PHOTOGENIC MANIPULATION: PART I. CONTAINING THE THEORY AND PLAIN INSTRUCTIONS IN THE ART OP PHOTOGEAPHY, OR THE PRODUCTION OF PICTURES THROUGH THE AGENCY OF LIGHT: INCLUDING CAIOTYPE, I CHROMOTYPE, rLUOEOTYPE, i CHEYSOTYPE, EERROTYPE, I CYANOTYPE, CATALISSISOTYPE AND ANTHOTYPE. BY ROBERT J. BINGHAM, CHEMICAL ASSISTANT IN THE LABORATORY OF THE LONDON INSTITUTION. miuslraletr SlSaootrcutg. FOURTH EDITION. LONDON: ,^^^7/ PUBLISHED BY GEORGE KNIGHT AND SONS, MANUFACTURERS OP CHEMICAL APPARATUS AND PHILOSOPHICAL INSTRUMENTS. FOSTER -LANE, CHEAPSIDE. Entered at Stationers' HalL London : Printed by Stewart and Murray, Old Bailey. MANIPULATIONS IN THE SCIENTIFIC ARTS. PART III. PHOTOGENIC MLANIPUIiATIOn. CONTENTS. Introductory Remarks : — page Definition of Photography ... 1 Brief History of the Science . . . .2 Hitter's Experiments ..... 2 Actinism . . . . . .3 Wedgewood's Experiments .... 4 Pleliography . . , . , .5 Discovery of the Calotype .... 6 Apparatus and Materials : — Paper . . . • • • .6 Bibulous Paper ..... 9 Distilled Water . . . . , .9 Methods of applying the Solutions ... 10 Nitrate of Silver . . . , ,13 Process for making Hyposulphite of Soda . . 14 Methods of Preparing Photographic Paper : — Nitrate Paper . . . , , .14 Chloride Paper . , . . .15 Bromide Paper . . . , . .17 Varieties of Photographic Paper ... 17 Making the Photographs : — Pressure Frame . . . • , .19 Simple form of Pressure Frame . • . 20 Negative and Positive Photographs . . .21 Method of Multiplying Designs ... 21 Nev7 method of Forming the Matrix • . .22 Time of Exposure ..... 22 Experiment of Mr. Hunt . . , .23 On the Chemical Change produced . . • 23 Fixing Process . . , , ,24 Applications of Photographic Drawing , . 26 Curious Restoration of Pictures . , . .27 Camera Pictures : — Description of the Camera . . , ,28 Portable Camera ..... 30 Sliding Front . • . , » .31 viii CONTENTS. PAGE The Lenses . • • • • 32 Spherical Aberration . • , , .32 Position of the Diaphrams ... 33 Chromatic Aberration . . , . .34 Adjustment to the Chemical Focus . . . 35 Calotype ; — Apparatus required . . . . .36 Preparation of the Iodized Paper ... 37 Applying the Sensitive Mixture . . . .39, Exposure in the Camera . . , , 41 Portraits . . . . . .42 Views ...... 43 Developing the Picture . . . . .44 Pixing the Process . . . . • , 44 Obtaining the Positive Picture . . , .47 Sir David Brewster's Method ... 49 Pluorotype : — Preparation of the Paper . , , .50 Bringing out the Picture .... 51 Ferrotype or Energiatype : — Description of the Process .... 52 Chromatype :— Description of the Process . . . .54 Modification ...... 55 Process by Mr. Mungo Ponton . , .55 Modification by M. Edmund Becquerel . , 56 Principles upon which the Process depends . . 57 ClIRYSOTY^PE : — Discoverer ...... 57^ Desciiption of the Process . . . .58 Cyanotype : — . Discoverer ...... 58 Description of the Processes . . . .58 Positive Calotype : — Discoverer ...... 60 Description of the Process . • . .60 Catalissisotype : — Discoverer ...... 61 Description of the Process . . . .61 Gaudinotype ..... 62 Anthotype : — Discoverer . . . . . .62 Description of the Processes .... 63 Action of Light upon Plants . . . .64 Concluding Observations ..... 65 PREFACE, In consequence of the lamented death of Mr. G. T. Fisher^ the author of " Photogenic Manipulation/' I was requested to prepare a Fourth Edition of that work for the press ; but on commencing my task, I found that the rapid strides which have been made in this interesting art, since the last edition was pub- lished; would require such extensive alterations, that the composition of an entirely new work appeared preferable. I hope the amateur will find in the fol- lowing pages, a complete Manual, embracing all the information requisite to his success in obtaining pictures, by that mysterious agent — Light. Robert J. Bingham. London Institution^ August 1847. PHOTOGENIC MANIPULATION. INTRODUCTORY REMARKS. 1. Several names have been given to this new art, and nearly all of them serve as definitions of it ; it has been called Photography, from two Greek words,* meaning, drawing by light. MM. Niepce and Daguerre originally called their process Heliography, or drawing by the sun ; the last name, like the first, being also derived from the Greek. Mr. Talbot has named a process invented by him, the Calotype, or, beautiful picture, but this name has lately been altered to Tal- botype, in compliment to its discoverer, and a process of producing photographs on metallic plates* by M. Daguerre is known as the Daguerreotype, and for a similar reason. 2. To the Alchemists, with all their charlatanry, we are indebted for the germs of a great many important chemical discoveries. The early history of Photography is an illustration of this remark ; for it seems that in tiieir fruitless researches after the Elixir vita, &c., they obtained a compound, which we know as the chloride of silver, but which they called, from its appearance, horn silver, and so far back as the year 1556, they * From ^Q ligl^.t, and ypa^w to write, to depict. PART I. B 2 PHOTOGENIC MANIPULATION. noticed that this substance was blackened by exposure to light ; and we have on record one or two experi- ments, expressed, it is true, in a very mysterious way, but which appear to indicate that they had applied this property as a means of forming pictures. 