharpness and field, requires to be 
 diaphragmed, but as the diaphragm shuts off 
 a large part of the light, it makes it impossible 
 to use this combination to reproduce images 
 of objects which require rapidity of action. 
 
 The portrait tube, or object-glass, is a double 
 combination of lenses. The front combination 
 is a bi-convex crown, sealed to a plano-concave 
 flint, and has the crown lens turned towards 
 the object; the back combination is composed 
 of a bi-concave flint, slightly separated from a 
 
22 
 
 bi-convex crown by means of a ring, the crown 
 lens facing the ground glass. The distance 
 between the two compound lenses is deter- 
 mined by calculation. 
 
 The portrait combination is generally used 
 without a diaphragm, so as to allow a short 
 exposure of the sensitive plate, by admitting 
 a large volume of light. 
 
 The most essential conditions required in a 
 portrait tube, are : rapidity of action, sharpness, 
 and depth of focus. The most important one 
 is the lust, as without it, the production of 
 good portraits is impossible, those parts only 
 on which the focus has been taken coming out 
 sharp and distinct, and the other being dis- 
 torted and out of focus. It is for want of depth 
 of focus, that in so many portraits the hands, 
 and other parts, are out of shape, and a great 
 deal larger than they are in nature. This de- 
 fect can be obviated, to a certain extent, by 
 setting the subject so that his body describes 
 a segment of a circle, as far as this is compe- 
 tent with a good and easy position. Operators 
 possessing instruments which have this defect 
 should diaphragm them as much as their 
 light and the sensitiveness of their plates 
 will allow, and they should not attempt to 
 make large heads, if they want to have good 
 likenesses. 
 
 The portrait combination can be used also 
 for views, by inserting a small diaphragm 
 between the lenses ; or the back lenses may be 
 
23 
 
 removed, and the front lens* turned with the 
 plane side towards the object, in which case, a 
 diaphragm has to be adapted in front. 
 
 The refraction of the light through a lens, 
 which produces chromatic aberration, separates 
 also the visual from the chemical focus. We 
 have seen that the most intense actinic effect 
 resides in the violet ray, and beyond it, and 
 that the most luminous portion of the spectrum 
 is the space occupied by the yellow ray. The 
 violet ray being more refrangible than the yel- 
 low ray, will be more strongly bent, and the 
 two rays will be brought to a focus at two dif- 
 ferent points. The most intense chemical 
 action will thus not take place at the point 
 where the image is the sharpest, but at a point 
 nearer the lens ; and whenever lenses are used, 
 which are not strictly achromatic, the slide 
 containing the sensitive plate should be shifted 
 to that point. In the lenses made by good 
 manufacturers, however, the visual and chem- 
 ical focus are made to correspond. 
 
 CHAPTER III. 
 
 General Theory of the Collodion Process. 
 
 Collodion is a solution of Pyroxyline or Grun- 
 cotton in a mixture of Sulphuric Ether and 
 Alcohol. 
 
24 
 
 Iodized collodion, is collodion in which a 
 certain quantity of some Iodkle has been dis- 
 solved, the iodide of potassium, for instance. 
 
 If a glass plate be coated with this iodized 
 collodion, and, after part of the ether and al- 
 cohol are evaporated, be immersed into a so- 
 lution of nitrate of silver, the iodide of potas- 
 sium and nitrate of silver will decompose each 
 other and will produce iodide of silver, which 
 will be retained on the plate by the film of 
 the collodion. In this state, the film will pre- 
 sent a blue, white, or creamy opaque appear- 
 ance according to the quantity of iodide of po- 
 tassium dissolved in the collodion. This ope- 
 ration has to be done in a dark room by arti- 
 ficial light. If we now expose this plate in the 
 camera, the film will be impressed by the rays 
 of light, strongly in the clear parts, to a small- 
 er extent in the darker. In examining the 
 plate at this moment, it will be found to have 
 the same appearance as before, presenting no 
 trace of an image. A latent image exists 
 however, which has to be brought out by means 
 of a developer. The developer, in the collodi- 
 on process is either protosulphate of iron 
 or pyrogallic acid. If then, we pour a solu- 
 tion of protosulphate of iron on the plate, the 
 image will appear, presenting the most inten- 
 sity in those places where the light was the 
 strongest. This image is formed by metallic 
 silver in a minute state of division retained on 
 the plate by the film of collodion. At this 
 
25 
 
 period we have on the plate metallic silver 
 and iodide of silver which have not been acted 
 upon. What remains to be done is to take 
 away this Iodide of silver by dissolving it in 
 cyanide of potassium or in hyposulphite of 
 soda. 
 
 Let us now examine the picture which we 
 have obtained, by holding it up to the light. 
 
 We will observe that the light parts present 
 a certain opacity and that the shadows are 
 transparent. If on the contrary, we examine it 
 by reflection we will find that the light parts 
 appear white and the shadows black. The 
 former appearance of the picture is called the 
 Negative, and the latter the Positive. 
 
 All collodion pictures made on transparent 
 surfaces such *as glass, etc present both as- 
 pects: Those made on ppi tuned iron plates or 
 on black paper, can aiy be viewed as posi- 
 tives. In practice, the name of positives is 
 given to such pictures on glass, iron, paper, etc, 
 that are designed to be viewed by reflected 
 light. On the contrary, negatives are judged 
 of by transmitted light and are a kind of type or 
 matrix, with which pictures on paper have to 
 be produced by means of a peculiar printing 
 process. 
 
 Although a collodion glass picture presents 
 both aspects, the positive and the negative, it 
 cannot be used in both qualities. A good 
 positive picture has never opacity enough in 
 the light parts to be used for making prints; 
 
 3 
 
26 
 
 and a negative picture, viewed by reflection is 
 imperfect, owing to the absence of good blacks 
 and of details in the light parts. Both kinds 
 jof pictures are produced by the same process, 
 but different conditions of the chemicals are 
 required. 
 
 For the positive picture, the silver reduced 
 on the surface of the plate has to be in a small 
 quantity only; for the negative picture, it is to 
 be so thick that it obstructs the light to a con- 
 siderable extent in the light parts. The 
 quantity of reduced silver, or the intensity of 
 the image, depends ; 1st, on the peculiar qual- 
 ities of the soluble cotton; 2nd, on the thick- 
 ness of the collodion; 3d, on the amount of 
 bromide dissolved in the collodion ; 4th, on the 
 condition of the silver solution and of the 
 developing solution ; 5th, on the length of ex- 
 posure in the camera. 
 
 CHAPTER IV. 
 
 On the different Compounds used in the Production 
 of Collodion Pictures. 
 
 Before we enter upon the practical details 
 for the production of collodion pictures, we 
 will give, first, the preparation of the different 
 solutions to be used. These are taken in the 
 following order: 1st, the collodion , 2nd, the 
 silver solution ; 3d, the developing solution ; 
 4th, the fixing solution. 
 
27 
 
 The collodion is the menstruum used to re- 
 tain the sensitive compound on the glass, or 
 on the iron plate ; the silver solution, in com- 
 bination with the iodine, which is in the col- 
 lodion, forms the sensitive compound ; the de- 
 veloping solution brings the latent image out ; 
 and the fixing solution removes from the film 
 the unreduced sensitive compound. 
 
 CHAPTER V. 
 
 On Positive Collodion Pictures. 
 
 A positive collodion picture is understood to 
 be a collodion picture viewed by reflected light. 
 Positive pictures are made on different mate- 
 rials. Those most commonly used are whi^e 
 or colored glass, japanned iron plates, or card- 
 board prepared in a similar way, mica, etc. 
 Positives made on glass are generally called 
 Ambrotypes, a name originally only applied to 
 such pictures as were sealed to another plate 
 of glass by means of balsam of fir, and in this 
 way were kept from deteriorating influences. 
 Pictures made on iron plates are called Me- 
 lainotypes or Ferrotypes; and those made on 
 card board or paper covered with asphaltum 
 varnish, are known by the name of Mellographs. * 
 The use of black paper and mica is now almost 
 entirely abandoned, professional photographers 
 confining themselves to the glass and iron 
 plates. 
 
28 
 
 The pictures on iron plates and on black 
 paper are like the daguerreotype reversed, 
 that is, the image is the same as seen in a 
 looking glass, the right side being left, and the 
 left right. The ambrotype alone can be 
 mounted so as to give an exact representation 
 of the subject, and in that case the black var- 
 nish, velvet or paper have to be applied on the 
 collodion side, and the color that may be put 
 on the picture, will not show through the film. 
 The fact of the* melainotype and niellograph 
 being reversed is not objectionable in most 
 cases in portraits, but is decidedly so in views 
 and in this case a parallel reflector, or a prism 
 will have to be used to invert the image, or 
 the picture will have to be made on glass. 
 
 *In our opinion the melainotype, covered with 
 benzine varnish, is the most durable picture 
 of all, as much because of the durability of the 
 material on which it is made, as from the 
 great adherance of the collodion film and var- 
 nish to the japanned surface. We never 
 knew a melainotype picture to crack off, 
 while this is quite common with the varnished 
 glass pictures, which are exposed in show 
 cases to the inclemency of the weather. The 
 iron plate is further incomparably easier 
 to manage than glass ; it can be grasped by 
 the pinchers, cut, heated for drying and var- 
 nished with ease and safety, and the subsequent 
 varnishing on the back, in mounting positives 
 on glass, after the impression is obtained, is 
 
29 
 
 avoided by its use. Another advantage is, 
 the facility with which the plates are cleaned, 
 a piece of canton flannel, and a few drops of 
 alcohol, are all that is required for the pur- 
 pose. 
 
 What has been said of the melainotype 
 plate, is applicable in a great measure to the 
 niello paper. However, the material of which 
 it is made is not as durable, and the paper 
 plates present the inconvenience of floating in 
 the silver solution, so that they have first to 
 be stuck on a glass before they are immersed 
 in it. 
 
 Sometimes pictures are first made on glass, 
 and then transferred on oil-cloth, or on patent 
 leather. They are not reversed, and require 
 no varnishing, the metallic silver forming the 
 picture being protected by the part of the col- 
 lodion film which adheres to the glass. These 
 cannot be colored. 
 
 CHAPTER VI. * 
 
 On Collodion. 
 
 Three compounds enter into the preparation 
 of collodion; ether, alcohol, and pyroxyline 
 or soluble gun-cotton. 
 
 Ether, — (Commonly but improperly called 
 sulphuric ether.) The purity of the ether is a 
 matter of great importance, in the preparation 
 of good collodion. It must be concentrated, 
 
30 
 
 free from much alcohol and water, without dis- 
 agreeable smell, and free from acetic and 
 sulphuric acids. 
 
 Three kinds of ether are ordinarily found in 
 the trade. 
 
 First, the common ether, which contains a 
 variable quantity of alcohol and water, and 
 presents ordinarily an acid reaction with lit- 
 mus paper, from the presence of sulphuric 
 acid. Ether in this state is unfit for use. 
 
 Second, the washed ether, or ordinary ether 
 which has been agitated with a certain quantity 
 of water, to take away the alcohol and the 
 acid. This might be used in connection with 
 very strong alcohol, and cotton of good qual- 
 ity, if it was washed so thoroughly as to pre- 
 sent no longer an acid reaction to test paper. 
 
 Third, ether both washed and redistilled, on 
 unslacked lime or on potash, which deprives 
 it of its water, and neutralizes any acid it may 
 contain. This ether is the best for use, and 
 should always be procured if possible. When 
 entirely pure, its specific gravity is 720, but, 
 it is but seldom found at that strength. The 
 ether expressly prepared for photographic pur- 
 poses, by reliable chemists, has a specific grav- 
 ity of about 725. The minimum of strength 
 of the ether to be used depends entirely on 
 the strength and quantity of alcohol used in 
 connection with it, to dissolve the pyroxline. 
 
 If the practitioner cannot find any ether 
 strong enough for use, he may take the com- 
 
31 
 
 mon or washed ether and deprive jt of its 
 water by digesting it with good white unslacked 
 lime. The effect of the quick lime is to absorb 
 the water and neutralize the acid. The ether 
 should be put in a bottle, and the lime added 
 to it by small quantities at a time, and at in- 
 tervals of half an hour, shaking after each ad- 
 dition. The quantity of lime to be used is 
 two or three ounces to a pound of ether. Af- 
 ter all the lime has been added, let it digest 
 for a day or two, shaking occasionally, after 
 which the ether will be deprived of its water. 
 The clear liquid can then be poured off and 
 kept for use. It will happen, sometimes, that 
 the lime absorbs the water very quickly, which 
 produces an elevation of temperature. If so, 
 groat care should be taken not to add too much 
 lime at a time, for the ether, being very vola- 
 tile, might blow off the cork of the bottle. — 
 The ether, concentrated this way, is slightly 
 alkaline, but the alkalinity is removed easily, 
 by adding hydrobromic acid to the collodion 
 till it takes a yellow straw color after being 
 kept a few hours. 
 
 Ether which is exposed to the light and to 
 the contact of the air, will decompose and gen- 
 erate acetic acid. In this state, it is unfit for 
 photographic purposes. It is necessary for its 
 preservation, to put it into well corked bottles, 
 and to keep it in a dark place. 
 
 Alcohol — It is necessary to use the purest 
 alcohol, not weaker than 90 per cent, when it 
 
32 
 
 is used with ether 725, and stronger when it 
 has to be used with ether of a greater specific 
 gravity. It should also be free from essential 
 oil. Quick lime will bring common alcohol to 
 a standard suitable for photographic purposes, 
 It should be used in the same proportion, and 
 in the same way, as for the concentration of 
 the ether. 
 
 Pyroxyline or soluble gun cotton.— Pyroxy- 
 line made from cotton has the same appearance 
 and physical properties as ordinary cotton, 
 with the difference that it is somewhat more 
 rough to the touch and that it grates in being 
 pulled apart through the fingers. 
 
 Pyroxyline is the result of the action of ni- 
 tric acid on ligneous substances, such as cotton, 
 paper, linen, wood, etc. 
 
 For the manner of its preparation, we refer 
 the reader to the 4 Chemistry of Pyroxyline? — • 
 We will only say here, that it is produced by 
 immersing the cotton in a mixture of nitric 
 and sulphuric acids. 
 
 The quality of the soluble cotton depends, 
 1st, on the strength of the acids. 2nd, on the 
 temperature of the acids during the immersion. 
 
 The strength of the acids determines the 
 more or less solubility of the cotton. Cotton 
 immersed into a mixture of nitric and sulphu- 
 ric acids of the maximum of strength is ex- 
 plosive, but insoluble in the mixture of ether 
 and alcohol. In proportion as the strength of 
 the acids is reduced by the addition of water, 
 
33 
 
 the cotton becomes less explosive and more 
 soluble, till it reaches a certain point, when 
 the solubility decreases. Thus both strong 
 and weak acids give insoluble or imperfectly 
 soluble cotton. The one obtained by strong 
 acids is more or less explosive ; the one ob- 
 tained by weak acids burns without explo- 
 sion. 
 
 The temperature of the acids during the 
 immersion, the acids supposed to be of the 
 proper strength, determines the physical pro- 
 perties of the plain collodion. Pyroxyline 
 made at the maximum of temperature, gives 
 a collodion presenting the following peculiari- 
 ties ; 1st. — -When added to the ordinary pro- 
 portion of ether and alcohol, it falls to the bot- 
 tom in . a gelatinous mass, and dissolves only 
 after considerable shaking. 2nd. — It yields a 
 fluid solution, and requires to be used in a 
 comparatively large quantity to make a collo- 
 dion of the proper thickness. 3rd. — It gives 
 a collodion spreading into a smooth and glassy 
 surface. 4th. — The film it gives is short, ad- 
 herant to the glass, and porous. 
 
 Pyroxyline made at a low temperature, pre- 
 sents the opposite characteristics. 1st. — It 
 dissolves in the mixture of ether and alcohol 
 without gelatinizing. 2nd. — It gives a thick 
 and glutinous solution. 3rd. — It gives a col- 
 lodion spreading over the glass in a slimy 
 manner, and setting into numerous small 
 waves. 4th. — The film is tough, contractile, 
 
34 
 
 coherant, apt to get loose from the glass and 
 devoid of porosity. 
 
 When acids of the minimum of strength, 
 and at a high temperature act on cotton, it is 
 liable to be partly decomposed and the collo- 
 dion made with it will be porous to a high de- 
 gree. Such cotton will have a short texture, 
 and sometimes, give a rotten film, which will 
 crack on drying. 
 
 Pyroxyline, mainly the one that has been 
 made at a high temperature, is liable to be de- 
 composed. The first symptoms of this decom- 
 position, are a strong acid smell, and a disin- 
 tegration of the cotton, the fibers becoming 
 short and broken. Then follows the reduction 
 to a fine white powder, and finally to a glutin- 
 ous mass, which on the addition of water de- 
 gages abundant vapors of peroxid of nitrogen. 
 The conditions most favorable to this decom- 
 position, seem to be heat and compression. 
 The contact of the air seems to be unfavorable 
 to it, contrary to what has been advanced, for 
 the soluble cotton will decompose much sooner 
 in closely stoppered bottles, than in tin or paper 
 boxes, or when wrapped up in paper. It 
 should thus be packed rather loosely, mainly 
 in the summer months, or in warm climates. 
 
 Acidity of the soluble cotton, resulting either 
 from imperfect washing, or a commencement 
 of decomposition, is very objectionable, as the 
 acid decomposes the iodides and bromides used 
 to sensitize, setting iodine free, and giving 
 
35 
 
 a red color to the collodion. If the cotton 
 has an acid smell, it should be washed 
 with water, until all the acidity has been 
 removed, which can be detected by means 
 of litmus paper. It should then be pressed 
 out in a towel, and allowed to dry. If you 
 wish it to dry rapidly, wash the remaining 
 water out with alcohol, and then press the 
 alcohol out. - 
 
 A mixture of ether and alcohol dissolves 
 the soluble cotton, but neither of these liquids 
 will dissolve it, when employed alone. Sup- 
 posing the ether to be of a specific gravity, 
 from 725 to 730, the alcohol from 92 to 95 per 
 cent, and the cotton of good quality, the fol- 
 lowing formula will be found to be most gen- 
 erally admissible. 
 
 Ether , 4 oz. fluid. 
 
 Alcohol 4 oz. fluid. • 
 
 Cotton from 30 to 60 grains. 
 
 Put the cotton into the bottle, pour on the 
 alcohol, shake, then pour on the ether, and 
 shake again, till all the cotton is dissolved. 
 Or, the ether and alcohol can be first mixed 
 together, and then the cotton added to it, but 
 in this way it takes longer to effect the solu- 
 tion. 
 
 The proportion of cotton to be used in the 
 collodion is variable, one cotton giving, when 
 used in the same proportion, a great deal 
 thicker collodion than another. This, as we 
 have seen already, is owing to the temperature 
 
36 
 
 of the nitro-sulphuric acid, the cotton made 
 at a high temperature giving a more fluid 
 solution than the one made at a lower. The 
 photographer can thus only judge of the quan- 
 tity of cotton he has to use by coating a glass 
 with the collodion made w^ith it. 
 
 Cotton, possessing to an extreme degree the 
 peculiarities resulting from having been made 
 at a low temperature, is not suitable for pho- 
 tographic purposes. If it has these peculiar- 
 ities only in a small degree, the plain collodion 
 made with it can be corrected in three different 
 ways. 1st, — By increasing the proportion of 
 alcohol, using for this purpose alcohol of at 
 least 95 per cent. 2nd, — By adding chloro- 
 form, in the proportion of one or two drachms 
 to a pound. 3rd, — By decomposing it par- 
 tially by the addition of aqua ammonia. The 
 ammonia, like all other alkalies, decomposes 
 the pyroxyline, and makes the solution fluid, 
 so that it yields a beautiful, even, and porous 
 film. The same effect is produced in iodized 
 collodion, by the alkaline iodides and brom- 
 ides, but to a smaller extent. The way of pro- 
 ceeding is to add five or six drops of strong 
 ammonia to about a pint of collodion, testing 
 it every clay, and when it has come to the 
 proper condition, neutralizing the remaining 
 ammonia with hydrobromic acid. The prac- 
 titioner should be cautious against using too 
 much ammonia, or letting it act too long a 
 time, for the film would become so rotten that 
 
37 
 
 a stream of water would wash it off the 
 glass, or, if the decomposition was not quite 
 carried to that point, it would, after drying, 
 be cracked all over, just as if the cotton had 
 been partly decomposed in the acid, or as if 
 too much water was present in the collodion. 
 If, however, the effect of the ammonia was 
 carried too far, the remedy would be to mix 
 the rotten collodion with some newly made, 
 till a mixture is obtained which has the de- 
 sired properties. 
 
 Independently of the quality of the pyroxy- 
 line, the resulting solutions differ in character, 
 according to the relative proportions of the 
 solvents employed. When the ether is used 
 in a large quantity, the collodion film spreads 
 with difficulty over the plate, owing to the 
 rapid evaporation. The film is very tough, 
 coherent and contractile, so that it will often 
 separate from the sides of the glass, if not 
 handled and dried with precaution. It is 
 also devoid of porosity. When, to such a 
 collodion, alcohol is added in suitable propor- 
 tions, all these inconveniences are removed, 
 and it will spread with more regularity, and 
 give an even, soft, and easily torn film, which 
 possesses great adherence to the plate, and has 
 no tendency to contract or peel in drying. 
 
 We see thus that the character of a plain 
 collodion, with an excess of ether, is similar 
 to the one made with the ordinary quantity of 
 ether, and a cotton produced at a low temper- 
 
38 
 
 ature.^ On the other hand, the use of a large 
 quantity of alcohol is equivalent to the use 
 of a cotton made at a high temperature. 
 The knowledge of these facts enables us to 
 employ, with success, cotton which other- 
 wise we w r ould, perhaps, condemn as useless. 
 Thus, when a collodion made with equal quan- 
 tities of the solvents, gives a wavy and con- 
 tractile film, an addition of strong alcohol may 
 improve it and bring it to the proper condi- 
 tion. If, on the contrary, the film was too 
 short and rotten, a larger quantity of ether 
 would give more toughness and cohesion to it. 
 
 The purity or strength of the solvents has, 
 also, an influence on the state of the film. 
 Alcohol and ether, of a high specific gravity, 
 contain much water, and their use should be 
 avoided. An excess of water in the collodion 
 is very injurious. It thickens it and makes 
 it flow with difficulty, and it makes the, film 
 sometimes so rotten that it washes off the 
 plate. The water is, also, one of the causes of 
 the reticulated appearance which the film pre- 
 sents in drying. It seems to be cracked all 
 over, and made up of a kind of network which 
 deprives the impression of sharpness. This 
 effect is more to be feared in cold than in 
 warm weather, so that in winter more care 
 has to be taken to procure good samples of 
 ether and alcohol than at any other season of 
 the year. 
 
 Collodion prepared in all the conditions 
 
39 
 
 which insure success, will, in being properly 
 poured on a clean glass plate, present the fol- 
 lowing peculiarities. 1st. It will not run off 
 the edges of the glass ; if it does, the quantity of 
 cotton is too small. 2nd. It will give, when 
 dry, a transparent film free from cracks. If the 
 film is semi-opaque or cracked, it indicates 
 either that the cotton is of bad quality, or that 
 the collodion contains an excess of water. 
 The cotton which gives a semi-opaque and 
 cracked film, is the one made with weak acids 
 at a high temperature, and which is partly de- 
 composed by the acids. 3rd. It will flow 
 evenly, giving a film without waves. If not, 
 the cotton is of the glutinous variety, or in too 
 large a quantity, and one of the remedies given 
 above will have to be applied. 4th. It must 
 be adherent to the glass, and tough enough to 
 bear a slight rubbing when it has set. 
 
 A plain collodion being obtained, which 
 possesses the qualities just enumerated, the 
 next thing is to charge it with a certain 
 quantity of iodide and bromide. 
 
 Collodion sensitized with iodide alone, will 
 often give images in which the high lights 
 are very dense by transmitted light, and the 
 middle tints deficient by reflected light. Such 
 collodion is made with cotton possessing the 
 intense qualities to an extreme degree, and is 
 more suitable for negatives than for positives. 
 If to such a collodion a small quantity of 
 bromide is added, the high lights will become 
 
40 
 
 less dense by transmission, and the relation 
 between whites and blacks more harmonious ; 
 at the same time, the duration of the exposure 
 in the camera will be shortened. This last 
 fact is unaccountable, and seems to be entirely 
 contrary to what might be expected. It is 
 known to a certainty that iodide of silver in 
 presence of nitrate of silver, is more sensitive 
 to the combined action of the light, and a de- 
 veloping agent, than bromide of silver in the 
 same condition. A paper prepared with iodide 
 of silver, will, under the influence of a devel- 
 oper, bring out an image with a shorter ex- 
 posure to the light than one prepared with 
 bromide of silver. Why then is bromo-iodized 
 collodion not less sensitive than iodized collo- 
 dion, instead of being more so? 
 
 The effect of bromide is thus to reduce inten- 
 sity or contrast, and increase sensitiveness. 
 With collodion, which does not, from the qual- 
 ity of the cotton, give very contrasted images, 
 it should be omitted, or only used in small 
 quantity. 
 
 The bromide of silver is more sensitive to 
 colored light than the iodide of silver. In 
 the case of the iodide of silver, the action 
 ceases in the blue ray of the spectrum, but 
 with the bromide it reaches into the green. 
 In both cases, however, the most intense 
 chemical action resides in the indigo and 
 violet, and goes on decreasing in measure as 
 the green is approached. The sensitiveness of 
 
41 
 
 the bromide of silver to the green ray, has in- 
 duced the supposition that a collodion, sensi- 
 tized with iodide and bromide, was best suited 
 to landscape photography, inasmuch as it 
 would reproduce the green foliage. This belief 
 is unfounded, however. The effect produced 
 by the green ray on the bromide of silver, 
 is very small when compared to the effect 
 produced by the indigo, violet and actinic 
 invisible rays. Even if it were possible 
 to obtain suitable collodion, sensitized with 
 bromide alone, the more actinic rays would 
 have arrived at the maximum of their action, 
 before the green tints would have had time to 
 produce an impression on the sensitive surface. 
 When bromide is used in connection with 
 iodide, which is insensible to the green ray, 
 the effect of the green tints would be still less. 
 That bromide is useful in landscape photo- 
 graphy, cannot, however, be denied; but -this 
 results from the property it possesses to harmon- 
 ize more the relation between light and shade, 
 or, as we have stated above, to reduce contrast. 
 What produces the superiority of bromo- 
 iodized collodion, for landscape photography, 
 is not the sensitiveness of bromo-iodide of 
 silver to green light, but its superior sensitive- 
 ness to feeble emanations of white light, such 
 as those which are scattered from even the 
 darkest green foliage, and by which iodide of 
 silver fails to be impressed. 
 
 4 
 
42 
 
 The iodides and bromides used to sensitize 
 collodion are the following : 
 
 Iodide and bromide of potassium. 
 
 Iodide and bromide of ammonium. 
 
 Iodide and bromide of cadmium. 
 
 Iodide and bromide of magnesium. 
 
 Iodide and bromide of zinc. 
 
 A great difference of opinion exists as to 
 which iodide or bromide is the most useful to 
 sensitize collodion. Some are said to give 
 superior results, others to be more sensitive. 
 A series of experiments, undertaken to te§t 
 the value of these assertions, proved to us, 
 however, that the bases of the iodides and 
 bromides, generally used, have no direct effect 
 on the beauty of the results, or on the sensi- 
 tiveness, if they are used in strictly the same 
 conditions,, and in such proportions as to 
 bring into the collodion the same quantity of 
 iodine and bromine. The iodide of iron makes 
 exception, as we will see further. 
 
 Amongst the compounds used as sensitizers, 
 some are readily soluble in the collodion. 
 These are the iodides of ammonium, cadmium, 
 magnesium and zinc, and the bromides of cad- 
 mium, magnesium and zinc. Others, the iodide 
 of potassium and bromides of potassium and 
 ammonium, are nearly insoluble in collodion, 
 made with concentrated solvents. When re- 
 quired for use, they should be dissolved in a 
 small quantity of water, and added to the 
 collodion. If the solvents are not very con- 
 
43 
 
 centrated, the salts may be first dissolved in 
 a part of the alcohol used to make the plain 
 collodion, and then added to the solution of 
 cotton. This last way of operating is prefer- 
 able to the other, as it does not introduce any 
 more water into the collodion. 
 
 Each one of the salts used to sensitize col- 
 lodion does, not contain the same quantity 
 of iodine or bromine ; so that one salt will 
 produce a smaller amount of iodide or bromide 
 of silver in the film than another. The fol- 
 lowing table gives the proportions of iodine 
 and bromine present in each one of the iodides 
 and bromides generally used : 
 
 1000 parts Iodide of magnesium contain 914 parts Iodine. 
 
 " " ammonium " 876 " " 
 
 " " " zine " 796 " " 
 
 " " " potassium " 764 " " 
 
 " " " cadmium " 694 " " 
 
 " " Bromide magnesium '* 870 " Bromine. 
 
 w " " ammonium *' 816 " 
 
 « « " zinc " 714 «' " 
 
 « " M potassium *' 672 " 
 
 « « " cadmium . " 588 * " 
 
 Collodion sensitized with the iodides of am- 
 monium, potassium, magnesium and zinc be- 
 comes red after a short time, and loses sensi- 
 tiveness. This coloration is due to the oxida- 
 tion of the ether and to the decomposition of 
 the pyroxyline. 
 
 Ether exposed to the contact of the air, and 
 to the influence of light, absorbs oxygen, and 
 . generates acetic acid. This acetic acid, com- 
 bining with the bases of the iodide, forms an 
 acetate, and sets iodine free, which dissolves in 
 
44 
 
 the liquid, and colors it yellow, orange or 
 red, according to the degree of decomposition 
 which has taken place. 
 
 The decomposition of the pyroxyline is pro- 
 duced by the alkaline iodides, such as those of 
 ammonium, potassium and sodium. The bases 
 of these iodides act on the pyroxyline, setting pe- 
 roxid of nitrogen free, which, in its turn, acts on 
 the iodide, and liberates iodine. The effect of 
 the alkaline iodides- on the, pyroxyline is the 
 same as that produced by ammonia and other 
 alkalies. The collodion becomes fluid and gives 
 a porous film, and when the effect goes farther, 
 becomes rotten. The iodides of cadmium, 
 zinc and magnesium, on the contrary, produce 
 a thickening of the collodion, immediately 
 after sensitizing, but have not the same de- 
 composing influence on the pyroxyline. 
 
 The decomposition of the collodion is favored 
 by heat and light. According to Mr. Tiffe- 
 reau, a collodion which has been exposed to 
 the sun's rays for a short time, becomes more 
 fluid, and acquires an exalted sensitiveness ; 
 but this sensitiveness is entirely lost soon 
 afterwards. 
 
 We have seen that a pyroxyline, made at a 
 high temperature and with weak acids, decom- 
 poses .spontaneously much quicker than one 
 made with strong acids. When such pyroxy- 
 line is used in the manufacture of collodion, it 
 communicates its decomposing properties to it. 
 It should thus be used only with good neutral 
 
45 
 
 ether and alcohol, and the collodion sensitized 
 with the compound least liable to decompose. 
 
 The most stable amongst the iodides is the 
 iodide of cadmium. Collodion prepared with 
 pure materials, and sensitized with iodide of 
 cadmium, will keep for months without disqol- 
 . oring. 
 
 Bromides are more stable than iodides ; a 
 bromo-iodized collodion will keep longer than 
 one which is sensitized with iodide alone. 
 
 The presence of much free iodine in collo- 
 dion affects its sensitiveness. The red color 
 can be removed, and the sensitiveness partly 
 * restored by dipping into it a strip of zinc, or 
 a stick of metallic cadmium. The zinc or cad- 
 mium will take up the free iodine, and form 
 iodide of zinc or of cadmium. The metal 
 should be removed as soon asj;he collodion is 
 yellow or orange. 
 
 A small quantity of free iodine in the col- 
 lodion, enough to tint it yellow or orange, is 
 not objectionable, as it does not interfere with 
 the sensitiveness. A well iodized collodion, 
 which has slightly turned red, can even be used 
 without much loss of sensitiveness, in connec- 
 tion with a neutral or very slightly acid silver- 
 solution of the full strength. In such cases, 
 there is no necessity for removing the color. 
 
 Independently of the state of the silver 
 solution and developing fluid, the sensitive- 
 ness of the film of collodio-iodide of silver 
 depends, 1st, On the absence of certain retard- 
 
48 
 
 ing compounds, such as iodates, carbonates, 
 xanthates, etc. introduced in the collodion by 
 sensitizing compounds, prepared in an im- 
 proper or careless way. — See Chemistry of Io- 
 dide of Potassium. 
 
 2nd. On the absence of much free iodine in 
 the collodion. 
 
 3rd. On the presence of bromide in the col- 
 lodion. When a collodion gives impressions 
 in which too much contrast exists between 
 light and shades, an addition of a small quan- 
 tity of bromide will lessen the contrast, and at 
 the same time cause the film to be impressed, 
 by a shorter exposure in the camera. 
 
 4th. On the purity of the solvents. Ether 
 which has been kept some time is acid to test 
 paper, and liberates iodine in the collodion. 
 Alcohol often contains fusel oil, which has a 
 retarding influence. 
 
 5th. On the relative proportions of the sol- 
 vents. An excess of alcohol in the collodion, 
 producing a soft and porous film, is favorable to 
 sensitiveness ; an excess of ether, making the 
 film tough and penetratable with difficulty, is 
 unfavorable to it. 
 
 6th. On the quality of the pyroxyline. A py- 
 roxyline which gives a film corresponding to 
 the one produced by the use of much alcohol, 
 gives a more rapid collodion than one giving 
 a tough and contractile film. 
 
 7th. On the decomposition of the collodion. 
 As we have seen, the presence of much free 
 
47 
 
 iodine in the collodion is unfavorable to sen- 
 sitiveness. A loose state of the film on the 
 contrary is favorable. If a tough and contrac- 
 tile collodion is iodized with an alkaline io- 
 dide, (iodide of potassium, sodium or ammo- 
 nium,) the decomposition which ensues will 
 liberate iodine, and make the film softer and 
 more porous ; and the retarding influence of 
 the free iodine will be overcome by the in- 
 creased sensitiveness produced by the soften- 
 ing of the film. If now the liberation of the 
 iodine be checked by using the iodide or 
 bromide of cadmium in connection with the alk- 
 aline iodide, the result will be a collodion 
 which will remain colorless, or become only 
 yellow, and which will, after the alkaline iodide 
 shall have acted sufficiently on the pyroxyline, 
 give a soft and porous film. In this case, de- 
 composition will have the effect of increasing 
 the sensitiveness of the collodion. 
 
 8th. Use of iodide of iron. Iodide of iron, 
 used in small quantity in the collodion, will 
 give it a great sensitiveness. This is owing 
 to the double decomposition which takes place 
 between the iodide of iron and nitrate of 
 silver and by which are produced iodide of 
 silver, and nitrate of iron, which is a develop- 
 ing agent. 
 
 We have seen already, that with collodion 
 sensitized with the cadmium compounds, an 
 addition of a few drops of tincture of iodine, 
 or hydrobromic acid, is a valuable improve. 
 
48 
 
 ment, especially when a neutral or a slightly 
 acid bath is used. The addition of iodine, or 
 better, of hydrobromic acid is necessary when 
 collodion is used, manufactured with ether or 
 alcohol, which has been concentrated by means 
 of quick-lime. In this case, hydrobromic acid 
 will have to be added till the collodion takes a 
 yellow color, which effect only takes place a 
 few hours after the addition. 
 
 Tincture of Iodine. — Tincture of iodine is a 
 solution of iodine in alcohol. When the 
 strongest alcohol is used, ten parts in weight 
 will dissolve one part of iodine. It is not ne- 
 cessary to have it as strong for photographic 
 purposes. It may be prepared by dissolving 
 one drachm of iodine in four ounces of alcohol, 
 95 per cent. 
 
 Hydrobromic acid. — The compound called 
 by photographers hydrobromic acid, and which 
 is a mixture of hydrobromic acid, hydro- 
 bromic ether, etc., is prepared in the fol- 
 lowing manner : Take one or two ounces of 
 alcohol, 90 per cent, and add to it a quantity 
 of bromine, sufficient to give it a red color. 
 The next day it will have become colorless ; 
 then add bromine again, and if the color is 
 again removed, continue adding bromine until 
 the liquid stays yellow or red. When this 
 arrives all the alcohol has been trans- 
 formed. What remains to be done is to re- 
 move the color by adding a few more drops of 
 alcohol. The hydrobromic acid acts on the 
 
49 
 
 collodion by liberating iodine. It is best to 
 add it only to a small quantity at a time, such 
 as is required for use the next clay, because 
 collodion to which it has been added loses too 
 much of its sensitiveness when it is kept some 
 time. 
 
 The film of collodio-iodide of* silver, which 
 is formed on the collodionized plate, by dip- 
 ping it into .the silver solution, varies in color 
 and appearance according to the quantity of 
 iodide used. A small quantity of iodide gives 
 it a blueish transparent color. A larger 
 quantity makes it white and translucid. A 
 larger quantity still makes it creamy opaque. 
 When the collodion contains so much iodide, 
 that the iodide of silver formed cannot be re- 
 tained in its pores, it is said" to be aver iodized, 
 If such collodion is poured on to a glass, and 
 dipped into the silver solution, flakes of iodide 
 of silver will come off and float in the bath. 
 The image will, also, be entirely on the sur- 
 face, and may be rubbed off, without the film, 
 of pyroxyline being injured. 
 
 The white and translucid film is the most 
 favorable. Blueish transparent films can be 
 used with weak neutral silver solutions, but the 
 collodion should not be colored deeper than 
 yellow. Creamy opaque films yield rough 
 pictures, deficient in middle tints, except when 
 acid silver solutions are used, and in this case 
 the sensitiveness is impaired. Films of mod- 
 erate thickness, iodized so as to appear white 
 
 5 
 
50 
 
 and semi-opaque, give the best gradation of 
 tone, and are uninjured by a moderate acidity 
 of the silver solution. 
 
 The quantity of bromide, to be used in the 
 collodion, depends on the character of the py- 
 roxyline. This can only be ascertained by trial. 
 The plan we think the best is to make a 
 bromo-iodized collodion, containing a rather 
 large quantity of bromide, and to add it to the 
 collodion found to be faulty until the desired 
 effect is obtained. 
 
 Iodized Collodion. 
 
 Plain collodion , 8 oz. fluid 
 
 Iodide of ammonium , . . . . 35 grains. 
 
 Iodide of cadmium 10 grains. 
 
 The plain collodion used in this formula 
 should be of the kind which gives a rather 
 tough film, as the large proportion of iodide of 
 ammonium it contains will soon act on the 
 pyroxyline, and soften the film. If the con- 
 trast it gives between whites and blacks is too 
 great, mix it with a certain quantity of the 
 following bromo-iodized collodion : 
 
 Plain collodion 8 oz. fluid. 
 
 Iodide of ammonium . . , 35 grains. 
 
 Bromide of cadmium .40 grains. 
 
 If instead of the iodide of ammonium you 
 wish to use the iodide of potassium, proceed 
 as follows : 1st, dissolve 40 grains of iodide 
 of potassium in the smallest possible quan- 
 tity of water; 2nd, pour this into 4 ounces of 
 alcohol, 92 per cent, and shake; 3d, add 
 to this alcohol 4 ounces of sulphuric ether, 
 shake and let settle ; 4th, draw oif the clear 
 
51 
 
 part by means of a syphon, and add the iodide 
 or bromide of cadmium ; 5th, dissolve into the 
 liquid the necessary quantity of pyroxyline. 
 
 Should you wish to substitute any other 
 iodide or bromide to those given above, it can 
 be done by taking into account the quantity 
 of iodine and bromine each one contains. The 
 following table will facilitate this : — 
 
 35 grains of iodide of ammonium contain the same amount 
 
 of iodine, as 
 40 grains iodide of potassium, 
 44 " iodide of cadmium, 
 33)^ " iodide of magnesium, 
 38)4 " iodide of zinc. 
 
 40 grains bromide of cadmium contain the same amount of 
 
 bromine, as 
 29 grains bromide of ammonium, 
 35 " bromide of potassium, 
 27 " bromide of magnesium, 
 33 " bromide of zinc. 
 
 Instead of using the sensitizing salts in a 
 dry state, it is sometimes more convenient to 
 make an iodizing solution, and to add it to the 
 collodion till it gives a white and semi-opaque 
 film. Any of the iodides or bromides can be used 
 for that purpose. The following is used in the 
 manufacture of Charles Waldack's Positive 
 and Negative Collodion : 
 
 Iodizing Solution. 
 
 Iodide of ammonium , 4 drachms. 
 
 Iodide of cadmium .4 drachms. 
 
 Alcohol (95 per cent) 3 oz. fluid. 
 
 Bromizing Solution. 
 
 Bromide of cadmium. 1 oz. 
 
 Alcohol (95 per cent), 3 oz. fluid 
 
52 
 
 From 4 to 5 drachms of the iodizing solu- 
 tion are sufficient to give to 8 oz. of collodion 
 the degree of opacity wanted. The quantity 
 of bromizing solution to be added depends, as 
 we have seen already, on the contrast existing 
 between the lights and shades. This iodizing 
 solution, containing less alkaline iodide than 
 is prescribed in the first formula, can be used 
 with a plain collodion, giving a rather short 
 and soft film. 
 
 The iodide and bromide most suitable to 
 sensitize collodion, which gives a soft film, are 
 the iodide and bromide of cadmium. The 
 iodides and bromides of potassium and of am- 
 monium should not be used, as, by their pow- 
 erful action on the pyroxyline, they would soon 
 make the collodion rotten. They may be used 
 with great advantage to sensitize tough collo- 
 dion, which they will bring in a short time to 
 a porous state, very favorable to sensitiveness 
 and intensity. 
 
 We will now give some formulas #f collodion 
 most used. JNTone of these formulas will hold 
 good under all circumstances. The operator 
 will have to use his own judgement in com- 
 pounding them, and if he has made himself 
 well acquainted with the different influences 
 which determine the character of the collo- 
 dion, it will be an easy task for him to obtain 
 any effect he desires. 
 
 $0. 1.— Plain collodion . 8 oz.^ 
 
 Iodide of ammonium 32 grains. 
 
 Bromide of cadmium 10 grains. 
 
53 
 
 Dissolve directly the iodide of ammonium, 
 and the bromide of cadmium, in the plain col- 
 lodion, and allow it to settle. The next day 
 it is fit for use. When pure materials are 
 used, this collodion will be of a straw^ color 
 the clay after it has been made, and it will 
 keep for a long time, in good condition, the 
 bromide of cadmium counteracting the decom- 
 posing influence of the iodide of ammonium. 
 The film should not be too tough, nor too soft, 
 but should possess intermediate qualities. The 
 cotton should be of the intense kind. 
 
 ft 0# 2.—- Plain collodion , , 8 oz.^ 
 
 Iodide of potassium 36 grains. 
 
 Bromide of cadmium 10 grains. 
 
 Put the iodide of potassium in an 8 oz. bot- 
 tle, and dissolve it in as small a quantity of 
 water as possible, then add the 8 oz. of collo- 
 dion, and finally the bromide of cadmium. 
 Or, better yet, modify the formula as follows : 
 make your plain collodion with 2 oz. less alco- 
 hol, and in this alcohol dissolve your iodide 
 of potassium, reduced to fine powder — 
 
 Plain collodion 6 oz. fluid. 
 
 Iodide of potassium 3b grains (dissolved in 2 oz. alcohol.) 
 Bromide of cadmium 10 grains. 
 
 NO. 3. — Plain collodion 8 oz. fluid 
 
 Iodide of cadmium. 50 grains. 
 
 Bromide of cadmium 6 grains. 
 
 This collodion will keep for a very long time 
 without decomposing. The plain collodion 
 should be of the kind which gives a soft and 
 porous film, for the cadmium sensitizers have 
 
54 
 
 no decomposing action on the pyroxyline, but 
 thicken the collodion, and make it more 
 glutinous than it was before. Collodion which 
 has been submitted to the decomposing action 
 of the ammonia, will answer very well for this 
 formula. A few drops of tincture of iodine, 
 or hydrobromic acid, added to it will be found 
 useful. 
 
 No. 4.— Plain collodion . 8 oz. fluid. 
 
 Dissolve the iodide and bromide of potas- 
 sium together in the smallest quantity of wa- 
 ter possible, add the collodion, shake, and let 
 settle. Or, better, make your plain collodion 
 with 4 oz. ether, and 2 oz. alcohol, reserving 
 the 2 other ounces alcohol to dissolve your 
 iodide and bromide of potassium. You will 
 have thus : 
 
 Plain collodion . . . . , 6 oz. 
 
 This collodion being sensitized with alkaline 
 iodide and bromide will have to- be made with 
 cotton giving a tough film. After a period of 
 about a week, the action of tKe alkaline salts 
 on the pyroxyline will have brought it to the 
 proper condition. 
 
 NO. 5. — Plain collodion 8 oz. fluid. 
 
 Dissolve the iodide of potassium and the 
 
 Iodide of potassium. . , 
 Bromide of potassium 
 
 40 grains. 
 10 grains. 
 
 f rains j dissolved in 2 oz - alcohol.) 
 
 Iodide of potassium . . 
 Iodide of cadmium. . . 
 Bromide of ammonium 
 
 . .20 grains. 
 .20 grains. 
 .10 grains. 
 
55 
 
 bromide of ammonium in the smallest quant- 
 ity of water possible, then add the collodion, and 
 finally the iodide of cadmium, or dissolve the 
 iodide of potassium and bromide of ammonium 
 in part of the alcohol prescribed for the prepa- 
 ration of the plain collodion. This collodion 
 will keep for a considerable time, the iodide 
 of cadmium it contains giving durability to 
 it. It should be made with cotton giving a 
 rather tough film. 
 
 K*0« 6. — Plain collodion 8 oz. fluid. 
 
 Solution of bromo- iodide of silver, a sufficient quant- 
 ity to give a white and semi-opaque film. 
 
 The solution of bromo-iodide of silver is pre- 
 pared in the following way : 
 
 Dissolve 120 grains nitrate of silver in 2 
 ounces of water, and 80 grains bromide of po- 
 tassium in 2 other ounces of water, and mix 
 these two solutions together; the result will 
 be a precipitate of bromide of silver and the 
 formation of nitrate of potash, which will 
 remain in solution. Let the precipitate settle 
 and pour carefully the liquid off; then add 
 some distilled water, 'shake, let settle, and 
 pour the liquid off again. Repeat these 
 washings three or four times in order to re- 
 move all the nitrate of potash. Then wash 
 once or twice with alcohol in the same way as 
 with water. Put the pure bromide of srker ob- 
 tained in this way into a ten or twelve ounce 
 bottle, and add it to one ounce of iodide of 
 potassium reduced to a very fine powder, and 
 
56 
 
 8 oz. fluid of alcohol, of ordinary strength. 
 Shake from time to time till the alcohol has 
 dissolved as much iodide of potassium as pos- 
 sible. The clear liquid is called a solution of 
 bromo-iodide of silver. 
 
 When bromide of silver is dissolved in a 
 solution of iodide of potassium, double decom- 
 position takes place between the bromide of 
 silver and a part of the iodide of potassium, 
 so that bromide of potassium and iodide of 
 silver are formed. The iodide of silver thus 
 formed dissolves in the iodide and bromide of 
 potassium. The so-called bromo-iodide of 
 silver is, therefore, an alcoholic solution of 
 iodide and bromide of potassium saturated 
 with iodide of silver. 
 
 It must be observed, that the more water 
 the alcohol contains the stronger the solution 
 will be ; so that, if prepared with 95 per cent, 
 alcohol (containing 5 per cent, water) it will 
 require a larger quantity to iodize collodion 
 than when prepared with 90 per cent, (con- 
 taining 10 per cent, water). It will thus be 
 best to use 90 per cent, alcohol, or if stronger, 
 to have it diluted with the required quantity 
 of water. 
 
 Very rapid Collodion with Iodide of Iron. — 
 We have seen already that iodide of iron 
 mixed with the collodion gives it a high degree 
 of sensitiveness. We will here describe the 
 process of Alph. De Brebisson, which, in our 
 
57 
 
 hands, has proved very successful, as far as 
 rapidity of impression is concerned. 
 
 Plain collodion .8 oz. fluid. 
 
 Alcoholic solution of iodide of silver in iodide of potassium 
 
 enough to give a white and semi-opaque film. 
 Alcoholic solution of iodide of iron 1 oz. fluid. 
 
 The plain collodion should be made with 
 5 oz. ether and 3 oz. alcohol. 
 
 The alcoholic solution of iodide of silver in 
 iodide of potassium is made in the following 
 way : 
 
 NO. 1.— Distilled water 2 oz. fluid 
 
 Nitrate of silver. .. 120 grains. 
 
 Xo. 2. — Distilled water 2 oz. fluid. 
 
 Iodide of potassium , 120 grains. 
 
 Mix these two solutions together and wash 
 the precipitate of iodide of silver which is 
 formed in several waters, and finally in alcohol, 
 just as is prescribed for the bromide of silver, 
 page 55. Now pulverize very finely one ounce 
 of iodide of potassium, add it to the iodide of 
 silver, add also 8 oz. alcohol, 90 per cent, and 
 shake. The clear liquid is an alcoholic solu- 
 tion of iodide of silver in iodide of potassium. 
 The iodide of iron is prepared as follows : 
 
 Distilled water 2)^ oz. fluid. 
 
 Iron wire or tacks , 1 drachm. 
 
 Iodine , 3 drachm*. 
 
 This combination gives, after two or three 
 days, a liquid of a light green color. Take of 
 it one drachm, to which you add three or 
 four drops acetic acid and one oume of alcohol. 
 
58 
 
 This gives an alcoholic solution of iodide of 
 iron, which keeps very well. 
 
 This collodion will have a red color, and will 
 remain sensitive but a few days. 
 
 The solution of iodide of iron may be added 
 to any other collodion and increase its sensi- 
 tiveness, but it is always followed by the same 
 results : total loss of sensitiveness after seven 
 or eight days. Another effect of the iodide of 
 iron is to make the collpdion thick like a jelly. 
 
 The iodide of iron collodion cannot be re- 
 commended except in extreme cases, as the 
 results it gives are inferior. The operator 
 should also be cautious not to use it in his 
 ordinary silver solution, as it would soon 
 bring decomposition into it. The best is to 
 have a silver solution apart, and to keep it ex- 
 posed to the light when not in use. 
 
 If one of the collodions prepared by the 
 above formula gives a creamy film, or one 
 that is too transparent, bring it to that state of 
 iodizing which is white or semi-opaque. The 
 opacity of the collodion film depending, 1st, 
 On the quantity of iodizing; 2d, On the 
 quantity of cotton, it can be increased or 
 decreased, in two different ways; 1st, By 
 increasing or decreasing the quantity of 
 iodizing; 2d, By increasing or decreasing 
 the quantity of cotton. Thus, when the 
 film is transparent and thin, add cotton to 
 give it more opacity. When transparent, and 
 of the required thickness, add iodizing. When 
 
59 
 
 It is opaque and thin, dilute with plain collo- 
 dion. When opaque and thick, dilute with 
 alcohol and ether in suitable proportions. 
 
 CHAPTER VII. 
 
 The Silver Solution for Positives. 
 
 The materials which enter into the silver 
 solution are the following: Crystalized or 
 fused nitrate of silver, water, iodide of potas- 
 sium and nitric acid. 
 
 Nitrate of Silver. — The nitrate of silver used 
 should be the best that can be obtained. It is 
 a false economy for operators to buy a cheap 
 article, which is either adulterated or carelessly 
 prepared. 
 
 Crystallized nitrate of silver is in the form 
 of white crystalline plates. When dissolved 
 in water it should be neutral to litmus paper. 
 It is very important that it should be free 
 from organic matter, with which that es- 
 pecially crystallized out of the acid mother 
 liquors is often contaminated. — See Chemistry 
 of Nitrate of Silver. When in this state it 
 is not fit for use, unless it be heated in a 
 porcelain evaporating dish or crucible, till 
 it fuses, and the organic matter be decom- 
 posed. 
 
 Fused nitrate of silver (lunar caustic) is 
 found in commerce in the form of white sticks. 
 
60 
 
 When not adulterated with nitrate of potash, 
 it can be used in photography. It contains a 
 small quantity of nitrite of silver, which makes 
 its solution alkaline to test paper; but this is 
 not objectionable, as a drop of nitric acid trans- 
 forms this nitrite into nitrate. 
 
 Water. — The water required to dissolve the 
 nitrate of silver must be pure, free from 
 organic matter and from salts. Distilled 
 water will answer the best, or rain water 
 which has been caught in an open jar and 
 boiled. Also, clean melted ice and boiled soft 
 spring water. Rain water which comes from 
 roofs, must be rejected on account of the large 
 quantity of organic matter it contains. The 
 tests for pure water are the following: 1st, If 
 a drop is put on a clean glass plate, and evap- 
 orated by a gentle heat, it leaves no residuum. 
 2nd, JSTo precipitate or milkiness is produced, 
 when a few drops of a solution of chloride of 
 Barium or nitrate of Baryta are added to it. If 
 the water becomes milky, or if a precipitate is 
 deposited, it contains a sulphate, probably 
 sulphate of lime. 3rd, Nitrate of silver pro- 
 duces no precipitate. If it did, it would be a 
 proof the water contains either a chloride or a 
 carbonate; a chloride, if the precipitate be 
 soluble in ammonia; a carbonate, if insoluble in 
 ammonia, and soluble in nitric acid. 4th, If a 
 few crystals of nitrate of silver are added to it, 
 and it is exposed to sunlight in a white bottle, 
 
 I 
 
61 
 
 the liquid remains colorless. If it turns brown 
 or black it contains organic matter. 
 
 Small quantities of chlorides, carbonates, or 
 of organic matter, are not very objectionable 
 in water to be used to make a silver solu- 
 tion. Their presence results in the loss of a 
 small quantity of nitrate of silver; quantity 
 generally too small to interfere with the 
 strength of the solution. 
 
 Iodide of potassium. — Such as is used in 
 iodizing collodion, answers for the silver-solu- 
 tion. 
 
 Nitric acid. — Use the chemical pure, or the 
 ordinary; but let this be free from sulphuric 
 acid, which would produce sulphate of silver 
 in the solution. 
 
 The strength of the silver solutions generally 
 made, is forty grains to the ounce. Twenty 
 grain silver solutions are recommended by 
 some to be used with slightly iodized collodion, 
 such as gives a blue transparent film when 
 dipped into the silver bath. We do not recom- 
 mend such a combination, although it may 
 sometimes give good results, but its use is 
 more difficult, especially in the development of 
 the impression. 
 
 The silver solution is prepared in the follow- 
 ing way. 
 
 The silver is dissolved in the water, and 
 
 Neutral crystallized nitrate of silver 
 
 Water 
 
 Tincture of iodine 
 
 . 1 oz. 
 
 12 oz. fluid. 
 10 drops. 
 
62 
 
 the tincture of iodine added to it. The iodine 
 will precipitate in the form of iodide of silver, 
 of which a part will be dissolved. Instead of - 
 tincture of iodine, you may use two grains of 
 iodide of potassium, which will produce the 
 same effect. 
 
 A solution of nitrate of silver dissolves io- 
 dide of silver to a certain extent. It is there- 
 fore necessary, previously, to saturate the ni- 
 trate solution with it. If no attention is paid 
 to this, the iodide of silver, after having been 
 produced in the film, would be partially dissolv- 
 ed. This is the reason why iodine or iodide of 
 potassium has to be added, which, by double de- 
 composition, changes into the iodide of silver. 
 
 If the silver solution has been made with wa- 
 ter suspected to contain organic matter, it will 
 be advisable to expose it to the sun-light for an 
 hour or so. Light has no action on a solution 
 of pure nitrate of silver in pure water, but if 
 any organic matter is present, the solution will 
 become brown, and a part of the silver will be 
 reduced and precipitated in the state of a 
 black powder. In the case where tincture of 
 iodine is used, it is best to expose the solution 
 to the sun-light before iodizing it. Iodine sets 
 nitric acid free, and nitric acid counteracts the 
 decomposition, so that the solution would have 
 to be exposed much longer to the sun-light 
 before all the organic matter be removed. 
 
 If iodide of potassium is used to iodize the 
 silver-solution, one or two drops of chemically 
 
63 
 
 pure nitric acid will have to be added. The 
 formula will thus be as follows : 
 
 Neutral crystallized nitrate of silver. . . •. .1 oz. 
 
 Water - 12 oz. fluid. 
 
 Iodide of potassium *2 grains. 
 
 Nitric acid 1 or 2 drops. 
 
 The fused nitrate of silver is sometimes of a 
 black color, owing to the decomposition of a 
 small quantity of it during the fusion. In 
 case it be used, the iodizing and nitric acid 
 should only be added after the black powder 
 has been separated by filtration. Filter 
 through Swedish filtering paper, or, better yet, 
 through cotton. Put a tuft of cotton into the 
 neck of a funnel, pour on 10 or 12 drops of al- 
 cohol,, remove the alcohol with water, and then 
 pour your silver-solution into the funnel. It 
 may, at first, not filter entirely clear, but it 
 will soon do so. Before filtering the silver-solu- 
 tion, it is necessary to let it settle ; if not, the 
 precipitate would soon obstruct the filter. 
 
 In case nitrate of silver is used, which is 
 acid, the solution should be first neutralized, 
 and then treated in the ordinary way. An 
 acid solution of nitrate of silver reddens, the 
 blue litmus paper. To neutralize it, make 
 the following solution. 
 
 Sesqui-carbonate of soda (the one used for effer- 
 vescent draughts) )4 oz - 
 
 Water 4 oz. fluid. 
 
 Add of this a few drops at a time, shaking 
 after each addition. The precipitate of car- 
 bonate of silver will redissolve as long as there 
 
64 
 
 is any acid present, and when all the acid has 
 been neutralized, the liquid will become 
 turbid ; it should then be filtered. The solu- 
 tion in this state is faintly alkaline, but this 
 alkalinity is removed by the small quantity of 
 nitric acid which is added to it, either directly 
 or indirectly through the iodine. 
 
 Neutral and acid silver solutions. — Neutral 
 solutions are those which , contain neither free 
 acids nor free oxides. They do not turn red 
 the blue litmus paper, as do the acid solutions ; 
 nor clo they turn blue the reddened litmus 
 paper, as do the alkaline solutions. 
 
 The presence of free nitric acid injures the 
 sensitiveness of the film of collodio-iodide of 
 silver. A slightly acid bath, such as the one 
 we have prescribed, is, however, preferable to 
 a neutral one. If the sitting-time is a little 
 longer, this disadvantage is amply compensa- 
 ted by a greater uniformity in working. A 
 larger quantity of acid should be added only 
 when the pictures obtained are foggy or covered 
 with a veil, and the operator has no time to 
 apply the remedy spoken of under head — De- 
 composition of the Silver Solution. 
 
 Decomposition of the Silver Solution. — A pure 
 solution of nitrate of silver, in water, is not 
 affected by light ; but when it contains organic 
 matter, it will, under the influence of light, be 
 decomposed, till all the organic matter has 
 been removed, and a corresponding quantity of 
 silver has been precipitated. Such a solution, 
 
65 
 
 when exposed to the sun's rays, will first turn 
 brown, and will then become clear again by 
 depositing a black powder, which is nothing 
 but reduced silver. 
 
 If a solution of nitrate of silver contains 
 organic matter, decomposition takes place very 
 slowly as long as it is kept from the light ; 
 but if it is exposed for a short time to it, and 
 then shielded from its influence, the decom- 
 posing action will be less energetic than if 
 it had been allowed to remain, but it will go 
 on with much greater rapidity than before. 
 
 As long as decomposition is going on in a sil- 
 ver solution, no good pictures can be obtained, 
 the free nitrate of silver, which is on the film, 
 being reduced all over the surface of the plate, 
 and covering it with a veil of metallic silver. 
 When this happens, the remedy is to neutral- 
 ize the silver solution with carbonate of soda, 
 filter it, and then expose it to the sun-light 
 till it has deposited the reduced silver, and 
 has cleared up again. The necessity for neu- 
 tralizing results from the fact that the reduc- 
 tion of the nitrate of silver by the organic mat- 
 ter is a great deal slower in the presence of 
 nitric acid. 
 
 From all that has been said on this ques 
 tion, we may deduct the following rules of 
 action: 1st, Never expose the solution you 
 are using to the action of the light, unless 
 it be exposed long enough to allow all the 
 organic matter to be removed. 2nd, If the 
 
 6 
 
66 
 
 , solution works foggy, neutralize it, expose it 
 a sufficient length of time to the sunlight, filter 
 it and acidify it again with one or two drops 
 of nitric acid. If it is impossible for want of 
 time to apply this remedy, add nitric acid, 4 
 or 5 drops at a time, till clear pictures are 
 obtained. This counteracts the decomposition, 
 but will not put the solution in good order, as 
 the organic matter is not removed. It should 
 then, on the first opportunity, be neutralized 
 and exposed to the light.* Organic matter 
 gains access into the bath through the collo- 
 dion, atmospheric dust, unclean glass, etc. 
 
 Every time a plate coated with collodion is 
 dipped into the bath, a portion of nitrate of 
 silver is transformed into iodide and bromide 
 of silver, and a portion of the silver solution 
 is taken out ; so that while the silver solution 
 decreases in volume, it also decreases in 
 strength. It will, therefore, be necessary to 
 fill up the bath every day with a solution which 
 
 * When a silver solution contains a large quantity of 
 nitric acid, it is objectionable to use carbonate of soda to 
 neutralize it, as in this way a too large quantity of nitrate 
 of soda gains access into it. Instead of carbonate of soda, 
 use oxide of silver, and proceed in the following way : To 
 two or three ounces of your silver solution, add a solution 
 of caustic potash till all the oxide of silver is precipitated ; an 
 excess of potash will do no harm. Then wash the precipi- 
 tate several times with clear, and finally with distilled water; 
 pour the water off and add the oxide of silver to the silver 
 solution, which will dissolve part of it. It can then be fil- 
 tered, and the remaining oxide of silver can be used for 
 another neutralization. 
 
67 
 
 contains a quantity of nitrate of silver sufficient 
 to restore it to its original strength. But that 
 quantity of nitrate of silver depends altogether 
 on the quantity of iodide and bromide con- 
 tained in the collodion film, and is difficult to 
 determine. As a general thing, it will answer 
 to fill up a bath containing 40 grains to the 
 ounce, with the following solution : 
 
 Water « 8 fluid ounces. 
 
 [Nitrate of silver 1 ounce. 
 
 It is recommended to add every night to the 
 silver bath a quantity of the above named 
 solution, corresponding in volume to the quan- 
 tity that has been taken out. If you wait un- 
 til you have to add a large quantity at a time, 
 the condition of your bath will change too 
 much. 
 
 We have not added to the solution used in 
 filling up the bath any iodide of potassium, 
 nor any nitric acid. The quantity of nitrate 
 of silver added every day is too small to dis- 
 solve sensibly the collodion film, so that the 
 iodide and bromide are useless in making the 
 addition. In regard to the omission of nitric 
 acid, it is to be observed that every plate, 
 coated with yellow or red collodion, imparts 
 acid to the bath, so that the supply of* acid is 
 always kept up, and will even sometimes in- 
 crease to an excess. 
 
 When the operator has some uncertainty in 
 regard to the strength of his silver solution, 
 
68 
 
 there exists an easy way to estimate it with 
 sufficient accuracy. 
 
 Take the best table salt you can get, put it 
 in a crucible and warm it gradually till it is 
 red hot. The salt (chloride of sodium) will 
 first crackle and then fuse. When it is well 
 in fusion, pour it out on a stone and put it in 
 well stoppered bottles. The chloride of sodium 
 in this state contains no water. Take of it 17 
 grains and dissolve it in 6 fluid ounces distilled 
 water. This gives you a standard solution of 
 which each drachm will precipitate one grain 
 of nitrate of silver. 
 
 Supposing that with this solution you want 
 to ascertain the actual strength of a bath 
 which was originally 40 grains, you will have 
 to proceed in the following way : 
 
 Measure exactly J ounce (2 fluid drachms) 
 of your silver solution and put it in a 4 or 5 
 ounce bottle. 
 
 Rinse your measure out with two or three 
 drachms of distilled water and add it to the 
 two drachms of the silver solution. 
 
 Acidify with two or three drops chemically 
 pure nitric acid. 
 
 Add to it 6 drachms of the standard solution, 
 shake or stir with a glass rod and let settle. 
 
 If the clear liquid is made milky by the 
 addition of a few drops more of standard solu- 
 
 * Since issuing the first edition, a useful little instru- 
 ment, called the Silver Indicator, has been introduced to the 
 trade by the Scovill Manufacturing Co, 
 
69 
 
 tion, the bath is stronger than 6 grains to \ 
 oz. or 24 grains to 1 ounce. 
 
 Add thus two drachms more, shake and let 
 settle. 
 
 If the clear liquid is made milky again by 
 a fresh addition of salt solution, add one 
 drachm more, and continue in the same way 
 till all the silver has been precipitated in the 
 state of chloride. In supposing that this be 
 done with nine drachms of the standard solu- 
 tion, the solution tested will be of nine grains 
 to \ ounce, or 36 grains to the ounce. 
 
 The testing of a new silver solution can be 
 done by means of an instrument called hydro- 
 meter, which is well known to most operators. 
 A solution which has been used, and which 
 contains nitrate of potash, ammonia, cadmium, 
 etc., cannot have its strength in nitrate of sil- 
 ver determined by means of the hydrometer, 
 as all these salts add to the specific gravity. 
 
 CHAPTER VIII. 
 
 Developing Solution. 
 
 The materials used in the developing solu- 
 tion are the following : 
 
 Protosulphate of iron. Water. 
 
 Acetic acid, No. 8. Nitric acid. 
 
 Alcohol. Nitrate of potash. 
 Nitrate of silver. 
 
70 
 
 Trotosulphate of Ixon. — This salt is known 
 in the trade by the names of copperas or green 
 vitriol. The common sulphate of iron requires 
 recrystalizing in order to render it sufficiently 
 pure for photographic purposes. 
 
 Water. — Distilled water, filtered rain, spring 
 and river water can be used. It does not re- 
 quire to be as pure as for the silver solution, 
 but it should not contain any chlorides, which 
 would transform the nitrate of silver in inso- 
 luble chloride. — See Tests for Chlorides in Chem- 
 istry of Chlorine. 
 
 Acetic Acid, No. 8. — This acid, as sold by 
 stock dealers and druggists, is generally pure. 
 It contains sometimes sulphuric, sulphurous 
 or hydrochloric acids, which can be detected, 
 the first by nitrate of baryta, the two others 
 by nitrate of silver. Acetic acid which has a 
 smell of tar should not be used. 
 
 Nitric Acid. — The nitric acid used in the 
 developing solution should be free from hy- 
 drochloric acid, which, like the chlorides, 
 would transform the silver in insoluble chlo- 
 ride. The chemically pure nitric acid should 
 thus be used, or if it cannot be procured, the 
 hydrochloric acid, contained in the common 
 nitric, should be precipitated as chloride of 
 silver, by adding to it some of the silver solu- 
 tion. To that effect proceed just like in all 
 other cases of precipitation. Add a few drops, 
 shake and let settle, then add a few more, and 
 so on till no more precipitate is formed. Some 
 
71 
 
 samples of nitric acid, of a red color, contain a 
 large quantity of hydrochloric acid, and it 
 would be wasting nitrate of silver to attempt 
 to bring them to a state fit for use. 
 
 Alcohol — Alcohol 90 per cent will answer 
 the purpose. 
 
 Mtrate of Silver. — Use the same as for 
 making the silver solution. 
 
 Nitrate of Potash. — None but the refined 
 nitre will answer, as the common nitre contains 
 chloride of potassium. 
 
 Reduce the sulphate of iron to powder in a 
 clean mortar, put it with the other ingredients 
 in a bottle, shake till all is dissolved, and filter 
 carefully through a tuft of cotton. 
 
 The strength of this solution is calculated 
 for an ordinary temperature. In warm 
 weather, when the development proceeds too 
 rapidly, it may be diluted with an equal bulk 
 of water, and two or three ounces more acetic 
 acid added to it, or the proportion of proto- 
 sulphate of iron may be lessened. 
 
 The effect of the alcohol and acetic acid is to 
 make the development uniform, by causing 
 the solution to flow evenly on the plate. The 
 acetic acid, also, whitens the lights, and makes 
 the shades brighter, and it cannot be omitted, 
 or the image will not be clear. 
 
 Formula Producing Dead Whites. 
 
 NO. 1.— Protosulphate of iron, 
 
 40 oz. fluid. 
 4 oz. fluid. 
 . 3 oz. fluid. 
 
 3 oz. 
 
 Water, r « 
 
 Acetic acid, No. 8, 
 Alcohol, 
 
72 
 
 The relative proportion of the ingredi- 
 ents used in the developing solution may be 
 changed according to circumstances. If the 
 development proceeds too rapidly or too 
 slowly, decrease or increase the quantity of 
 sulphate of iron. If the developer does not 
 flow evenly over the plate, add more alcohol. 
 If the picture obtained is not bright and clear, 
 supposing the collodion and silver solution 
 to be in good order, increase the quantity of 
 acetic acid. 
 
 The developing solution given above, and 
 all those in which the same compounds, and 
 no other, enter, will, in the course of few days, 
 take a reddish color, and in that state will 
 work more evenly. 
 
 Different Formulas for Developing Solutions. 
 
 No. 2.— Water 1 quart. 
 
 Protosulphate of iron, 1 oz. 
 
 Acetic acid, No. 8, 1 oz. 
 
 Alcohol, , 1 oz. 
 
 Nitrate of Potash, 2 drachms. 
 
 Silver Solution 2 fluid drachms. 
 
 No. 3.— Protosulphate of iron, 3 oz. 
 
 Acetic acid, No. 8, 3 oz. 
 
 Alcohol,. . . , 4 oz. 
 
 Nitrate of silver, 20 grains. 
 
 Sal Prunella, or Eefined Nitre.. oz. 
 
 Water, 40 oz. 
 
 NO. 4.— Water, , , ; 10 fluid oz. 
 
 Protosulphate of iron, , 1 " 
 
 Acetic acid, No. 8, 1 " 
 
 Alcohol, ... 1 " 
 
 Nitrate of silver, 20 grains. 
 
 Nitrate of potash, 120 " 
 
 NO. 5.— Water, 12 fluid oz. 
 
 Protosulphate of iron,. ^ oz. 
 
73 
 
 Acetic acid, No. 8, 1 oz. fluid. 
 
 Nitric acid,. . . , 2 dr'ms" 
 
 N i trate of s i i ver, 20 gi-a i us. 
 
 Nitrate of potash, ... 150 " 
 
 XO. 6.— Water, 48 fluid oz. 
 
 Protosulphate of iron, 2 oz. 
 
 Nitric acid 1 drachm. 
 
 Acetic acid, No. 8, 2 " 
 
 All these developing solutions give more 
 or less metallic whites, and develop slower 
 than the first one given. They will, also, re- 
 quire a little longer exposure in the camera, 
 owing to the retarding influence of the nitric 
 acid they contain.* 
 
 Wherever nitric acid is used in the for- 
 mulas given above, care should be taken to 
 add it only after the sulphate of iron has been 
 mixed with the water. The effect of nitric 
 acid on protosulphate of iron is to oxidize 
 end transform it in persulphate of iron, which 
 is not a developing agent. 
 
 CHAPTER IX. 
 
 Tub Fixing Solution. 
 
 The materials used as fixing agents are the 
 cyanide of potassium and the hyposulphite of 
 
 soda. 
 
 The fused cyanide of potassium, although it 
 
 * It is to be remarked here that in some of these solutions 
 the nitric acid is introduced through the decomposition of 
 the nitrate of silver by the sulphate of iron. 
 
74 
 
 contains a great deal of carbonate of potash, fa 
 suitable. One drachm of this, dissolved in four 
 ounces of water, will give a solution of the 
 proper strength. 
 
 If hyposulphite of soda is used, six ounces 
 should be dissolved in a pint of water. The 
 hyposulphite solution should not be used 
 more than once, or it will give a grey tinge to 
 the whites of the image. The cyanide of po- 
 tassium is generally preferred, because its use 
 is less costly, and it does not make the whites 
 grayish. Its solution can be used as long as 
 it retains its solvent power. 
 
 The operator must be very cautious in using 
 the cyanide of potassium, as it is a deadly 
 poison. Its contact with wounds and sores 
 on the hands should be avoided. Its smell, or 
 rather the gas that emanates from it, when in 
 contact with the air, produces violent head- 
 ache, and irritation of the throat. We may 
 here remark that the best antidote against the 
 cyanide is the protosulphate of iron. The 
 developing solution, which is always on hand, 
 can be used immediately, in case of accident ; 
 or, better yet, one drachm of protosulphate of 
 iron, dissolved in half a tumbler of water. 
 
CHAPTER A. 
 
 Cleaning the Plate. 
 
 The surfaces used for the product 
 itive pictures are, as we have seen ay, 
 glass, melainotype plates, and japanned paper. 
 
 In the choice of the glass great care should 
 be taken ; it should be perfectly flat, without 
 scratches, and quite free from scoria and air- 
 bubbles. The polished plate glass answers 
 the best, but is found generally too expensive, 
 and the best kinds of window glass are used 
 in its place. Common window glass is not 
 suitable on account of the many air-bubbles, 
 the unevenness, and the difficulty of cleaning 
 it. 
 
 Before proceeding to clean the glass, the 
 sharp edges should be filed off, to prevent the 
 fingers from being cut, and the collodion film 
 from separating from the sides. It is then to 
 be immersed in a solution of one part of nitric 
 or sulphuric acid in four or five parts of water, 
 where it should be left for several hours. This 
 solution corroding the skin, the glass should 
 be removed out of it with a glass rod, or a 
 piece of wood, after which it should be well 
 rinsed with clean water, and wiped dry with a 
 clean towel. The towel used for this purpose 
 should be used for no other, and should not be 
 washed with soap, but with a weak solution of 
 carbonate of soda, and then carefully rinsed. 
 Instead of wiping the glass dry with a towel, 
 
76 
 
 it can be set to dry on a sheet of bibilous pa- 
 per, or on two nails driven in the wall. 
 
 The operator must be careful not to set it 
 while wet in a dirty place, as in virtue of the 
 laws of capillarity, all the dust it touches will 
 settle on its surface. The washing of the 
 glass is very important, and should be careful- 
 ly attended to, as the success of all the subse- 
 quent operations depends upon it. A glass 
 which is well washed is easy to clean, but any 
 amount of rubbing will not clean one which is 
 not well washed. 
 
 When a washed glass is breathed upon, the 
 moisture settles upon it in an irregular man- 
 ner, affecting the form of lines in the direction 
 it has been rubbed dry. If it were used in 
 this state, these lines would, in all proba- 
 bility, interfere with the action of the de- 
 veloping fluid, and be reproduced on the pic- 
 " ture. 
 
 The following operation is designed to pro- 
 duce a surface on which the moisture of the 
 breath will condense uniformly. For this, 
 prepare a mixture of rottonstone or polishing 
 powder, and good pure alcohol. Put a small 
 quantity of this mixture upon the glass, and 
 rub it all over it for half a minute with a piece 
 of canton flannel ; then, before the alcohol has 
 had time to dry, change your flannel for a 
 clean piece, and continue the rubbing for a 
 few moments longer. Finally, finish gently 
 with a clean piece of buckskin. 
 
-77 
 
 In rubbing let your motion be circular, and do 
 not let the powder dry on the plate, but wipe 
 the plate dry with the second piece of flannel. 
 
 The glass has in this way to be cleaned on 
 both sides, the finishing with buckskin on the 
 side which is not used being dispensed with. 
 The rottenstone on the edges should be well 
 wiped off, and any particles of powder or fila- 
 ments of cotton removed by means of a soft 
 camel-hair brush. 
 
 While cleaning the glass, it may be held 
 in a wooden vice, or in any of the plate hol- 
 ders sold for that purpose; or it may be 
 simply laid on a clean piece of paper. 
 
 All glasses, after they have been used, 
 should be put into the acidulated water, just 
 like the new ones. Those which have been 
 varnished should be allowed to remain in it 
 till the film of varnish scales off. 
 
 The melainotype plates are less troublesome 
 than the glass. When new they do not want 
 any cleaning ; simply brushing off with a soft 
 hair brush, to remove any particles of dust, is 
 all that is required, unless the plate has been 
 handled and touched on the surface with the 
 fingers. In this case, put on it a few drops of 
 alcohol and rub dry with a piece of flannel. 
 jNTo rottenstone or scouring material is required, 
 as the surface of the plate will not bear this. 
 But very light pressure is needed in cleaning. 
 
 If an unsatisfactory picture has been made 
 on the plate, rub it off when it is yet wet, 
 
78 
 
 wash with clean water, and wipe with a silk 
 handkerchief or a piece of canton flannel ; it is 
 then again ready for use. If the picture is dry 
 rub it off with a little alcohol, and then go 
 through with the aforesaid process of washing 
 and wiping;. 
 
 When the plate has been varnished, the 
 varnish must be dissolved with alcohol and 
 ether, using several pieces of clean flannel till 
 the varnish has been all taken off. 
 
 Care has to be taken not to scratch the me- 
 lainotype plates in cleaning them. It should 
 be well understood that they do not require 
 polishing. The object in cleaning them is only 
 to remove foreign matter. 
 
 The Niello paper passes through the same 
 process of cleaning as the melainotype plate. 
 
 CHAPTER XI. 
 
 Formation of the Film of Collodio-Iodide of Silver. 
 
 Having cleaned the glass the next operation 
 is coating it with the iodized collodion. This 
 part of the manipulation should be properly 
 performed, as much depends on the evenness of 
 the film. Grasp the plate firmly between the 
 thumb and forefinger, holding it at the lower 
 left hand corner, and after having dusted it 
 off with a camel-hair brush, hold it as nearly 
 level as possible, and pour a sufficient quan- 
 
79 
 
 tity of collodion in the middle, then incline it 
 down, so as to cause the collodion to flow 
 toward the corner by which it is held, from 
 thence toward the upper left hand corner, then 
 toward the upper right, and finally down to 
 the lower right, allowing the excess of liquid 
 to pass back into the bottle. It is best now to 
 hold the plate in an oblique position, moving- 
 it slowly back and forth, so as to cause the 
 collodion to flow together in one smooth sur- 
 face. Should you neglect this, you will inva- 
 riably have lines running diagonally across 
 the plate. The difficulty of obtaining a 
 smooth surface depends greatly on the collo- 
 dion itself. The thicker it is, the more dex- 
 terity will have to be used in coating the 
 plate. If lines should be formed, notwith- 
 standing the proper care has been taken to 
 avoid them, the fault lays with the collodion, 
 and it should be diluted with ether and alcohol, 
 or thinned by one of the means we have de- 
 scribed. 
 
 The bottle which contains the collodion 
 should be wiped at the mouth before flowing 
 each plate, as small particles of dried collodion, 
 hanging at the mouth of the bottle, will often 
 be loosened in pouring from it, and, settling on 
 the film, will cause a spot on the picture. 
 When large plates are flowed, it is advisable 
 to pour the excess of collodion, which runs 
 from the plate, into another bottle, in order 
 not to stir up the deposit, which is often on 
 
80 
 
 the bottom. If the collodion which has been 
 used has become too thick, it will have to be 
 thinned with a little ether. 
 
 The next operation is to immerse the col- 
 lodionized plate into the silver solution. This 
 should not be done before the film is perfectly 
 set, that is, when it is so dry it receives the 
 impression of the finger at its lower end, with- 
 out sticking to it. If the plate were immersed 
 too soon, lines would appear at the end which 
 had been dipped first. The time the film re- 
 quires to set is dependent on the temperature 
 and on the quantity of ether and cotton which 
 is in the collodion. It will take from half a 
 minute to two minutes. 
 
 The baths holding the silver solution are 
 made either of gutta percha, stone ware, glass, 
 or vulcanised ritbber. The gutta percha baths, 
 not being made out of one piece, soon get dis- 
 joined and leak. The gutta percha serais, 
 also, to decompose slowly the silver solvrlon. 
 The use of vulcanised rubber for batlv; we 
 think objectionable on account of the suifhur 
 it contains. The photographic ware baths (Gr. 
 Mathiot's patent) are excellent, and hold the 
 solution better than any other kind except 
 those in glass. They are generally made in 
 the overflowing style, and are the cheapest in 
 the market. They should previously be filled 
 with water, to see if they are not cracked. 
 The stoneware baths, improperly called 
 porcelain, are, after long use, more or 
 
81 
 
 less penetrated by the silver solution ; they are 
 valuable, however, on account of the facility 
 with which they are cleaned, and the small 
 quantity of solution they require. The glass 
 baths are, of all, the least objectionable, "but 
 they are heavy, and require a large quantity 
 of solution ; if they could be made lighter, and 
 in the overflowing style or pattern, they would 
 be the great desideratum. 
 
 The film being set, place the plate carefully 
 on the dipper and lower it gradually without 
 stopping. Any check of the plate, while being- 
 put into the bath, will cause an horizontal line 
 across the surface. The plate must be left in 
 the. bath a time sufficiently long to allow all 
 the iodide and bromide contained in the col- 
 lodion film to be transformed into iodide and 
 bromide of silver. If taken out as soon as the 
 greasy appearance, caused by the solution of 
 the alcohol and ether, is gone, as is recom- 
 mended by some operators, it will appear when 
 it is removed from the tablet to be developed 
 a great deal more opaque than at the time it 
 was taken out of the silver solution. This is a 
 conclusive proof that all the iodide and bromide 
 was not transformed into iodide or bromide 
 of silver during the immersion in the bath, and 
 that the transformation was continued after the 
 plate was removed out of it, at the expense of 
 the nitrate of silver that was on the surface of 
 the film. This nitrate of silver on the film is 
 necessary, and required in the process of devel- 
 
82 
 
 oping the impression ; so that removing a plate 
 out of the silver solution too soon weakens the 
 nitrate of silver on its^surface, and is the same 
 as using a bath that is too weak ; in such a case 
 the necessary relation between collodion and 
 the silver bath does not exist, and no satisfac- 
 tory result can be expected. 
 
 It is sometimes the case that irregular lines, 
 most visible by transmission, are produced on 
 the end of the plate which has been dipped 
 first. This occurs when the collodion has not 
 been well set. These lines occur mainly in 
 weak solutions, and with collodion which has 
 been made with an excess of alcohol of insuf- 
 ficient strength. 
 
 The length of time the plate has to remain 
 in the solution depends : 1st, On the porosity 
 of the film ; 2nd, On the quantity of sensiti- 
 zing; 3rd, On the strength of the bath; 4th, 
 On the temperature. Generally from two to 
 four minutes' immersion will answer the pur- 
 pose. 
 
 The film, sometimes, shows a disposition to 
 get loose from the plate, while being taken out 
 of the bath, or in the following operations. 
 This want of adherance may be produced by 
 different causes: 1st, Want of adherance of 
 the film to the glass resulting either from the 
 character of the cotton, or the excess of ether 
 in the collodion ; 2nd, Imperfect setting ; 3rd, 
 Excess of acidity of the silver solution. These 
 three causes suggest the remedies to be applied. 
 
83 
 
 As we have already mentioned, on page 
 62, the silver solution has to be saturated 
 with iodide of silver to prevent the iodide of 
 silver in the collodion film being removed. 
 Now, the power of nitrate of silver to dissolve 
 the iodide, depending on the strength of the 
 solution, it is easy to understand that a 
 bath, in getting weaker by use, will lose, to 
 some extent, its power to keep the iodide of 
 silver in solution ; it will then assume the 
 form of needle-like crystals, which will float 
 in the solution, and deposit on the sides 
 of the dish. When a collodionized plate 
 is coated in such a solution, these crystals 
 will also deposit on the film, which will some- 
 times, on removal from the bath, appear as if 
 it had been sprinkled with sand. In the sub- 
 sequent operations this crystalline deposit is 
 washed off or dissolved, leaving the surface 
 pierced by a multitude of small holes, com- 
 monly known as pinholes. 
 
 It is not only the weakening of the bath by 
 use which will produce this effect. It has been 
 ascertained lately, by .Mr. Vogel, that iodide 
 of silver is less soluble in nitrate of silver 
 when warm than when cold ; so that a bath, 
 which in cold weather will be free from the 
 defect mentioned above, will be subject to it 
 during hot days. This also explains the fact 
 so often complained of, that baths, working 
 well in the morning, produce pinholes later 
 in the day. 
 
84 
 
 The remedy for this difficulty is suggested 
 by what we have just said. A bath should 
 not be saturated with iodide of silver, especi- 
 ally when there is but a small volume of it, 
 or when it is to be used in a warm room. 
 