3. Here the matter appears to have rested, until that eminent chemist, Charles William Scheele, noticed that the chloride of silver was affected very differently by the different-coloured rays of light ; it being blackened in the violet and blue rays, whilst pure red and yellow light had no effect upon it. But a still more extraor- dinary fact was observed, in 1801, by Ritter, of Jena, whilst repeating the experiments of Scheele ; for he found, on throwing the solar spectrum upon a piece of paper impregnated with chloride of silver, not only that there was a greater blackening effect at the blue or more refrangible end of the spectrum, but that the paper was darkened beyond any of the visible rays of light. 4-. These experiments of Ritter appear to have given rise to tUe idea, that there must be some peculiar and separate fluid accompanying light, which produces all the chemical changes we notice and attribute to mere light. Several modern philosophers have experimented upon this subject, of whom the most distinguished are Mv, Robert Hunt, and Sir F. W. John Herschel. Mr. Hunt gave to this peculiar principle or influence the name of Energia, but Sir John Herschel, at a meet- ing of the British Association, proposed that it should be called Actinism, and this name appears to be generally adopted. To return, however, to our short history. In the year 1800, the famous Dr. (afterwards Sir William) Herschel, in making some experiments INTRODUCTORY REMARKS. 3 on coloured glasses, prepared for the purpose of de- fending his eye from the heat of the sun, when examining it with his large telescopes, noticed, that if he used a deep red glass, although it obstructed an immense quantity of light, yet it had little or no protecting influence from the heat. On the contrary, a blue or gray glass defended his eye very perfectly ; j this induced him to examine the subject, and he discovered that not only had the red ray of light the greatest amount of heating power, but that he could detect heat even below the red ray, in other words,' he could detect heat in the spectrum without any light accompanying it. 5. This is an analogous experiment with heat, to that of Ritter's with regard to chemical' power, and we d Fig. 1. c B 2 4 PHOTOGENIC MANIPULATION. are, therefore, led to divide the influence proceeding from the sun into three distinct and separate fluids, viz., Ac- tinism, Light, and Heat, The relation of these one to another, and their relative intensities in different parts of a decomposed sunbeam, are clearly shown in which the various colours of the spectrum are indicated in the order in which they occur, between the points A and B. We have already stated that Sir William Herschel found the greatest amount of heat in the red ray ; this is shown at D ; from this point the curve of greatest heat declines, until it arrives at the lavender ray a, where it is altogether lost, but where the actinic power is greatest. It will be observed that this power extends to some distance beyond the spectrum as far as d. It also extends downwards as far as the lumi- nous rays G, where a negative influence is exerted, after passing which, the curve again increases, and a second maximum is found at F, the chemical power entirely ceasing at e. Upon reference to the curves formed in the diagram, it would appear that these three forces are antagonistic one to another ; for where we have the greatest amount of light, there is the least heat, and where the greatest heat, less actinic power. 6. In the year 1801, we find the first notice of a picture being taken by light, by the celebrated Joseph Wedgewood, the porcelain manufacturer, who endea- voured to apply it for making designs for his ware. His process was to sponge leather or paper over with a solution of nitrate of silver, and to place it behind a painting on glass, or other objects of which he wished a copy. The light passed through this with INTRODUCTORY REMARKS. 5 different degrees of intensity, and the paper or leather behind it was darkened, according as the glass was more or less permeable to its rays. But the greatest difficulty in this process was, to render the picture produced per- manent, the same agent — light — which produced them, infallibly destroyed them. Sir Humphry Davy and Mr. Wedgewood were equally unsuccessful in their en- deavours to remove this difficulty. 7. In 1814, M. Niepce, of Chalons-on~Soane, turned his attention to this subject, and he found the resins to be curiously affected by the action of light, with regard to their solubility, and the result of his researches was the discovery of a process named Heliography.* These pictures were produced upon metal plates, having the polished surface of the metal to form the shadows of the picture, and a resin forming the light parts : they were very indistinct, and wanted depth. M. Niepce, through accident, became acquainted with M, Da- guerre, and they agreed to pursue their experiments together, and amongst other things they tried the effect of sulphur and of iodine to deepen the shadows of their Heliographs ; and it is extremely probable that M, Daguerre noticed a darkening effect in some of those plates, upon exposure to light, and that this laid the foundation for his brilliant discovery of the Daguerreo- type, which was announced in 1839, 8. About this time, Mr. Fox Talbot sent a paper to the Royal Society, with an account of his discoveries in this branch of science. f The process he communicated * From HX(o(7 the sun, and ypacpoj to depict, to draw, t Published in the London and Edinburgh Philosophical Maga- zine, Yol. xiv. p. 126. 