 When the bath is regularly filled up with a 
 stronger uniodized solution of nitrate of silver, 
 as recommended on page 67, it will very sel- 
 dom get to such a state as to produce pinholes. 
 When this accident does happen, add a few 
 ounces of distilled water, which will precipitate 
 a certain quantity of iodide, then filter and 
 add a quantity of nitrate corresponding to the 
 quantity of water added. 
 
 When one is compelled to use a bath in 
 such condition for want of time and opportu- 
 nity to apply the remedy, the crystalline de- 
 posit can be prevented by keeping the plate in 
 motion while it is being coated, or by coating 
 the plate collodion side down, either by using 
 a horizontal bath, or by inclining the vertical 
 bath and plate. 
 
 Pinholes may also be produced by the pres- 
 ence of acetate of silver in the bath, intro- 
 duced by the use of carbonate of soda or 
 oxide of silver for neutralizing, and the sub- 
 sequent, addition of acid. In this case a 
 drop or two of nitric acid will speedily re- 
 move the difficulty. They are also supposed 
 to be produced by the use of old and decom- 
 posed collodion, or of collodion made with 
 partly decomposed pyroxyline. 
 
85 
 
 The silver bath should be kept covered, to 
 avoid dust and evaporation. The dust brings 
 on decomposition of the solution, and the re- 
 sult is foggy pictures. When small particles 
 of dust, or a black scum, are discovered on the 
 surface of the silver solution, they should be 
 taken off with a strip of blotting paper ; or 
 when an overflowing bath is used, the solu- 
 tion should be made to flow over into its 
 smaller portion, from which it is discharged 
 into the bottle. This over-flowed liquid may 
 be used again after filtering. 
 
 The silver solution should remain excluded 
 from the light as long as it is in use. It may 
 be kept constantly in the bath, but some pre- 
 fer pouring it into a bottle every night. 
 
 Sometimes the silver solution gets out of 
 order without it being possible to determine 
 the cause. This results, most frequently, 
 from uncleanliness and carelessness ; dipping 
 into the bath plates which are not perfectly 
 cleaned, leaving it uncovered, so that the dust 
 floating in the air is deposited in it ; exposing 
 it to the light which accelerates the decompo- 
 sition, and not exposing it long enough to allow 
 it to terminate ; accidental contact with devel- 
 oping and fixing solution, etc. 
 
 All the causes enumerated above produce 
 the same effect — fogging of the pictures. In 
 all these circumstances the remedy to apply 
 is exposure to the direct sun-light for a few 
 
86 
 
 hours. When no opportunity exists to do this, 
 try an increased addition of nitric acid. 
 
 In order to avoid all interruption, resulting 
 from solutions getting out of order, we would 
 recommend to every operator, to have at least 
 two, Mid to keep the one exposed to the light 
 while the other is being used. With such an 
 arrangement, much trouble is avoided ; for a 
 solution which has been used some time 
 always contains organic matter, which, under 
 favorable circumstances, will be decomposed. 
 The proof of this is found in the fact, which 
 every operator can verify, that a solution 
 which has been worked, discolors under the 
 influence of light. 
 
 It has been proposed, as a remedy for foggy 
 baths, to precipitate the silver by means of 
 carbonate of soda, and to redissolve the carbo- 
 nate of silver, thus obtained, in nitric acid, 
 leaving a small quantity undissolved. By 
 this process, the solution is freed from the. 
 alkaline nitrates it may contain, leaving in 
 it the nitrates .of magnesium, cadmium, or 
 zinc, if any of the iodides or bromides of these 
 metals have been used. This remedy might 
 be used in case the exposure to the direct sun 
 light should fail to restore the bath. We will 
 here give it as described by F. B. Gage, in 
 No. 1, vol. x. of Humphrey's Journal. 
 
 "Put the foggy solution into a strong bottle, 
 about three times larger than the bulk of the 
 solution ; then pulverise and add pure bi-car- 
 
87 
 
 bonate of soda, until the silver is all precipi- 
 tated to the bottom, in the form of carbonate 
 of silver. If there is any acid in the solution, 
 the soda must be added with caution (stirring, 
 meanwhile, with a glass rod), as the soda will 
 dissolve " fuming," and may boil up and run 
 over, to your loss. After you have added 
 soda until the silver is all precipitated,* fill the 
 bottle with soft water, stir it up thoroughly 
 with the glass rod, then let the precipitate 
 settle. When 1 it has done so, pour off the 
 water, as closely as you can, without letting 
 any of the precipitate escape. Repeat this 
 six or eight times, so as to be sure of washing 
 off all the free soda. Now drain off the water 
 as closely as possible. (It would be well to 
 use distilled water for the last washing, or the 
 kind that you intend to make your bath 
 with.) After having drained it as closely as 
 possible, proceed to add chemically pure nitric 
 acid, to dissolve the precipitate ; add it, stir- 
 ring with the glass rod at the same time, aud 
 with some caution, as it will fume strongly; 
 continue to add until the precipitate is nearly, 
 but not quite all dissolved. The solution, at this' 
 point of the proceeding, will probably be 
 opaque, and'almost inky-black. This need not 
 cause any alarm as it will filter out clean and 
 pure. Then take a quantity of dear cotton in 
 
 * Add the soda until you are sure tbe silver is nil thrown 
 down. Any excess of soda will be carried oF in the sub- 
 sequent washings, and will do no harm. 
 
88 
 
 your hand, hold it under water and squeeze 
 and work it in your hand until it is thoroughly 
 saturated; then press out the superabundance 
 of water, put it into a funnel and filter the 
 solution through it; test it with the hydro- 
 meter, and add water until it is of the right 
 strength ; wash your funnel, and put in some 
 clear cotton ; filter it again thoroughly, and it 
 is right for a negative bath. For positives, it is 
 only necessary to add one drop of nitric acid, 
 chemically pure, to each three" ounces of the 
 solution. Baths for negatives, treated in this 
 way, work decidedly clearer, better, and 
 quicker, than in any way I have ever tried. 
 It also gives better delineations in positives. 
 The experimenter, by this method, will be 
 astonished at the amount of black organic 
 matter that will be found in the funnel, after 
 filtering the first time, and will be able to see 
 what fogged his pictures. 
 
 " There are some points of importance to be 
 attend to in this process. They are these : 
 
 "1st; That the bi-carbonate of soda be 
 pure. 
 
 " 2d. That the resulting precipitate be well 
 washed, to free it from all soda that is not 
 absorbed and combined with the silver. 
 
 "3d. That the precipitate be not all dissolved 
 before it is filtered. 
 
 "If this part is not attended to, you will lose 
 all your labor. The theory of this is, that 
 the organic matter in- the bath is soluble in 
 
89 
 
 acid, and cannot be filtered out while the bath 
 is acid. There need be but very little preci- 
 pitate left in, as the least amount undissolved 
 will leave the bath perfectly neutral." 
 
 It is the opinion of some, that several 
 samples of collodion, sensitized with different 
 salts, cannot be used in the same bath. This, 
 on investigation, has been found to be an 
 error, the bases of the salts used having no 
 action on the film, with the exception of the 
 iron, as we have seen already. 
 
 Collodionizing the melainotype plate and 
 immersing it into the bath, are done w r ith the 
 same facility as the glass plate. It has 
 been objected by some, that the iron plate 
 would decompose the silver solution. This, 
 on trial, is not found to be so, except by a very 
 prolonged immersion. Pure iron has no effect 
 on the nitrate of silver ; but iron rust decom- 
 poses it. Rusty plates should thus be care- 
 fully cleaned before being used. 
 
 The niello paper being less dense than the 
 solution of nitrate of silver, cannot be dipped 
 in the same way as the glass or melainotype 
 plate. It is necessary to stick it on a piece of 
 glass of the same size by means of a few drops 
 of water or alcohol 
 
 The coating of the plate may be done in the 
 light, but the silvering and developing have 
 to be done in the dark closet. The dark 
 closet should be lighted either by artificial or 
 colored natural light; gas, oil, or burning fluid 
 
 8 
 
90 
 
 will answer; but as small a flame as possible 
 should be used. Natural light is colored by 
 transmitting it through a deep orange pane of 
 glass, or through muslin or paper of the 
 same color. 
 
 CHAPTER XII. 
 
 Exposure in tiie Camera. 
 
 After having removed the plate out of the 
 bath, allow it to drain a few seconds before 
 putting it into the tablet or plate-holder. The 
 tablet should be carefully wiped after each op- 
 eration, if not, the nitrate of silver, which has 
 drained in the lower part, and which has come 
 in contact with the wood, will flow over the 
 plate again, and produce silvery stains on the 
 corners. It may, also, happen that it be 
 splashed over the plate, either in putting it 
 into the tablet, or in removing or putting back 
 the slide. The tablet must always be kept in 
 a perpendicular position, to prevent the solu- 
 tion from flowing back, which would cause the 
 same silvery stains. 
 
 The plate-holders to be preferred are those 
 with solid glass corners. Those in which the 
 corners are of several pieces, sealed in with glue, 
 are more liable to produce stains than the 
 others, and should be more carefully wiped It 
 will be found useful to varnish, occasionally, 
 the plate-holders, with a solution of gum shel- 
 
91 
 
 lac, in strong alcohol. This will decrease the 
 chances of staining, and Will preserve the 
 wood from the corrosive action of the silver 
 solution. 
 
 As short a time as possible should be al- 
 lowed between the withdrawal of the plate 
 from the silver solution and the development. 
 The preliminary arrangements for the sitting 
 should thus be made before the plate is ready. 
 It would not be advisable, however, to have 
 the subject in position and ready to be taken, 
 for he will be tired before the plate is taken 
 out of the solution, and the picture obtained 
 will not have a good expression. 
 
 In giving a position every part of the sitter 
 should be arranged in such a way as to be 
 brought in focus on the flat surface of the 
 ground glass. The hands, knees and feet 
 should not be too much forward, or they will 
 appear out of proportion. This should be 
 attended to, mainly, when such object glasses 
 are used which have a curved field, as far 
 as it is compatible with a good and easy 
 position. In case the field of an object glass 
 is too curved, make only small images with it, 
 and use a diaphragm. The camera should 
 be put about at the same height as the head 
 of the sitter. 
 
 The way the light should fall on the model 
 depends on the taste of the operator. A 
 northern side light, at 65 or 70 degrees incli- 
 nation, is generally preferred. The point 
 
92 
 
 where the mod§J. should be set depends on 
 the effect of light to be obtained. The im- 
 age should stand out well on the ground 
 glass, if not, only a flat picture can be the 
 result, 
 
 The length of time the coated plate must be 
 exposed in the camera, depends— 1st, on the 
 sensitiveness of the collodion film ; 2nd, on the 
 strength of the light ; 3d, on the focal length 
 of the lenses ; 4th, on the quantity of nitric 
 acid in the developer. The melainotype 
 plates, and the niello paper, require the same 
 sitting time as does the glass. 
 
 A film prepared in a neutral bath is more 
 sensitive than one prepared in an acid bath. 
 The more acid the bath contains, the less sen- 
 sitive is the film. Between the sensitiveness 
 of a plate prepared in a neutral bath, and the 
 one prepared in a slightly acid bath, such as 
 we recommend, the difference is trifling. 
 
 CHAPTER XIII. 
 
 Development of the Picture. 
 
 The development consists in bringing out 
 the latent image which has been impressed by 
 the light. Several substances have the pro- 
 perty of doing this. The most important ones 
 are the protosulphate of iron, the pyrogallic 
 acid, and the gallic acid. They act in pre- 
 
93 
 
 cipitating metallic silver, in a very reduced 
 state, on the parts of the film which have been 
 impressed by the light. The protosulphate of 
 iron is the only one which is used in the pro- 
 duction of collodion positives ; pyrogallic acid 
 has, until now, been used by the European 
 artists in developing negatives, but the pro- 
 tosulphate of iron is now coming more into 
 use for this purpose. The gallic acid is used 
 mainly to develop albumen and dry collodion 
 plates and calotype paper. 
 
 To develop an ambrotype or a melainotype 
 hold the plate by one corner, and pour the so- 
 lution on at the bottom of the side clasped in 
 the hand. Use enough of the solution to 
 cover the plate instantly, so that it be covered 
 entirely before the action commences ; other- 
 wise the development would go on unevenly. 
 The length of time required to bring the image 
 out will vary, and must be determined by the 
 operator. In supposing the right time be 
 given in the camera, it will depend — 1st, On 
 the temperature of the atmosphere ; 2nd, On the 
 strength of the developing agent; 3d, On the 
 quantity of acid in the developing agent. The 
 warmer the weather, the stronger the developer 
 and the smaller the quantity of acid, the more 
 rapidly the development proceeds. Nitric acid 
 will retard the development much more than 
 acetic acid. As soon as the image is entirely 
 visible, which will require from eighteen seconds 
 to a minute, throw off the developing solution 
 
94 
 
 and wash the plate immediately with clean 
 water, so as to remove every trace of theviron 
 salt. This is most easily done under a tap. 
 i The appearance of a melainotype or a niello 
 plate, after development, is somewhat different 
 from the one of a glass picture, owing to the 
 black surface which is beneath. The proper 
 development of these pictures will require 
 some more practice by those who are accus- 
 tomed only to develop the ambrotype. 
 
 It is advisable, at times, to vary the propor- 
 tions of acetic acid and alcohol in the develop- 
 er. The alcohol has the effect to cause the 
 solution to flow more evenly and unite with 
 the film. The acetic acid produces, to a cer- 
 tain extent, the same effect as the alcohol, and, 
 also, brightens the whites, and preserves the 
 blacks. If the acid is too strong in the devel- 
 oper, the reduction is checked, and the devel- 
 opment is slow ; if too weak, it is sudden and 
 violent. In the first case it retards the devel- 
 opment, and gives a gray tin-foil hue, and the 
 surface is bright and sparkling like frosted 
 silver ; in the second case, the image is dull 
 and without luster, of a white color, inclining, 
 when imperfect, to a yellow or gray. 
 
 All acids tend, not only to retard the devel- 
 opment, but also to increase the length of ex- 
 posure in the camera. Mtric and sulphuric 
 acid principally do so ; acetic acid acts more 
 feebly. When too much nitric acid is present 
 in the developer, or in the bath, it will prevent 
 
95 
 
 the deposition of nitrate of silver in the shades, 
 and thus give a picture without half tones. 
 This is principally seen when thin films or 
 weak baths are used. The remedy is to lessen 
 the acid in the developer, or neutralize^ it in 
 the bath by means of carbonate of soda, or to 
 iodize more highly the collodion and strengthen 
 the silver solution. 
 
 If the protosulphate of iron is in excess, it 
 will be difficult to pour it on the plate suffi-* 
 ciently quick before the action of developing 
 begins. In such a case, after fixing with the 
 cyanide, curved lines will be seen, such as 
 would be produced by a wave of fluid flowing 
 forward, and resting, for an instant, at a par- 
 ticular spot. If the iron is too weak, the de- 
 velopment will be slow, and the picture will 
 become slightly metallic on drying. 
 
 Free nitrate of silver is required on the 
 plate during the developing process. If, after 
 its exposure to the light, the plate is washed 
 carefully with water, no image will be brought 
 out by the developer. During the exposure 
 of the plate to light in the camera, free nitrate 
 of silver is not required, since a plate washed 
 carefully with water, before its exposure, will 
 give an image if it is dipped in the silver bath 
 before developing. In such a case, however, 
 it is necessary to increase the sitting time ; for 
 the free nitrate of silver, on the surface of the 
 film acts as an accelerator. The proportion 
 of nitrate of silver required on the collodion 
 
98 
 
 film — or, what is the same, the strength of the 
 silver solution — should he such as to yield 
 sufficient metallic silver in the development. 
 If the quantity of nitrate of silver was too small, 
 the image would be feeble and imperfect ; if too 
 large, it would be too intense and apt to be 
 over developed. 
 
 The rapidity of the development depends, 
 in a great measure, on the time the plate has 
 been exposed in the camera. If over exposed, 
 the image will make its appearance in a very 
 short time, and will be too light before the de- 
 velopment can be checked by the water. 
 If under exposed, it will appear slowly, the 
 more delicate half tints will not be brought 
 out, and the shades will not be clear. This 
 last effect is most to be feared when there 
 exists any tendency to fogging resulting from 
 the silver solution containing organic matter in 
 decomposition. 
 
 An over exposed plate can, with some dex- 
 terity, be developed so as to be serviceable. 
 For that, it will have to be watched closely 
 % during the action, and the water poured on 
 before the image has become too light. 
 None, however, but imperfect results can be ob- 
 tained in this way. 
 
97 
 
 CHAPTER XIV. 
 
 Fixing the Picture. 
 
 The fixing of the picture consists in dissolv- 
 ing in cyanide of potassium or in hyposulphite 
 of soda, the iodide and bromide of silver which 
 remain in the film. The fixing solution can 
 be poured on the plate and flowed back and 
 forth till the picture is cleared off, or it can be 
 used in a flat dish, or in a vertical bath. 
 When cyanide is used, this last -method is to 
 be preferred, as the liquid is in this way less 
 exposed to the action of the air, which degages 
 from it vapors of hydrocyanic (prussic) acid. 
 The plate is dipped into it in the same way as 
 it is dipped into the silver solution. Cyanide 
 should never be used in the dark closet. Be- 
 fore proceeding to the fixing, it is very impor- 
 tant to have every trace of sulphate of iron 
 > washed off, to avoid blue marks, which would 
 otherwise be formed in the film. 
 
 The fixing solution should never be too 
 strong. The cyanide mainly, has a dissolving 
 action on the metallic silver which has been 
 deposited. A strong solution can, however, 
 sometimes be used with advantage to darken 
 an image which is slightly too light. 
 
 As soon as the iodide of silver has been dis- 
 solved from the surface, the plate should again 
 be well washed with clean water. If cyanide 
 of potassium was left on it, the picture would 
 soon change to a brownish hue. 
 
 9 
 
98 
 
 The washing, performed, the plate is ready 
 to dry, which can be done spontaneously or by 
 means of a gentle heat from an alcohol lamp. 
 
 CHAPTER XV. 
 
 Mounting the Picture. 
 
 A glass picture can be mounted in various 
 ways. It can be sealed to another glass by 
 means of balsam of fir in the same way as the 
 flint and crown are sealed together to make an 
 achromatic lens. For this, pour a few drops 
 of the balsam on a fine plate glass, lay the 
 picture on it, with the collodion side down, and 
 press gently the two together, so as to spread 
 the balsam all over the surface. One of the 
 glasses should then be coated with asphaltum 
 varnish. None but very level glass plates 
 can be used for this purpose, otherwise the 
 contact would not be perfect. Ambrotypes 
 put up in this way are very permanent, as they 
 are preserved from the influence of air and 
 moisture. For large pictures, which have to be 
 hung up, it will not do, however, the oozing out 
 of the balsam forming air-bubbles between 
 the two glasses. This is especially the case 
 when they are exposed to the heat of the sun. 
 
 The ambrotype can also be preserved by 
 coating it with benzine or alcohol varnish, and 
 then backing it with a glass which has been 
 
99 
 
 previously covered with asphaltum varnish, 
 taking care to keep the glasses separated with 
 a paper mat. In this way the color should be 
 applied before varnishing, and will show but 
 very little through the film of collodion. 
 
 The most common way is to put up the am- 
 brotype reversed, showing the collodion side 
 which is coated with benzine or alcohol varnish, 
 and backing the glass with asphaltum varnish ; 
 then covering with a mat and glass. 
 
 Some operators cover the collodion side of 
 the picture first with a white varnish, and then 
 with the black asphaltum varnish; but this 
 throws down the whites, and will in time prove 
 very injurious, by discoloring and cracking. 
 
 The pictures on black surfaces can only be 
 put up reversed, like the daguerreotype. They 
 should be coated with white varnish, and then 
 mounted with mat and glass. 
 
 To apply the benzine varnish, pour it on 
 the surface of the plate, and let it run off at 
 one corner, as is done in flowing with the col- 
 lodion. To avoid dust settling on the face, 
 hold the plate downward, after having held it 
 in a vertical position for a sufficient time to 
 set. If the varnish is dirty, filter it through 
 filtering paper, taking care to cover the funnel 
 with a glass plate to prevent evaporation. It 
 is not necessary to use any heat in drying good 
 benzine varnish ; it dries rapidly, giving a beau- 
 tiful surface. In using an alcoholic varnish, it 
 will be necessary to warm the plate slightly. 
 
100 
 
 The picture can be colored, before applying 
 the varnish, or after. In applying them upon 
 the varnish the colors look more brilliant, but 
 will not stand so well. 
 
 Pictures for lockets, breast pins, etc. must be 
 taken on melainotype plates or on niello pa- 
 per, these being easily cut to any size and 
 shape. 
 
 Positives on glass can be transferred to oil 
 cloth or on patent leather. For this, they 
 have to be made with tough collodion, which 
 leaves the plate easily. The manner of pro- 
 ceeding is as follows : — The picture being well 
 washed, dried and colored, flow over it the 
 following mixture in quantity sufficient to 
 cover it : 
 
 Alcohol, 1 ounce. 
 
 Nitric acid, < 2 drops. 
 
 Then pour the liquid off, lay the plate flat, 
 and lay on it a piece of oil-cloth or patent 
 leather of a size a little larger than the picture. 
 The oil-cloth or patent leather should be pre- 
 viously well cleaned by means of a little flour 
 and a piece of canton flannel. On the oil-cloth 
 or leather lay another glass, and put a spring 
 clothes-pin on each corner, so that the surface 
 on which the picture has to be transferred be 
 pressed between the two glasses. After five or 
 ten minutes remove the clothes-pins, and the 
 back glass and raise carefully the oil-cloth by 
 one corner, when the film will be found to ad- 
 here to its surface. Then remove the oil-cloth 
 
101 
 
 a little at a time and with great precaution, and 
 hang up to dry. Transferred pictures need no 
 varnishing, they being preserved by the part 
 of the collodion film which is next to the glass. 
 
 CHAPTER XVI. 
 
 On Collodion Negatives. 
 
 We have seen, in the introductory chapter, 
 that a negative is a kind of type, or matrix, by 
 which an indefinite number of positive pictures 
 on paper can be produced, by means of a pho- 
 tographic printing process. 
 
 It has been remarked, in both the positive 
 and negative collodion pictures, that the whites, 
 when viewed by transmitted light, are opaque, 
 and the blacks transparent. If such a picture 
 is placed on a piece of paper, prepared in such 
 manner that it blackens when exposed to the 
 action of light, the rays of light will pass 
 through the dark or transparent parts of the 
 glass, and impress the paper; while in the 
 light, or opaque parts, no reduction will take 
 place. Through the middle tints, the light will 
 of course blacken the paper, more or less, ac- 
 cording to the degree of transparency. The 
 picture, thus obtained upon the paper, will 
 be a natural representation of the object, as 
 it appears to the eye, and is termed "a positive 
 m papery 
 
102 
 
 Although all collodion pictures, made on 
 transparent surfaces, present the negative as- 
 pect as well as the positive, yet all can not be 
 used to produce "positives on paper." A pic- 
 ture which is seen with advantage by reflected 
 light, that is to say, as a positive, has never 
 intensity enough to give a good print. A "positive 
 on paper," made w T ith it, will be very feeble, 
 or will be dark in the white parts, and devoid 
 of definition and middle tints. Therefore it is 
 required that the deposit of silver should be 
 proportionately thicker than in a positive. To 
 give good positives on paper, the negative 
 should be transparent in the shades, and of 
 such intensity in the high lights, that the light 
 can with difficulty be transmitted, and this 
 must be combined with a natural gradation in 
 the middle tints. Such results are obtained, 
 1st, by using collodion made with pyroxyline, 
 which gives porosity to the film ; 2nd, by using 
 a neutral, or very slightly acid silver solution ; 
 3rd, by giving a longer exposure in the camera ; 
 4th, by omitting nitric and sulphuric acids 
 in the developing solutions ; 5th, by redevelop- 
 ing, strengthening or coloring the negative 
 which has been obtained. 
 
 The absolute intensity of a negative does 
 not depend entirely on the thickness of the de- 
 posit of metallic silver, but to a great extent on 
 the color it has when viewed by transmitted 
 light. Some negatives are translucent, and of 
 a brown yellow ; others of a dark bluish black ; 
 
103 
 
 others are grey, etc. It is easily understood, 
 that a brown yellow negative will be a great 
 deal more opaque to the chemical rays, than 
 one that is grey, supposing the deposit, in both 
 cases, has the same thickness; so that often 
 negatives, having comparatively a slight in- 
 tensity, will give very good positive proofs. 
 
 The color of negatives depends on so many 
 causes, that it is impossible to determine them 
 all. The condition of the bath, the nature of 
 the developer, the quantity of acetic acid con- 
 tained in the developer, the presence or absence 
 of organic matter in the silver bath, the time 
 of exposure to light, are the principal causes, 
 ~No positive rules can, therefore, be given, to 
 determine whether a negative is intense enough 
 or not. This can only well be seen, when a 
 positive has been produced from it. A few days 
 practice will, however, teach, on this particular 
 part, more satisfactorily, than what can be 
 given in written instruction. 
 
 CHAPTER XVII. 
 
 Collodion for Negatives. 
 
 In the chapter on Positive Collodion, many 
 things have been mentioned, which are also 
 applicable to negative collodion, and which it 
 would be useless to repeat. 
 
 We will thus refer the reader to what we 
 
104 
 
 have said on that subject, and invite him to 
 make a careful perusal of it before he commen- 
 ces the study of this chapter. 
 
 A negative has to exhibit in bold contrast 
 by transmitted light all the details which are 
 seen by reflected light in a positive. This re- 
 quires a dense deposit of silver in the film, 
 which result is arrived at mainly by the quali- 
 ties of the collodion. The intense qualities of 
 the collodion depend on the pyroxyline, and on 
 the sensitizing. 
 
 We have seen already in the chapter on 
 Positive Collodion, that pyroxyline, made at, 
 a high temperature, gives a more intense col- 
 lodion than that which has been made at a 
 lower temperature. The peculiar effect of an 
 addition of bromide to intense collodion has also 
 been spoken of in the same chapter. 
 
 In preparing collodion for negatives the 
 operator should dissolve in his ether and alco- 
 hol as much cotton as is compatible with good 
 flowing qualities. The object to be attained 
 is to obtain a collodion with much body, and 
 which will at the same time give an even and 
 structureless film. As no definite proportion 
 of cotton can be prescribed, this cannot be al- 
 ways arrived at on the first trial. The best 
 way to proceed, is to mix the ether and alcohol 
 together, and to put into it the cotton, a little 
 at a time, till the liquid obtained is a little 
 thicker than positive collodion, then to let it 
 settle and to coat a plate with it, when it can 
 
105 
 
 be seen if more cotton has to be added, or if 
 the solution has to be thinned. The quantity 
 of cotton to be used being once determined, the 
 same proportions can be adhered to as long as 
 the same sample lasts. 
 
 A plain collodion being obtained having 
 body with good flowing qualities, it may be 
 sensitized according to one of the formulas 
 given in the chapter on Positive Collodion, 
 omitting altogether the bromide which may 
 be prescribed. After having allowed it to 
 settle, make a sitting. 
 
 The picture, you will obtain will generally 
 be very contrasted and very intense in the 
 high lights, while no half tints will be brought 
 out. If so add a small quantity of bromide or 
 of bromo-iodized collodion, which will reduce 
 the contrast, and bring out the middle tints. 
 If the true relation between lights and shades 
 does not exist yet, add another small quantity 
 of bromide, but be always careful not to add 
 too much of it, or the intensity will be reduced 
 to such an extent that the collodion will be 
 Vcilueless for the purpose it was required. An 
 addition of ten grains bromide of cadmium at 
 a time to one pound of cojlodion will be found 
 suitable. 
 
 It may be also that the collodion, after the 
 addition of iodide, gives the amount of intensity 
 required, and no more. In this case, of course, 
 no bromide should be added. In case the 
 iodized collodion gives images wanting in in- 
 
106 
 
 tensity, it is a proof that the cotton is not of 
 the right kind, and there is no remedy but to 
 allow it to become, old. 
 
 The alkaline iodides and bromides have, as 
 has been mentioned already, a powerful action 
 on the pyroxyline which has been dissolved 
 in the ether and alcohol. This action results 
 in the change of the film from the tough and 
 contractile to the soft and porous state. This 
 soft and porous state of the film is favorable to 
 intensity, for it allows a dense deposit of me- 
 tallic silver ; whereas, when a tough film is 
 used, the deposit is only on the parts nearer 
 the surface. It is owing to this action of the 
 alkaline iodides and bromides that a collodion, 
 which gives no intensity when fresh, acquires 
 this quality by age. 
 
 Ammonia, potash and soda affect the col- 
 lodion in the same way, but with a great deal 
 more energy. A few drops of ammonia added 
 to collodion, which gives images wanting in in- 
 tensity, will in a short time bring it to the 
 porous state. Such addition should not be 
 made to collodion sensitized with the salts of 
 cadmium, zinc, etc., as the oxides of these 
 metals would be precipitated. In all cases 
 when ammonia has been added, the collodion 
 becomes alkaline, and should be, after the 
 action is fully produced, made slightly acid 
 again by the addition of a few drops of tincture 
 of iodine or hydrobromic acid. 
 
 Negative collodion, the same as positive, 
 
107 
 
 should not be iodized beyond the white and 
 semi-opaque state, and, as it has generally 
 more body, this state is attained by the use of 
 a smaller quantity of iodide than is required 
 for positive collodion. 
 
 The intensity of collodion can be much in- 
 creased by the addition of a few drops of an 
 alcoholic solution of giycyrrhizine, or liquorice 
 sugar. It is, however, not advisable for con- 
 stant use, as it tends to bring decomposition 
 in the bath. 
 
 CHAPTER XVIII. 
 
 The Silver Solution for Negatives. 
 
 The presence of free nitric acid in the silver 
 solution counteracting the reduction of silver on 
 the film makes it necessary to have the solution 
 for negatives as little acid as possible. Great 
 care should thus be taken to procure a sample 
 of good nitrate of silver. Nitrate of silver, 
 which contains free acicl, is generally contam- 
 inated also with a substance which is the result 
 of the action of nitric acid on organic matter. 
 The presence of this substance is very unfavor- 
 able to intensity, and can only be removed by 
 fusing the nitrate of silver before dissolving it, 
 or, when it is in solution, by neutralizing and 
 
V 
 
 108 
 
 exposing to the light. The following is the 
 formula for the negative silver solution : 
 
 Dissolve the nitrate of silver in eleven 
 ounces of the water, and the iodide of potas- 
 sium in the remaining ounce, and add the two 
 solutions together, after which let settle, and 
 filter the clear part. 
 
 The solution obtained in this way is per- 
 fectly neutral, and is very likely to give misty 
 pictures. It has to be made very slightly acid, 
 just enough to produce clear shades. One drop 
 of nitric acid might be too much. Instead of ad- 
 ding nitric acid of the ordinary strength, it is 
 best to use a solution of ten drops of the 
 chemically pure to one ounce of water, and to 
 add of this solution one or two drops at a time, 
 till the pictures obtained are clear in the 
 shadows. Instead of nitric acid, acetic acid 
 can also be used. 
 
 The strength of this bath should be kept up 
 by the addition of a solution of one ounce 
 of nitrate of silver in eight ounces of water. 
 
 The use of dark colored collodion develops 
 nitric acid in the bath. When such collodion 
 has been used, and the appearance of the 
 negatives is pale, and without the required in- 
 tensity, the solution has to be tested, and if 
 found very acid, neutralized by the addition of 
 a few drops of a solution of carbonate of soda, 
 
 Neutral nitrate of silver. 
 
 Water 
 
 Iodide of potassium, . . . 
 
 1 oz. 
 12 oz. fluid. 
 
 , 2 grains. 
 
109 
 
 until the liquid becomes permanently turbid, 
 It should then be filtered and made faintly 
 acid again by adding a little of the solution of 
 nitric acid. 
 
 CHAPTER XIX. 
 
 The Developing Solution. 
 
 Two different substances are used to develop 
 collodion negatives ; the protosulphate of iron 
 and the pyrogallic acid. Each of these devel- 
 oping agents possesses advantages peculiar to 
 itself. The protosulphate of iron requires only 
 about one-half of the exposure which is 
 required when the pyrogallic acid is used, but 
 it is more difficult to produce a sufficient 
 amount of intensity with the former than with 
 the latter. The protosulphate of iron develops 
 very rapidly, the pyrogallic acid develops 
 slowly. The time of exposure to light must 
 be calculated with greater accuracy when the 
 sulphate of iron is used, because the develop- 
 ment, being very rapid, cannot be checked 
 when the sitting has been too long, nor can it 
 be pushed further when it has been too short. 
 When developing with pyrogallic acid, on the 
 contrary, the development can be checked with 
 more facility ; and when too short a sitting has 
 been given, the bringing out of the picture can 
 be " pushed." But from this the operator 
 
110 
 
 must not, however, conclude that the time of 
 sitting is not of much importance in the latter 
 case ; the advantage gained with the pyro- 
 gallic acid is, that he has more latitude in the 
 lime of exposure. 
 
 Tht- sulphate of iron developer is prepared 
 as follows : 
 
 The quantity of the iron salt can be reduced 
 in warm weather when the development pro- 
 ceeds too rapidly, or the quantity of acetic 
 acid can be increased. 
 
 Pyrogallic acid, although termed an acid, is 
 a strictly neutral substance, and would act with 
 too much violence, and produce decomposition 
 of the silver salt all over the plate, if a cer- 
 tain quantity of acetic acid was not added to it. 
 
 Prepare its solution according to the follow- 
 ing formula : 
 
 Water,. . - 1 ounce fluid. 
 
 Pyrogallic acid,. . . . , — 2 grains. 
 
 Alcohol, 1 drachm. 
 
 Acetic acid, No. 8 1 
 
 In warm weather, the quantity of acetic acid 
 may be increased, and in cold weather it may 
 be diminished, or the proportion of pyrogallic 
 acid increased. The alcohol is added to make 
 the solution flow more evenly over the plate. 
 This solution decomposes after a few days, and 
 becomes brown, so that it is advisable to make 
 
 Protosulphate of iron, 
 
 Water, 
 
 Acetic acid, No. 8. . . 
 Alcohol, 
 
 , 3 ounces. 
 .40 ounces. 
 . 4 ounces. 
 . 3 ounces. 
 
Ill 
 
 only a small quantity at a time. If, however, 
 
 it is made four or five times more concentrated 
 than is required for me, it will keep longer. 
 In such cases it can be diluted with pure water 
 as required. 
 
 The water used for the developer is required 
 to be pure soft spring, rain, or distilled water. 
 
 CHAPTER XX. 
 
 The Fixing Solution. 
 
 Any of the two fixing solutions employed 
 for positives can be used for negatives. We 
 prefer always using cyanide of potassium, it 
 being more economical and easier washed from 
 the plate than the hyposulphite of soda. In 
 its use, observe that it be diluted to such a 
 point; that it will dissolve the unreduced iodide 
 of silver, without attacking the film itself. 
 Negatives, developed with pyrogallic acid, are 
 more easily attacked by the cyanide, than 
 those developed with protosulphate of iron. 
 If, however, the cyanide takes more than half 
 a minute to fix a whole size plate, no fear need 
 be entertained in regard to its use, when the 
 pyrogallic acid is employed in developing. 
 
112 
 
 CHAPTER XXI. 
 
 Practical Details of the Negative Process. 
 
 It will not be necessary to say anything in 
 regard to the formation of the film of collodio- 
 iodide of silver in the negative process, it 
 being exactly the same as in the positive pro- 
 cess. 
 
 The exposure to light of a negative is never 
 less than twice the time required to make a posi- 
 tive. The rule is, to give such a length of time 
 that after development the feeblest radiations 
 are marked by transmitted light. With py ro- 
 gallic acid it requires about three times longer 
 exposure in the camera than with the iron salt. 
 
 As regards the development of the picture, 
 it is about the same as with positives, when 
 protosulphate of iron is used ; but somewhat 
 different with pyrogallic acid. In the produc- 
 tion of positive pictures it is necessary to stop 
 the development at a certain stage in order 
 to have good, clear shadows ; when nega- 
 tives are required, the development must be 
 carried to its utmost limits, provided the sit- 
 ting time has been given right. This is the 
 case both with protosulphate of iron and with 
 pyrogallic acid. 
 
 " The development with the protosulphate of 
 iron is easier and quicker, the image appear- 
 ing almost immediately. It is important not 
 to throw the developer off too soon, but to let 
 it remain till no further change is produced. 
 
113 
 
 If, after being developed, the image has not 
 sufficient intensity to give good prints, it must 
 be redeveloped or strengthened. The strength- 
 ening is done after the image has been washed 
 and fixed. (See Chapter 22.) The redevelop- 
 ing is done before exposing the plate to the light. 
 Several methods are in use. 
 
 1st. Redevelopment with nitrate of silver and 
 protosulphate of iron. — Your image being fully 
 developed, pour the solution off and let the 
 plate drain a moment. Then pour over it a 
 mixture of one part of your silver solution and 
 three parts of distilled water, in quantity suf- 
 ficient to cover it. Move back and forth with 
 dexterity, so as to have the action equal all 
 over the plate, pour the excess off, and spread 
 your developing solution over the plate again. 
 During each of these two operations metallic 
 silver is reduced on the parts where a deposit 
 has not already taken place, and thus makes 
 them more opaque. If sufficient intensity is 
 not obtained after a first redevelopment, repeat 
 the same operations. 
 
 2nd. Redevelopment ivith pyrogallic acid and 
 
 nitrate of silver. — Wash your plate well so 
 
 that no sulphate of iron remains in the film, 
 
 after which you pour over it enough of the 
 
 pyrogallic acid developer as is necessary to 
 
 cover the plate ; move back and forth so that 
 
 the solution unites well with the film and pour 
 
 it off into a small glass ; then add from five 
 
 to ten drops of your silver solution, pour the 
 10 
 
114 
 
 solution on again, and keep the plate moving 
 till a sufficient quantity of silver has been de- 
 posited. If more intensity is required, repeat 
 the same operations. 
 
 3rd. Redevelopment with gallic acid and ni- 
 trate of silver. — Operate entirely in the same 
 way as when pyrogallic acid is used. The so- 
 lution of gallic acid for redeveloping is as fol- 
 lows : 
 
 Saturated solution of gallic acid, 1 ot. fluid. 
 
 Acetic acid, No. 8 . 1 drachm. 
 
 Alcohol, 1 drachm. 
 
 When developing with pyrogallic acid, hold 
 the plate by one corner, and pour on the de- 
 veloping fluid in quantity sufficient to cover 
 the whole surface. After one or two minutes 
 the image will have come out in all its details; 
 If this image is not intense enough, take a 
 fresh quantity of the developing solution, add 
 to it five or ten drops of the silver solution 
 and pour over the plate again. Repeat the 
 same thing till the image has attained the re- 
 quired intensity. The glass that has contained 
 the mixture of pyrogallic acid and nitrate of 
 silver should be carefully washed out after 
 each operation, or the black deposit that forms 
 in it will cause the fresh solution to decompose. 
 
 Redevelopment with nitrate of silver, protosul- 
 phate of iron and tartaric acid. — A method of 
 redeveloping by adding a few drops of silver 
 to the ordinary developer, and flowing it again 
 over the plate, has been and is yet in use to 
 
115 
 
 some extent. The objection to it is, that the 
 solution gets muddy in a very short space of 
 time, hj the silver being precipitated. By 
 adding to the mixture of sulphate of iron and 
 nitrate of silver a few drops of saturated so- 
 lution of tartaric acid, the liquid will remain 
 clear, and all the silver it contains will be 
 deposited on the developed image. 
 
 The redeveloping solution can be prepared 
 according to the following formula : 
 
 Water, 1 ounce. 
 
 Sulphate of iron, 20 grains. 
 
 Tartaric acid, 6 grains. 
 
 Add a few drops of silver solution when 
 leady to use it. This method of intensifying 
 requires no previous washing. 
 
 The redeveloping of the negative can be 
 done also after the fixing. In the following 
 chapter we describe some methods of intensi- 
 fying, which can only be applied after fixing. 
 
 A plate which has not been exposed long 
 enough to the light develops slowly. If de- 
 veloped with pyrogallic acid, and much silver 
 solution, the high lights are found to be very 
 opaque, and the shadows transparent ; but the 
 half tones are not well marked. When pro- 
 tosulphate of iron has been used, the image 
 will have the same appearance, except that 
 the silver will not be reduced as much on the 
 high lights. 
 
 When a negative has been over-exposed, 
 the development proceeds rapidly, and no dis- 
 
116 
 
 tinct image can be seen by reflected light; 
 viewed by transmitted light there is a want of 
 proper contrast between the high lights and 
 the shadows, so that the picture appears flat. 
 
 After the image has been developed, the 
 plate must be washed, and the fixing done in 
 the same way as for positives. 
 
 The negative requires to be preserved by a 
 coating of gum arabic or varnish, to prevent 
 it from being scratched during the printing. 
 When but few prints are to be made from it, 
 and it is to be handled by a careful printer, 
 the gum arabic solution will answer all pur- 
 poses. This is made by dissolving by heat one 
 ounce of gum arabic in ten ounces of w r ater, 
 and filtering. It is applied on the negative 
 before it is dry, after it is well drained of the 
 excess of water. 
 
 Varnishing the negative reduces its inten- 
 sity. Thin varnish has this effect less than 
 the thick. It is advisable in all cases to use 
 the gum arabic solution first, as the negative 
 is then made less transparent by the varnish. 
 
 The varnishes in the market are made 
 either with alcohol or benzine. Alcohol var- 
 nishes require heat in drying, with the excep- 
 tion of Anthony's flint varnish, which is 
 made w r ith ammoniated alcohol ; benzine var- 
 nishes, on the contrary, dry without heat. 
 
 The gums used in the preparation of alco- 
 hol varnishes are the white or the shellac, 9 
 mixed with a small quantity of sandarac or 
 
117 
 
 mastic. Those used in the preparation of 
 benzine varnishes are the gum dammar, copal 
 or amber. The two first will not answer, as 
 they give a film which is sticky. Amber 
 alone furnishes a varnish which answers the 
 purpose. It gives a film almost as hard as the 
 glass itself, and which is not liable to crack. 
 Negatives varnished with it, will stand a 
 greater amount of rough use than those pre- 
 served by any other preparation. The amber 
 and benzine varnish is known in the trade as 
 the Adamantine Varnish. 
 
 CHAPTER XXII. 
 
 Strengthening of the Negative. 
 
 It is often the case, more especially when 
 the protosulphate of iron has been used as a 
 developing agent, that the negative obtained, 
 although all the feeblest radiations are im- 
 pressed, has not intensity enough to yield 
 good positives, in which case it must be sub- 
 mitted to a process by which the intensity is 
 increased. This object is attained by rede- 
 veloping or by strengthening. 
 
 Before proceeding it may be well to under- 
 stand the difference between the terms rede- 
 veloping and strengthening. Redeveloping, 
 as is indicated by the name, means to increase 
 the intensity of the negative by repeating the 
 operations of the development. Strengthening 
 
118 
 
 means, to increase the intensity, by other 
 processes. We have already described in the 
 previous chapter the processes of redeveloping. 
 This chapter will treat specially of the processes 
 of strengthening. Several methods are in use. 
 
 1st. Treatment of the image by sulphuret of 
 potassium, or any other alkaline sulphuret. — This 
 is the most convenient mode of strengthening, 
 when but little has to be added to the inten- 
 sity. Dissolve one ounce of sulphuret of potas- 
 sium in half a pint of water, filter it and keep 
 it in a corked bottle. Fix the negative, wash 
 it carefully, and pour this solution over it. 
 The color will change to a bluish black by trans- 
 mitted light. When the action has gone 
 through the film, wash carefully, gum, and let 
 dry. By this process the metallic silver is 
 changed into sulphuret of silver. The film is 
 not made much denser, but more impermeable 
 to the chemical rays. 
 
 2nd. Treatment of the negative with tincture of 
 iodine. — The object of this operation is to con- 
 vert the metallic silver into iodide of silver, 
 which, by reason of its greater mass and its 
 color, is less permeable to the light. 
 
 The plate should be dried and washed with 
 alcohol, before pouring the tincture of iodine 
 over it. When the desired effect has been 
 produced, wash well, first with water, then 
 with alcohol, in order to remove the excess of 
 iodine, which would otherwise act on the sil- 
 vered paper during the printing. 
 
119 
 
 3rd. Strengthening with bichloride of mercury 
 and sulphur et of ammonium. — The film, before it 
 is dry, must be converted, partially or entirely, 
 into the double chloride of mercury and silver 
 by the application of a solution of bichloride of 
 mercury, then washed thoroughly, and treated 
 with a solution of hydrosulphate of ammonia. 
 The effect of the bichloride of mercury is, 
 firstly to blacken the image, after which it 
 commences whitening till it has reached a 
 bluish white color. During its action, the 
 operator should inspect the picture from time 
 to time, by holding it up to the light. When 
 the required thickness of the deposit is at- 
 tained, the action of the mercury salt should 
 be stopped by washing. Care should be taken 
 not to push the action of the bichloride too far, 
 as, after the application of the sulphuret of 
 ammonium, the opacity would be such that it 
 would be impossible to print from the nega- 
 tive. 
 
 On pouring the hydrosulphate of ammonia 
 on the negative, it blackens immediately, the 
 double chloride of silver and mercury being 
 transformed into sulphuret of silver and sul- 
 phuret of mercury. When it has blackened 
 all through, so that no trace of the former 
 white image can be seen on the side of the 
 glass, the picture should be washed; "it has 
 then to be dried and varnished in the ordinary 
 way. 
 
 The solution of bichloride of mercury should 
 
120 
 
 not be too strong, in order to prevent the 
 action from being too rapid. One part of the 
 saturated solution with two parts water is suf- 
 ficient. The saturated solution is made by di- 
 gesting an excess of bichloride of mercury with 
 water. 
 
 The sulphuret of ammonium, or hydrosul- 
 phate of ammonia, is sold in solution by drug- 
 gists. It should be diluted with ten parts of 
 water. As it has a strong and disagreeable 
 smell it should be used out of doors, or near a 
 window where there is a powerful draught. The 
 presence of this gas in the operating rooms is 
 sufficient to cause fogginess of the pictures. 
 
 The double chloride of silver and mercury, 
 although in greater mass than the metallic 
 silver which was originally on the plate, 
 transmits the light, so that the blackening or 
 transformation into sulphuret can not be dis- 
 pensed with. 
 
 4th. Strengthening with iodine, pyrogallic 
 acid and nitrate of silver. — The image is con- 
 verted into iodide of silver by leaving it for 
 five or ten minutes in the following solution : 
 
 Iodine, 1 grain. 
 
 Iodide of potassium, 2 grains. 
 
 Water, ; 1 ounce. 
 
 This is done by daylight. The plate is 
 then well washed, taken into the dark room, 
 and redeveloped with pyrogallic acid and sil- 
 ver in the ordinary way. If not intense 
 enough, repeat the operation. By this pro- 
 
121 
 
 cess any amount of intensity can be ob- 
 tained from weak negatives. It is thus very 
 valuable in making copies of engraviiigs, 
 pencil sketches, etc. 
 
 5th. Strengthening with bichloride of mercury 
 and bromide of potassium. — The modus operandi 
 is the same as in No. 3. Instead of hydro- 
 sulphate of ammonia, a two-grain solution of 
 bromide of potassium is used. The color of 
 the image changes to a slate color by reflected, 
 and to orange brown by transmitted light. 
 
 Oth. Strengthening with bichloride of mercury 
 and chloride of gold. — The application of the bi- 
 chloride of mercury is done in the same way 
 as described in 'No. 3, and the film is then 
 covered with a one-grain solution of chloride 
 of gold, which changes the color to a bluish 
 black. 
 
 7th, Strengthening with bichloride of mercury 
 or chloride of gold. — The application of either of 
 these agents darkens the color of the film and 
 makes it more impenetrable to the chemical 
 rays. The bichloride should not be left on 
 longer than is necessary to blacken the film. 
 Both these methods are very useful when the 
 negative has to be strengthened but little to 
 be sufficiently intense, 
 n 
 
122 
 
 CHAPTER XXIII. 
 
 Alcoholic Collodion. 
 
 The proportions of ether and alcohol, which 
 will dissolve pyroxyline, are very variable. , 
 Almost any mixture of the two, when they are 
 in the most concentrated state, will do it ; but 
 all cannot be used for photographic collodion. 
 The quantity of alcohol which can be used for 
 this purpose is, however, very variable, It is 
 much larger than the ordinary proportion re- 
 commended when the cotton is of the variety > 
 which gives a tough and contractile film. The 
 advantages claimed for collodion containing 
 an excess of alcohol, are the following : 
 
 The film is smooth, structureless and very 
 adherent. 
 
 In consequence of its softness and porosity, 
 the film is in a favorable condition for inten- 
 sity and sensitiveness. 
 
 The film sets slowly, allowing plenty of time 
 in the hottest weather before silvering. 
 
 The formation of the collodio-iodide of sil- 
 ver in the bath proceeds rapidly. 
 
 The collodion keeps longer from the low 
 temperature at which the pyroxyline is made, 
 and the small quantity of ether which enters 
 into its composition. 
 
 Ether, 7§0 S. G 
 
 60 grains or more 
 1 2 ounces. 
 , 4 ounces. 
 
 Put the pyroxyline in four ounces of the al- 
 
123 
 
 eohol, shake well, add the ether, and when all 
 is dissolved, add the balance of the alcohol. 
 Iodize according to the directions given in the 
 chapter on Positive Collodion. 
 
 The ether and alcohol used should be of the 
 greatest strength. If none sufficiently strong 
 can be procured, the best that can be found 
 should be concentrated by means of quicklime, 
 as described in the chapter on Collodion. 
 
 CHAPE R XXIV. 
 
 Imperfections in Collodion Photographs.* 
 
 We may divide the imperfections in collo- 
 dion photographs into three sections : 
 
 1st. Imperfections common to positives and 
 to negatives. 
 
 2d. Imperfections peculiar to positives. 
 
 3d. Imperfections peculiar to negatives. 
 SECTION I. 
 Imperfections common to Positives and to Negatives. 
 
 These are fogging, spots, markings of all 
 kinds, etc. 
 
 FOGGING. 
 
 The causes which produce fogging are of 
 two kinds : 
 
 1st. Irregular action of the light. 
 2d. Impurity of the chemicals. 
 
 * The method of classification of this chapter has been 
 adopted from T. Hardwich's Photographic Chemistry, a 
 work which we consider of the greatest value, and the study 
 of which we recommend to every photographer 
 
124 
 
 First — Irregular Action of the Light. 
 
 A. Over-exposure of the plate. — This is often 
 the case with beginners, who do not know the 
 sensitiveness of the collodion process. Over- 
 exposure gives only the appearance of foggi- 
 ness, when three or four times longer sitting 
 is given than what is required. If the plate 
 is not so much over exposed, the image is 
 pale and flat in the lights, and misty in the 
 shadows. 
 
 B. Too much light in the dark room. — 1st, 
 Owing to the orange pane of glass through 
 which the light is admitted into the dark room 
 being too pale. It is best to work by trans- 
 mitted light, through either two thicknesses 
 of orange, or one of orange and one of red 
 glass combined. 2d, By the light of the can- 
 dle or lamp being too strong. When the film 
 is very sensitive, it is prudent to keep the 
 lamp screened by an orange glass. The fog- 
 giness resulting from the action of the light 
 may sometimes only be on a part of the plate, 
 as is the case when the light acts on it while 
 it is in the silver bath. 
 
 C. Light entering in the camera, or in the 
 tablet. 
 
 D. Direct light of the sun falling upon the lens. 
 — This produces a reflection in the camera 
 and diminishes the vigor of the image. 
 
 E. Diffused light of the sky falling upon the 
 lens.. — This is often the case when taking 
 views. Put on the mouth of the object 
 
125 
 
 glass a tube seven or eight inches long, and 
 blackened inside. In this way there will be 
 admitted only the rays proceeding directly 
 from the object exposed, and the diffusion pro- 
 duced by the lateral rays will be avoided. 
 The same result may be obtained by using a 
 diaphragm with a small aperture, placed two 
 or three inches distant from the lens. 
 
 Second — Impurity of the Chemicals. 
 
 A. Use of fused nitrate of silver in prepar- 
 ing the bath. — The fogging is caused by an ex- 
 cess of nitrate of silver. The remedy is the 
 addition of a few drops of the diluted nitric 
 acid. Baths prepared according to the form- 
 ulas given in this work will not present this 
 inconvenience. 
 
 B. Use of Alkaline Collodion. — Collodion can 
 be made alkaline by the use of iodide of potas- 
 sium which contains carbonate of potash, as is 
 sometimes the case. Alkaline collodion is al- 
 ways colorless ; it restores the blue color to 
 reddened litmus paper. The remedy is to put 
 in a few drops of hydrobromic acid, so as to 
 give it a pale yellow color. 
 
 Collodion prepared with iodide or bromide 
 of cadmium remains colorless too when the 
 ether, alcohol, and gun cotton are free from 
 acid. This is not, however, a mark of alka- 
 linity, but of neutrality. A few drops of hydro- 
 bromic acid can only improve such collodion 
 
126 
 
 when it is used with a neutral bath, or very 
 slightly acid developing solution. 
 
 C. Alkalinity of the bath. — The bath becomes 
 alkaline when an excess of carbonate of soda, 
 or of any other alkali, is added to it for the 
 purpose of neutralizing the acid. In this 
 case, filter and add nitric acid until it does 
 not, by a long immersion, restore the blue 
 color to reddened litmus paper, and the images 
 obtained are clear. 
 
 Rain water sometimes contains traces of 
 ammonia, which may make the bath alkaline. 
 Hard water, containing carbonate of lime h will 
 produce the same effect. 
 
 D. Decomposition of the bath by organic mat- 
 ter. — This decomposition is accelerated by ex- 
 posure to light. If exposed to sunlight, the 
 solution will discolor, and, after a short time, 
 deposit a black * powder, which is nothing but 
 reduced silver. It is then again ready for 
 use. Before being exposed to the light, it is 
 best to neutralize the solution by the addi- 
 tion of carbonate of soda. (See pp. 14 and 64.) 
 
 E. Introduction of developing or fixing fluids 
 into the solution, —prolonged contact with rusty 
 iron, etc.— -If the neutralization and exposure to 
 sunlight have no effect, precipitate the silver 
 with carbonate of soda, and re-dissolve in nitric 
 acid, as prescribed on page 85. 
 
 F. Vapors of ammonia, hydrosidphate of am- 
 monia, cyanide of potassium, etc. in the darkroom. 
 
 G. Re-dipping the plate into the silver solution 
 
127 
 
 before developing it, without allowing it to drain 
 well 
 
 H. Imperfect cleaning of the glass. — In this 
 case the reduction is observed between the 
 collodion film and the glass. It results often 
 from the cleaning rags not being dry, or soiled 
 with the developing or fixing solution. 
 
 SPOTS. 
 
 Spots are opaque or transparent by trans- 
 mitted light, white or black by reflected light. 
 
 Opaque Spots are Produced : 
 
 A. By collodion having small particles in sus- 
 pension. — Comet-shaped specks are produced 
 by this cause. Also little circular specks, 
 which, after washing, leave holes. 
 
 B. By not cleaning the month of the bottle, so 
 that fragments of dried collodion are floated on 
 to the plate. 
 
 C. By dust in the tablet or in the camera, or 
 by moving the slide in and out of the tablet with 
 violence, so that small particles of organic matter 
 or drippings of the plate are spattered on the film. 
 
 D. By the drippings of the plate not coming in 
 contact with the wood frf the tablet or with the 
 glue with which the glass corners are sealed 
 in. — The plate should be well drained, and 
 a piece of blotting paper put on the back, so 
 that all the drippings be absorbed by it. The 
 corners should also be dried after each oper- 
 ation, Tablets with solid glass corners are 
 
128 
 
 preferable to any other kind. Those with 
 pieces of glass glued in the corners give great 
 trouble when they are new. The best course 
 in this case is to take the pieces of glass out 
 and seal them in again with beeswax. This 
 is easily done by putting a small piece of wax 
 in the corner, warming the piece of glass on 
 the point of a knife, and pressing it down on 
 the wax. The spots produced by the tab- 
 let are mostly on the lower corners, above the 
 head, in a portrait. 
 
 Transparent Spots are Produced, 
 
 A. By the silver solution being over-saturated 
 tvith iodo-nitrate of silver. — The solution be- 
 coming weakened by use, the iodo-nitrate will 
 take a crystalline form and deposit on the 
 film, and will afterwards be washed off, or 
 dissolved by the fixing solution, leaving little 
 transparent spots like pin-holes. The remedy 
 has been given on page 83. 
 
 B. By small particles of iodide of potassium, 
 or of bromide of potassium, or ammonium in the 
 collodion. — Allow the collodion to settle, and 
 add some collodion iodized with the cadmium 
 salts. 
 
 C. Small particles in suspension in the develop- 
 ing solution. — The developing solutions should 
 always be carefully filtered before being used. 
 
 D. By a deposit formed on the side of the bath, 
 a deposit which is the result of the decomposi- 
 tion of the silver solution by organic matter. 
 
129 
 
 The remedy is to clean the bath well out and 
 filter the solution. 
 
 E. By irregular action of the developing fluid. 
 — The silver solution which is on the plate 
 may be washed off in some places by the devel- 
 oper not being properly poured on. In this 
 case the reduction of silver will not take place 
 on that part of the plate, and a greenish trans- 
 parent spot will be produced. 
 
 Markings of Various Kinds. 
 
 A. A reticulated appearance of the film, affect- 
 ing the form of a net-work or honey-comb. — 
 The collodion is glutinous, or contains too 
 much water. In the first case ammonia will 
 improve it, as will also the action of alkaline 
 iodides. In the second case it is worthless, or 
 can only be used to mix with collodion made 
 with very concentrated ether and alcohol. 
 
 B. The film is cracked all over when dry. — 
 The collodion is rotten from the cotton having 
 been decomposed in the nitro-sulphuric acid, 
 or from the action of alkalies or alkaline 
 iodides or bromides. Such collodion can be 
 mixed with advantage with a sample which is 
 glutinous, their respective peculiarities des- 
 troying each other. Mixed with a variable 
 quantity of good negative collodion, it is just 
 the thing for the dry collodion processes. 
 Such collodion may be improved by an addi- 
 tion of good cotton. 
 
 C. Straight lines traversing the film horizon- 
 
130 
 
 tally. — These are caused by checks having 
 been made during the immersion of the plate 
 into the bath. 
 
 D. Streaks or lines in the direction the "plate 
 has been dipped. — These streaks or lines are 
 in the film or on the surface. In the first 
 case, they are the result of the action of 
 water on the pyroxyline, and denote one of the 
 following states ; The silver solution is too 
 weak ; the silver solution is at too low a tem- 
 perature ; the collodion is not well set, or 
 it contains too much alcohol. If the lines or 
 streaks are on the surface so that after the 
 plate is dry they can be dusted off with a 
 camel-hair brush, they are the result of the use 
 of a silver solution which has a tendency to 
 fogging. 
 
 E. Oily spots of 9 lines.- — These occur when 
 the plate is taken out of the silver solution 
 before the alcohol has been dissolved into the 
 bath. They are also caused in the develop- 
 ment, when the developing solution does not 
 unite readily with the film. The remedy in 
 the last case is an addition of alcohol to the 
 developing solution. When the solution is 
 poured off before the action ceases, oily lines 
 are formed on the end of the plate which is held 
 uppermost. 
 
 F. Curved lines of irregidar development. — 
 These result, 1st, from over exposure of the 
 plate. 2d, From excess of protosulphate of 
 iron or pyrogallic acid. 3d, From unskillfully 
 
* 131 
 
 covering the plate with the developing fluid. 
 4th, From using too small a quantity of devel- 
 oping fluid. 
 
 G. Uneven film of collodio-iodide of silver. — 
 This is produced, 1st, When the collodion 
 contains too much ether, so that it dries too 
 soon. 2d, When the collodion is made with 
 a bad sample of cotton. 3d, When it is too 
 thick. 
 
 In the first case, add strong alcohol, until 
 the collodion contains equal parts of alcohol 
 and ether, and dissolve into it more cotton. 
 In the second, add a large quantity of alco- 
 hol, so as to have it in excess. In the third 
 case, dilute with equal parts of ether and alco- 
 hol, previously mixed together, and iodized 
 if necessary. 
 
 H. Irregular stains of metallic silver on the 
 surface of the film, which can be dusted off and 
 leave a transparent mark. — These marks are 
 produced by a scum floating on the surface of 
 th,e solution, and sticking on the plate when 
 it is dipped. Add new solution so as to cause 
 this scum to flow over in the small part of the 
 overflowing bath, or remove it with a piece 
 of blotting paper. 
 
 I. Marks like fern leaves in the film. — . 
 Are caused by an inferior sample of cotton 
 being used, made with weak afcids and at a 
 high temperature. 
 
 J. Peeling up of the collodion film after drying. 
 — This results from a peculiarity of the pyrox- 
 
132 
 
 yline. It happens most frequently on glasses 
 which have not been well cleaned. To pre- 
 vent it, coat the plate with gum arabic before 
 drying, and if the film commences peeling, 
 varnish the edges with benzine varnish by 
 means of a small soft brush. The remedy is 
 to increase the quantity of alcohol in the collo- 
 dion, so as to make it softer and less contractile. 
 
 SECTION II. 
 Imperfections Peculiar to Positives. 
 
 A. The image shoivs well in the high lights, 
 but the shadows are dark and heavy. — This 
 results mainly !Tfrom excess of intensity, in 
 which case add bromide to the collodion 
 till the contrast is sufficiently reduced. If 
 such an appearance exists without the high 
 lights being intense by transmitted light, it is 
 the result either of under exposure, or excess 
 of nitric acid in the bath or in the developer. 
 
 B. The shadows are good, but the lights are 
 over done. — The collodion gives too intense 
 images. Thin with ether and alcohol, or add 
 more bromide. 
 
 C. The image is flat, without sufficient contrast 
 between the lights and shadows. — This results, 1st, 
 From over exposure. 2d, From the use of col- 
 lodion which is either too thin or contains too 
 much bromide. 
 
 D. The shadows are grey and misty. — The 
 bath has a tendency to fogginess, or the image 
 has been over developed. 
 
133 
 
 E. The whites are grey and metallic, or yellow 
 and dead. — Good whites are very much the 
 result of a favorable molecular condition of 
 the film. A rather short and porous film 
 gives the best whites. Tough and hard films 
 give generally grey and metallic whites in 
 connection with much acid in the bath or in 
 the developer, and yellow and dead whites 
 when acid has been sparingly used. 
 
 F. The shadows are covered with little specks, 
 similar to those produced on daguerreotypes, by 
 leaving them too long on the mercury. — The bath 
 contains organic matter. It should thus be 
 exposed to sunlight and filtered. When there 
 is no time for doing this, give an exposure a 
 little longer and develop a little less. This 
 effect is also often produced in re-developing. 
 
 SECTION III. 
 Imperfections Peculiar to Negatives. 
 
 A. Want of intensity. — 1st, From the collo- 
 dion being made with unsuitable cotton. 2d, 
 From the collodion being too thin. 3d, From 
 excess of bromide in the collodion. As a 
 remedy, add to it as much good cotton as it 
 will bear. If this is not followed by a good 
 result, let it become old. The action of the 
 alkaline iodides or bromides it contains will 
 soon change the condition of the film and 
 cause it to produce intense images. The addi- 
 tion of a quantity of old and red collodion 
 may be 4 resorted to. 4th, Want of intensity 
 
134 
 
 from acidity or impurity of the silver solution. 
 Remedy : Neutralize and expose to the light. 
 5th, From the plate being kept too long be- 
 tween silvering and developing. 6th, From 
 want of intensity in the light. 
 
 B. Excess of intensity in the high lights and 
 want of definition in the shadows. — 1st, The 
 collodion possesses the intense qualities to 
 a too great extent. Remedy: Addition of 
 bromide or of positive collodion. 2d, The 
 light is too contrasted. 
 
 C. Intensity all over and absence of contrast 
 between lights and shades. — The plate has been 
 over-exposed. 
 
 D. The high lights are well marked without 
 being very intense, the shadows are deficient in de- 
 tails, and the image looks quite well by reflected 
 light. — The plate has been under-exposed. 
 
 The imperfections mentioned above are 
 common to negatives developed either by 
 pyrogallic acid or by the iron salt, without 
 being pushed or re-developed. 
 
 CHAPTER XXV. 
 
 Positives on Paper. 
 
 Two methods are adopted to produce posi- 
 tives on paper. 1st, the ordinary positive 
 process, in which the silver is reduced directly 
 by the light ; and 2d, the process called nega- 
 
135 
 
 tive, because it is used also to produce nega- 
 tives on paper, in which the silver is reduced 
 by the subsequent action of light and of a de- 
 veloper. 
 
 In the ordinary positive process, the paper 
 is immersed into a solution of some chloride, 
 then treated with a solution of nitrate of silver, 
 so that by double decomposition chloride of 
 silver is produced. It is now dried and ex- 
 posed under the negative to the light, until a 
 sufficient reduction has taken place, after which 
 the unreduced chloride of silver is dissolved 
 by a solution of hyposulphite of soda. 
 
 In the process called negative, the paper is 
 floated on a solution of iodide, or bromide, or 
 chloride, and then on a solution of nitrate of 
 silver. Having dried it and placed it under 
 the negative, expose it to the light, and develop 
 the image by means of gallic acid. The un- 
 reduced iodide of silver is finally dissolved by 
 hyposulphite of soda. 
 
 Selection of the Paper. — The ordinary paper, 
 containing substances which are injurious -in 
 the photographic operation, and being of an 
 unequal texture, is unfit for use. Several 
 papers are manufactured purposely. The 
 Saxe of German and the Rive of French 
 manufacture, are best known. The former 
 is much the best as to texture, and printing 
 and strength, but the Rive is preferred by 
 many, principally when albumenized, on ac- 
 count of the rich tone of the prints. 
 
136 
 
 A good photographic paper is smooth, uni- 
 form in texture, of an equal thickness in every 
 part, and free from spots. The smoothest side 
 should be used to receive the impression, and 
 the opposite side marked with a pencil. The 
 wrong side of the paper can be easily detected 
 by the wire markings, mainly after it has been 
 salted. These can best be seen by holding 
 the sheet in such a way that the lig : ht strikes 
 it at an angle. 
 
 CHAPTER XXYI. 
 
 Direct Positive Process. 
 
 The points to be considered in the prepara- 
 tion of the sensitive paper are : Sensitiveness, 
 intensity, contrast or vigor, delineation, and 
 +one or color. 
 
 Sensitiveness. — The sensitiveness of the pa- 
 per depends : 
 
 1st, On the quantity of chloride of silver 
 on the paper. The quantity of chloride of 
 silver is determined by the quantity and species 
 of alkaline chloride used in the salting, and by 
 the process of salting. The sensitiveness of 
 highly salted paper is greater than of one in 
 which but a small quantity of salt has been 
 used, provided, however, the quantity of nitrate 
 of silver be in proportion. The sensitiveness 
 however does not increase after a certain point 
 
137 
 
 is reached, and this point depends on the 
 thickness and sizing of the paper, or on the 
 process used in salting. Thick paper and 
 paper sized with gelatine will retain a larger 
 proportion of salt than that which is thin or 
 sized w T ith starch. Immersing salts more 
 than floating, and floating more than brushing. 
 The alkaline chloride used is also a point of 
 great importance, the chloride of ammonium 
 containing more chlorine than the chloride 
 of sodium (common salt), and this more than 
 the chloride of barium. 
 
 5 grains chloride of ammonium yield the same quantity 
 
 of chloride of silver as.. 5^ grains chloride of sodium. 
 
 ** H 11 grains chloride of barium. 
 
 2d, On the quantity of nitrate of silver on 
 the surface, and on the greater or less facility 
 with which this nitrate of silver is reduced. 
 — When a salted paper is floated on a solu- 
 tion of nitrate of silver, the chloride which is 
 in the paper and the nitrate of silver will de- 
 compose each other, forming chloride of silver, 
 which, with the nitrate of silver retained by 
 the paper, forms the sensitive compound on 
 which the image is produced. ». If the bath is 
 strong, the quantity of free nitrate of silver 
 will also be larger, 'and the paper will be sen- 
 sitive in proportion. In case it is brushed on, 
 the quantity of solution which is used will be 
 much reduced in strength, and the paper wil$ 
 be less sensitive than if it is floated. It wilj 
 thus be necessary in the latter case to ' use % 
 
138 
 
 stronger solution, if the same result is to be 
 attained. Paper sensitized with an acid silver 
 solution is less sensitive than the one sensi- 
 tized with a neutral one. The one prepared 
 with the solution of oxide of silver in ammo- 
 nia (ammonia nitrate of silver) is the most 
 sensitive of all, from the greater facility with 
 which this compound is reduced. 
 
 3d, On the use of organic matters. Those 
 generally used are the albumen, gelatine, and 
 iceland moss. All increase the sensitiveness 
 of the paper, but the albumen a great deal 
 more than the others. 
 
 Intensity, Contrast, Yigor. 
 
 The intensity of the print depends in 
 some measure on the disproportion between 
 the amount of salt and the amount of silver. 
 Salt determines sensitiveness, and silver in- 
 tensity. Nothing is gained in intensity, how- 
 ever, in using an amount of silver unusually 
 large, and an amount of salt unusually small. 
 The ammonia nitrate gives, in proportion, 
 much more intensity than the plain nitrate 
 of silver. With a weak negative, it should 
 thus be used in preference. Albumen paper 
 gives more intensity than gelatine paper, and 
 this one more than the plain. The presence 
 on the paper of easily reduced salts of silver, 
 such as the acetate, the citrate, etc., also in- 
 crease the intensity. 
 
339 
 
 Delineation or Shakpness. 
 
 Independently of the texture of the paper, 
 the sharpness of the print depends on the use 
 of albumen, gelatine, gum arabie, iceland 
 moss, etc. These substances act in keeping 
 the image on the surface of the paper, and in 
 filling up its pores. Albumen paper gives 
 the sharpest prints of all. Papers prepared 
 with the other substances mentioned, although 
 giving less definition than the albumen, are a 
 great improvement on the plain. 
 
 Tone or Color. 
 
 The color of a print, both before and after 
 toning, depends in a great measure on the 
 sizing of the paper. The German or Saxe 
 papers print black or bluish black ; the Rive 
 or French papers print reddish. The charac- 
 ter of these papers remains after they are 
 albumenizecl. 
 
 Weak silver solutions give red tones also, 
 more especially so when used in connection 
 with weak salting. Paper prepared with am- 
 monia-nitrate of silver, or prepared with plain 
 silver, and fumed with ammonia, prints 
 blacker than plain silvered paper. 
 
 Whatever be the color of the print on 
 being removed from the printing frame, it 
 can be brought to a more or less pure black 
 in the toning bath. Saxe paper as a general 
 thing, gives a purer black than the Rive paper, 
 
140 
 
 which gives prints of a warmer tone. These 
 remarks hold good whether the paper be 
 albumenized or not ; but in the former case, 
 the toning is more difficult and takes longer. 
 
 CHAPTER XXVII. 
 
 Preparation of the Sensitive Paper. 
 
 In the former editions of this work we gave 
 three different direct printing processes : 1st, 
 The process on plain salted paper, floated on 
 a plain solution of nitrate of silver. 2d, The 
 ammonia-nitrate process, or process on plain 
 paper, brushed over with ammonia-nitrate of 
 silver. 3d, The process on albumenized 
 paper. Since then certain modifications have 
 been introduced into the printing processes, 
 which render obsolete a good deal of what we 
 said. We have thus entirely re-written all 
 that appertains to the printing processes, and 
 noticed or mentioned every improvement 
 Avhich has been made in this important branch 
 of photography. 
 
 Printing being done generally either on 
 plain or gelatinized paper, or on albumenized 
 paper, we will divide our description of the 
 sensitizing into two parts : 1st, Preparation 
 of the sensitive plain paper ; 2d, Preparation 
 of the sensitive albumen paper. 
 
 Preparation of the sensitive plain paper. — 
 
141 
 
 Either the Saxe or the Rive paper, can be 
 used in this process ; the latter giving, under 
 the same conditions, a warmer tint than the 
 former. 
 
 The first preparation is the salting, which 
 can be done either with chloride of sodium, 
 of ammonium, or of barium ; but the chloride 
 of ammonium, being easier obtained in a pure 
 state, is generally preferred. As regards sen- 
 sitiveness, color and intensity, these three 
 salts give the same results, when used in 
 equivalent proportions.* The salting solution 
 is made according to the following formula : 
 
 Water, 
 
 Chloride of ammonium, 
 White gelatine, 
 
 32 ounces. 
 .80ft grains. 
 .40 grains. 
 
 The gelatine is used in order to introduce 
 into the paper a larger quantity of the kind 
 of organic matter, which easily reduces the 
 silver salts. The effect of its introduction 
 is more boldness and vigor in the print. 
 
 The gelatine is put into a part of the water 
 for about an hour, when it will have become 
 soft and swollen. A slight application of 
 heat will then suffice to dissolve it, after which 
 the chloride of ammonium and the rest of the 
 water are added, and the solution is filtered. 
 
 A larger quantity of chloride of ammonium 
 may be used, and will increase the sensitive- 
 
 * We are aware that a contrary view is entertained by- 
 high authority, but we came to this conclusion after some 
 careful experiments undertaken to test this matter. 
 
142 
 
 ness of the silvered paper; but unless the in- 
 tensity of the negative be increased in pro- 
 portion to the amount of chloride, the print 
 produced will be grey and cold. 
 
 For solar camera dry printing, where a 
 greater sensitiveness is required than for con- 
 tact printing, as much as ten grains to the 
 ounce may be used with advantage ; but no 
 good effect can be expected by the use of fif- 
 teen and twenty per cent salt solutions, (cor- 
 responding to seventy and ninety grains to 
 the ounce,) such as were used a few. years 
 back, principally in Continental Europe. 
 
 Some printers add to this salting solution 
 168 grains of citric acid, and 200 grains bicar- 
 bonate of soda. These two substances, acting 
 on each other, form citrate of soda, which, on 
 floating the paper on the silver solution, is 
 transformed into citrate of silver. The effect 
 of this citrate of silver is to give a warmer 
 tone to the print. This addition is not to be 
 recommended when the Rive paper is used. 
 
 The paper is immersed in this salting solu- 
 tion, and the air-bubbles removed with a soft 
 brush, after which it is hung up to dry. It 
 is advisable not to leave it in 'longer than is 
 necessary, in order to avoid the picture sink- 
 ing into the texture of the paper. 
 
 The plain paper can be sensitized in two 
 different ways : 1st, By brushing over it a 
 solution of ammonia-nitrate of silver ; 2d, by 
 floating the paper on, or brushing over it, a 
 
143 
 
 solution of plain nitrate of silver, and when 
 dry, exposing it to the fumes of ammonia. 
 Both processes give about the same result. 
 
 We will here describe the first process of 
 silvering, and refer the reader for the second 
 process to the heading, Preparation of the 
 sensitive albumen paper. 
 
 The ammonia-nitrate of silver solution is 
 made in the following way : Dissolve one 
 ounce of nitrate of silver in four ounces of 
 water ; of this, reserve for future use about h 
 ounce fluid, and to the other 3^ ounces add 
 ammonia, a small quantity at a time, stirring 
 with a glass rod after each addition. A brown 
 precipitate of oxide of silver will form, which, 
 on the addition of a sufficient quantity of am- 
 monia, will be re-dissolved. When this point 
 is attained, the liquid becomes clear again, 
 (unless the nitrate of silver contained certain 
 impurities,) but it will contain an excess of 
 ammonia, which would cause the prepared 
 paper to become brown very quick. To avoid 
 this, add the half ounce nitrate of silver solu- 
 tion which had been set apart, and filter the 
 liquid to separate the precipitate which is 
 thrown down ; finally add water until you have 
 a bulk of eight ounces, and put in three or four 
 drops of nitric acid. In this way a solution 
 of nitrate of silver, of the strength of sixty 
 grains to the ounce, is obtained. 
 
 The ammonia-nitrate of silver solution 
 should be applied on the paper by means of 
 
144 
 
 a brush or a tuft of cotton, and not by floating 
 it on the solution. The reason for this is, 
 that by the reaction of the chloride of sodium 
 on the ammonia nitrate of silver, ammonia is 
 set free and dissolves in the solution, which 
 in this way takes an excess from the first 
 paper which is floated. This excess of am- 
 monia dissolves the chloride of silver which 
 is formed, and also causes the paper to become 
 brown very shortly after it is sensitized, and 
 sometimes evefti while it is on the solution. 
 
 The most convenient way to apply the am- 
 monia-nitrate of silver solution is by the use 
 of a cotton brush. To make a cotton brush, 
 take a tuft of cotton wool, about four inches 
 long and half as wide, tie a piece of twine in 
 the middle, and by means of this draw the 
 cotton into a glass tube, then cut off what is 
 superfluous. 
 
 To silver the paper, pin it on a flat board 
 which you have covered with a sheet of blot- 
 ting paper, pour on it a small quantity of the 
 silver solution, and brush firstly lengthways, 
 and then across, taking care to distribute it 
 equally all over, after which you hang it up to 
 dry. 'Be careful to use nitrate solution enough 
 to transform all the chloride of ammonium 
 into the chloride of silver. This will take 
 about four drachms for a sheet of photographic 
 paper. For the first sheet you silver you will 
 have to take one drachm more, that much 
 being absorbed by the brush. The drippings 
 
145 
 
 should not be returned to the stock bottle, as 
 this would bring an excess of ammonia into 
 the solution it contains. The brush can be 
 used several* times, if kept out of the dust 
 
 Ammonia-nitrate paper should only be pre- 
 pared on the same day it has to be used, for 
 it soon becomes brown and loses sensitiveness. 
 
 Preparation of the Sensitive Albumen Paper. 
 
 Albumenized photographic paper is kept on 
 hand by stock dealers. Both Saxe and Rive 
 papers are used for the purpose. The former 
 is superior in texture to the . latter, and is also 
 more free from spots ; but the Rive gives 
 prints of a warmer and more pleasing tone. 
 This is on account of the substances which 
 are used for sizing it. The Saxe paper is 
 almost the only one used in this country. 
 Three kinds of Saxe are manufactured : the 
 negative, the half thick, and the thick. The 
 negative and half thick are .ghostly used for 
 albumenizing. 
 
 The albumen for albumenizing paper is 
 prepared in the following manner: Take 
 the whites of fresh eggs well separated from 
 the yolk, and beat with a wooden fork or a 
 bundle of quills, or by means of a patent egg- 
 beater, until the whole has become a perfect 
 froth. This point is reached when the vessel 
 in which the albumen is beaten, can be turned 
 upside down without any liquid running out. 
 Then allow the froth to subside, which will 
 
 13 
 
146 
 
 take several hours ; to each ounce of liquid 
 add from five to ten grains of chloride of am- 
 monium, Filter through a sponge or through 
 a tuft of cotton, or let settle, and pour the 
 clear parts into a glass or porcelain tray. 
 
 The floating of the paper on the albumen 
 requires some skilly and this is only acquired 
 by practice. The most convenient and easiest 
 way is, to take* the sheet by its upper corners, 
 lay it on the surface of the albumen, with its 
 upper end near the lower end of the tray, 
 and then let it come down slowly, gradually 
 pushing the sheet before you. The paper is 
 left on the albumen for one or two minutes, 
 after which it is hung up to dry, suspending 
 either with patent clips, or slinging it over a 
 cord. 
 
 The albumen should never be used when it 
 is decomposed and emits a strong smell. Al- 
 bumen paper should also be kept in a dry 
 place, in order to keep the albumen on the 
 surface from decomposing. 
 
 Mr. Thomas Sutton recommends passing 
 the paper through a solution of india rubber 
 in benzine, before albumenizing it. In this 
 way the albumen is kept from sinking in 
 the paper, and the sizing, it is claimed, does 
 not interfere, to the same extent, with the 
 color of the print. The process is patented 
 in Great Britain. 
 
 The fuming of the paper with ammonia 
 after it has been sensitized, dispenses with the 
 
147 
 
 use of a strong silver solution. A forty grain 
 solution used in connection with fuming, 
 seems to produce about the same effect as the 
 use of an eighty grain solution used without. 
 The fuming process is now generally adopted. 
 
 The question of advantage in the use of 
 strong or weak baths, is one which has lately 
 occupied much of the attention of photo- 
 graphic writers. In our opinion, the strength 
 of the silver solution should depend on the 
 strength of the salting, and on the intensity 
 of the negative ; or, to be more explicit, on the 
 contrast existing between the high lights and 
 the shadows. 
 
 Weak salting requires only a weak silver 
 solution, and all beyond a certain strength is 
 superfluous. Strong salting, on the contrary, 
 requires strong silvering. A weak negative 
 requires strong silvering ; an intense one 
 will produce the best results with a weak sil- 
 ver solution. 
 
 As a rule, the strength of a silver solution 
 for a given negative or a class of negatives, 
 should be such, that in printing, the shadows 
 are bronzed at the time the lighter parts are 
 sufficiently brought out. If this effect is not 
 produced, either a stronger silver solution 
 should be used, or the paper should be fumed, 
 or both expedients should be used in connec- 
 tion, if one does* not give the expected result. 
 If, on the contrary, the dark parts get bronzed 
 long before the lights are sufficiently printed, 
 
148 
 
 producing a print devoid of transparency in 
 the shadows, the solution should be weakened. 
 
 The plain silver solution generally used, is 
 prepared according to the following formula : 
 
 The alcohol is added to keep the solution 
 from becoming discolored by use. The way 
 an addition of alcohol produces this effect is 
 explained in the following manner : Albumen 
 forms, with the silver salt, an insoluble com- 
 pound ; but before the compound has time to 
 be completely formed, a small portion of the 
 albumen is dissolved into the bath and dis- 
 colors it in the same way as any other kind 
 of organic matter would. But, by adding 
 alcohol to the bath, its solvent pow r er is de- 
 creased, and with it also its tendency to dis- 
 color. 
 
 The strength of the solution given above 
 should be kept up by the addition of another 
 one made as follows : 
 
 It can also be tested from time to time, by 
 means of the Silver Indicator* and the neces- 
 sary amount of nitrate of silver added to it. 
 
 To sensitize a paper by floating, take it by 
 
 * Sold by Scovill Manufacturing Company. 
 
 Nitrate of silver, 
 Distilled water,. 
 
 Alcohol, 
 
 Nitric acid,. . . . 
 
 4J^ ounces fluid, 
 lj/o ounces fluid. 
 2 drops. 
 
 ounce. 
 
 titrate of silver, 
 
 Water, 
 
 Alcohol, - ... ... 
 
 Nitric acid, 
 
 , 1 ounce. 
 3 ounces fluid. 
 , 1 ounce fluid. 
 .2 drops. 
 
149 
 
 two opposite corners, and having bent it into 
 a curved form, lay it on a silver solution, the 
 middle part touching first, and lowering grad- 
 ually down, taking care to avoid air-bubbles. 
 If these occur, lift the paper up again by one 
 corner, and remove them with a glass rod, or 
 by lifting it up and lowering it down re- 
 peatedly. 
 
 The paper is left on the solution for about 
 three minutes, after which one corner is lifted 
 up with a strip of glass, and it is removed 
 and hung up to dry, using for this purpose 
 patent clips or clothes pins. In order to 
 make it dry quicker, it is advisable to remove 
 the superfluous silver from the surface, by 
 drawing a glass rod across it. 
 
 It is understood that the sensitizing and 
 drying are to be done in a dark room, that is, 
 in a room out of which the chemical light has 
 been excluded. A room with yellow or 
 orange panes of glass in the windows, or with 
 orange paper or muslin stretched before them, 
 will be found a more convenient place to 
 operate in, than a real dark room from which 
 all natural light is excluded, and which is 
 only lighted by a lamp or a candle. 
 
 When the paper, after sensitizing, is fumed 
 with ammonia, the formula for the silver solu- 
 tion is as follows : 
 
 Nitrate of silver, 1 ounce. 
 
 Water, 9 ounces fluid. 
 
 Alcohol, 3 ounces fluid. 
 
 Nitric acid, 2 drops. 
 
150 
 
 The manipulatory details are the same as 
 described above. 
 
 The sensitized paper, being dry, is then 
 fumed with ammonia. This is done in what 
 is called a fuming box. V arious models of 
 fuming boxes have been proposed. The one 
 we prefer is made on the same plan as the 
 old daguerreotype coating boxes. It is com- 
 posed of an oblong box, twenty by twenty- 
 four inches, and about twelve inches deep, with 
 a cover fastened to it by hinges. In the bot- 
 tom is put a saucer filled with concentrated 
 ammonia, Near the top is a board which can 
 be slid out and in. The sensitized paper is 
 tacked on the inside of the cover, which is 
 shut down and the board pulled out. The 
 ammonia gas which had collected in the space 
 between the bottom and the slide, will fill the 
 upper part of the box, and act upon the paper 
 tacked on the cover. After ten or fifteen min- 
 utes, the slide is shut, and the paper taken 
 off when it is ready for printing. 
 
 The ammonia used should be of the most 
 concentrated kind, known as liquid ammonia 
 cone. It contains in solution as much ammo- 
 nia gas as it will hold at a low temperature. 
 It should be kept in a cool place, and opened 
 with great care, as accidents often occur from 
 a portion of the liquid being thrown out forci- 
 bly, upon the removal of the stopper, when at 
 all warm. 
 
 The paper can be over-fumed or under- 
 
151 
 
 fumed. When over-fumed it is more or less 
 discolored, prints of a slaty blue, and tones 
 out of a cold steel color. When under-famed 
 it prints red and without vigor, and is diffi- 
 cult to bring to a good tone. Paper properly 
 fumed prints vigorous and of a black color, 
 verging slightly on the red, and tones to a 
 warm black tone. 
 
 Fumed paper keeps perfectly well for two 
 or three days, and is, in fact, not more apt to 
 turn yellow than the paper prepared on a 
 strong solution of silver, and not fumed. In 
 damp and warm weather, it is advisable, bow- 
 ever, to keep either kind in a chloride of cal- 
 cium box, where it remains perfectly dry, and 
 can be preserved for weeks and even months. 
 This apparatus consists of a zinc or a well 
 varnished wooden box, with a tight fitting 
 cover. In the bottom of this box is a sheet 
 iron pan, filled with dry chloride of calcium. 
 This salt absorbs moisture with great avidity, 
 and is for this reason used as a dessicatiner 
 agent in chemical operations. Above the 
 iron pan, and resting on a border, is a wire 
 frame, on which is laid the sensitive paper. 
 The box should be kept open as little as pos- 
 sible, to keep out the moisture. After being 
 used some time, the chloride of calcium be- 
 comes wet When this happens, take out 
 the sheet iron pan containing it, and warm it 
 on a stove until the salt is again dry. This 
 
152 
 
 operation can be done over and oyer again, 
 without the salt losing its properties. 
 
 Before concluding this chapter we will have 
 to say a few words on a subject which has 
 lately elicited much discussion among pho- 
 tographic writers, to wit : The effect of the 
 addition of nitrate of soda to the silver bath. 
 It is claimed that the addition of a certain 
 quantity of these salts produces an effect 
 similar to that of fuming the paper with am- 
 monia ; that is, allows the use of a weaker 
 bath. This assertion is made on apparently 
 good authority, while equally good authority 
 regard the whole matter as absurd. 
 
 In our hands the mixed bath of nitrate of 
 silver and of soda has not produced any bet- 
 ter results than the silver bath used without 
 this admixture. A series of experiments, 
 undertaken at different periods, with different 
 solutions, and with different kinds of paper, 
 has forced us to come to the conclusion that 
 no advantage arises from the use of the above 
 named salt, either as regards intensity, rap- 
 idity or tone, or freedom from mealiness or 
 toning accidents. 
 
 The bath containing nitrate of soda always 
 gave a redder print on removal from the 
 printing frame than the plain silver solution : 
 but both prints were brought to the same 
 color in the toning bath. 
 
 Mr. Henry Anthony recommends the use 
 of oxide of silver, dissolved in nitrate of am- 
 
153 
 
 monia, for the silvering of paper. The prints 
 obtained by this process equal those on paper 
 fumed with ammonia, the strength of the sil- 
 ver solution being the same. 
 
 The way to proceed is as follows : Dissolve 
 one ounce of nitrate of silver in three or four 
 ounces of water, and about one ounce of caus- 
 tic potash in two or three ounces of water, 
 and mix the two solutions together ; a precipi- 
 tate w^ill be formed, which, in a few minutes, 
 will settle to the bottom. The liquid is then 
 poured off carefully, a fresh quantity of water 
 is added, and after the oxide of silver has 
 again subsided, the water is again poured off. 
 In this way the oxide of silver is washed care- 
 fully five or six times, after which crystallized 
 nitrate of ammonia is added, a few drachms 
 at a time, until all but a small quantity of 
 the oxide of silver is dissolved. Finally, the 
 solution is brought to a bulk of twelve ounces, 
 by the addition of three ounces alcohol and a 
 sufficient quantity of water. It is also ad- 
 visable to add a few drops of nitric acid. 
 
 CHAPTER XXVIII, 
 
 The Printing. 
 
 Printing frames of different forms are used 
 by photographers. They are constructed in 
 such a way that the picture can be examined, 
 
154 
 
 without its position being disturbed. In some, 
 the negative is laid in the frame, collodion 
 side uppermost, the sensitive paper is then 
 placed upon it, then a piece of black cloth is 
 laid upon the paper, the shutter is placed 
 upon the black cloth, and the whole is pressed 
 together by means of two springs. In other 
 frames of a different construction, the paper is 
 laid upon the frame, and the negative is placed 
 on it, and is kept pressed down by means of 
 springs. It is essential that the pressure be 
 equal everywhere, so that the paper be in 
 close contact with every part of the negative. 
 
 The paper should be perfectly dry before it is 
 used, if not, it might spoil the negative, mainly 
 when this has been gummed, and it will print 
 of a reddish color in the spots where it is moist. 
 
 The preliminary preparations for the print- 
 ing may be done in diffused light, unless the 
 light be so strong and the chloro-nitrate of 
 silver so sensitive as to cause the paper to 
 darken, which is very seldom the case. Weak 
 negatives should be printed by diffused light ; 
 negatives of good intensity may be printed in 
 sunlight, except when the heat is very strong, 
 in which case the varnish might soften and the 
 glass will be in danger of cracking. The 
 printing frame should be laid in such a posi- 
 tion as to cause the rays of light to fall per- 
 pendiculary on the plate. 
 
 The time of exposure is very variable ; it 
 depends, 1st, on the sensitiveness of the pa- 
 
155 
 
 per ; 2d, on the strength of the light ; 3d, on 
 the intensity of the negative. The print 
 should be taken out when it appears slightly 
 darker than it is intended to remain, the 
 toning and fixing reducing its intensity. A 
 little practice will soon teach the operator how 
 far the printing has to be pushed. 
 
 On removal from the printing frame, plain 
 paper silvered with ammonia-nitrate, is gen- 
 erally black or purplish black. So is the 
 same paper when silvered and then fumed. 
 The addition of citrate of soda to the salting 
 gives it a slight red tinge. Albumen paper 
 prepared with strong silver, prints slightly 
 red. When prepared with weak silver and 
 fumed, it has a greater tendency to the black. 
 When prints come out of the printing frame 
 too red, the probability is that the silver is 
 too weak ; or that the paper has not been 
 sufficiently fumed. 
 
 When, on removal from the printing frame, 
 the paper remains white in certain parts, or 
 is covered with white spots, it is a proof 
 that all the alkaline chloride has not been 
 transformed into chloride of silver, which 
 may result from the silver solution being too 
 weak, or from the paper not having been left 
 on it a sufficient time, or also from imperfect 
 silvering with the brush. 
 
156 
 
 CHAPTER XXIX. 
 
 Toning, Fixing, Washing, and Mounting of the Prints. 
 
 The toning and fixing are two very impor- 
 tant operations in the production of the pho- 
 graphic print. If the intensity and vigor, 
 and, to a certain extent, the tone of the print, 
 depend on the preparation of the sensitive 
 paper, the permanency depends principally 
 on the toning and fixing. 
 
 It is but a short time since the process of 
 toning and fixing together was in general use. 
 Toning properties were communicated to the 
 fixing solution either by repeated use, or by 
 the addition of various substances, such as 
 acids, iodine, chloride of gold, chloride of sil- 
 ver, etc. In all cases, except when chloride 
 of gold was used in connection wdth a new 
 hyposulphite solution, the red color of the 
 photograph was altered by a combination of 
 the silver compound with sulphur, which, in 
 the hyposulphites, is but loosely combined. 
 This sulphur and silver compound is very 
 unstable, and is acted upon by air, moisture, 
 acid, etc. causing the lading of the photo- 
 graph. When gold was used in a new hypo- 
 sulphite bath, the first prints were toned by 
 gold, but after being used some time, the bath 
 would acquire also the property of sulphur 
 toning, so that this process was in the main 
 not more reliable than the others. 
 
157 
 
 The method universally adopted now, is 
 the toning and fixing of the prints separately. 
 This method is at the same time safer, more 
 economical, more expeditious, and gives re- 
 sults superior to those used before. 
 
 The operations to be performed to finish 
 the print, after it is removed out of the print- 
 ing frame, are as follows : 
 
 1st, Washing to get rid of the free nitrate 
 of silver. 
 
 2d, Toning. 
 
 3d, Washing to remove the toning solution. 
 4th, Fixing. 
 
 5th, Washing to remove the hyposulphite. 
 
 On removal from the printing frames, the 
 prints are put away in a box or in the dark 
 room ; or, better yet, in a chloride of calcium 
 box, and kept there until a sufficient number 
 are collected to begin the toning and fixing. 
 The use of the chloride of calcium box is to 
 be recommended in damp and warm weather, 
 and whenever the prints have to be kept 
 longer than a few hours. 
 
 When ready to be toned, the prints are put 
 in a tray with water, to soak out the free ni- 
 trate of silver. After five or ten minutes, 
 the water is poured out, and the tray is again 
 filled up with fresh water. This operation 
 should be repeated three or four times, so as 
 to remove all the free nitrate.* 
 
 * See Chapter on " Recovery of Silver in Photographic 
 Operations." 
 
158 
 
 The toning bath is prepared according to 
 the following formula : 
 
 Water, 40 ounces. 
 
 Chloride of sodium, 20 grains. 
 
 Bicarbonate of soda, . . » . . . 2 grains. 
 
 Chloride of lime, 2 grains. 
 
 Solution of chloride of gold sufficient quantity. 
 
 The solution of chloride of gold is made 
 by dissolving fifteen grains of the pure chlo- 
 ride in one pint of water ; or a one dollar 
 gold piece* in forty ounces of water. 
 
 The chloride of sodium or common salt is 
 added to the toning bath to transform into 
 chloride the nitrate of silver which may 
 remain in the prints, and which would other- 
 wise decompose the chloride of gold. 
 
 The bicarbonate of soda has the effect of 
 causing the chloride of gold to yield more 
 readily the metallic gold to the prints. An 
 excess of this salt should be guarded against, 
 or after a short time a double salt of gold and 
 soda would be formed, which does not possess 
 toning properties. 
 
 The addition of a small quantity of chlo- 
 ride of lime to the toning bath improves it 
 considerably. Black tones and pure whites 
 seem to be more easily produced. The chlo- 
 
 * A one dollar gold piece can be dissolved in four drachms 
 of a mixture of one part nitric and three parts hydrochloric 
 acid, then diluted with three or four ounces of water '; after 
 which a strong solution of carbonate of soda is added a 
 little at a time, until a green precipitate of carbonate of 
 copper is formed. The solution is then filtered and diluted 
 with sufficient water to measure forty ounces. 
 
159 
 
 ride of lime possesses great advantages when- 
 ever the paper, for some reason or other, is 
 discolored. 
 
 The quantity of chloride of gold solution 
 to be added depends entirely on the number 
 of prints to be toned. Fifteen grains of the 
 pure chloride should tone about ten sheets 
 photographic paper, and the solution made 
 with a dollar gold piece should tone about 
 twenty sheets. Whenever but a small number 
 of prints have to be toned, it is preferable to 
 add the necessary quantity of gold to a smaller 
 quantity of the bath. 
 
 The toning bath should have been pre- 
 pared a short time before being used, for if 
 too fresh it is apt to produce mealiness. One 
 made according to the formula given above, 
 will work best an hour or two after it has 
 been mixed. If it should lose its energy 
 before all the prints are toned, more of the 
 gold solution should be added. 
 
 The prints are taken out of the water, and 
 immersed in the toning bath, where they are 
 kept in motion during the whole process of 
 toning. They may at first get slightly redder, 
 but they will afterwards pass through all the 
 intermediate stages, between the color they 
 have on immersing and the blue black. The 
 toning can be stopped at any stage by im- 
 mersing the print in a tray of clear water, 
 kept on hand for the purpose. The real color 
 of the print is only seen after the immersion 
 
160 
 
 in the hyposulphite fixing solution, so that 
 the operator will have to discern to what tint 
 the print should be brought to assume, after 
 fixing the color he wants. As a general thing 
 the bluish black changes to a pure black in 
 the hyposulphite ; less toning than is required 
 to give the bluish black produces prints more 
 or less brown ; if the toning is pushed fur- 
 ther, the prints are liable to be bluish and 
 ashy colored when dry. This holds good for 
 plain or for albumen paper. Albumen paper 
 silvered and fumed, tones much easier and is 
 less liable to mealiness than the one which 
 has not been fumed ; the same can be said of 
 albumen paper prepared on the solution of 
 oxide of silver in nitrate of ammonia. If a 
 large number of prints have to be toned, the 
 toning bath should of course be made larger ; 
 but in most cases it would be hardly neces- 
 sary to use more than a quart or three pints 
 of solution. The gold necessary for the ton- 
 ing should not be used all at once, but one or 
 two ounces of the solution at one time. In 
 this way is avoided a too rapid action, which 
 most always brings with it spots or mealiness 
 on albumen paper. 
 
 The time necessary for toning an albumen 
 print should be from two to five minutes. 
 Prints on plain paper, fumed or silvered with 
 ammonia-nitrate, tone much quicker. 
 
 The toning bath may be used over and over 
 again, by adding a fresh supply of gold, if 
 
161 
 
 care be taken to avoid the introduction of 
 hyposulphite. The effect of the introduction 
 of hyposulphite in the toning bath, is to 
 make it lose its energy. 
 
 The prints, as soon as they are taken out of 
 the toning bath, are immersed in water. 
 They are then washed several times and put 
 into the fixing bath, which is composed as 
 follows : 
 
 The fixing will not require more than ten 
 minutes. It is done when the paper presents, 
 by transmitted light, an uniform appearance, 
 showing no opaque spots of undissolved chlo- 
 ride of silver. 
 
 The fixing solution will, by being used, ac- 
 quire toning properties which are very objec- 
 tionable, as they are due to liberation of sul- 
 phur. The operator should thus not, for rea- 
 sons of economy, use this solution too often, 
 and in such way endanger the permanency of 
 his prints. The above given quantity can be 
 used to fix about sixty 4-4 size prints. 
 
 On immersion in the hyposulphite, the real 
 color of the print shows itself immediately. 
 Prints toned to black change very little during 
 the fixing ; those which are less toned become 
 slightly redder. 
 
 Different Formulae for Toning Baths. 
 
 A great variety of toning baths are used 
 
 Hyposulphite of soda, 
 >Bi-carbonate of soda. 
 Water, 
 
 8 ounces. 
 1 drachm. 
 32 ounces fluid. 
 
162 
 
 by photographers, and each one is claimed to 
 "be superior to the other. The one we have 
 given above is very simple, and, we are 
 inclined to think, will produce as good results 
 as any. We are not prepared to pronounce 
 on the value of the use of the different sub- 
 stances claimed to possess peculiar virtues in 
 the toning, for want of well attested facts on 
 wilich to base -our opinion. We will confine 
 ourselves here to giving a number of formulae 
 recommended by the most successful operators. 
 
 Toning Bath with Citrate of Soda (Hardwich). 
 
 Bi-carbonate of soda 240 grains. 
 
 Citric acid 160 grains. 
 
 Water 1 quart. 
 
 Chloride of gold, lj^ grains to a sheet of albumen paper. 
 
 In making this solution, an effervescence 
 will be produced, resulting from the freeing 
 of carbonic acid. When it has ceased, the 
 combination of the citric acid with the soda 
 has taken place, and the liquid contains citrate 
 of soda with an excess of bi-carbonate of soda. 
 
 Maxwell Lyle's Formula. 
 
 Water 32 ounces. 
 
 Phosphate of soda % ounce. 
 
 Chloride of gold as above. 
 
 Formula with Acetate of Soda. 
 
 Water ... .32 ounces, 
 
 Acetate of soda %, ounce. 
 
 Phloride of gold as above. 
 
 Chloride of Lime Bath. 
 
 Chloride of lime (hypochlorite of lime) 5 grains. 
 
 "Water - 32 oanoee. 
 
 Chloride of gold as above. 
 
163 
 
 Nitrate of Uranium Bath. 
 
 Nitrate of uranium 
 
 Acetate of soda 
 
 Water 
 
 Chloride of gold as above. 
 
 60 grains . 
 120 grains. 
 . 32 ounces 
 
 Carbonate of Lime Bath. 
 
 Precipitated or pulverized chalk 
 
 Chloride of calcium 
 
 Water 
 
 Chloride of gold as above. 
 
 120 grains. 
 24 grains. 
 32 ounces. 
 
 For all these baths the chloride of gold 
 should be neutral. If acid, a few grains of 
 bi-carbonate of soda should be added to the 
 toning bath. 
 
 The washing is another point of great 
 importance. To insure the permanency of 
 the prints, it is essential to wash out all the 
 hyposulphite of soda they contain. The 
 methods of washing used by photographers 
 are various, and depend a great deal on local 
 conveniencies and the quantity of water of 
 which they dispose. The most simple method 
 is to have several trays filled with water, and 
 to change the prints, one at a time, from one tray 
 into another, leaving them ten or fifteen min- 
 utes in each. Mr. Shadbolt proposes to drain 
 the prints every time they are changed. If 
 this is done the washing will be a great deal 
 more effectual. What is better yet, is to pass 
 them, after each washing, through one of the 
 patent clothes wringers. In this way the larger 
 quantity of the water is pressed out between 
 the rollers, and the print comes out nearly 
 
164 
 
 dry. These clothes wringers are invaluable 
 to amateurs, who make only a small number 
 of prints, but the manual labor they require 
 make them not so well adapted to the use of 
 professional photographers, who have large 
 numbers of prints to wash. Another draw- 
 back to the use of the clothes wringer is, that 
 the prints require to be made on strong Saxe 
 paper, the Rive and other papers getting 
 injured during the operation. 
 
 An excellent way of washing, but which 
 can only be practiced in cities where water- 
 works exist, is to lay the prints on a coarse 
 muslin screen stretched on a frame, and allow 
 the water to sprinkle over them through the 
 head of a watering pot fixed to the hydrant 
 by means of a vulcanized rubber tube. This . 
 screen or frame should be laid inclined, so as 
 to allow the water to run off easily. The 
 greater the pressure of the column of water, 
 the more effectual the washing will be. The 
 position of the print should be frequently 
 changed. By combining this method with 
 that of Mr. ^Shadbolt, that is, allowing the 
 prints to drain from time to time while on the 
 screen, a very effectual cleansing is obtained. 
 
 Some operators lay the prints flat on a 
 piece of thick plate glass under a stream of 
 water, and press them with a sponge, or roll 
 them with a thick glass tube. Either of these 
 two last ways are effectual, but they entail too 
 much labor. 
 
165 
 
 Messrs. T. E. & C. Bull, of London, con- 
 structed a print washing apparatus in which 
 the consecutive washing and draining, recom- 
 mended by Mr. GL Shadbolt, are performed au- 
 tomatically. It is composed of a tub with a false 
 bottom at about half the height. This false 
 bottom is made of zinc or wood, and is per- 
 forated with holes. A syphon of wide diame- 
 ter is put either in the middle or at the side, 
 at such a height that when the tub is lilled up 
 with water, the syphon is started, and the 
 water is rapidly discharged, leaving the prints 
 on the false bottom, where they drain until 
 there is again sufficient water in the tub to lift 
 them off. The stream of water is directed so 
 as to strike the side of the tub slanting ; in 
 this way a rotary motion is given to the water, 
 which prevents the prints from sticking 
 together, and keeps them rolling and turning 
 around. 
 
 The Rive and some other kinds of paper 
 are very apt to get injured during this opera- 
 tion ; and when the prints are of large size, 
 even the strong Saxe paper gets broken and 
 torn. 
 
 Mr. Hanbury has recently brought out a 
 washing apparatus, which we think is the 
 best one yet made. It consists of a cradle 
 about eight feet long, two feet wide, and two 
 feet deep. In the middle is a partition which 
 divides it in two, thus forming two troughs, 
 two feet w r ide and two feet deep. The cradle 
 
166 
 
 is balanced in the middle on an axis, and can 
 tip down about six inches either on one side 
 or on the other. The water-cock is disposed 
 over the cradle in such a way, that when the 
 right hand compartment is down, the water 
 runs in the left hand compartment, and vice 
 versa. At the end of each compartment, and 
 at two or three inches from the top, is a 
 syphon, which, as the water reaches its upper 
 extremity, is started and the water discharged. 
 On the side of the cradle and running the 
 whole length of it, is an oblong water-tight 
 box, about four inches square, which is kept 
 half filled with water. Let us suppose that 
 the right hand compartment is down, so that 
 the water is being discharged through ' the 
 syphon, and the water in the water-box is 
 in the right hand side. The water thus runs 
 into the left hand compartment, and as 
 soon as its weight is sufficient to overcome 
 the weight of the water in the water-tight 
 box, the cradle will tip down, the syphon will 
 be started, the water in the box will flow to the 
 left hand side, and the right hand compart- 
 ment will come under the water-cock. Then 
 the same operation will be repeated on the 
 right hand side, etc. The quantity of water 
 in the box should, of course, be regulated by 
 experiment, to balance exactly the quantity 
 of water in each trough, when filled up to 
 about six inches from the upper part of the 
 syphon. It may be necessary to have the 
 
167 
 
 water box longer than the cradle, so that the 
 water be further from the center of gravity. 
 
 Each trough can be filled with a false bot- 
 tom, like in Bull's washing machine ; or the 
 prints can be hung perpendicularly in the 
 water, in which case the false bottom is use- 
 less. 
 
 The prints have to be washed until the 
 whole of the hyposulphite is removed. The 
 different tests for hyposulphite are not suffi- 
 ciently delicate to be of use, quantities 
 of hyposulphite, which are inappreciable to 
 these tests, being sufficient to cause the 
 fading of the print. It is thus impossible to 
 say how long a print should be washed. The 
 great points to be attended to, no matter what 
 system of washing be used, are : 1st, That 
 the prints be drained from time to time, to 
 discharge most of the water they hold ; and, 
 2d, That they be kept well separated, so that 
 the hyposulphite be able to diffuse itself into 
 the water. We are inclined to think that 
 when these conditions are observed, ten or 
 fifteen changes of water, either by hand or by 
 the use of any of the washing apparatus de- 
 scribed, are sufficient. 
 
 The prints being well washed are hung up 
 to dry, either by means of clips or patent 
 clothes pins. When the paper will stand it, 
 they may be passed through a patent clothes- 
 wringer. They can also be dried between 
 sheets of blotting paper. 
 
108 
 
 Mounting of the Prints. 
 
 The print is first properly trimmed to the 
 required size. To do this, it is laid on a 
 piece of glass, another piece of glass of the 
 form and shape of the print is laid on it, and 
 a sharp knife is passed along the edges of the 
 glass. Brass or tin mats are also used for trim- 
 ming, the point of the knife being then passed 
 along the inside of the mat. 
 
 The paste used generally is made with 
 starch or flour. Grum arabic, dextrine, and 
 gelatine can also be used. Starch flour, 
 gum arabic, and dextrine paste become acid 
 by keeping. They should thus, as much as 
 possible, be used fresh. 
 
 CHAPTER XXX. 
 
 On the Fading of Positive Prints. 
 
 When the sensitive paper has been acted 
 upon by light, the image is supposed to be 
 free of silver and organic matter. After im- 
 mersion in a solution of salt, the nitrate is 
 transformed into chloride, which is afterwards 
 dissolved in the hyposulphite. If without 
 being toned the print is immersed in a solu- 
 tion of hyposulphite, the composition of the 
 image will be very little affected. Prints 
 treated this way are permanent. 
 
 When the print is fixed in a bath which, 
 
169 
 
 through unskillful management or otherwise, 
 
 contains sulphuretting principles, the image 
 in composed of silver, organic matter and 
 sulphur. Experience has shown that this 
 compound is less permanent than the other, 
 f specially under the influence of moisture. 
 
 If the print before being fixed is immersed 
 in a solution of chloride of gold, the chlorine, 
 which is combined with the gold, will pass to the 
 silver, forming pro to-chloride of silver in the 
 middle tints, and sub-chloride of silver in the 
 deep shades, while the gold is deposited in the 
 metallic state. On immersion in the hyposul- 
 phite of soda, the sub-chloride of silver is de- 
 composed in metallic silver and proto-chlor- 
 ide of silver, and the proto-chloride is dissolved. 
 The image in this case is thus composed 
 of gold, silver and organic matter, the gold 
 predominating when the toning has been 
 pushed far. Prints toned this way have stood 
 the destructive tests better than any other, 
 mainly when containing much gold. 
 
 In the gold fixing and toning bath the print 
 goes through several changes which have not 
 been very well explained, and which result in 
 the image being composed of silver, sulphur, 
 gold and organic matter. The better the sup- 
 ply of chloride of gold is kept up, the more 
 gold and the less sulphur the prints contain. 
 Prints toned in the gold fixing and toning bath 
 are less permanent than those toned with gold 
 and fixed with plain hyposulphite. 
 
 15 
 
170 
 
 1 
 
 When to a solution of hyposulphite of soda 
 an addition of acid of any kind is made, hy- 
 posulphite is decomposed, and sulphur is set 
 free, by which the prints which are immersed 
 nnto it will be toned. 
 
 m The addition of iodine, per-chloride of iron, 
 nitrate and chloride of silver, etc., to the hypo- 
 sulphite solution, produce in it unstable salts 
 which have sulphurating properties. It is to 
 the addition by constant use of the nitrate and 
 chloride of silver that the plain fixing solu- 
 tion acquires the property of darkening the 
 image. 
 
 The presence of sulphur in the photographic 
 print being one of the main causes of its fad- 
 ing, we have to discard all processes in which 
 it is used as a toning agent. These pro- 
 cesses, as we have seen, already, are, 1st, 
 The hyposulphite bath which has acquired 
 toning properties by being used. 2d, The 
 one to which acid has been added. 3d, Those 
 made with iodine, per-chloride of iron, et c. 4th f 
 The gold fixing and toning bath. The last 
 one is the least objectionable when the supply 
 of gold is well kept up, as in this case the 
 quantity of sulphur in the print is very small. 
 
 Besides the presence of sulphur in the print, 
 fading may be produced by the following 
 causes : 
 
 Imperfect washing. — It is important that th 
 least trace of hyposulphite of soda should be 
 washed out of the paper. The water giving 
 
171 
 
 no precipitate with nitrate of silver or bi-chlo- 
 ride of mercury, is no proof that the print is 
 sufficiently washed, as none of these salts are 
 tests for a very small quantity of hyposulphite. 
 The presence of hyposulphite in the print 
 causes it to become yellow firstly in the half 
 tints, and afterwards in the shadows. 
 
 Prints properly toned by gold are less af« 
 felted by a minute quantity of hyposulphite 
 than those toned by sulphur, which in a short 
 time are entirely destroyed. 
 
 Moisture and impure air, — Moisture is al- 
 - ways a condition favorable to decomposition. 
 If the print has not been properly toned, 
 the fading will go on very rapidly under its 
 influence. Prints toned by gold and well 
 washed resist the effect of dam]) air quite as 
 well as engravings. But when air, besides 
 being damp, contains sulphuretted hydrogen, 
 sulphuric acid, etc., (products of the combustion 
 of coal and coal gas,) no photograph can long 
 resist its deleterious effects. 
 
 Acid 'paste used in mounting, — Starch and 
 flour paste and gum arabic become sour by 
 keeping, and should be avoided, even when 
 freshly made, as the acetous fermentation 
 which produces this acidity may take place 
 after the photograph is mounted, when it is 
 exposedto the influence of moisture. This 
 acidity is very destructive to prints toned by 
 sulphur. Its effect on prints toned by gold 
 seems to be very limited. 
 
172 
 
 Prints developed to the black stage and 
 fixed in plain hyposulphite are less affected by 
 the destructive causes spoken of above, than 
 those which have not been pushed further 
 than the red or purple stage If these how- 
 ever are toned in the gold toning bath, they 
 are in the same condition as direct prints 
 treated the same way. 
 
 The toning by sulphur of developed prints 
 deposits also in the paper the substances which 
 cause their destruction. 
 
 CHAPTER XXXI. 
 
 Instruments used for Making Enlarged Prints froj* 
 Collodion Negatives.— The Solar Camera. 
 
 If a negative be put in a camera at the 
 place occupied by the plate holder, and the 
 camera be then placed in a hole cut in a dark 
 room, in such a position that the light falls on 
 the negative, and can only be admitted into 
 the dark room by passing through the nega- 
 tive and the tube, an enlarged image will be 
 formed at some distance from the tube. Sup- 
 posing the same camera to have been used to 
 make the negative, the image will .be of the 
 size of life, if the negative occupies the same 
 position as when it was made, and the focus- 
 sing screen is at the same distance from the 
 tube as the sitter was. If the focussing screen 
 
173 
 
 be brought nearer the tube, and the distance 
 between tube and negative increased so that 
 the two foci correspond, the image will become 
 smaller. On the contrary, if the distance be- 
 tween tube and screen be increased, and the 
 one between negative and tube be decreased 
 to a corresponding focus, the image will be 
 larger than life. 
 
 It will be remarked that in this arrange- 
 ment the position of the tube is reversed, so 
 that the front lens is nearest the focussing 
 screen, and the back lens nearest the nega- 
 tive. This is the disposition to be adopted in 
 all cases where copies have to be made larger 
 than the original. 
 
 In order now to obtain an enlarged print, 
 all that is necessary is to put a sheet of 
 sensitive paper at the place occupied by the 
 focussing screen. 
 
 To make the image more luminous the light 
 of the sun can be reflected on the negative by 
 means of a mirror. The mirror should be 
 fixed in front of the negative, and should both 
 swing and turn on a pivot. The centers on 
 which it turns and swings should be on a level 
 with the axis of the lens. When such an ar 
 rangement is used, the box should face the 
 south if possible, in order to be able to use 
 0 sunlight the larger part of the day. The ne- 
 gative should be covered with a ground glass 
 so as not to have the disc of the sun reflected 
 on the sensitive paper. 
 
174 
 
 The solar camera is an instrument express- 
 ly made for the printing of enlarged images. 
 It is constructed on the same principles as the 
 apparatus described above, but has in addition 
 to it a bi-convex or plano-convex lens, of a 
 large diameter, on which the light is reflected, 
 and which condenses it and brings it to a 
 focus at a distance of twelve or fifteen inches. 
 The reflector is a plane mirror, a little wider 
 than the condensing lens, and about three 
 times as long as it is wide. It is arranged by 
 means of two movements so as to be put in all 
 positions, and follow the march of the sun so 
 that the rays may be always reflected perpen- 
 dicularly to the condensing lens. The tube 
 used may be either a portrait combination or 
 a view lens. A diaphragm with a small aper- 
 ture is put between the lenses in one case, or 
 in front of it in the other, and the box is made 
 of such a length that the light condensed by 
 the bi-convex or plano-convex lens comes to a 
 focus at the spot where is the aperture of the 
 diaphragm. 
 
 The negative is put in a slide which is 
 moved forward and backward by means of a 
 rack work. It will be easily understood that 
 the nearer the negative is to the condensing 
 lens, the larger and the less luminous will be 
 the disc of light thrown on it, and the nearer 
 it is to the tube, the smaller ancf the more 
 luminous it will be. 
 
 The solar camera should, as much as pos- 
 
175 
 
 sible face the south. If it was a little to the 
 
 east or to the west, the reflector would not be 
 found long enough to throw the sunlight on the 
 entire surface of the condensing lens during 
 the whole day in the winter months. 
 
 When the large size solar camera is used, 
 is convenient to have two single lenses, one of 
 about eight inches focus, and the other of about 
 five and a half inches ;• or, instead of these, a 4-4 
 and a half size portrait combination. In con- 
 nection with a small size solar camera, use a 
 lens of five and a half inches focus, and another 
 one of three or three and a half inches, or a 
 half size and a quarter size portrait tube. 
 The long focus lenses or combinations of lenses 
 are used with large negatives, and the short 
 focus ones with smaller negatives. 
 
 The solar camera being placed in the hole 
 cut in the dark room, the negative is put in one 
 of the grooves, and the focussing screen put at 
 a certain distance from the tube. It is to be 
 remarked that the larger the image has to be, 
 the further the focussing screen will have to 
 be in the dark room, and the nearer the nega- 
 tive has to be brought toward the tube. The 
 image is brought to a focus by moving the neg- 
 ative without touching the lens. The focus- 
 ing should be done by diffused light, using 
 the whole aperture of the instrument, with 
 a portrait combination, or a large diaphragm 
 with the single lens. A diaphragm of half 
 an inch or quarter of an inch diameter, 
 
176 
 
 is then adapted at the place where the rays of 
 light comet) a focus, and the sun is turned on. 
 We will remark hare, tint in this combina- 
 tion the diaphragm, when it is pub in the pro- 
 per place, does not cut off any of the light, all 
 the rays emanating from the negative being 
 condensed to a point at the spot where is the 
 aperture. The function of the diaphragm here 
 is to increase the sharpness of the image and 
 flatten the field, and to cut off the rays which 
 are transmitted through the parts of the nega- 
 tive not covered by the disc of condensed light, 
 and those which are reflected from the sides of 
 the box. 
 
 In order not to have in the dark room more 
 light than is necessary, the parts of the nega- 
 tive which have not to be printed should be 
 covered with a mat. The observance of these 
 recommendations is not of such great impor- 
 tance when the direct positive process is used 
 as when the prints are made by development. 
 
 The stand which supports the focussing 
 screen, or the sensitive paper, should be per- 
 fectly vertical, and rigorously parallel with 
 the negative and the tube, the least deviation 
 causing a distortion of the image. The sup- 
 port on which the solar camera rests should 
 also be perfectly level. To insure the paral- 
 lelism of the camera and the stand, the opera- 
 tor should paint a series of parallel lines on 
 the floor of his dark room. 
 
 The stand should be made on the same 
 
177 
 
 principle as a painter's easel. It should have 
 parallel sides, and be about six feet high, and 
 two and a half feet wide. The part on 
 which the focussing screen or the prepared 
 surface rests, slides up and down, and is 
 fastened with a catch. The stand is kept 
 steady by means of a brace. 
 
 CHAPTER XXXIV. 
 
 Enlarged Prints by the Direct Positive Process. 
 
 Negatives used in this process should have 
 little intensity, and be well marked in all the 
 details. They should also be distinct and 
 clear in the shadows, without great contrast 
 and free from spots and marks. To insure 
 these conditions, the collodion should give an 
 even and structureless film, the silver bath 
 should be in a condition to give images with- 
 out the least fogginess ; the exposure in the 
 camera should only be a little more than for 
 a collodion positive, and the image should be 
 fully developed. The negative should not be 
 varnished, as no varnished surface is free 
 enough of unequalities. It may be protected 
 with a coat of gum arabic or of plain collodion 
 prepared as described on page 114. 
 
 In order to obtain prints in as short a time 
 as possible, it is necessary to use a larger pro- 
 portion of salt or chloride of ammonium in the 
 
178 
 
 paper than for prints by contact. Ammo- 
 nia nitrate paper salted, with ten grains to the 
 ounce of chloride of ammonium, and silvered 
 with a 60 or 70 grain silver solution, can be 
 used with advantage. The solutions can be 
 prepared according to the directions given in 
 Chapter XXVII, the citric acid and carbonate 
 of soda being used or omitted in the salting, 
 according to the taste of the operator. Albu- 
 men paper, strongly salted — that is, 10 or 12 
 grains to the ounce- — will also answer. 
 
 The focus having been taken beforehand, 
 the sensitive paper is tacked on a board or 
 stretched on a frame, and put in the place oc- 
 cupied by the focussing screen. The reflector 
 is then turned, so as to throw the sunlight on 
 the negative in such a way as to bring the 
 spark or focus of the rays in the middle of the 
 aperture of the diaphragm. Gradually as the 
 sun moves, the reflector will have to be moved, 
 so as to keep the spark always in the same 
 place. This requires to be done about every 
 one or two minutes. 
 
 The time of exposure is regulated by the 
 following conditions : 
 
 1st, The strength of the light. 
 
 2d, The intensity of the negative. 
 
 3d, The sensitiveness of the paper. 
 
 4th, The proportion between the size of the 
 negative and the one of the print. It is easy 
 to comprehend that the larger the negative 
 is, the more luminous will be the image, and 
 
179 
 
 the larger the image is the less luminous it 
 will be. 
 
 5th, The distance the negative is from the 
 condensing lens. — The further the negative 'm 
 from the condensing lens, the smaller and the 
 more luminous is the disc of light thrown on 
 it. In order to make prints rapidly, it is thus 
 essential to use a lens of such a focus, that the 
 negative be as far from the condensing lens as 
 possible, so as to be coverd with a small but 
 luminous disc of light. 
 
 The toning, fixing, etc., of the image having 
 been fully described in chapter XXIX, it is un- 
 necessary to repeat it here. 
 
 The dishes for toning, fixing and washing, 
 can be made of dry wood, and are made water- 
 tight by pouring a cement, composed of equal 
 parts of wax and rosin, in the cracks and cor- 
 ners, and varnishing with shellac or copal 
 varnish. 
 
 CHAPTER XXXIII. 
 
 Enlarged Prints by the Developing Process. 
 
 The room which is used for the production 
 of developed prints must be perfectly dark, 
 and all the precautions required in producing 
 . collodion pictures should be taken. 
 
 The solutions should be well filtered, and 
 everything kept in perfect cleanliness. 
 
180 
 
 The silver solution should be prepared with 
 as much care as in the collodion process, and 
 it should be kept as much as possible free 
 from organic matter. 
 
 We will describe here two processes, one 
 which is adapted best to the production of 
 plain prints, on ordinary photographic paper ; 
 another, which for reasons of economy and 
 celerity, will be found more useful whenever 
 images have to be made of a larger size. 
 
 Developing process on photographic paper.— 
 For this process, it is necessary to have one 
 or several dishes, for iodizing, silvering and 
 developing, a little larger than the picture you 
 want to print. The most economical dishes, 
 and the best and cleanest, are composed of a 
 framework in which a plate of glass is sealed 
 with a cement composed of equal parts of rosin 
 and beeswax. The sides of the framework 
 should be about four inches high and one inch 
 thick. In these sides is a groove half an 
 inch deep and a quarter of an inch wide. The 
 framework is fastened together with screws. 
 Join firstly three pieces, then slide the plate 
 of glass into the groove, and screw on the 
 fourth pieca After that pour into the groove 
 your melted cement, and finally varnish the 
 wood several times with shellac dissolved in 
 alcohol, or with copal varnish. These dishes 
 can be used on both sides, and are very easily 
 cleaned. This is done first with a clean 
 sponge, and then the dish is put with one cor- 
 
181 
 
 ner into a bucket, and water sprinkled over 
 with a watering pot. 
 
 For fixing, toning and washing, wooden 
 dishes, well cemented and varnished, will • 
 answer. 
 
 The paper is floated one minute on the fol- 
 lowing solution : 
 
 The solution can also be brushed over the , 
 paper by means of a cotton brush. The paper 
 being iodized is hung up to dry. 
 
 The proportion of chloride of ammonium 
 can be varied. When negatives are used, 
 which are intense enough to give good ammo- 
 nia nitrate prints by contact, the quantity of 
 chloride of ammonium maybe reduced to one 
 drachm. With very weak negatives, such as 
 are required to make direct prints by means of 
 the solar camera, it can be increased to one 
 half ounce. The proportion given in the for- 
 mula is adapted for negatives of medium in- 
 tensity, and will be found generally useful. 
 
 The French and German papers take, after 
 being iodized, a reddish color, which is due to 
 the starch used as sizing. The English pa- 
 pers, which are sized with gelatine, remain 
 white. 
 
 The paper should not be iodized longer than 
 a few days before it is used. 
 
 Iodide of potassium,. . , 
 Chloride of ammonium 
 Distilled water 
 
 , ounce. 
 , k£ ounce. 
 40 ounces. 
 
182 
 
 The following is the formula for the silver 
 solution : 
 
 This solution has first to be saturated with 
 fjdide of silver, if not, it dissolves the iodide 
 of silver from the surface of the paper, and 
 nothing but a faint image can be obtained. 
 Two grains of iodide of potassium, dissolved 
 in a small quantity of water, will yield iodide 
 of silver enough to saturate the solution. The 
 solution being filtered, pour into it, a few 
 drops at a time, a solution of acetate of am- 
 monia, until the precipitate of acetate of silver 
 which is formed ceases to be dissolved by agi- 
 tation, after which filter again. The solution 
 of acetate of ammonia is made by neutralizing 
 aqua-ammonia by means of acetic acid, till the 
 smell of the ammonia has disappeared, and 
 the liquid has a faint acid reaction on litmus 
 paper. 
 
 As a developer use in cold weather a satur 
 ated solution of gallic acid in distilled or rain 
 water, and add to it a few drops of acetic acid, 
 to prevent it from decomposing. During the 
 summer months, dilute it with an equal bulk 
 of water. 
 
 The fixing solution is prepared according to 
 the following formula. 
 
 Nitrate of silver,. 
 Distilled water, . . 
 Acetic acid, No. 8 S 
 
 1 ounce. 
 12 ounces fluid. 
 , 2 ounces. 
 
 Hyposulphite of soda, 
 
 Water, 
 
 Bi-carbonate of soda, . , 
 
 .16 ounces. 
 . 40 ounces. 
 . ounce. 
 
183 
 
 The paper having been iodized and dried, 
 set the image in focus, using to focus upon one 
 of your dishes on the glass of which has been 
 pasted a piece of white paper. The focussing, 
 as we have seen already, should not be done 
 with the sunlight reflected upon the negative, 
 but by diffused light. This being done, pour 
 the silver solution in the glass dish and inl- 
 ine rge the paper for about five minutes. 
 When the one sized with starch is used, it is 
 very easy to see when all the iodizing is trans- 
 formed into iodide and chloride of silver, for the 
 reddish color disappears, and the paper, from 
 opaque, becomes transparent. 
 
 In order to have pictures free from stains and 
 spots, the greatest cleanliness is required. The 
 dishes have to be well washed and the solutions 
 filtered. The silver solution has also to be in 
 such a quantity as to enable you to pass the 
 paper through it without pauses, otherwise 
 lines will be produced similar to those found 
 on collodion plates, when checked while dip- 
 ping them. 
 
 After the paper has been silvered, pour 
 off the silver solution, and put the dish in 
 its place on the stand. Fasten the upper part 
 of it to the stand, by means of a string or an 
 iron wire, and put a bottle and funnel under it 
 to receive the silver solution which drains from 
 the paper. Then put on the cover of your 
 tube, put the diaphragm in its proper place, 
 and bring the reflector in such a position that 
 
184 
 
 the spark passes through the center of the 
 aperture. The time of exposure cannot be 
 given, it must be judged by the appearance 
 of the paper. The more intense the negative 
 is, the more it will be necessary to see the 
 image before developing. The more chloride 
 of ammonium has been used in the first pre- 
 paration, the stronger also the image will have 
 to be printed. If a weak negative was used 
 to produce an image, on paper in which little 
 chloride of ammonium is used, it will be neces- 
 sary only to see the stronger outlines which 
 will, in good light, take only a few seconds. 
 Chloride of silver thus gives strength to the 
 image, but causes the paper to be less sensi- 
 tive. 
 
 It will be necessary, if the spark changes 
 perceptibly its place during the exposure of the 
 sensitive paper to light, to bring it again into 
 the center by moving slightly the reflector. 
 
 The next operation is the development. 
 Lay the dish containing the impressioned pa- 
 per flat on the table, and cover it with the de- 
 veloping solution, using to pour it on a bottle 
 with a wide mouth. This requires to be done 
 with some dexterity, as lines of irregular de- 
 velopment might be produced. It will be 
 necessary in the start to use about eight or ten 
 ounces of the developer to cover well a sheet 
 of photographic paper, but with a little prac- 
 tice, the operator will be enabled to do it with 
 half this quantity. When the paper, by long 
 
185 
 
 exposure, has partially dried, a larger quanti- 
 ty of developer has to be used than otherwise, 
 as it is difficult to cover it in this case. 
 
 Two stages in the development are noticed: 
 the first stage, in which the picture appears 
 with almost all of its details, but has a red 
 tint ; the second stage, in which but very little 
 more appears, but in which the tint of the 
 picture from red is changed to black. An 
 over exposed print develops with great rapi- 
 dity, and entirely, before the second stage is 
 reached, and, if the development is carried to 
 that point, will lose the purity of its whites. 
 An under exposed print develops slowly, and 
 becomes black before all the half tones have 
 made their appearance. 
 
 The black image obtained by full develop- 
 ment to the second stage changes little in the 
 hyposulphite. The tint of such an image is 
 not as pleasing as the one of a direct positive 
 print, properly toned. A much better tone 
 can be obtained by exposing the paper a little 
 longer to the light, developing it to the red 
 stage and toning it in the alkaline chloride of 
 gold bath. Such prints are altered slightly 
 during the toning and fixing, so that they will 
 have to be developed a little stronger than they 
 are intended to appear. 
 
 In warm weather the development proceeds 
 rapidly, in cold weather it goes on very slowly. 
 It is advisable then to keeo the developing so- 
 ls 
 
186 
 
 iution slightly warm, by letting it remain near 
 a fire. 
 
 It is easy to be deceived by the appearance 
 of the print during the development, for by 
 artificial light it seems always darker than by 
 day light. 
 
 When the picture has arrived at the re- 
 quired intensity, the development has to be 
 stopped. This cannot be done by washing it, the 
 gallic acid and nitrate of silver remaining long 
 in the paper, and the development continuing 
 while the proof is soaking in the water. The 
 proper way is to precipitate the silver in an 
 insoluble state by pouring on a solution of 
 common salt. The salt transforms the free 
 nitrate of silver into chloride, and the develop- 
 ment is stopped instantaneously. There is no 
 necessity of pouring out the developing solu- 
 tion before adding the salt water. The chlo- 
 ride of silver thus formed can be collected and 
 transformed into metallic silver in the ordi- 
 nary way. 
 
 The picture should not be allowed to remain 
 in the solution of salt, as the salt has the power 
 of transforming into white chloride, the finely 
 divided silver which forms the image. 
 
 The development being stopped, the print 
 is washed several times in clean water to re- 
 move all the gallic acid, after which it is toned, 
 fixed and washed in the same way as the 
 direct positives. The first washing, the toning 
 find the fixing should not be done in strong light, 
 
187 
 
 as the purity of the whites would be affected. 
 The fixing is done when the yellow appear- 
 ance given to the paper by the iodide of silver 
 has disappeared by transmitted light. The 
 hyposulphite has then to be washed out with 
 the same care and by the same means as in 
 the ordinary printing process. 
 
 Instead of silvering, exposing and develop- 
 ing in a dish, the paper can be pinned on 
 a board covered with a sheet of blotting pa- 
 per, and the solution brushed on. This 
 requires to be done with some dexterity, to 
 avoid marks of the brush or cotton. It is also 
 advisable, to make the silver solution a little 
 stronger, using, for instance, nine or ten, in- 
 stead of twelve ounces of water to the ounce 
 of nitrate of silver. The focus is taken on 
 the paper itself before sensitizing. After 
 sensitizing, the paper is found to have ex- 
 panded considerably, so that it has to be 
 stretched out again. The focus also may have 
 to be adjusted again; the sensitive paper 
 being a little nearer the lens. 
 
 Another Process. 
 
 The process we are going to describe now 
 is different in two respects from the foregoing : 
 1st, The iodide of silver, instead of being 
 formed by floating the paper alternately upon 
 solutions of iodide of potassium and nitrate of 
 silver, is formed by brushing on it the double 
 iodide of potassium and silver, and decompos- 
 
188 
 
 ing the double iodide by soaking in water, 
 2d, The paper is rendered sensitive by means 
 of aceto-nitrate of silver and gallic acid, instead 
 of aceto-nitrate of silver alone. 
 
 Iodizing. — A solution of double iodide of 
 silver and potassium is prepared in the follow- 
 . ing way : Take 120 grains iodide of potassium ♦ 
 and 120 grains nitrate of silver, dissolve each 
 of these salts in ten ounces of distilled water, 
 and mix the solutions together in a quart bot- 
 tle. The precipitate which is thrown down 
 is iodide of silver, and is allowed to settle, 
 when the liquid is poured off, and the precipi- 
 tate is washed several times with distilled 
 water, in the manner described on page 55, 
 the washing with alcohol, of which there is 
 question there, being dispensed with. The 
 iodide of silver is then put into a measure, the 
 measure is filled up to six ounces with distilled 
 water, and iodide of potassium is added to it 
 until the whole of the iodide of silver is dis- 
 solved. This will take about two and a half 
 ounces. The double iodide of silver and 
 potassium thus obtained has to be filtered 
 through Swedish paper into a clean and dry 
 bottle. 
 
 The paper is floated on this solution, or the 
 solution is brushed over the paper by means 
 of a cotton brush, such as is used to silver the 
 ammonia-nitrate paper, after which it is hung 
 up to dry. One sheet of photographic paper 
 
189 
 
 will take up four or five drachms of the so- 
 lution. ' 
 
 The next operation consists in decomposing 
 the double iodide of potassium and silver by 
 means of water. We must remark here, that 
 when to a solution of this salt water is added, 
 the iodide of silver will immediately precipi- 
 tate, for a concentrated solution of iodide of 
 potassium only has the power to dissolve the 
 iodide of silver. When the paper prepared 
 as described above is immersed in a tray of 
 water, the iodide of potassium will dissolve 
 and leave the iodide of silver in the texture of 
 the paper. The paper should be allowed to 
 soak in the water for about half an hour, the 
 water is then changed, and it is left in for half 
 an hour or an hour longer, after which it is hung 
 up to dry. Instead of the first soaking, it may 
 be washed for five or ten minutes under a 
 hydrant or tap, in the way prescribed to 
 remove the hyposulphite out of prints. See 
 page 157. When a number of sheets of paper 
 have to be washed, several may be immersed 
 at a time, if abundance of water is used, and if 
 frequently turned over and changed. 
 
 The paper prepared this way is said to keep 
 any length of time. It is of a pale yellow 
 color and is insensitive to light 
 
 Sensitizing.— When required to be used, it is 
 laid down flat, and the back is moistened with 
 a sponge to prevent unequal expansion in the 
 subseouent* operations. It is then pinned 
 
X 
 
 190 
 
 or tacked on a screen. The preliminary 
 arrangements to the exposure may have been 
 made beforehand, or the paper which has to 
 receive the image can be used to focus upon. 
 The last plan is more expeditious. 
 
 The paper is now ready to be made sensi- 
 tive to the light. For this, prepare the four 
 following solutions, which we will call, Nos. 1, 
 2, 3 and 4 
 
 N0» 1 — Nitrate of silver, 480 grains. 
 
 Acetic acid, No. 8 4 ounces fluid. 
 
 Distilled water, 8 ounces fluid. 
 
 NO. 2— Gallic acid 1 drachm. 
 
 Alcohol, h 2 ounces fluid. 
 
 Acetic acid, No. 8, 1 ounce fluid. 
 
 Distilled water, 9 ounces fluid. 
 
 NO. 3— Solution, No. 1, 1% ounces fluid- 
 
 Distilled water, 10 ounces fluid, 
 
 NO. 4— Solution, No. 2, 2 drachms fluid, 
 
 Distilled water, 12 ounces fluid. 
 
 Mix four drachms of solution No. 3, and the 
 same quantity of solution No. 4 together, pour 
 the mixture on the paper, and with a cotton 
 brush spread it equally over the surface, brush- 
 ing it across the paper and up and down. 
 This should be well attended to, otherwise the 
 marks of the brush might show after develop- 
 ment. 
 
 When the paper is well saturated, the ex- 
 cess, if there is any, is drained off, and the 
 paper is exposed to the light. 
 
 The quantities given above are for a whole 
 sheet of photographic paper. 
 
 Exposure to light — The paper prepared by 
 
191 
 
 this method is more sensitive than the one 
 described before. The developing going on 
 already while the light is acting, it will be 
 necessary to see more of the image before the 
 final development than when no gallic acid is 
 used in the sensitizing. With such negatives 
 as give good prints by contact on ordinary 
 ammonia-nitrate paper, the exposure will have 
 to be continued until the image is well seen in 
 all the outlines, and the half dark shadows are 
 marked. With weak negatives, it should not 
 be pushed so far. 
 
 Development. — The developing fluid is com- 
 posed of one part of solution 'No. 1, mixed with 
 six parts of solution No. 2. This mixture is 
 spread over the paper with the same brush 
 which has been used to sensitize. This should 
 be done with dexterity and rapidly to prevent 
 marks of the brush being produced. If the 
 paper is of a large size, or if it has been over 
 exposed, it is best to dilute the developing 
 fluid with an equal quantity of water. This is 
 also to be recommended in warm weather. If 
 the paper, by being exposed a long time, has 
 become too dry, it is advisable to brush it over 
 with the mixtures, No. 3 and No. 4, before ap- 
 plying No. 1 and ~No. 2. The image develops 
 generally slower than when the other process 
 is used. When it has fully appeared, spread 
 over it a solution of salt, which, in precipitating 
 the nitrate of silver in the state of chloride, will 
 stop the development. 
 
192 
 
 Toning, fixing and washing. — The image can 
 be toned in the alkaline gold bath, if any 
 toning is required. For prints which have to 
 be painted, the development can be pushed to 
 the second stage, when no toning will be neces- 
 sary. The fixing is done in the same solution 
 which has been prescribed for the other pro- 
 cess. 
 
 It is perhaps well to repeat here that before 
 toning or fixing, the gallic acid should be 
 washed out, to prevent decomposition of the 
 toning or discoloration of the fixing solution. 
 
 To work successfully this process, every 
 thing should be kept with the greatest clean- 
 liness. The measuring glass, in which solutions 
 Nbs. 1, 2, 3 and 4 are mixed, should be washed 
 out after each operation, and care should be 
 taken to remove the black deposit which forms 
 in it. The mixture of gallic acid and nitrate 
 of silver will keep for hours in the dark,- but 
 if the slightest trace of this deposit was present, 
 it would discolor in a few minutes. The same 
 cause necessitates the use of a new brush for 
 each picture. 
 
 The great sensitiveness of this process will 
 oblige the operator to use the utmost caution 
 to shield his sensitive paper from the influence 
 of light. Every part of the negative, which is 
 not to be printed, should be covered with a 
 mat, and the diaphragm should be as small as 
 possible, so as to admit no unnecessary light 
 
I 
 
 193 
 
 in the dark room. The artificial light should 
 also be as feeble as possible. 
 
 0 
 
 CHAPTER XXXIV. 
 
 Preserved and Drf Collodion Processes. 
 
 If a sensitized collodion plate is kept for 
 some time, the solution of nitrate of silver, 
 concentrating by evaporation, will dissolve 
 the iodide of silver, and afterwards crystallize, 
 thus destroying the film. The collodionized 
 and sensitized plate should thus be exposed 
 and developed immediately after its prepara- 
 tion, so that the landscape photographer is 
 obliged to have on the spot, where he wishes 
 to take a view, all the paraphernalia belong- 
 ing to the wet process, including a dark 
 closet or tent, in which to sensitize and de- 
 velop the plate. 
 
 The great disadvantage of this process for 
 out-door work, principally when the site for 
 operating is of difficult access, has naturally 
 induced researches as to the practicability of 
 preserving the collodion film. It was pro- 
 posed at first, by Messrs. Spiller and Crookes, 
 to use, mixed with the silver bath, some salt pos- 
 sessing strong deliquescent properties, so that 
 the film, after sensitizing, was kept moist. 
 This process, however, gave but imperfect 
 results. Mr. G. -Shadbolt then proposed to 
 ir 
 
194 
 
 cover the plate, after sensitizing, with diluted 
 honey. This was done immediately after 
 withdrawing the plate from the bath; or 
 the plate was washed to remove the larger 
 quantity of nitrate of silver, before the honey 
 was applied. Mr. Llewellyn substituted ox- 
 ymel, in diluted solution, to honey. Oxy- 
 mel is a mixture of honey and acetic acid. 
 Both processes were, however, abandoned,, 
 on account of the difficulty of keeping the 
 plates longer than a day, and the tendency to 
 fogging, caused by the action of the honey 
 on the free nitrate of silver. 
 
 Experiments were then made to use the 
 collodion plate in a dry state. It was dis- 
 covered, that under certain conditions, a plate 
 which had been washed and then dried y was 
 still sensitive ; and, that after a comparatively 
 long exposure, such a plate yielded an image 
 by development with gallic orpyrogallic acid, 
 and nitrate of silver. In this process success 
 seems to depend on the molecular state of 
 the collodion, and on the presence in it of cer- 
 tain kinds of organic matter, which produce 
 a sensitive compound with nitrate of silver. 
 Collodion prepared with a certain variety of 
 pyroxyline, and allowed to ripen, seems gen- 
 erally to possess these qualities. Also, collo- 
 dion which has been partly decomposed, or 
 to which a small quantity of resin has been 
 added. 
 
 The theory of the dry collodion process is 
 
195 
 
 a problem which we will not here attempt to 
 solve* We will merely dwell somewhat on 
 the two conditions necessarv to success, which 
 we have just mentioned. First, The collo- 
 dion film, instead of being hard and horny, 
 should be soft and porous. The reason for 
 this is easily understood. For if the film, 
 after washing and drying, presents a glassy 
 or polished surface, impenetrable to liquids, it 
 will be impossible to deposit reduced silver in 
 its texture during the process of development. 
 Second, The collodion should also contaui 
 matter capable of forming a sensitive sub- 
 stance by combination with silver ; for it is a 
 well known fact, that iodide of silver, perfectly 
 washed, is quite insensitive to light ; and that 
 pure pyroxyline, free from the species of or- 
 ganic matter alluded to, is entirely unaftected 
 by the salts of silver. But iodide of silver, 
 in the presence of nitrate of silver, or of an 
 organic silver compound, is a sensitive sub- 
 stance ; so that a plate imperfectly washed, or 
 one prepared with the species of collodion 
 spoken of above, is still in a sensitive con- 
 dition. But imperfectly washed plates keep 
 but a very short time, so that this means of 
 preserving the sensitiveness is unavailable. 
 
 The collodion for the dry process should be 
 prepared with pyroxyline made at a high 
 temperature, and with excess of sulphuric 
 acid, as recommended by Harclwich. Such 
 collodion contains the organic principle neces- 
 
196 
 
 sary in the dry processes ; and after it has been 
 kept some time, or when mixed with about 
 one-fourth of old .decomposed collodion, the 
 quantity of this principle is increased, and 
 the collodion becomes sufficiently porous. 
 
 Although, under the conditions we have 
 spoken of, that is, a porous film, and the pres- 
 ence of a sensitive organic silver compound, 
 negatives can be obtained on plates merely 
 washed and dried, success is more certain, 
 when the plate, after washing, is coated with 
 some organic substance, like albumen, gela- 
 tine, gum arabic, tannin, etc. The function 
 of these substances seems to be : First, To 
 fill up the pores of the collodion film, so that 
 it be penetrable by liquid when dry ; and, 
 second, To facilitate the deposit of silver 
 during the development. 
 
 We will describe now some of the dry pro- 
 cesses most in use : 1st, The tannin process; 
 2d, The tannin and honey process ; 3d, The 
 colloclio-albumen process ; 4th, The Fother- 
 gill albumen process. 
 
 CHAPTER XXXV. 
 
 The Tannin Process. 
 
 In the tannin process, as described by 
 Major Russell, the plate is first coated with a 
 solution of gelatine, then collodionized, ex- 
 ciled and washed, and finally coated with a 
 
197 
 
 solution of tannin, and dried. In the case, 
 however, when the collodion used is well 
 adapted to the dry process ; that is, when it 
 contains the organic principle before alluded 
 to, and gives a film which is porous when dry, 
 the coating with gelatine can be dispensed 
 with. According to Major Russell, the pre- 
 vious coating with this substance makes suc- 
 cess independent of the state of the collodion, 
 and causes the film to adhere better to the 
 glass. 
 
 We will divide the description of the tan- 
 nin process into seven parts : 
 
 1 . Cleaning of the glass. 
 
 2. Collodionizing, exciting and washing. 
 
 3. Coating with tannin. 
 
 4. Exposure in the camera. 
 
 5. Developing. 
 
 6. Fixing." 
 
 7. Drying and varnishing. 
 
 Major Russell recommends that the edges 
 of the glass should be ground, and that the 
 grinding should extend a little way on the 
 surface when the previous coating with gela- 
 tine is dispensed with. This operation he 
 describes as follows : The neatest way to 
 grind the glass in this manner, is with a piece 
 of stout sheet copper, along the middle of 
 which has been soldered a narrow strip of the 
 same metal, about one-sixteenth of an inch 
 thick ; on the other side a piece of wood may 
 be screwed, to give a better hold. Mix some 
 
198 
 
 silver sand, brown sugar and water, and with 
 a little of this mixture in the angle, rub the 
 thick copper against the edge of the glass, at 
 the same time grinding the upper surface with 
 the lower edge of the thin strip. The plate 
 is held down with the left hand on a piece of 
 wood, or other convenient place, with the 
 edge that is being ground slightly projecting ; 
 if it project far, the glass may be broken. 
 The edge and a narrow strip on the surface 
 can in this way be ground without wanding 
 off the angle. The use of the sugar is to 
 render the dirt more easy to w r ash off. If the 
 plates are to be coated with gelatine, it is 
 better to grind only the edges, for the ground 
 glass impedes the flow of the gelatine, and is 
 not in this case required to make the film 
 adhere. 
 
 The cleaning of the glass should be done 
 with the greatest care, as any greasiness 
 would repel the gelatine with which they have 
 to be coated. 
 
 The following is the formula of the gela- 
 tine solution : 
 
 Put the gelatine with the w T ater in a porce- 
 lain evaporating dish, leave it until the gela- 
 tine has softened, and warm to effect its solu- 
 
 Coating with Gelatine. 
 
 Cox sparkling patent gelatine 
 
 Distilled water, k 
 
 Acetic acid, No. 8, 
 
 Alcohol, c 
 
 60 gains. 
 12 ounces. 
 3 drachms, 
 2 ounces. 
 
199 
 
 tion. Then add the alcohol and the acetic 
 
 acid, and filter through a tuft of cotton. 
 
 The coating with gelatine should be done 
 In a warm room, free from dust, and the so- 
 lution itself should be warm enough to flow 
 easily. It can be poured on to the glass out of 
 a wide-mouthed bottle in the same manner as 
 collodion, or the plate can be put on a level- 
 ing stand and the solution poured on it, using 
 a "glass rod bent at one end, to spread it over 
 the surface, In either case the excess is re- 
 turned to the funnel to be filtered. The use 
 of the india-rubber pneumatic plate-holder is 
 much to be recommended, as it will avoid the 
 handling of the glass with the fingers. 
 
 The plate being coated with the gelatine 
 solution, is set to drain on a sheet of blotting 
 paper. 
 
 Care should be taken to have no gelatine 
 on the back of the plate, for it would certainly 
 spoil the nitrate of silver bath. 
 
 Gelatinized plates will remain good any 
 length of time if kept perfectly dry. 
 
 The collodion should be allowed to dry 
 longer than in the wet process, before dipping, 
 so that the film adheres well to the plate. 
 The plate should also be kept longer in the 
 silver solution, so as to ensure the transfor- 
 mation of the iodide and bromide in the col- 
 lodion, in iodide and bromide of silver. 
 
 COLLODIONIZING, EXCITING AND WASHING*. 
 
 With the previous coating with gelatine, 
 
200 
 
 almost any good negative collodion can be 
 used. If you want to prepare it expressly 
 for the purpose, use it according to the follow- 
 ing formula : 
 
 Iodide of ammonium*. 24 grains. 
 
 Iodide of cadmium, 8 grains. 
 
 Bromide of cadmium, 20 gra na. 
 
 Negative pyrosyline,. „ .59 to 65 grains. 
 
 Alcohol, 4 ounces. 
 
 Ether, 4 . . 4 ounces. 
 
 When the plate has not been coated with 
 gelatine, it will be necessary to use a collo- 
 dion, giving a short and powdery film. The 
 one prepared according to the following direc- 
 tions, will answer the purpose : To four 
 ounces of alcohol add ten grains of bromide 
 of ammonium, dissolved in a small quantity 
 of water, and mix with four ounces of ether. 
 Add then thirty-two grains of iodide of am- 
 monium, and. eight grains of bromide of cad- 
 mium, and shake until dissolved. If the 
 liquid be opalescent, let it become clear by set- 
 tling, and to the clear part add from fifty to 
 sixty-five grains of negative pyroxyline, made 
 at a high temperature. 
 
 This collodion may give a suitable film im- 
 mediately after its preparation, but if it does 
 not, it will have the required qualities after 
 being kept a short time. 
 
 The silver solution is prepared as follows : 
 
 Nitrate of silver, 1 ounce. 
 
 Distilled w.4 r, 12 ounces. 
 
 Iodide of potassium, & grains. 
 
 Acetic acid, .No. 8, 4 drops* 
 
 The plates are to be coated with collodion. 
 
201 
 
 sensitized and washed. The col- 
 lodion should be allowed to dry 
 longer than in the wet process, 
 before clipping, so that the film 
 adheres well to the plate. The 
 plate should also be left longer 
 in the silver solution, so as to 
 insure the transformation of 
 all the iodide and bromide in 
 the collodion, in iodide and bromide of 
 silver. If the common water which is 
 on hand, is pure enough not to give a pre- 
 cipitate with nitrate of silver, it can be used 
 for all the washings ; if not, distilled water 
 should be used at first. The washing can be 
 done by means of the washing bottle, (see 
 annexed figure,) or under a tap, or in vertical 
 or horizontal baths. 
 
 A very expeditious way is the following : 
 Fill two vertical baths with distilled water, 
 and two or three porcelain dishes, one of 
 which should be large, with common water, 
 and place all near the silver bath. Coat a 
 plate with collodion and sensitize it in the 
 ordinary way, only leaving it a little longer 
 in the silver solution than in the wet process. 
 When it is about ready, collodionize another 
 plate and lay it down on the mouth of a bot- 
 tle. Now take out the first plate, drain it, 
 and put it in the first washing bath ; then 
 sensitize your second plate. If your bath is 
 large enough to hold two plates, you will find 
 
202 
 
 it more convenient to clip the second before 
 taking out the first. Wait now till the sec- 
 ond is nearly ready, when yon put the first in 
 the second bath, coat a third one, put the 
 second in the first bath and dip the third. 
 Proceed in this way until all your plates are 
 done, removing them from one bath or dish to 
 the other, and leaving them all in the last one, 
 which should be of large size. While the 
 plates are in the washing baths or dishes, they 
 should be moved up and down, to facilitate 
 the washing. The flat dishes or trays should 
 be kept covered to avoid light and dust. The 
 plates are left in the last dish for half an 
 hour or an hour, as it is very important that 
 all the nitrate of silver be removed. They 
 are then ready to be coated with tannin. 
 
 Coating With Tannin. 
 
 Dissolve four drachms of tannin in twelve 
 ounces of distilled water, filter the solution 
 till it is clear, and add one ounce of alcohol. 
 
 The plate having been washed and drained 
 for a minute or two, the tannin solution is 
 poured on it and moved back and forth, till 
 an even coating is obtained, when it is 
 poured off. The same thing is then done with 
 a fresh quantity. The tannin solution used 
 for the first coating may be used over and 
 over again, and the draining of the second 
 added to it ; but for the second coating, fresh 
 solution has always to be used. 
 
203 
 
 Figure 2. 
 
 The plate being coated is set to drain and 
 dry on blotting paper, or on a draining stand. 
 (See figure 2.) 
 
 Some dry plate workers wash the plate 
 again at this period of the operation, but we 
 have found that the development did not pro- 
 ceed so well when this was done. 
 
 It is almost useless to say that all these 
 operations must be done at night or in a dark 
 room. It is even necessary to use a very 
 feeble artificial light, as the plates would 
 otherwise be acted upon, they being exposed 
 to its influence during a long time. 
 
 The drying should not be done by direct 
 application of heat, but rather spontaneously 
 in a room warmed at a moderate temperature. 
 
 If the plates have not been coated with 
 gelatine, dip a little brush in any quick dry- 
 
2Q4 
 
 ing varnish, and run it round the edge of the 
 film. 
 
 The plates should be kept in a grooved box, 
 with a well fitting cover. If well washed, 
 they will keep their sensitiveness for one 
 month, or perhaps longer. It is safest, how- 
 ever, to put as little time between the prepar- 
 ation and development as possible. The use 
 of a changing box, to change the plate in the 
 open air from the plate-holder, and vice versa, 
 is recommended. 
 
 (Figure 3.) 
 
 The accompanying cut represents one of 
 these boxes. It is an ordinary grooved box, 
 of which the cover, F G, has an opening 0, 
 large enough to slide a plate through. This 
 opening, is kept shut to prevent the admittance 
 
of the light by means of the spring R. The 
 cover slides right and left, and can be set so that 
 the opening 0 is over any one of the grooves 
 in the box. 
 
 The plate-holder 
 is represented in 
 figure 4. 0 is an 
 opening to slide the 
 plate through. The 
 back, P, is pushed 
 out by means of 
 springs, and when 
 in that state the 
 slide 0 is open, but 
 if P be pushed back 
 and T turned, the 
 slide 0 is shut.— 
 Now to change a 
 plate from the 
 plate-box to the 
 holder slide this on 
 
 Figure 4. the part I, J, M, N 
 
 of the cover, loosen the back P, pull the 
 knob R, and turn the box upside down, 
 when the plate will fall in the holder, and 
 the back P is pushed down to secure it. 
 To change the plate from the holder to the 
 box, slide the holder on the cover, loosen the 
 back and pull back the knob. 
 
 Some difference will be found in the sensi- 
 tiveness of the plates. The principal causes 
 of insensitiveness are the use of a collodion 
 
206 
 
 containing no bromide, or of too old a sam- 
 ple, or of a bath containing much more acid 
 than is required to make a bright picture. 
 
 Exposure in the Camera. 
 
 The time of exposure will range from four 
 to ten times as much as for wet collodion. 
 
 Developing. 
 
 If the exact time of exposure could be al- 
 ways insured, it would be easy to give a form- 
 ula for a developing solution, which would 
 always answer. In the dry processes this is 
 impossible, as the time of exposure must al- 
 ways be more or less uncertain, unless each 
 plate is immediately developed, and so the 
 proper time for exposure be ascertained for 
 the next. We can thus only give general 
 rules, which, to produce the best results, must 
 be slightly varied in almost every case. The 
 following formula will be found to give devel- 
 oping fluids suitable for this purpose: 
 
 No. 1. — Pyrogallic acid 26 grains. 
 
 Strong Alchohol , , 1 ounce. 
 
 No. 2. — Nitrate of Silver 10 grains. 
 
 Citric acid.. « 20 grains. 
 
 Distilled water 1 ounce. 
 
 For a stereoscopic plate, put one drop of 
 No. 1 in two or three drachms of distilled wa- 
 ter and filter into a small glass measure. 
 While this is being done, dip the exposed 
 plate into a bath or dish of distilled water, 
 and after a few T seconds immersion, lift it out, 
 allow it to drain and wipe the back dry. Lay 
 l 
 
207 
 
 it then oil a levelling stand, and having mixed 
 one drop of No. 2 to the diluted No. 1, which 
 has been filtered, pour the mixture on the end 
 of the plate and incline it so as to cause it to 
 flow towards the other end and back in the 
 glass. Repeat this several times, examining 
 the plate by transmitted light, and If nothing 
 appear in three or four minutes add one drop 
 more of pyrogallic. If, on the contrary, the 
 image appears quickly and is full of detail, 
 but looks flat from want of contrast, add more 
 silver. It may happen, also, that from great 
 over exposure the film begins to redden imme- 
 diately ail over, showing the image but faintly ; 
 if so pour off the developer and replace with 
 a few drops of No. 2 diluted, when the py- 
 rogallic acid left in the film will be quite suffi- 
 cient to complete the development. If the 
 image shows about the right contrast and the 
 middle tints begin to appear at the proper time, 
 the No. 1 and No. 2 may be added together, 
 and if too much of either has inadvertently 
 been added, the developer is poured off and 
 replaced by a fresh one in the proper propor- 
 tions. Should the solution get turbid, reject 
 and make a fresh one. 
 
 When no previous coating of gelatine has 
 been used, the collodion will sometimes, on 
 being wetted, expand strongly, so as to be 
 forced up into ridges, but it will generally 
 contract again in ten or fifteen minutes. The 
 
208 
 
 development must not be begun before this 
 contraction takes place. 
 
 The development being completed, wash 
 until the oily appearance is removed. The 
 film, when the plate is coated with gelatine, is 
 so strong that it cannot be injured by a heavy 
 stream of water. 
 
 Fixing. 
 
 Cyanide should not be used for fixing, as 
 any alkaline liquid will losen the film. The 
 strength of the hyposulphite is of little conse- 
 quence. The proportion we have given for 
 wet collodium, six ounces to a pint, will an- 
 swer. The film will sometimes become loos- 
 ened in the first washing. When this hap- 
 pens, wash with a small quantity of water, 
 changing often. The film, if not on gelatine, 
 may crack or split off on drying. It is then 
 the best to cover it after draining with a thin 
 solution of gum arabic. 
 
 Drying and Varnishing. 
 
 The plates are set to dry on blotting paper, 
 and when dry are coated with any of the ordi- 
 nary varnishes used for negatives. 
 
 CHAPTER XXXVI. 
 
 The Tannin and Honey Process. 
 
 By using as a preservative a mixture of ] 5 
 grains of tannic acid 15 grains of honey to 
 the ounce of water, greater sensitiveness is 
 
209 
 
 said to be obtained than by the use of tannin 
 alone. Mr. England, who proposed this modi- 
 fication of the tannin process, and who prac- 
 tices it successfully, gives the following for- 
 mula : 
 
 Plain Collodion. 
 
 Alcohol .„ 3 parts. 
 
 Ether , , 5 parts. 
 
 Pyroxyline, sufficient to give a tolerably thick film. 
 
 Iodizing Solution. 
 
 Plain eollodion. 2J^ ounces fluid. 
 
 Bromide of cadmium 40 grains, 
 
 lodideof ammonium 30 grains. 
 
 Iodised Collodion. 
 
 Plain collodion 3 ounces fluid. 
 
 Iodizing solution * , 1 ounce fluid. 
 
 Sensitize in a 40-grain neutral bath and 
 wash in a bath or tray with distilled water, 
 slightly acidulated with acetic acid. Give it a 
 final washing under a tap. Then coat with 
 the solution of tannin and honey, fifteen grains 
 to the ounce of each, and set to dry on blot- 
 ting paper. If properly prepared and stored 
 away these plates will keep ten months. To 
 prevent the film from leaving the glass pass a 
 sable pencil, previously clipped in a solution 
 of white wax and benzine, round the edge of 
 the plate, to the extent, say, of one-eighth of 
 an inch. 
 
 Before developing, the plate is left for about 
 one minute in a bath prepared with 10 grains 
 of nitrate of silver and 5 drops pf acetic acid 
 to the ounce of water. By adopting this plan 
 the action of the developer is almost as rapid 
 
 18 
 
210 
 
 as in the wet process. Develop afterwards 
 with the pyrogallic acid solution as usual. 
 
 The method of development recommended 
 by Major Russell, and described in the pre- 
 ceding chapter, can also be adopted. 
 
 CHAPTER XXXVII. 
 
 The Collodio- Albumen Process. 
 
 In the Collodio- Albumen Process success is 
 less dependant on the presence of organic 
 matter in the Collodion than in any other dry 
 process used. The reason for this is that the 
 film of iodized albumen, with which the 
 washed plate is covered, is itself transformed 
 into a sensitive substance similar to the one 
 found on the ordinary albumen plates. In 
 fact Faupenot's process is in all respects the 
 same as the albumen process first practiced by 
 Mepe de St. Victor, with the exception that 
 the iodized albumen, instead of being directly 
 used as a coating on glass, is . used on a collo- 
 dionized, sensitized and washed plate. 
 
 As far as sensitiveness and success is con- 
 cerned, the collodio-albumen process, although 
 more complicated, is superior to the plain al- 
 bumen process. The only drawback is the 
 want of adhesiveness of the film, producing a 
 great tendency to blistering during the devel- 
 opment. This can be remedied by using old 
 and decomposed collodion, or collodion made 
 
211 
 
 with a sample of pyroxyline, giving a soft and 
 porous film. 
 
 The operations to be performed can be 
 divided as follows : 
 
 1. Formation of the sensitive collodion film. 
 
 2. Formation of the sensitive albumen film. 
 
 3. Exposure. 
 
 4. Development and fixing. 
 
 Formation of the Sensitive Collodion Film. 
 
 The collodion, as we have already noticed, 
 should give a short and powdery film. If 
 prepared expressly for the purpose, the follow- 
 ing formula may be adopted : 
 
 Sulphuric Ether 
 
 Alcohol 
 
 Pyroxyline... 
 
 Iodide of Ammonium... 
 Bromide of Ammonium 
 
 8 ounces, fluid. 
 8 ounces, fluid. 
 100 grains. 
 80 grains. 
 40 grains. , 
 
 The pyroxyline should be of the variety 
 
 producing the qualities already spoken of, and 
 
 the collodion should be allowed to stand for one 
 
 or two months, so that the alkaline iodide and 
 
 bromide, by their action on the dissolved cotton, 
 
 improve the adhesive qualities of the collodion. 
 
 The plate is coated, sensitized, and washed in 
 
 the ordinary way, after which it is drained 
 
 previous to coating with the albumen. 
 
 i 
 
 Formation of the Sensitive Albumen Film. 
 
 The albumen solution is prepared according 
 to the following formula: 
 
212 
 
 Albumen from fresh Eggs 
 
 White Sugar 
 
 Distilled Water 
 
 Cone. Ammonia 
 
 Iodide of Ammonium 
 
 Bromide of Ammonium 
 
 10 drops. 
 10 grains. 
 5 grains. 
 
 0 ounces, fluid* 
 J ounce. 
 
 1 ounce, fluid. 
 
 Beat to a froth and allow to subside. 
 
 The washed and drained plate is covered 
 with the albumen solution and drained for 
 half a minute. It is then covered with a 
 fresh portion, and set to drain and dry on 
 blotting paper, or on a draining stand. The 
 second portion used on the first plate can be 
 used to coat the second, and that of the second 
 can be used for the third. It should never be 
 returned to the stock bottle. The dried plates 
 should be put in a dark box for future use and 
 can be kept a great length of time. 
 
 One or two clays before the plates have to 
 be exposed, they are dipped into a silver 
 solution prepared as follows : 
 
 Nitrate Of Silver 1 ounce. 
 
 Distilled Water 10 ounces. 
 
 Alcohol 2 ounces. 
 
 Acetic- Acid No. 8 2 ounces. 
 
 An old collodion silver-bath, charged with 
 alcohol, to which the required quantity of 
 acetic acid is added, answers the purpose very 
 well. The addition of alcohol to this silver 
 solution decreases its tendency to discoloration 
 produced by the action of the albumen. If 
 it should discolor, nevertheless, it should be 
 shaken with freshly precipitated and washed 
 chloride of silver, which will absorb the organic 
 
213 
 
 matter producing the discoloration. The plates 
 should be perfectly dry before dipping, in order 
 to avoid blistering. They should be left in the 
 bath about one minute, after which they are 
 washed in two or three dishes of water, and 
 set to dry. 
 
 Exposure. 
 
 The collodio-albumen plates, like those pre- 
 pared with tannin, require a long exposure. 
 Much, however, depends upon the collodion, 
 new collodion being a great deal more sensitive 
 than old collodion, but its use has to be avoided 
 on account of the tendency to blistering. 
 
 Development and Fixing. 
 
 The development is done with pyrogallic 
 acid and nitrate of silver. The process of 
 development given by Major Russell, and 
 described under head of the tannin process, is, 
 in all cases, the safest. The fixing and wash- 
 ing need not be dwelt upon, these being the 
 same as in all other dry processes. 
 
 CHAPTER XXXVIII. 
 
 On Kapid Dry Collodion Plates. 
 
 One of the great drawbacks to the dry col- 
 lodion process is the long exposure required. 
 By various means, however, the sensitiveness 
 of the plates can be greatly increased; but, in 
 
214 
 
 measure, as the sensitiveness becomes greater, 
 the difficulties of the development and the 
 tendency to fogginess increase also. Mr. 
 Thomas Sutton claims that in using a bromo. 
 iodized collodion, containing iodine and bro- 
 mine in equal atoms (126 of iodine to 78 of 
 bromine,) and using gum arable instead of 
 tannin, dry plates can be made as sensitive as 
 wet plates. In the hands of many good photo- 
 graphers, who have experimented with this 
 process, great increase of sensitiveness has not 
 been observed. 
 
 Dr. Draper recommends that the tannin 
 plates should be dipped in hot water, and 
 developed while yet warm. By this means, 
 the plate can be developed with a much 
 shorter exposure. Doubtless, the same effect 
 is produced on plates prepared by other dry 
 processes. 
 
 At the suggestion of Mr. Henry Anthony, 
 Mr. Borda, from Philadelphia, exposed the 
 tannin plate, before using it, to the action of 
 ammonia gas, and in this way obtained a great 
 increase of sensitiveness. Mr. Seahy after- 
 wards found that, after a short exposure, a solu- 
 tion of ammonia developed an image on a tan- 
 nin plate, which could afterwards be strength- 
 ened up with pyrogallic acid and nitrate of 
 silver to any extent. This observation of 
 Mr. Seahy led to what is called alkaline 
 development. The exposed tannin plate, after 
 having been wetted with distilled water, is 
 
•315 
 
 submitted to the action of a dilute solution 
 of ammonia, carbonate of ammonia, or car- 
 bonate of soda. If the exposure has been 
 full, a faint image appears, but it is no con- 
 dition of success that it should. The alka- 
 line solution is then poured back, and about 
 one-fourth of a three-grain solution of pyro- 
 gallic acid, without acetic or citric acid is 
 added, and it is again poured over the plate. 
 This causes the image to appear, in all its 
 details, but very faintly. The plate is then 
 well washed, and the image is intensified to 
 its proper degree of intensity, with the ordin- 
 ary pyrogallic acid solution, additioned with 
 a few drops of nitrate of silver. By this 
 method of development, the exposure is re- 
 duced to twice or three times that given in 
 the wet collodion process ; but we repeat here, 
 again, there is a great tendency to fogging or 
 deposition of the reduced silver on the shad- 
 ows, and it requires great nicety of manipula- 
 tion, and, before all, great patience in the 
 intensifying, to carry out the process to a 
 successful result. 
 
 CHAPTER XXXIX. 
 
 On Copying. 
 
 As a general thing, copying should be done 
 by the light of the sun reflected by means of a 
 
# 
 
 216 
 
 mirror. The room in which the copying is 
 clone, should, if possible, be exposed to the 
 South. No light should be admitted back of 
 the object to be copied. It matters little if 
 there be any windows back of the copying 
 camera; but, in order to avoid reflections, 
 those on the north side and those back of the 
 object should be darkened. This is, however, 
 also the case in the glass room used for por- 
 traits. In the morning the copying apparatus 
 is turned toward the East, and in the afternoon 
 toward the West. 
 
 When the copy is to be smaller than the 
 original, the ordinary portrait camera can 
 be used, but whenever the object is to be 
 copied larger, the portrait camera will not be 
 found to expand sufficiently. To meet the 
 requirements in this case, a camera special- 
 ly made for the purpose is necessary. It 
 should expand as much as four or fife feet, 
 and be constructed either with bellows or 
 drawers. It is placed on a flat board, at the 
 height of an ordinary table. At one end of the 
 board is placed vertically another board, one 
 and a half or two feet high, on which the picture 
 to be copied is tacked or stuck fast with gum 
 paper. By a little ingenuity, a system can be 
 devised by means of wdiich the picture is 
 raised or lowered, or moved toward the right 
 or left. 
 
 The picture should be at right angles with 
 the camera, so that its shape may not bo 
 
217 
 
 altered in the copy. It should also be placed 
 in such a position that its center is on a level 
 with the center of the lens. 
 
 The lens most generally useful in copying 
 is the single achromatic lens, known common- 
 ly as view lens. The photographer will find 
 it advantageous to have two or three of these, 
 of different focus; for instance, one of six 
 inches, another one of ten inches, and a third 
 one of sixteen inches. A quarter size and a 
 half size portrait lens, with central stops, will 
 also answer the purpose. The lens to be 
 used depends not on the size the picture has 
 to be made, but on the size of the original. 
 For instance, a six-inch focus lens may an- 
 swer very well to enlarge a ninth size daguer- 
 reotype, etc., to almost any size; but if the 
 original was a whole size, only the center 
 would be sharp and well defined. In such 
 case, a longer focus lens> giving a larger field, 
 is required. The aim is to use only the rays 
 passing through the central part of the lens, 
 or, in other words, to use only the center of 
 the field. 
 
 When line-drawings, engravings, or ob- 
 jects with straight lines have to be copied, 
 the recommendation of using only a small 
 part of the field should be more closely ad- 
 hered to than when the original is a portrait 
 or landscape. The reasons for this is, that 
 when the whole field, or the larger part of it, 
 is made use of, the single lens produces a dis- 
 
 19 
 
218 
 
 tortion of the marginal lines. To illustrate 
 this, suppose the photographer traces, on a 
 sheet of paper, a diagram in the shape of Fig, 
 5, about five inches square, and produces an 
 image of it on the ground glass of his camera 
 the same size as the original, by means of a 
 lens which gives only a circle of light, or field? 
 of seven or eight inches. The image, instead 
 of being similar to the original, will assume 
 the shape represented by Fig. 6. 
 
 Fig. 7. Fig. 6. Fig. 5. 
 
 But if a lens of longer focus be used, for 
 instance, one giving a field of fifteen inches 
 diameter, the distortion will be scarcely visible. 
 
 The portrait, or ordinary double combina- 
 tion lens, although quite free from distortion, 
 is not well adapted for copying the style of 
 pictures referred to, on account of the eurva- 
 ture of its field. The orthoscopic lens, man- 
 ufactured by Voightlander & Son, for which 
 freedom from distortion w^as at one time 
 claimed, produces a distortion of another kind, 
 illustrated by Fig. 7> The globe lens and the 
 triplet (either Ross' or Dallmeyer's,) give 
 
219 
 
 images practically free from distortion, and 
 should, in consequence, be used, whenever that 
 quality is required, in preference to the long 
 focus meniscus, which requires a copying 
 camera, expanding much more than will be 
 found practicable. 
 
 Whenever the illumination of the image on 
 the focusing glass will admit of it, it may be 
 recommended, to improve its definition, and 
 other optical qualities by a use of stops. This 
 should, of course, not be carried too far; for a 
 point exists in which the improvement in the 
 image, obtained by this means, is not a com- 
 pensation for the disadvantages resulting from 
 the long exposure of the plate. 
 
 The objects or originals which the profes- 
 sional photographer generally finds to copy, 
 are daguerreotypes, collodion positives, either 
 on glass or on iron plates, photographs on 
 paper, ink and crayon drawings, engravings, 
 and oil paintings. 
 
 In copying daguerreotypes, a recommenda- 
 tion, which should not be overlooked, is to 
 cover the shining brass-work in which the lens 
 is mounted with a scrap of black velvet, so as 
 to avoid its reflection on the highly-polished 
 plate. 
 
 Daguerreotypes and collodion positives re- 
 quire about the same time of exposure. This, 
 howeter, varies greatly, according to the color 
 of the picture. Varnished collodion positives 
 require a longer exposure than those which 
 
220 
 
 have not been varnished. Whenever there 
 is no harmony between the different parts of 
 a picture — for instance, when in a portrait the 
 head is light and the drapery very dark — one 
 part may be shaded off by means of a black- 
 ened piece of card-board, and the exposure 
 continued on the other part until the desired 
 effect is obtained. 
 
 Photographs on paper require but a short 
 exposure. Whenever circumstances will admit 
 of it, they should be copied by diffused light, 
 in order to avoid the disagreeable roughness 
 resulting from the unequality of the paper 
 when copied by sunlight. By making the 
 photograph wet, and sticking it on a plate 
 glass, this roughness can, however, be avoided. 
 
 Engravings, drawings, etc., also require but 
 a short time of exposure. It should be such 
 that when fully developed and fixed, the image 
 looks well as a positive. If the exposure be 
 pushed further, the cleanliness of the lines is 
 lost after redevelopment. The method of re- 
 development to be recommended, is that with 
 nitrate of silver and pyrogallic acid, or sulphate 
 of iron and tartaric acid, the film being first 
 partly transformed into iodide of silver by the 
 application of a solution of iodine and iodide 
 of potassium. The collodion used should be 
 simply iodized, or only contain a small quan- 
 tity of bromide. When the drawing is made 
 on a rough kind of paper, the sunlight should 
 be reflected on it with as little obliquity as 
 
221 
 
 possible, in order to avoid the production of 
 shadows by the inequalities of its surface. 
 
 Lead-pencil drawings are among the most 
 difficult subjects to copy, on account of the 
 reflection produced by the pencil-marks and 
 of their grey color. They require a very short 
 exposure, so that the image looks well as a 
 positive. As it is often difficult to bring the 
 negative up sufficiently by redevelopment, 
 without stains and irregularities in the sur- 
 face, it is advisable to redevelop it only up to 
 a certain point, and then to intensify it with 
 bichloride of mercury and bromide of potas- 
 sium, or, instead, sulphide of ammonium. 
 
 Oil paintings are best copied by diffused 
 light. The glass house, or sky and side light 
 room, used by the portrait photographer, is 
 well suited to this kind of work. The great 
 difficulty consists in avoiding reflections. To 
 attain this, the painting is hung up one or two 
 feet back of the place ordinarily occupied by 
 the sitter, and the light is made to fall on it 
 as much as possible from the front. All un- 
 necessary light, and all that which comes from 
 the sky or the side, should be excluded. The 
 collodion used should be newly made, and con- 
 tain a maximum of bromide, if the non-active 
 colors predominate in the painting, or if it has 
 become brown by age. Modern oil paintings, 
 however, which are a more faithful represen- 
 tation of nature, are easily reproduced with 
 the ordinary portrait collodion. 
 
222 
 
 CHAPTER XL. 
 Out-Door Photography. 
 
 The outfit for out-door photography should 
 be selected with reference to small weight, 
 compactness and portability. It should con- 
 sist of the following articles : 
 
 A dark tent or developing box; a water- 
 bag ; a light folding camera with plate-holder 
 lens, etc. ; a light and solid tripod stand ; a 
 water level ; a bath dish of gutta percha or 
 vulcanite ; a grooved box, with glass ; a soft 
 camel hair-brush ; a bottle of collodion ; a 
 strong bottle, well wrapped up, holding the 
 silver solution ; a bottle with developing solu- 
 tion ; a bottle with the pyrogallic acid or tar- 
 taric acid and iron redeveloping solution ; a 
 small bottle of twenty-grain silver solution 
 for redeveloping ; a bottle with fixing solution ; 
 a bottle with glycerine. 
 
 These articles should be packed in two 
 light boxes, with strap, so as to be easily 
 carried — one of these boxes to hold the cam- 
 era, plate-holder, water-bag, etc.; the other 
 to contain the chemicals. When a develop- 
 ing box is used, the chemicals may be packed 
 into it. The tripod stand can be strapped on 
 one of the boxes. 
 
223 
 
 Fig. 8. 
 
 The developing box is best suited for small 
 plates, such as those of the stereoscopic and 
 I size. Figure 8, represents one of these 
 boxes. Its dimensions are, height, 20 inches ; 
 width, 18 inches ; depth, 7 inches. The door, 
 which is represented open, is used to take the 
 plate-holder and plate in and out. In it is a 
 
224 
 
 window, with a yellow glass, which can, 11 
 necessary, be shut. On the slanting roof is 
 another yellow glass. The tent part of the 
 box is made of India-rubber cloth, and has 
 two sleeves to introduce the hands. It is held 
 up by means of brass rods, which, when the 
 box is to be shut, bend inside of it. On its 
 upper part are two openings to apply the 
 eyes, so as to see the inside while operating. 
 These can be arranged in the same way as in 
 a stereoscope. The horizontal part, to which 
 the India-rubber cloth is attached, is fitted 
 with a sink, made of gray India-rubber cloth, 
 and to this sink is fastened an India-rubber 
 waste-pipe, which is represented in the cut 
 hanging down. The whole box is supported 
 on a light tripod stand, which, when not in 
 use, is strapped on the side of it. 
 
 The way to use the box is as follows : The 
 plate and plate-holder are introduced in the 
 box, through the door, and the operator puts 
 his hands through the sleeves and prepares 
 the plate, examining the operation through 
 the holes in the cloth. The plate being* 
 ready, it is put into the plate-holder, taken out 
 of the box through the door, and exposed. 
 The development and fixing are done in the 
 same way. 
 
 This developing box can be modified, so that 
 the head and upper part of the body be put 
 under the cloth. The tent part will then 
 have to extend about one and a half feet 
 
225 
 
 farther, and be made to hang down, so as to 
 encircle the operator below the waist. This 
 system gives more freedom of motion to the 
 operator, but is very uncomfortable on a hot day. 
 
 When large plates have to be used, it is 
 best to have a tent, or a van, covered with oil- 
 cloth. Many models for tents have been pro- 
 posed, all, more or less, objectionable, either 
 on account of weight or solidity. The handiest 
 one we have used was a piece of double-thick 
 muslin, thrown over a tripod stand about eight 
 feet high, and extended by having five or six 
 ropes attached by one end to the upper part 
 of the cloth, and by the other to some tree or 
 other object near by, or to a spike driven in 
 the ground. The objection to tents is, the 
 annoyance caused by the dust. They should 
 thus be pitched in a grassy place, and, if nec- 
 essary, the ground around should be sprinkled 
 with water. 
 
 A good water-bag can be made of India- 
 rubber, by taking a piece of tubing about six 
 inches in diameter, and cementing both ends by 
 means of India-rubber dissolved in benzine, 
 inserting at one end a mouth of hard rubber, 
 through which the water is poured in, and on 
 the other a tube about eight or ten feet long, 
 which passes into the tent, or developing box, 
 through a little hole. The bag is hung on a 
 tree, or other object, and the end of the tube 
 is closed by means of one of the wooden clips 
 used for hanging up prepared paper. 
 
226 
 
 The camera should be as light as possible, 
 and fold up so as to present but a small vol- 
 ume. The lens should be fixed on a board 
 which slides up or down, so as to allow of more 
 sky or more foreground, according to circum- 
 stances. The tripod stand should combine 
 the advantages of small weight with that of 
 solidity. A light and very solid stand can be 
 made of the kind of cane used for fishing-rods. 
 
 The bath dish ought to be made of a mate- 
 rial which is not liable to break. Vulcanite, 
 or gutta percha, answer best. If the cover be 
 made to fit tightly, it will save the carrying of 
 a bottle to hold the silver solution. 
 
 Some landscape photographers cover the 
 plate, after it has been developed and drained, 
 with a diluted solution of glycerine, and per- 
 form the fixing and redeveloping as strength- 
 ening at home. When this plan is adopted, 
 the outfit is considerably reduced, no water, 
 fixing solution nor redeveloping solution being 
 required. 
 
 The lenses used for making views, are the 
 meniscus, or single achromatic lens, the globe 
 lens, the triplet, the orthoscopic, and, some- 
 times, the double combination or portrait lens. 
 The single achromatic lens is the best for gen- 
 eral purposes. When sufficiently diaphragmed, 
 it gives a definition superior to that given by 
 any other lens. For architectural subjects, 
 it will not answer so well, unless used at a 
 sufficient distance, on account of the distor- 
 
227 
 
 I 
 
 tion of the marginal lines. The globe lens is 
 free from this defect, and is thus well suited 
 to architectural subjects, especially when there 
 is little space in front. 
 
 The globe lens possesses, also, much depth 
 of focus; that is, it brings objects situated at 
 different planes in focus at the same time. 
 It is not equal in definition, however, to the 
 single lens, and always requires to be strongly 
 diaphragmed to correct the spherical aberra- 
 tion. It has the advantage of giving an image 
 including an angle of view two or three times 
 as wide as that given by the meniscus. 
 
 The triplet, manufactured by Dallmeyer, 
 (London) also gives images free from distor- 
 tion, and includes the same angle of view as 
 the globe lens. It has somewhat less depth 
 of focus, but, when used with a large diaphragm, 
 is superior to it in definition. 
 
 The same may be said of the triplet man- 
 ufactured by Ross as of that made by Dall- 
 meyer, with the exception that it gives an 
 image including a smaller angle. 
 
 Petzval orthoscopic lens, as we have seen 
 already, gives an image in which the mar- 
 ginal lines, instead of bending inward, bend 
 outward. Architectural subjects may be re- 
 produced by it quite correctly, by tilting the 
 camera slightly upward. The qualities of 
 the orthoscopic lens are great definition and 
 flatness of field. 
 
 The double combination or portrait lens is 
 
used in out-door photography, when eveiy 
 other quality has to be sacrificed to rapidity 
 of action, as, for instance, when moving objects 
 have to be photographed. The great defect 
 of the portrait lens is the curved field it gives. 
 
 The camera should be perfectly level. If it 
 was pointed downwafd or upward, the verti- 
 cal lines in the view would fall inward or 
 outward. If by having the camera horizontal 
 there is too much foreground or too much sky 
 in the image, raise or lower the slide to 
 which the lens is attached. 
 
 The most favorable moment to take a view, 
 is when the rays of the sun fall obliquely on 
 the object. When the sun is right behind the 
 camera, the picture produced is too flat. The 
 peculiar manner of illumination depends, how- 
 ever, greatly on the object itself and on the 
 taste of the operator. 
 
 The camera should be placed so that the 
 rays of the sun do not fall on the lens, in 
 order to avoid reflections, which would cause 
 fogginess in the picture. When the picture 
 includes a large amount of strongly illumin- 
 ated sky, and a double or triple lens is used, a 
 light circular spot is seen in the center of the 
 ground glass, which is the more visible as the 
 stop used is smaller. This appearance is 
 known to photographers by the name of 
 ghost. Single lenses are not liable to it, it 
 being produced by the reflection of the light 
 from one lens to the other. The only way to 
 
229 
 
 obviate this defect, to some extent, is to cut off 
 the sky part, during the larger part of the ex- 
 posure, and allow it to impress the sensitive 
 plate for a very short time toward the end* 
 This is easily done by using, as a cover to the 
 lens, a small square board hinged on the upper 
 part, so that it can be raised and lowered. 
 By looking on the ground glass it can be set 
 in such a position that it cuts off the sky. 
 Giving, then, three-fourths of the proper ex- 
 posure, it is raised more, so as to allow the 
 sky to be impressed, the rest of the exposure 
 is given, and the lens is covered up. As the 
 appearance of the ghost is generally accom- 
 panied by a solarized sky, the short exposure 
 given to that part of the image prevents the 
 solarization. When the means described is not 
 practicable, on account of the outline of the 
 sky being irregular, an imperfect remedy is 
 found in adapting in front of the lens a funnel, 
 made of blackened pasteboard, so that all rays, 
 not active in producing the impression, be 
 excluded. 
 
 The size of a stop to be used is a matter 
 of consideration for the photographer. The 
 smaller the stop, the longer exposure is re- 
 quired. If the length of the exposure is no 
 object, a small stop should be used, for a 
 superior definition will be the result, and 
 objects, in different planes, will be made 
 equally sharp. For a landscape, in which 
 there is no principal object, to which every 
 
230 
 
 thing else should be sacrificed, if need be, the 
 focus should be taken on a part of the scenery 
 which is half way between the principal ob- 
 jects in the foreground and those in the back- 
 ground. By inserting a stop, every plane is 
 then pictured with sufficient definition, When 
 a picture is wished of a single object, such as 
 a building, or a monument, the focus is taken 
 on a point half way between the center and 
 the edge of the object. In taking the focus, 
 make use of a magnifying glass. Darlot's eye- 
 piece is very well suited to the purpose; it 
 magnifies the image sufficiently to see plainly 
 the smallest details. It is composed of a com- 
 bination of lenses, set in a tube. This tube 
 itself slides into another tube, and can be 
 fastened at any point, by means of a screw. 
 The eye-piece, before being used, is to be set 
 to the eyesight of the operator. This is done 
 in the following way : Take a piece of ground 
 glass, make a pencil-mark on the ground side, 
 and set it against the window, the ground side 
 outward. Then put the mouth of the eye- 
 piece against it, and draw the inside tube 
 forward or backward, just as in focusing, 
 until you see a sharp image of the pencil-mark, 
 after which you tighten the screw. All the 
 operator has to do now, when he wishes to 
 look at the focus, is to apply it against the 
 ground glass of the camera. 
 
 In photographing foliage, a bromo-iodized 
 collodion is necessary. Sufficient detail is 
 
231 
 
 brought out by a long exposure. The image 
 is generally weak, and needs a good deal of 
 redeveloping or strengthening to acquire suffi- 
 cient intensity. In such subjects, the sky is 
 generally thin from being solarized, unless the 
 contrivance spoken of above, to give a shorter 
 exposure to the sky than to the landscape^ 
 be made use of. 
 
 CHAPTER XLL 
 
 Instantaneous Photography. 
 
 The term instantaneous, which has been 
 adopted by photographers, is, in the proper 
 sense, wrong; for the so-called instantaneous 
 pictures are taken in a space of time which 
 is appreciable, as can be seen in many of 
 them, where the outlines of moving objects 
 are found to be less sharp and defined, than 
 those of other immovable objects around. 
 
 The conditions required to produce pictures 
 with the shortest exposure are, a good light, 
 the use of a quick-working lens, and the use 
 of solutions in the most sensitive condition. 
 
 Pictures of moving objects should only be 
 attempted to be taken by a very good light. 
 The light, as we all know, is most actinic in 
 the spring, between the hours of ten and two, 
 and on a sunshiny day, or while the sky is 
 covered with white clouds. In these condi- 
 
232 
 
 tions, supposing the lens and chemicals to 
 answer all requirements, small portraits of 
 fair complected persons maybe taken in a glass 
 room, in from one to three seconds, and out- 
 side views as rapidly as the lens can be un- 
 covered and covered up again. A good deal 
 will depend, however, on the subject, for dis- 
 tant landscapes and sea scenes are taken much 
 quicker than street scenes, etc. 
 
 The lens is the next thing to be considered. 
 It should be of short focus, and used with a 
 wide aperture. This precludes the use of the 
 single lens and of the globe lens, and of all 
 such lenses which can not be used without 
 small stops. The double combination, or por- 
 trait lens, is the one best adapted to this kind 
 of work. It should be of a short focus, and 
 possess every possible excellency, as no small 
 diaphragms can be used to correct its faults. 
 The English opticians manufacture lenses ex- 
 pressly for the purpose. Among these, the 
 only one which came to our notice, is Dall- 
 meyer's stereoscopic lens, which, we think> 
 answers all requirements, and is as near to 
 perfection as it can be made. This, we say, 
 without wishing to detract from the merits of 
 the lenses of other makers, having had no 
 occasion to try them. 
 
 The most favorable condition of the solu- 
 tions, as far as sensitiveness is concerned, is 
 the third thing to be considered. The collo- 
 dion should be made with pyroxyline, prepared 
 
233 
 
 at a low temperature, (about 120 degrees,) 
 and with acids in about equal parts. The 
 character of such pyroxyline, is to give a rapid 
 collodion, producing little intensity. Inten- 
 sity should always be avoided, for intense 
 collodion never works quick. The aim is to 
 obtain an image sufficiently developed, how- 
 ever thin it may be, and to bring it up after- 
 wards by redeveloping or strengthening. The 
 collodion should also be iodized to the creamy 
 state, and contain a full proportion of bromide. 
 Four grains to the ounce of iodide of ammonium, 
 and three of bromide of cadmium, is a very 
 good proportion. This collodion will keep sev- 
 eral weeks in its most sensitive state. Col- 
 lodion containing nothing but the cadmium 
 salts, only acquires its maximum of sensitive- 
 ness after having been kept for several weeks. 
 
 The bath should be made with pure fused 
 and recrystalized nitrate of silver, and should 
 only contain a trace of nitric acid. After it 
 has been worked some days, it will be re- 
 marked that the plates are not as sensitive as 
 before. In this case there is no remedy but 
 to make a new one. The ordinary iron de- 
 veloper is the one best suited. It may be 
 used in the proportion of one ounce of sul- 
 phate of iron to sixteen or twenty of water. 
 
 Some precautions should be observed, which 
 are indispensable to success. A rapidly moving 
 object, at a short distance, should be taken 
 moving toward the operator or away from 
 
 20 
 
234 
 
 Mm, and never while it passes him, for the 
 shortest exposure could not prevent it from 
 being blurred in the picture. Great care 
 should always be taken to admit no diffused 
 light in the camera. To this effect, fix in 
 front of the tube a funnel made of card-board r 
 blackened inside and projecting about six 
 inches, and have your stops between the ^ 
 lenses. Ascertain, also, if no light enters 
 through the sliding tubes, and cover the 
 camera with a black cloth while you are 
 exposing.. 
 
 The caps with which lenses are provided, 
 can not be taken off and put on again quick 
 enough. A soft hat or cap, or a black cloth, 
 will answer the purpose better. When the 
 exposure has to be shorter than can be given 
 by this means, the drop shutter can be used. 
 It is composed of a thin board, pierced with a 
 hole, the same diameter as the lens, which 
 slides in a groove in front of the lens. The 
 lens being covered by the lower part of the 
 slide, the latter is allowed to drop, and the 
 lens is, for a moment, uncovered. The same 
 arrangement can be used in a horizontal posi- 
 tion. In this case, the shutter is provided 
 with an India-rubber spring which is stretched 
 and then let loose again by touching a catch. 
 
 It is important, in order to secure the 
 greatest degree of sensitiveness, that as short 
 a time should elapse between the preparation 
 of the plate and the development as is possi- 
 
235 
 
 ble. The operator should thus have his tent, 
 or developing-box, near at band, 
 
 CHAPTER XLIL 
 
 Photography on Painters' Canvas. 
 
 Ever since enlarged prints on paper were 
 made, it has been the aim of photographers, 
 who practice this branch of the art, to pro- 
 duce similar pictures on the canvas • used by 
 painters. The first attempts consisted in salt- 
 ing and silvering the canvas in the same way 
 as the paper; but the coating of white-lead 
 with which the canvas is covered, not being 
 a porous substance, the prints obtained were 
 very faint. A modification of the glass albu- 
 men process was then tried. The canvas was 
 washed with an alkali, coated with iodized 
 albumen, silvered, developed with gallic acid, 
 and fixed with hyposulphite. This gave from 
 the start beautiful results, but the process was 
 soon given up, on account of the peeling and 
 cracking of the film of albumen after the pho- 
 tograph had been painted. The writer of this, 
 who was then, and is now, engaged in the 
 enlarging business, substituted a thin solution 
 of gelatine to the albumen, and met with such 
 success that he has continued to use the pro- 
 cess ever since. It may be thought that the 
 gelatine, like the albumen, leaving a film on 
 
236 
 
 the surface of the canvas, the image is also 
 liable to peel off and crack, but this is not the 
 case. For, while the film of albumen is horny 
 and like parchment, and consequently adheres 
 but imperfectly, the gelatine film is very por- 
 ous and adherent, and leaves the canvas in the 
 same state as it was before. It is this process 
 which we now propose to describe; we will 
 divide it as follows : 
 
 1. Repainting the canvas. 
 
 2. Cleaning. 
 
 3. Iodizing. 
 
 4. Sensitizing. 
 
 5. Exposure. 
 
 6. Developing. 
 
 7. Fixing and washing. 
 
 Repainting the Canvas. 
 
 Different kinds of canvas give different 
 results. Some kinds are easily cleaned by 
 rubbing with a piece of canton-flannel, moist- 
 ened with alcohol ; others require rubbing with 
 a sponge and soap-water, to which an alkali 
 has been added. One variety requires a longer 
 exposure than another, and almost every 
 sample gives a picture different in appearance. 
 To work with uniformity, and produce the 
 best results, it is thus advisable to give tcx the 
 canvas a coat of paint always prepared in a 
 uniform way. The paint we have found to 
 answer the best, is made with one pound of 
 white-lead, ground with oil, and eight fluid 
 
237 
 
 ounces of turpentine, or common petroleum 
 benzine. (The refined petroleum benzine and 
 that made from coal or coal-tar is too volatile.) 
 The white lead is the best kind used for com- 
 mon purposes, and is sold in kegs. The 
 white lead and turpentine are well mixed, and 
 the mixture is strained through a coarse cloth, 
 and applied with a flat varnish brush. After 
 two or three days, the paint is perfectly dry, 
 and the canvas is ready for the next operation. 
 
 CleXning of the Canvas. 
 
 The canvas is now rubbed with a piece of 
 canton-flannel moistened with alcohol. The 
 object of this is to take off the greasiness, so 
 that the iodizing solution adheres to the sur- 
 face. The rubbing should be done gently, so 
 that the paint does not come off. It is suffi- 
 cient to go over the surface two. or three 
 times, after which, the canvas is rubbed dry 
 with a new piece of flannel. 
 
 Iodizing the Canvas. 
 
 The iodizing solution is prepared according 
 to one of the two following formulas. 
 
 Gelatine 200 grains. 
 
 Iodide of Potassium 400 " 
 
 Bromide of Potassium 100 " 
 
 Chloride of Ammonium . 100 u 
 
 Water 80 ounces. 
 
 Gelatine 200 grains. 
 
 Iodide of Potassium 400 " 
 
 Bromide of Potassium 200 " 
 
 Water 80 ounces. 
 
238 
 
 The first solution is used when the negative 
 is thin, and the second when it is intense. 
 
 The gelatine is soaked in the water until it 
 is well softened. It is then dissolved by a 
 gentle application of heat, the other ingredi- 
 ents are added, and it is filtered through a 
 tuft of cotton-wool previously moistened with 
 alcohol. 
 
 The iodizing solution is applied by means 
 of a flat brush, and the canvas set to dry in 
 a warm room, free from dust. If the coating 
 should dry in lines, the fault lays in the clean- 
 ing. It should then be washed off with warm 
 water, and cleaned again. 
 
 The silver solution is prepared according 
 to the following formula : 
 
 Old collodion silver solutions reduced to 
 the proper strength, and additioned with 
 acetic acid, can be used up very -economically 
 in this process. 
 
 The silver solution can not be applied with 
 cotton, for the thin film of gelatine would rub 
 off. The way to proceed is as follows : Get a 
 square frame made of walnut, one inch thick, 
 two and a half inches high, and the size of 
 the canvas. Grive it several coats of shellac 
 dissolved in turpentine. Then take India- 
 
 Sensitizing the Canvas. 
 
 Nitrate of Silver . 
 Distilled Water.... 
 Acetic Acid No. 8. 
 
 1 ounce. 
 16 ounces. 
 
 2 ounces. 
 
239 
 
 rubber tubing, one-half inch thick, pass it 
 through a hot mixture of wax and turpentine, 
 let dry, and tack it around the frame with 
 thin nails about one-half inch long, driving 
 the nails through the outer surface of the tube, 
 so that the silver solution can not come in 
 contact with the iron. The canvas is now 
 laid on the tubing and is fastened to the frame 
 by means of wooden clamps. The whole thus 
 forms a tray of which the canvas is the bottom, 
 and which is kept from leaking by the tubing, 
 To sensitize the canVas, tilt it up to an 
 angle of forty-five degrees, pour the solution 
 in the lower part of the tray, and, by bringing 
 this back to a horizontal position, cause the 
 fluid to flow over the surface. Keep in 
 motion by moving one end of the tray up and 
 down for three or four minutes, and then pour 
 into a bottle. The canvas is now ready for 
 exposure. 
 
 The silver solution should be used but 
 once, for it becomes contaminated by the 
 gelatine, and would give foggy pictures. It is 
 best to precipitate it with copper or salt, with- 
 out waiting till it becomes discolored. 
 
 Exposure. 
 
 The focus should have been taken pre- 
 viously to the sensitizing. The canvas is then 
 put in the same place on the stand or easel 
 which it occupied before, and the sun is 
 turned on. 
 
240 
 
 The time of exposure varies considerably. 
 It depends on the strength of the light, the 
 intensity of the negative, the proportion of 
 the enlargement, and the formula used for 
 iodizing. The formula, without chloride of 
 ammonium, produces the most sensitive sur- 
 face, and is, consequently, better suited for 
 intense negatives. The exposure should gen- 
 erally be continued until the image is partly 
 visible. When the negative is intense, it will 
 have to be quite plainly marked, but when it 
 is very weak, it may be necessary to proceed 
 with the development before the least trace 
 of an image can be seen. When negatives 
 are made on purpose for this kind of work, 
 they should be made clear and transparent in 
 the shadows, and without density in the high 
 lights. Such negatives will, with the first 
 formula for iodizing, give the best prints. 
 
 How long the exposure will have to be, is, 
 as can be concluded, from what we have 
 already said, entirely a matter of judgment, 
 guided by experience. We have made can- 
 vas pictures in five seconds, and at other 
 times have been obliged to expose eight and 
 ten minutes. 
 
 Develop31ent of the Image. 
 
 The image is developed with a solution of 
 gallic acid, slightly acidulated with acetic 
 acid. The. strength of this solution varies 
 according to the temperature. In warm 
 
241 
 
 weather, the saturated solution, diluted with 
 twice its bulk of water will answer. In cold 
 weather, it may be used twice as strong. 
 Very little difficulty will be found in this part 
 of the manipulation, for if a weak solution is 
 used, the only trouble is that the image will 
 come out slowly. 
 
 The gallic acid solution is flowed over the 
 surface of the canvas in the same way as the 
 silver solution. 
 
 If the development proceeds too slowly, 
 from under exposure, or any other cause, it 
 can be activated by adding a little silver solu- 
 tion and a few drops of a solution of acetate 
 of ammonia, or acetate of soda. 
 
 When the image is fully brought out, further 
 development should be stopped, by adding a 
 few drachms of a solution of common salt. 
 The canvas is then rinsed, and is ready for 
 the next operation. 
 
 Fixing and Washing. 
 
 The fixing is done with the ordinary solu- 
 tion of eight ounces of hyposulphite of soda 
 in one quart of water. It is advisable to per- 
 form this operation after the canvas is taken 
 off the frame, for if any hyposulphite remained 
 on the wood, or got in the tubing, the next 
 attempt would result in a failure, the canvas 
 becoming entirely black on applying the de- 
 veloper. The hyposulphite solution is poured 
 over the surface, and flowed forward and back- 
 
 21 
 
242 
 
 ward, after which, the picture is washed under 
 a tap for five or ten minutes. 
 
 Observations. 
 
 * After a picture has been made, the frame 
 is washed, by means of a sponge, with soap- 
 water, to which a little cyanide of potassium 
 has been added. It is then rinsed in an 
 abundance of water and set to dry, 
 
 A canvas which has been used, is also 
 cleaned with soap-water and cyanide. It will 
 generally have to be painted over again, for 
 the cyanide solution will take off part of the 
 paint. 
 
 The quantity of silver solution to be used 
 for a twenty-nine by thirty-six picture, can, 
 by skillful manipulation, be reduced to eight 
 or ten ounces. The silver can be precipitated 
 out of this solution by copper or salt, and 
 afterward transformed again into nitrate. 
 
 CHAPTER XLIIL 
 
 Binocular Vision — The Stereoscope — How to take 
 Stereoscopic Pictures. 
 
 When a solid object is examined with both 
 eyes, each eye receives different impressions, 
 the right eye seeing more of the right side of 
 the object, and the left more of the left side. 
 These two impressions combining together. 
 
243 
 
 form an image, which conveys to the mind of 
 • he observer the relative proportions of the 
 hject examined better than if the object was 
 viewed by either eye separately. In other 
 terms, the object is seen more solid. 
 
 If from the object, which we will suppose 
 to be a marble bust, two photographs are 
 taken from two points, two and a half or three 
 inches distant from each other, and the left 
 hand photograph is examined by the left eye, 
 while the right hand one is examined by the 
 right eye, the two images will resolve them- 
 selves in one, and the bust will have the 
 appearance of being solid, or standing out in 
 relief. 
 
 To facilitate the examining of such pictures, 
 an instrument is used which is called a stereo- 
 scope. A stereoscope is a box made of wood 
 or board, fitted at one end with two lenses, or 
 prisms, at a distance, from center to center, of 
 two and a half or two and three-fourth inches. 
 The two pictures, mounted side by side on a 
 piece of card-board, are called a stereograph. 
 The stereograph is placed at one end of the 
 box, at about six inches from the lenses. The 
 stereoscope has, in the middle, between the 
 lenses, a piece of board or wood, which divides 
 it in two compartments, so that each eye can 
 only see one image. 
 
 It is easy to understand that only solid 
 objects can be used as subjects for the stereo- 
 scope. For if a drawing or engraving be con- 
 
244 
 
 sidered with each eye separately, the image 
 conveyed to one is exactly the same as that 
 conveyed to the other. Solid objects at a 
 great distance, also, do not appear in relief, 
 and photographs of them, taken from two 
 points corresponding to the eyes, will have 
 no stereoscopic effect when examined in the 
 •stereoscope. 
 
 Stereoscopic pictures are generally taken 
 by means of a camera fitted with two lenses, 
 of equal focal length and rapidity of action. 
 Such a camera is called binocular. The lenses 
 best adapted to the purpose are those of 
 shorter focus, as they allow a wide angle of 
 view to be included. For groups or indoor 
 work, the double combination or portrait 
 lenses are, of course, the most useful. They 
 should be of the quarter or third size, and 
 not over four and a half inches in focal length. 
 For moving out-door scenes, they are also to 
 be preferred, as they allow of being used with 
 a larger diaphragm, thus giving a very lumin- 
 ous image. For landscapes, two single menis- 
 cus, of short focus, are recommended, or, in 
 case pictures are wanted including a very 
 wide angle of view, the two and a half or 
 three-inch focus globe lens. 
 
 When the object is at a short distance from 
 the camera, or when the picture includes 
 many objects in the foreground, the stereo- 
 scopic effect is all what can be desired. But 
 when the principal object is at a considerable 
 
245 
 
 distance, and the foreground presents an even 
 surface, such, as a sheet of water or a lawn, no 
 relief is perceptible, and it becomes necessary 
 to make the two pictures from two points 
 wider apart than the distance between the 
 eyes. It is true, the effect will then be un- 
 natural, for beyond a certain distance the eyes 
 perceive no relief. What is wanted, however, 
 is to make distant objects appear as if they 
 were taken from points nearer to them, for 
 otherwise they would be but uninteresting 
 subjects in the stereoscope. No positive rules 
 can be given as to the separation between the 
 two positions. One foot for every fifty feet 
 distance from the main object, will, however, 
 generally be found to answer. 
 
 To make stereoscopic negatives from two 
 points distant more than two and a half or 
 three inches, use a small camera with a double 
 plate-holder, so arranged that only half of the 
 plate be exposed at a time, the other half 
 remaining covered by the slide. This camera 
 is made to slide right and left on a frame 
 of oblong shape, two or three feet long. The 
 frame itself is fixed to the tripod stand by 
 means of a screw, driven in the center of the 
 front part. The way to operate it is as fol- 
 follows: Slide the camera in the center and 
 focus, then move it toward the left, turn the 
 frame so that the objects occupy the same 
 position on the ground glass which they did 
 when the camera was in the center, and make 
 
246 
 
 the left hand picture on the right half of the 
 plate. Now slide the camera toward the 
 right, turn the frame in the opposite direction 
 so that the objects to be represented fall again 
 in the same place, and make the right hand 
 picture on the left half of the plate. The 
 right and left positions of the camera can be 
 indicated by putting a peg on each side, in 
 holes provided for the purpose. To regulate 
 the motion of the frame, mark in the middle 
 of the back part, an arc of a circle, of which 
 the center is the screw by which the frame is 
 fastened to the tripod stand. This arc of a 
 circle should be divided in sixteenths of an 
 inch. A small hand is fixed to the stand. 
 When focusing, the hand and center division 
 should correspond. In making the right hand 
 picture, the frame should be moved as many 
 divisions to the right as it was to the left. 
 
 In mounting stereographs printed from neg- 
 atives made with the binocular camera, the 
 position of the prints should be inverted ; that 
 is, the left hand print should be brought to 
 the right, and the right hand one to the left. 
 "When the negative is made with the one-lens 
 camera, as described above, the respective 
 positions of the prints are maintained. Care 
 should be taken that the two pictures be not 
 more distant from center to center than two 
 and a half or two and three-fourths inches, 
 this being the ordinary distance between the 
 eyes. Two and three-fourths is generally 
 
247 
 
 preferred, as it allows more subject to be 
 included, and requires but little strain on the 
 eyes in case these should be nearer together. 
 
 CHAPTER XLIV. 
 
 Transparent Positives — The Opaltype — Enlarging 
 Negatives. 
 
 If a negative be put against a pane of glass 
 in a window, and be copied with the camera, 
 by means of the wet collodion process, the 
 copy produced will be a transparent positive. 
 This means of producing positives is very 
 simple, but is quite imperfect, for the follow r - 
 ing reasons: 1st. The diffused light which 
 enters the camera from all sides, causes the 
 image to be fogged. 2d. The action of the 
 light is not equal on all parts of the plate, the 
 lower part being less acted upon than the 
 higher part. The remedies to these defects 
 are easily suggested. 1st. All light should be 
 excluded except that which comes through 
 the negative. 2d. Instead of the light of the 
 horizon, the light of the zenith should be used; 
 that is, the camera should be raised at an 
 angle of about forty-five degrees toward the 
 north, and the negative put in a position 
 parallel to it. 
 
 An apparatus well adapted to the produc- 
 
 • 
 
248 
 
 tion of transparent positives is a long box, at 
 one end of which is a groove for the negative, 
 and at the other end, one for the ground 
 glass or plate-holder. The lens should be half- 
 way between the two, when the print has to 
 be of the same size ; nearer the negative when 
 to be larger, and nearer the ground glass 
 when to be smaller. The best arrangement 
 is, to have the groove for the board holding 
 the lens, and that for the ground glass, move- 
 able forward and backward. The distance 
 between the negative and lens, and lens and 
 ground glass, and consequently the length of 
 the box, depends on the equivalent focus of 
 the lens. The longer the focus of the lens, the 
 longer the box has to be. . 
 
 Instead of the apparatus just described, an 
 ordinary solar camera can be used to good ad- 
 vantage. The condensing lens is removed, 
 and when the sun shines, a ground glass is 
 put in its place. The negative is put in the 
 rack, and the image produced by the lens is 
 projected on the ground glass of a camera 
 placed on a solid stand. The reflector, or 
 heliostat, is worked in the ordinary way. 
 When the sky is covered, it should be kept 
 as much as possible in the position it would 
 occupy if the sun was visible. 
 
 The lenses most suitable are those which 
 give a flat field and great definition. The 
 orthoscopic, and either Ross' or Dallmeyer's 
 triplets, are the best for this purpose. Single 
 
249 
 
 lenses and portrait lenses can also be used in 
 some cases. 
 
 Negatives made on purpose to produce trans- 
 parent positives, should be thin and trans- 
 parent, and possess great detail. The collo- 
 dion used should be new, and with a full pro- 
 portion of bromide, so that it works with little 
 contrast. When a transparent positive is to 
 be made of an intense negative, the aim should 
 be to procure collodion producing so little 
 intensity, that for ordinary purposes it would 
 be worthless. The silver bath and developer 
 are the same as for ordinary work. The time 
 of exposure should be regulated, so that the 
 half tones be well reproduced. The fixing is 
 done with cyanide of potassium. After fixing 
 and washing, the picture requires to be toned. 
 This is done by blackening the film with a 
 solution of bichloride of mercury, washing, and 
 then applying a one-grain solution of chloride 
 of gold. 
 
 The opaltype is made in the same way as 
 the transparent positive, using opal instead 
 of transparent glass. The opaltype is ex- 
 amined either by reflected or transmitted light. 
 It is a very beautiful style of picture, which 
 promises to become very popular on account 
 of its pure whites, and the facility with which 
 it takes dry colors. 
 
 The apparatus described above can be made 
 very useful for copying and enlarging nega- 
 tives. This is done by copying a transparent 
 
250 
 
 positive from the original negative, and then 
 copying this positive again to a negative in 
 the same way. The success of the operation 
 depends mostly on the qualities of the trans- 
 parent positive. It should not be larger than 
 a half plate, be made with an excellent instru- 
 ment, and the exposure timed so that no 
 detail be lost. It is not necessary to tone it 
 with bichloride of mercury and gold. 
 
 Negatives enlarged by this process possess 
 many advantages over those made directly 
 with a large lens. Where the use of mam- 
 moth cameras requires one or two minutes of 
 exposure, thus trying greatly the patience of 
 the sitter, a negative for enlarging is pro- 
 duced in ten or twenty seconds. On the other 
 hand, large lenses are alw r ays less perfect than 
 small ones. A half or quarter size portrait 
 lens will, at a certain distance from the sitter, 
 produce an image practically correct in pro- 
 portion, when a mammoth size will, at the 
 same distance, reproduce the original out of 
 shape. Examine, on the other hand, a head, 
 three-fourths or one inch in size, made with a 
 good half size lens, and you will find every 
 part sharp and well defined. A head made 
 with a mammoth camera possesses no such 
 qualities. If the focus is taken on one plane, 
 the other planes will appear blurred ; so we 
 see, in most large pictures, the eye well 
 defined, and the hair, beard, and shoulders 
 out of focus. This defect is, of course, reme- 
 
251 
 
 died, to some extent, by the use of stops; but 
 this, again, increases the time of exposure. 
 
 The original negative made for enlarging, 
 should not be larger than quarter or half 
 size. It should be made with greater care 
 than is generally taken for ordinary negatives. 
 The collodion should be thin, and made with 
 the best pyroxyline, so that the film be struc- 
 tureless. Clean manipulation is indispensa- 
 ble; in short, the operator should keep in 
 mind, that the least imperfection will become 
 more apparent in magnifying. 
 
 The process described has this great ad- 
 vantage for enlarging over the solar camera 
 process, that it can be practised in all kinds 
 of weather. The photographer is thus enabled 
 to make his enlarged negatives on dull days, 
 when he is not otherwise occupied, while the 
 solar camera can only be used on clear days, 
 when he is generally kept busy in the portrait 
 room. 
 
 CHAPTER XLV. 
 
 Recovery of Silver from Old Solutions — Taper 
 Clippings, Washings, etc. 
 
 As only a small quantity of the silver used 
 ?n photographic processes, goes to constitute 
 the image, it is greatly to the interest of the 
 photographer to keep the washings, and other 
 
252 
 
 wastes, in order to recover the silver they 
 contain. 
 
 Old solutions out of order, either those used 
 for sensitizing collodion plates, or for prepar- 
 ing paper, are precipitated by leaving them 
 in contact with a copper plate. The metallic 
 silver thus obtained,* is well washed, redis- 
 solved in nitric acid, evaporated and fused, 
 until the small quantity of nitrate of copper, 
 which is always present, is decomposed. The 
 nitrate thus obtained can then be used as it 
 is, or recrystalized. 
 
 The development and redevelopment should 
 be clone over a tub or barrel. The mud which 
 collects at the bottom, contains a large amount 
 of metallic silver. 
 
 The washings of the prints before toning, 
 are all poured into a tub or barrel, in which 
 are put some plates of copper. The next day 
 all the silver is precipitated, and the clear 
 liquid can be drawn off. 
 
 The scraps of silvered paper, which have 
 not passed through the hyposulphite, the blot 
 ting paper used to absorb the drainings in 
 the plate-holder, the filters used for filtering 
 silver solutions, etc., are burned in an iron 
 pot, standing in the open air. The ashes con 
 tain chloride and metallic silver. 
 
 The cyanide and hyposulphite are deprived 
 of their silver by plates of copper. It takes 
 two or three days to precipitate all the silver 
 the solution contains. The precipitate is me- 
 
253 
 
 tallic silver mixed with a small quantity of 
 sulphide. The clear hyposulphite can be 
 used over again to fix negatives. 
 
 The metallic silver, ashes, etc., may be put 
 together and given to the refiner. When this 
 is done, care should be take to wash perfectly 
 the precipitate of the hyposulphite solution. 
 It is best, however, to keep this precipitate 
 apart, as it may, sometimes, contain a great 
 deal of sulphide, which is more difficult to 
 reduce to the metallic state than other silver 
 compounds. 
 
 The different recommendations we make 
 here, are those described by Messrs. Davanne 
 and Grirard, who have made the reducing of 
 wastes a special study. 
 
 We would not recommend to the photo- 
 grapher to reduce his wastes himself; we 
 consider it his interest to leave this to the 
 chemist or refiner, who have the necessary 
 practical knowledge, and possess the necessary 
 apparatus to accomplish this end. We will, 
 however, briefly describe the different pro- 
 cesses. 
 
 Metallic silver, precipitated by means of 
 copper, may, as we have already mentioned, 
 be directly transformed into nitrate of silver, 
 by dissolving in nitric acid. Chemists, how- 
 ever, prefer to melt the silver before convert- 
 ing it again into nitrate. This is done as 
 follows : 
 
 The silver powder, washed and dried, is 
 
254 
 
 mixed in a mortar with half its weight of 
 fused and pulverized borax, and one-fourth 
 of its weight of fused and pulverized nitre. 
 A crucible is then put in a good furnace, and 
 made red-hot, when the mixture is thrown 
 into it, little by little. When the ebullition 
 has ceased, the fire is increased, and the cru- 
 cible is kept white-hot for fifteen or twenty 
 minutes, after which it is left to cool, when 
 it must be broken to remove the button of 
 silver. 
 
 The waste resulting from development and 
 redevelopment, can be mixed with the silver 
 precipitated by means of copper, when this is 
 melted, or if this is transformed into nitrate, 
 without being previously melted, it is added 
 to the ashes of the burned paper. The ashes 
 of burned paper are mixed with half their 
 weight of dry carbonate of soda, and one- 
 fourth of their weight of quartz sand, and 
 reduced in a crucible in the manner described 
 before. 
 
 If the metallic silver and the ashes are put 
 together, the whole mass is fused with car- 
 bonate of soda, nitre, and sand. 
 
 When the precipitates contain sulphide of 
 silver, the reduction is more difficult. It is 
 necessary, then, to keep the mass at a white- 
 heat for at least an hour. 
 
 The method generally used by photograph- 
 ers is, to precipitate their washings by means 
 of salt. This method is good enough when 
 
255 
 
 the silver solution is of a certain strength, but 
 when the water contains but a small amount 
 of silver, quite a quantity is lost by the chloride 
 not all settling to the bottom, or by dissolving 
 in an excess of salt. The use of copper, in- 
 stead of chloride, secures the precipitation of 
 all the silver the water contains. 
 
 The process of precipitating the silver out 
 of the hyposulphite solution, by means of 
 sulphide of potassium, is also inferior to the 
 one we describe above. The precipitate ob- 
 tained is sulphide of silver mixed with sul- 
 phur, and before it can be reduced in the 
 crucible, which itself is an operation attended 
 with many difficulties and accidents, it has to 
 be roasted; that is, the sulphur has to be 
 burned up by heating the precipitate on an 
 iron plate. 
 
 To save the gold of old toning baths, acidify 
 them with hydrochloric acid, and add a small 
 quantity of a solution of iron. This will pre- 
 cipitate the gold in the metallic state. Sep- 
 arate the precipitate by filtration, wash well 
 and redissolve in nitro-hydrochloric acid. An 
 acid solution of chloride of gold is then ob- 
 tained, which is neutralized by leaving it in 
 contact with a piece of chalk. When all 
 effervescence ceases, and the solution is neutral 
 to test-paper, filter, and use it for toning. 
 
256 
 
 CHAPTER XLVI. 
 
 Removing Stains from the Skin, Linen, etc. 
 
 Stains of nitrate of silver can be easily 
 removed from linen, by the application of a 
 saturated solution of hypochlorite of lime, 
 (chloride of lime.) This requires from one 
 to five minutes. In this case, the metallic 
 silver is changed into white chloride. 
 
 Instead of chloride of lime, the following 
 solution can be used: 
 
 Cyanide of Potassium 
 
 Water 
 
 Dry Iodine 
 
 1 ounce. 
 16 ounces, fluid. 
 1 drachm. 
 
 This solution is applied with a small brush. 
 It removes the stains in a few seconds. 
 
 Hyposulphite of soda may be substituted to 
 the cyanide of potassium, in which case, the 
 stains will not be removed so quickly. Sub- 
 sequent applications of tincture of iodine and 
 cyanide of potassium, or hyposulphite of soda, 
 will also produce the same effect. 
 
 The same substances which remove the 
 stains from linen will remove them from the 
 skin. 
 
 When the color of the fabric is liable to be 
 injured by the chloride of lime, or cyanide of 
 
257 
 
 potassium, the solution of iodine in hyposul- 
 phite of soda is preferable. 
 
 Iron stains are removed by the application 
 of a weak solution of oxalic acid. 
 
 Stains of collodion will dissolve in a mixture 
 of ether and alcohol. 
 
 Iodine, cyanide of potassium, oxalic acid, 
 and chloride of lime, having a corrosive action, 
 these substances should be removed by rins- 
 ing the linen in clean water, as soon as their 
 full effect is produced. 
 
 22 
 
HOLMES, BOOTH & HAYDENS, 
 
 49 Chambers Street, New Yorlc, 
 (Opposite New City Hall,) 
 MANUFACTURERS, IMPORTERS, AND DEALERS 
 
 IN 
 
 PHOTOGRAPHIC MATERIALS 
 
 OF EVERY DESCRIPTION. 
 
 Dealers and Artists will always find at onr Establishment 
 A LARGE AND WELL ASSORTED STOCK, 
 
 ZEUVCIBIR^CIILTG- 
 
 CASES, MATTINGS, PRESERVERS, CARD-BOARDS, MOUNT'S PAPER MATS, ETC. 
 
 Every article required by the dealer, or amateur, will always be 
 of the latest and best designs and qualities. 
 
 PARTICULAR ATTENTION GIVEN TO THE SELECTION OF 
 
 SAXI PHOTOCRAPH.IG FAFIE. 
 
 Our arrangements for procuring this article are such, that we 
 shall always be supplied with the best quality 
 that the foreign market affords. 
 
 "We are constantly receiving from abroad invoices of 
 
 PORCELAIN WARE, EVAPORATING DISHES, GLASS, FILTERING PAPER, ETC., 
 
 which we shall always sell as low as the rates of Exchange will 
 
 allow. 
 
 HOLMES, BOOTH & HAYDENS' 
 
 Celebrated Cameras, 
 
 are guaranteed equal, in every respect, to the best of any other 
 manufacturer, either foreign or domestic. We can 
 
 furnish Cameras made expressly for the 
 O^R/TJES I>JE VISITE PICTURES, 
 
 and carefully matched in sets of two or four. Also, one-ninth 
 size tubes, for Ferrotype work. 
 
 HOLMES, BOOTH &' HAYDENS' 
 
 EUHEKA PLATES 
 
 are, also, deserving of special notice. These Plates are manufac- 
 tured by us, under the direction of a party who has had more than 
 twenty-five years experience in this branch, and we warrant every 
 box to be uniform and perfect. 
 
 HOLMES, BOOTH & HAYDENS, 
 
 No. 49 Chambers Street, New York. 
 MANUFACTORY AT WATERBURY, CONN, 
 
SCOVILL MANUFACTURING CO. 
 
 IMPORTERS AND DEALERS, 
 
 Manufactory, \ IS a. <L Beekman St., 
 WATERBURY, CONN. I NEW YORK. 
 
 OFFER TO THE TRADE, ARTISTS, AND THE AMATEUR, 
 
 A COMPLETE ASSORTMENT OF 
 
 Mostly of their own manufacture, but all of the best known makers, embracing 
 
 Apparatus, Cases, Glass of all Kinds, 
 
 Chemicals. Frames, Photographic Paper, 
 
 Preservers, Mattings, Photographic Albums, etc. 
 
 AGENTS FOR 
 
 Harrison & Schnitzer's Patented Globe Lenses, 
 
 C. C. Harrison's Renowned Portrait Cameras, 
 Whitney's Patent Printing Frame, 
 
 Tagliabue's Actino-Hydrometers, 
 
 Mowry's Photographic Presses, 
 
 Campbell's "Verms" Plates, 
 We would respectfully invite attention to our extensive 
 
 STOCK OF CASSS, 
 
 manufactured by ourselves, including 
 MANILLA, LEATHER, CUPID, JEWEL, EANCY, 
 
 AND THE 
 
 "UNRIVALED" UNION CASES, FRAMES, AND TRAYS, 
 
 now manufactured by us in increased variety, and to which all parties concede 
 superior excellence in design and workmanship. 
 
 EXCELSIOR ALBUMENIZED PAPER, 
 prepared from the best saxe and rive papers, by one of the most experienced 
 parties in the country, and guaranteed to give satisfaction 
 equal to any other in the market. 
 
 Plain Saxe and Rive Paper furnished to Albumenizers at the Lowest Importation Rates. 
 
 Pure Nitrate of Silver, Chloride of Gold, and Positive and Negative 
 Collodion, of the best Qualities. 
 
 Card Camera Boxes, (with and without Ferreo. Attachment,) Card 
 Mounts, Card Board, Paper Mats, Focussing Glasses, 
 Backgrounds, etc., etc. 
 
 CARD & FERROTYPE CAMERAS FURNISHED, MATCHED, IN SETS FROM TWO TO SIX TUBES. 
 
 JS®" Orders attended to with care and dispatch, and expressed (or sent 
 otherwise) to any part of the country. Address 
 
 SCOVILL MANUFACTURING COMPANY, 
 
 2Vo» 4 Beekman St., New York. 
 
BENJ. FRENCH & CO. 
 
 IMPORTERS AND SOLE AGENTS IN THE UNITED STATES FOR 
 THE CELEBRATED 
 
 VOIGTLANDER & SON CAMERAS! 
 
 ALSO 
 
 THE JAMIN CAMER AS. 
 
 We can furnish the 1-4, 1-3, 1-2, and 3-4 Tubes and Lenses in sets of two or 
 four, precisely matched, of same length of focus. The Voigtlander & Son's 
 Tubes and Lenses are much shorter focus, and work much quicker, and have 
 more depth of focus than any other instrument in use. The great reputation 
 these instruments have throughout the world, needs no recommendation from 
 us. We warrant every one to give entire satisfaction. 
 
 WE KEEP CONSTANTLY ON HAND A LARGE STOCK OF 
 
 SAXE'S AND RIVES' POSITIVE PAPER. 
 
 ALBUMEN PAPER OF VARIOUS KINDS AND OF SUPERIOR QUALITY. 
 Photographic Albums in Great Variety of Styles and Bindings. 
 
 Gilt, Imitation Rosewood, and Black Walnut Frames, in Great Variety of Styles. 
 ENGLISH, FRENCh7gERWAN,^ND AMERICAN GLASS, 
 
 For Negatives, 3-4 White Plate ; also, 1-9, 1-6, 1-4, 1-2, and 4-4 White Porcelain 
 Glass. Also, every description of Goods used in the Photographic 
 business, which will be sold at all times at the lowest 
 PRICES. 
 
 IMPROVED PHOTOGRAPHIC BACKGROUND, 
 
 MANUFACTURED BY PETER FALES, NEW BEDFORD, MASSACHUSETTS. 
 
 BE N J FIIE NC H & CO. 
 
 INT o • 159 W asliington Street, 
 
 SOLE AGENTS FOR THE UNITED STATES. 
 
 PATENT APPLIP^D FOR. 
 
 The above Backgrounds have the appearance of unfinished cloth, which 
 gives a very soft effect; are very durable, not liable to show indentures or 
 marks from rubbing against it — so prominent faults in the painted Back- 
 grounds. We shall keep constantly on hand the different sizes, varying from 
 6x7% to 7%xl0 feet, in all desirable colors and shades. Larger sizes made to 
 order. The Backgrounds come on wood rolls, packed in neat boxes, and in 
 condition to send any distance. Samples sent by mail. 
 
 Price, 25 Cents per Square Foot. 
 
WESTERN HEAD-QUARTERS 
 
 — FOR 
 
 PHOTOGRAPHIC AND AMBROTYPE STOCK. 
 
 L. B. DARLING, 
 
 2To. 1 00 West Fifth Street, Cincinnati, O. 
 MANUFACTURER, IMPORTER, AND DEALER 
 
 IN EVERY KIND AND VARIETY OF 
 
 GOODS AND CHEMICALS REQUIRED BY OPERATORS. 
 
 The following articles, of my own manufacture, are not excelled by any in 
 
 the United States : 
 
 Photographic Chemicals, 
 
 Negative Collodion, 
 
 Chloride of Gold, 
 
 Nitrate of Silver, 
 
 Albumen Paper. 
 
 Those who have had trouble in getting a good reliable Collodion 
 are invited to send for 
 
 DARLING'S NEGATIVE COLLODION, 
 
 and they will have no further difficulty. Large buyers are par- 
 ticularly invited to look at my stocky or get prices 
 before purchasing. I am Agent for 
 
 HOTiTWiTS fliTSTAL YABHI8H, 
 
 the best now in the market. Those who have used it will have 
 
 no other. 
 
 DRIE8 WITHOUT IIIlJAlT. 
 
 ALSO, SOLE WESTERN AGENT FOR 
 
 MOUNTFORT'S CALCINED ROTTEN STONE, 
 
 — FOR — 
 
 CLEANING AND POLISHING GLASS. 
 
 There is nothing better for the purpose. 
 
 ARTISTS' WASTES REFINED ON THE BEST TERMS. 
 
 ALL ORDERS FILLED THE DAY THEY ARE RECEIVED AND GOODS CAREFULLY SELECTED. 
 
 Xj- IB. DARLING, 
 
 (Box £313,) 
 
 W. D, GATCHEL, Manager. Cincinnati, Ohio. 
 
SOUVEETIilZN-Q- NEWI 
 
 IMPORTANT TO PHOTOGRAPHERS. 
 
 FOR 
 
 AMBKOTYPES, NEGATIVES, AND MELAINOTTPES. 
 
 JVo Heat Necessary in Drying* 
 
 The only perfectly reliable Varnish in use, and which is sup- 
 ported and recommended by the most eminent 
 Photographers in this Country. 
 
 It contains ingredients never before used in Varnishes, and 
 possesses the following merits over every other brand : 
 
 It is used without heat, thereby saving the cost of burning 
 alcohol. 
 
 It never chills if the plate is dry. 
 
 It is perfectly transparent, and does not diminish the intensity 
 of the negative. 
 
 It will not stick to the paper or become soft in printing. 
 
 It is equally good for positives or negatives. 
 
 Bichloride Mercury should not be used in strengthening 
 the negative. 
 
 ALSO, 
 
 MOUlsTTFORT'S 
 
 CALCINED ROTTEN STONE, 
 
 MAW UFACTUEED FROM 
 
 Superior English Rotten Stone, 
 
 Selected expressly for the purpose. It is warranted perfectly free 
 from grit, and all foreign substances, and will be found to pos- 
 sess qualities superior to any preparation of the kind in use ; it 
 will clean very quick, yet perfectly free from scratches. 
 
 L. B. DARLING, 
 
 Manufacturer, Importer and Dealer in Photographic Goods, 
 100 West Fifth Street 9 Cincinnati, Ohio* 
 Sole Agent for the Western States, 
 W. D. CATCHEL, Manager at Cincinnati. 
 
BETVZITVE VARNISH 
 IFOIEt WEG-ATIVES, 
 
 PREPARED BY 
 
 CHARLES WALDACK, 
 
 26 West Fourth Street, 
 CINCINNATI, OHIO. 
 
 This Varnish Dries without Heat in a few Seconds, 
 
 And gives a very hard surface, perfectly protecting- the Neg- 
 ative, and not liable to crack or split* It does not 
 reduce the intensity of Negatives except when 
 these have been strengthened with 
 mercury, ( a method now gen- 
 erally abandoned.) 
 
 THE COLOR OF THE 
 
 Is Brown when in the Bottle, but it gives a Colorless Film on the Negative. 
 
 N. B. — When a collodion is used giving a very porous film, or when the 
 Negative has been much strengthened with mercury, it is necessary to coat 
 the surface with a solution of one ounce of gum-arabic in twelve ounces 
 of water, before applying the Varnish. If this not be done, the half tone 
 of the Negative may be made more transparent, while, when the deposit 
 is the thickest, the original intensity of the dried film persists, thus pro- 
 ducing a mottled effect, which makes the Negative unfit for printing. All 
 varnishes, whether made with alcohol, benzine, or chloroform, will produce 
 this, provided they give a film possessing sufficient body to protect the Neg- 
 ative. Very thin varnishes are free from this defect, but they leave the 
 Negative hardly less tender and liable to be scratched than if only gum- 
 water was used. 
 
 FOR 8ALE BY 
 
 CHAELES WALDACK, 
 
 No. 28 Vest Pourtli Street, Cincinnati, Ohio, 
 
 AND BY 
 
 Dealers in Photographic Materials Generally. 
 
PHOTOGKAPHERS' 
 
 GOLD AND SILVER WASTE 
 
 CAREFULLY REFINED, 
 
 And the Product returned in Nitrate of Silver and Chlor. of Gold 
 
 TERMS : ------- Twenty Per Cent. 
 
 FREIGHT AND EXPRESS CHARGES PAID BOTH WAYS, 
 fi&- send for a Circular giving full Directions for Collecting Wastes, 
 Address 
 
 "W_ -A— STEWART, 
 
 North- West Cor. Seventh & IAnn, 
 
 CINCINNATI, OHIO. 
 
 PLAIN, POSITIVE, AND NEGATIVE 
 
 COLLODIONS 
 
 Prepared from the Best Materials by 
 
 CHARLES WALDACK, 
 
 NO. 28 WEST FOURTH STREET, 
 CINCINNATI, O. 
 
 FOR SALE BY DEALERS IN PHOTOGRAPHIC MA- 
 TERIALS GENERALLY. 
 
 23 
 
SHIVE'S PATENT PORTABLE HELIOTROPIC SOLAR CAMERA. 
 
 This instrument is, perhaps, one of the most important to the Photographer 
 •Ter invented for his use. Its advantages are : 
 
 It supplies the place of large instruments, therehy obviating the trouble and 
 expense of making large negatives, and keeping up large baths. 
 
 From a fourth or half size negative, it will make a four-fourth, life size, or, 
 indeed, any size print that may be desired, as sharp and as deep-toned as a 
 contact print. It is, in every sense, a Solar Camera, does not require a dark 
 room, but can be operated under a skylight, at a window, out of doors, or 
 
 * ^lace where the sun's rays can reach it. 
 
 It is complete in itself, having every appliance to print every style of picture 
 that can be printed by any other arrangement. It prints by the direct rays of 
 the sun, which gives it power nearly three to one over refected light. It dis- 
 penses with all reflectors, and trappings and machinery for operating them, 
 and is furnished at one-half the cost of a reflector apparatus, the power being 
 equal. It is so simple in its construction and operation that the most inex- 
 perienced can work it successfully. 
 
 For particulars of Price, Sizes, etc., address the manufacturer, 
 
 JOHN II. SIMMONS, 
 MANUFACTURES, IMPORTER, AND DEALER 
 
 IN EVERT DESCRIPTION OP 
 
 fkotogragMe Apparatus a&$ Materials, 
 
 607 Chestnut Street, TMladelpMa, Tenn. 
 
Stnpv'm $xt\uh ®%pU\ WmuhU. 
 
 THE CRYSTAL VARNISH 
 
 Has been in use for more than Seven Years, and no Varnish has been fonnd to excel it for Positive* 
 
 PICTURES FINISHED WITH THE 
 
 IFIELEIIXrOEC CRYSTAL "V-A.KlSriSHC 
 
 never change from exposure to light. This can be said of no other, more 
 particularly the Spirit Varnish, which will, in time, cause pictures to 
 change to a brownish hue, especially if made on an iron plate. 
 
 The Crystal Varnish is Warranted Superior to all others in use for Positives on Glass or Iron. 
 
 WBITE FOR MAGGINFS FRENCH CRYSTAL VARNISH 
 
 Kone Genuine unless Signed «T. A. Magginl. 
 
 POE SALE BY ALL AMBEOTYE AND PHOTOGEAPH STOCK DEALEES, 
 
 JOHN B. PURDY, 
 
 (LATE WITH ASHE, DAYTON & CO.) 
 
 PHOTOGRAPHIC BACKGROUNDS, 
 
 A.T REDUCED PRICES. 
 
 Plain, (Equal to any in the Market, and TWENTY-FIVE PEE CENT, 
 CHEAPEB,) Landscapes, Military, Naval, Parlor, Hall, Library, 
 Park Scenery, Imitation Columns, Eails, Pedestals, 
 Window Scenes, Bine Eeflectors, etc. 
 
 OLD BACKGROUNDS REPAINTED, 
 
 EQUAL TO NEW. 
 
 I am now happy to inform Photographers that I have succeeded in an object 
 heretofore pronounced by background-makers as impossible; namely, the 
 repainting of old Backgrounds. Any Photographer having an old ground, (oil 
 and flock excepted,) if not torn, can have any tint or design repainted on it, at the 
 rate of ten cents per foot, for plain, or a proportionate price for scenery, ac- 
 cording to the amount of labor in the execution. Expenses paid one way. 
 
 J-OHCIST 33. IPTTRID^r, 
 52 Franklbi Street, near Broadway, JK F. 
 
HARRISON CAMERA FACTORY. 
 
 Office, 458 JBroaclivay, New York. 
 
 PORTRAIT TUBES, 
 
 AND — 
 
 0. 0. HAEEISOFS AND J. SOHJTITZEB'S 
 
 FATIITIB (SJk©BI MISSIS. 
 
 The " C. C. Harrison's" Portrait Tubes, which, for the past sixteen years, 
 have been so favorably known, and are now almost exclusively used in the 
 first-class Photographic Galleries in the Union, are being made in larger 
 quantities, and, if possible, in still greater excellence than ever. 
 
 Tlieix- Ilig-lx Character will l>e Sustained. 
 Not an instrument will be sent out that Mr. Harrison, by the severest tests, 
 has not found perfect. Every tube is warranted to be thus, and to give entire 
 satisfaction. The 
 
 C. C. HARRISON & J. SCHNITZER 
 PATENTED GLOBE LENSES, 
 
 For taking Landscapes and Architectural views, and for copying Prints, Maps, 
 Drawings, etc., far excel all Lenses heretofore introduced for these pur- 
 poses. The advantages claimed for them are : 
 
 First.— They will embrace almost twice as much subject upon the same 
 »zed plate as that of any other combination. 
 
 Second. — Their great depth of focus — objects near by and distant being 
 equally sharp and well defined. 
 
 Third. — An equal illumination and perfect definition of the whole field. 
 
 Fourth. — The property of rapid working, with very small aperture. 
 
 Fifth. — The heretofore unattainable, but so long sought for, quality of pro- 
 ducing, when used in copying negatives, perfect in definition and entirely free 
 from distortion. 
 
 All these qualities we guarantee these Lenses to possess, and any pur- 
 chaser, who, after a month's trial, is not satisfied, is at liberty to return ttie 
 Lens to us, and receive the amount paid. 
 
 Our Portrait Tubes and Globe Lenses may be obtained from all the stock- 
 dealers in this and other cities. 
 Orders should be addressed to 
 
 NELSON WRIGHT, 
 
 458 BROADWAY, STEW YOEK. 
 
JOHN STOCK & CO, 
 
 207 and 209 Center Street. 
 
 OFFICE, S-A-3yCFXiE, SALESROOM, 
 
 458 Broadway, Corner Grand Street, New York. 
 
 The Subscribers, owing to the great and increasing demand for their Photo- 
 graphic work, have been compelled to change their plan of business, and have 
 taken extensive Rooms, with ample steam power, in Center street; and, with 
 machinery made expressly for and exactly adapted to their work, they wiU 
 hereafter be able to supply the demand, no matter how large, with Camera 
 Boxes, Baths, Stands, Printing Frames, etc., of unequaled quality. 
 
 They take pleasure in informing their friends and the public, that they have 
 made an arrangement with Mr. NELSON WRIGHT, (Harrison Camera Fac- 
 tory,) by which they will be relieved from the selling and other business 
 operations, and devote their time wholly to manufacturing. Soliciting the 
 continuance of the public favor, which has heretofore been so liberally be- 
 stowed, we are, Yours respectfully, etc., JOHN STOCK & CO. 
 
 The undersigned will be happy to show samples, and take orders for 
 JO 11?* 8TOC I£ «& CO.'H 
 BOXES, BATHS, STANDS, AND OTHER, PHOTOGRAPHIC APPARATUS. 
 
 With very great facilities in machinery and power, and with large supplies 
 of superior seasoned timber and other materials, it is hoped orders will be 
 filled with a promptness that will satisfy every one. Prices will be made as 
 low as possible, kept regular, and no deviation made. Stock-dealers will be 
 allowed a liberal discount. The especial attention of amateurs and of all 
 artists, who appreciate and wish to possess perfect-working apparatus, is called 
 to the New Patented Improved Camera Boxes, which consist of the following : 
 
 THE IMPERIAL CAMERA, 
 
 FOR TAKING PICTURES BOTH IN THE GALLERY AND IN THE FIELD. 
 
 UNIVERSAL CAMERA, 
 
 FOR ALL KINDS OF WORK— SINGLE PICTURES, TWO OR FOUR ON A PLATE, AND FOB 
 
 COPYING. 
 
 IMPERIAL FOLDING CAMERA, 
 
 FOR COPYING; ADAPTED FOR FIELD AND GALLERY USE. 
 
 PATENT ARTISTS' CAMERA. 
 
 STEREOSCOPIC CAMERAS, 
 
 DOUBLE AND SINGLE, WITH THE PATENT DRY-BOX. 
 
 CAMERA TABLE, 
 
 THE MOST PERFECT AND CONVENIENT ARTICLE KNOWN. 
 
 PATENT GLASS BATH, 
 
 ESTEEMED THE ONLY PERFECT SILVER BATH EVER INTRODUCED. 
 
 An Illustrated Pamphlet, with Prices, will soon be issued, and will be sent 
 
 to any one wishing it, 
 ALL ORDERS SHOULD BE ADDRESSED TO 
 
 NELSON WRIGHT, 
 
 458 Broadway, Comer Grand Street, New York, 
 
HERMAN ROBTTGER, 
 
 NO. 402 LIBB&RY STKEET. 
 PHILADELPHIA, PENN. 
 
 MANUFACTURER OF 
 
 TELESCOPES, ETC. 
 
 09 
 
 Pi 
 O 
 
 02 
 
 PRICE-LIST OF CAMERAS. 
 
 Mammoth Size, Lenses 6 J- by 6} inches diameter, 
 
 $350 00 
 
 5J by 5:} » " 200 00 
 4J by 4£ " " 160 00 
 3£ by Sf " " 120 00 
 H by 3J « " 90 00 
 2| by 2| « « 45 00 
 1J by If « " 30 00 
 2J by 1J « « 45 00 
 » 3 by 2\ « « 70 00 
 Twin Tubes with Center Stops, for " Cartes de Visite," 90 00 
 Triplets, (an improved instrument for landscapes, copy- 
 ing, etc.) - - 30 00 to 160 00 
 
 Solar Camera Tube, - - - - - - 45 00 
 
 LENSES FOR SOLAR CAMERAS. 
 Piano-Convex Lens, 5 inch, diameter, 10 to 12 inch, focus, $ 8 00 
 
 Extra Double Whole, 
 Double Whole, 
 Extra Whole, 
 Whole, 
 Half, 
 Quarter, 
 Orthoscopic Tube, 
 
 6 
 7 
 8 
 9 
 
 10 
 11 
 
 10 to 15 
 10 to 18 
 12 to 18 
 19 to 25 
 22 to 25 
 22 to 30 
 
 9 00 
 12 00 
 15 00 
 20 00 
 30 00 
 35 00 
 
 Larger Lenses furnished upon special orders. 
 TELESCOPES. 
 With Object Glass 2£ inches aperture and Stand, 
 
 3 " 
 
 4 « 
 
 5 « 
 
 6 " 
 
 7 " 
 
 8 " 
 
 Object Glasses for Mathematical Instruments, etc.* furnished any size upon orders 
 
 $100 00 
 160 00 
 275 00 
 420 00 
 650 00 
 1000 00 
 1500 00 
 
PORTABLE DARK-ROOM, 
 
 FOR 
 
 @iTi©@@I WORK, 
 
 This Dark-room, when put up for use, leaves 
 ample space for operating. It holds the bath, 
 collodion, developing solutions, etc., and is 
 fitted with a sink and waste-pipe to carry off 
 the washings. When folded up, it can be 
 easily carried in one hand. It can be put up 
 ready for use in two minutes. It is made of 
 such a size that plates 10 by 12 inches can be 
 easily operated upon. It is supplied with 
 water by means of an India-rubber bag, which 
 is suspended to some object near by. 
 
 CHARLES "W-A.XjI>-A.OEC 3 
 JSo. 28 West Fourth Street, 
 CINCINNATI, O. 
 
FOB 
 
 OUT-DOOR WORK AND COPYING. 
 
 This Camera possesses all the requirements for out-door 
 work. It is light, compact, portable, and strong. It is 
 constructed so that the lens slides up or down, thus avoid- 
 ing the necessity of tilting in case it is wished to include 
 more sky or foreground. It can be used in its width or 
 in its length, according to the nature of the subject. As 
 it extends two or three feet, according to its size, it can be 
 made very useful as a copying and enlarging Camera. 
 When used for that purpose, it is fastened to a board con- 
 structed so that the picture to be copied can be raiseil or 
 lowered, and set nearer to the Camera or further from it. 
 The Camera and plateholder, when folded up for traveling, 
 form a package which can be easily carried in one hand. 
 
 When used- in the field, the Camera is supported on a 
 light and solid tripod stand. 
 
 The following sizes are constructed : 
 
 4f by 8 inches, (Binocular Stereoscopic Camera.) 
 
 6£ by Si « 
 
 8 by 10 " 
 10 by 12 «« 
 12 by 15 " 
 14 by 17 " 
 
 The Binocular Camera is made either for one or two 
 lenses. When one lens is used, it is attached so that it 
 can be moved from right to left, or vice versa. This 
 Camera is also accompanied with a platform, which is used 
 when the two pictures have to be made from two points, 
 wider apart than the distance between the two lenses. 
 
 FOR. SALE BY 
 
 CHAELES WALDACK, 
 JVb. 28 West Fourth Street, 
 CINCXBTNATI, O. 
 
The Philadelphia Photographer, 
 
 A MONTHLY JOURNAL, DEVOTED TO THE PHOTOGRAPHIC ART. 
 
 , In soliciting patronage for the Second Volume of this useful Magazine, the 
 Publishers would call the attention of Photographers, Artists, Amateurs, and 
 all lovers of the art to the following 
 
 TESTIMONIALS : 
 
 "I have read with much interest the Numbers of the Philadelphia Photographer, 
 and hope that it may prosper. I shall be glad to contribute to its pages."— Prof, Oyden 
 N. Rood. 
 
 "The contents arc of an interesting nature, and to all photographers will be useful and 
 valuable ; for they are evidently the productions of clear-headed, practical men. Our 
 cotemporary promises to be a valuable acquisition to the cause of progressive science." — 
 Scientific American. 
 
 "It will supply a want experienced by the profession as well as by amateurs. We per- 
 ceive it has been indorsed by some leading Photographic journals in England, Paris, and 
 Brussels."— Dr. R. She I ton Mackenzie. 
 
 " Of this young Review, organ of one of the most justly reputed Photographic Societies, 
 it may be said that no prospectus was ever more faithfully carried out than it has been. 
 It is a rich and valuable publication, both as respects its execution and in a scientific 
 point of view." — Bulletin Beige. 
 
 " The frontispiece is a very successful photograph, not having a single defect, and is 
 well worth twice the price of the Number as a specimen of art in respect to sharpness and 
 toning." — Prof. Towler, Editor Humphreys Journal of Photography . 
 
 " I have read a great part of every Number, and with great interest and profit; .... 
 almost ready to send you a negative of my own make as a candidate for your frontis- 
 piece/'— Prof. Oliver Wendell Holmes. 
 
 "The only Photographic Journal in the world, giving a Photograph in each number, is 
 the Philadelphia Photographer, an excellent Journal, ably conducted, and beautifully 
 printed." — Photographic News. 
 
 No pains will be spared by the Publishers to keep up the appearance and 
 interest of the Journal in a way even surpassing the last volume. 
 
 The coming volume will be copiously illustrated with engravings and photo- 
 graphs. 
 
 The working, practical operator will find it a useful and reliable text-book, 
 the amateur a worthy counselor, the lover of art a valuable and beautiful addi- 
 tion to his center-table ; and the artist will find the landscape photographs use- 
 ful as rock, tree, and landscape studies. 
 
 M. Carey Lea, Esq., will continue his valuable resume on "Photography 
 Abroad," and contribute frequent original articles. Mr. Coleman Sellers will 
 continue his " Letters to an Engineer on Photography, as Applied to his Pro- 
 fession." Rev. H. J. Morton, D. D., is preparing a series of his charming 
 articles for its pages; and occasional papers may be anticipated by Prof. 
 Ogden N. Rood, Dr. R. Siielton Mackenzie, M. A. Root, Esq., and may other 
 well-known lovers of and co-workers in the art it advocates. 
 
 The Publishers believe that such a staff must secure the publication of a 
 first-class Photographic Journal, and ask the support and influence of all whose 
 ideas substantially accord with theirs Its pages are open to all. It is the 
 special organ of the Philadelphia Photographic Society; but the minutes of 
 other Photographic Societies are requested from their secretaries, and will be 
 regularly published cheerfully. The discussion or all photographic topics is 
 invited. 'Correspondents cheerfully answered through its pages by the Editor. 
 The Photographic news of the world regularly published. 
 
 It is gotten up in the very best style, on heavy fine white paper, royal octavo 
 size, each number containing sixteen double-column pages, in clear readable 
 type, and embellished with a superb specimen photograph. 
 
 Subscription, Three Dollars per annum, in advance. Postage payable at the 
 office where received. Single copies mailed on receipt of Thirty Cents. 
 
 BENERMAN & WILSON, Publishers, 
 Office South-west Corner Seventh and Cherry Streets (Sherman's Building), 
 
 PHILADELPHIA. 
 
CHARLES WALDACK, 
 
 PHOTOGRAPHER. 
 
 ISo. 88 West Fourth Street, 
 
 CINCINNATI, OHIO. 
 
 SPECIALTY POE COPYING AND ENLAEGING. 
 PRICE LIST 
 
 — FOR — 
 
 NL19TIB8 MM PH0T00RAPHIE8 
 
 ENLARGING ON PAINTERS' CANVAS, 
 
 (PROOFS PRODUCED AS FINE AS ON PAPER.) 
 
 14 by 17 $3 00 
 
 16 by 20 4 00 
 
 18 by 22 5 00 
 
 20 by 24 6 00 
 
 22 by 27 7 00 
 
 25 by 30 8 00 
 
 27 by 34 9 00 
 
 29 by 36.... 10 00 
 
 32 by 40 11 00 
 
 34 by 42 ! 12 00 
 
 3J by 4J feet 14 00 
 
 5 by 7 " ... 20 00 
 
 THESE PBIOES DO NOT INCLUDE THE CANVAS. 
 
CHARLES WALDACK — CONTINUED. 
 
 State whether you want the picture on smooth, twilled, Roman, 
 or Saxon Canvas. 
 
 All kinds of Negatives, giving good prints by contact printing, 
 can, if necessary, be used ; but, to produce the best results, the 
 Negative should be made expressly for the purpose. It should 
 not be larger than half size, and should be thin, sharp, and 
 transparent in the shadows. Avoid over-exposure. It is, also, 
 best not to varnish it. 
 
 One Dollar extra is charged when a Negative has to be made 
 of a daguerreotype, photograph, or positive collodion picture. 
 
 ENLARGING ON PAPER. 
 
 The Prices are the same as for Canvas.— The same kind of 
 Negative is required. 
 
 I5«UfcEI@I© NE8AT0VK8, 
 
 COPIED FROM DAGUERREOTYPES, PHOTOGRAPHS, ETO, 
 
 1-2 size $1 00 
 
 4-4 size 1 50 
 
 8 by 10 2 00 
 
 10 by 12 2 50 
 
 11 by 14 3 00 
 
 12 by 15 3 50 
 
 14 by 17 4 00 
 
 COPIED FROM SMALL NEGATIVES. 
 
 1-2 size $2 00 
 
 4-4 size 2 50 
 
 8 by 10 3 00 
 
 10 by 12 3 60 
 
 11 by 14 4 00 
 
 12 by 15 4 50 
 
 14 by 17 5 00 
 
ASHE, DAYTON & CO. 
 
 ISO Sc 161 MERCER STREET, 
 NEW YORK, 
 
 Abe making all kinds of Furniture, Window-Shades, Backgrounds, etc., at 
 the lowest prices, and of the best quality, of the latest, new, and original 
 styles, both of this country and Europe. 
 
 Baekg-rousids. 
 
 Our Grounds are superior to any others, and lower in price. We can give 
 thousands of testimonials from the best Photographers in the country, Can- 
 ada, Cuba, and the West Indies. We make Scenery to a given sketch or 
 description, interior or exterior, park, landscape, drawing-room, boudoir, 
 parlor, etc., with imitation pillars, balustrades, etc.; and, being practical 
 Photographers and Artists, can produce all the effects requisite in a picture. 
 They are sold from twelve to twenty-five cents per superficial foot, according 
 to price of canvas and amount of labor in the execution. Warranted perfect 
 and unfading in color. 
 
 Slcyliglits. 
 
 We also mix for Skylights a fluid which we name Blue Frosting, to be 
 stippled on the glass, to prevent the sun's rays from passing through, giving a 
 blue, mellow light. Sold in pint cans, which will cover about one hundred 
 and twenty square feet. 
 
 We are making an article called a Skylight Phosgrade, to be hung under the 
 skylight, somewhat in the form of a common-window blind, of a photogenic 
 blue lint, which will graduate the light in part or whole ; when entirely closed 
 will give a good light in the brightest day, but can be graduated to any shade. 
 We have taken measures for a Patent. It will be cheap and effective for any 
 light, and can be easily put up. 
 
 Mock ITujrnitua-e. 
 
 Our new style of Furniture is from the English and French. It co rists of 
 various portions of Tables, Desks, Bureaus, Libraries, etc. One piee of Fur- 
 niture can be changed to any configuration, according to the taste of i e artist, 
 by joining the several parts together, making a complete furnish* J room. 
 
 We solicit your favors, and feel confident we can give satisfacti a, having 
 had experience since the birth of Photography. Instructions give in the art 
 for any thing new, gratis. 
 
 References. 
 
 Fredricks, Gurney, Brady, Lewis, Thompson, Kimball, Bill, omington, 
 Kertson, Percival, Adams, 'Holmes, Morse, Farris, Johnson Broo Hoot, and 
 others, New York; Benden Bros., Baltimore; Germon, Guteku': it, Philadel- 
 phia; Bennet, Gordon, Benjamin, Washington, D. C. ; Howe, T<**», Vermont; 
 Coner, Cuba ; Clarke, Victor, Peard, New Jersey; Davis, Bill, Prescot & Gage, 
 Hartford; Moulthrop & Williams, New Havem Connecticut; Silsbee, Case & 
 Co., Boston, Massachusetts, and others — in fact, all the best Photographers 
 in the country. 
 
 Important Notice. 
 
 We have made arrangements with the Patentee, in England, for an impor- 
 tation of ten thousand dollars' worth of a new manufacture of plain Back- 
 grounds made of woolen cloth; will last forever and never fade ; can not be 
 injured by water or rubbing; can be sent in a small parcel to any distance 
 without injury. Will be sold by all Stock Dealers. We shall give notice on 
 the receipt of them. The shades of the Grounds will be the same as the num- 
 bers we have sold these ten years — from 1 to 10. These Grounds will be far 
 superior to oil grounds, distemper, felt, sanded, or any other; for having made 
 all of them ourselves, during twenty years experience in daguerreotype, am- 
 brotype, and photography in general, we can, most assuredly, recommend 
 them, as one of our firm has proved them. Wait awhile. 
 
 ASHE, DAYTON" &c CO., 
 
 159 & 161 Mercer Street, N. Y. 
 
BIST GOODS! LARGEST STOCK!! LOWEST PRICES I ! ! 
 
 J. V. ESCOTT, 
 
 ^inmxfnttnzez, ||mptrrt*r, tmir JmUr 
 
 IN 
 
 PHOTOGRAPHIC AND AMBR0TYP1 
 
 APPARATUS. 
 
 Cases, Glass, 
 Mattings, Chemicals, 
 Preservers, Back Grounds, Card Mounts, 
 Photographic Albums, 
 Gilt and Rosewood Frames, 
 PLAIN AND ALBUMEN PAPER, 
 
 J. V. ESCOTT'S STAR PLATE, 
 
 AND EVERT DESCRIPTION OF GOODS USED IN THE BUSINESS, 
 
 Agent for Mowry's (Sibley Patent) Presses. 
 
 CARD MOUNTS PRINTED ON THE PREMISES. 
 
 All Orders Promptly Attended to. 
 
 J". V. ESCOTT, 
 
 Depot, 231 Main Street. Factory, First Street. 
 LOUISVILLE, KY. 
 
I