6 PHOTOGENIC MANIPULATION. was upon paper, whilst that of Daguerre was upon sil- vered plates. Mr. Fox Talbot's more recent discovery, the Calotype, was somewhat the result of accident ; he had prepared papers in a variety of ways, and only exposed them for a certain limited time in the camera, these were thrown on one side in a drawer, and left as failures ; but he was surprised to find, on examining one or two which had been washed with gallic acid, that perfect pictures had appeared of the objects at which the camera had been directed. 9. These processes excited a great amount of interest and attention, and the photographic art has advanced since this time with great rapidity. A number of different methods of taking pictures by sunlight have been published ; the most important of which we shall endeavour to make the reader fully acquainted with, our object being to instruct him in all the little requisites to success as a photographer, and at the same time to point out some of the chemical principles upon which the different processes depend. APPARATUS AND MATERIALS. 10. Paper, — The selection of good paper is the most important and troublesome matter the photographer has to contend with. There are a great many points to be attended to in choosing paper fitted for photographic processes. In the first place, it is essential the paper should be quite uniform in thickness. This may be ascertained by holding it between the eye and a strong APPARATUS AND MATERIAS. 7 light : a gas or candle light is preferable to dayliglit. It will be found on examining most paper in this way, that the sheet is full of irregularities in thickness, and very often minute holes may be detected. These defects exist mostly in very highly glazed thin papers. A mo- derately thick paper is not at all objectionable, provided it has been made without sulphate of lime ; this is an impurity which occurs in some kinds and should be carefully avoided. The paper should be well sized, for it is found that the organic matter in the size renders the paper, when prepared, much more sensitive ; but it is also important in another respect, for the photographer will sometimes find that, upon applying the solutions, transparent patches will appear, i, e., the solution will penetrate quite through the paper in some parts, while the rest will dry properly on the surface. This will be found to be the case in nearly all new paper. It ap- pears to be essential that the size should have had some time to get hard and insoluble, for we have never found this defect in old paper. Several descriptions have been made by the manufacturers purposely for the calo- type, &c. ; but, being new, they are all more or less liable to this defect. It has been stated that this may be overcome by applying a varnish on one side of the paper, but we have not obtained any good results by this plan. 11. A paper having much blue in its composition should be avoided. The colouring matter contains several substances which considerably injure a good photograph. It generally gives a disagreeable dirty appearance to the light parts. This defect exists in some of Whatman's papers, which otherwise 8 e PHOTOGENIC MANIPULATION. would be excellent. A description known as thick yellow wove post, made by Turner, Chatford Mill, is decidedly the best paper we have found for the calotype process. It should be chosen as old as possible ; we have some made in 1840, and find it excellent; the only defect is that a number of little brown spots appear when the iodide of potassium is applied : these consist of iodide of iron ; but this defect is fully coun- terbalanced by other advantages. This year's paper will not do, for the reason stated 10). 12. For obtaining the positive pictures (§ 30), the tex- ture of the paper is not of so much consequence. We find the best for this purpose to be a variety manufactured by Nash; it contains no water-mark, and is very white: it also contains a small quantity of the chloride of lime used for bleaching the paper, but which is accidentally a great advantage, for the silver wash may be applied without any previous preparation of the paper ; and the chlorine exists in the paper in the proper equivalent proportion. We have seen some very fine pictures said to have had their negative photographs taken (§ 30) upon this paper, but we confess that in our hands it has not proved at all successful for this purpose. The defect is, it is too new (§ 10); and the positive pictures ob- tained are very coarse and w^oolly in appearance (§ 30). 13, For some purposes, unsized paper answers very well ; for Mr. Ponton's process (§ 69) with the bichro- mate of potash, good blotting-paper is very good. In choosing paper for Mr. Hunt's Chromotype, great care should be taken to have no chloride in the texture of the paper, otherwise the pictures can never be rendered permanent. APPARATUS AND MATERIALS. 9 14. Bibulous Paper, — This should be chosen with- out colour, and of the description called white machine wove ; this has an even regular surface, which is an advantage. Fresh paper should be used for each stage of the process, and for each picture ; but old paper may be used for absorbing moisture by interpos- ing a clean piece at the back and front of the photo- graph, and it is as well to keep the paper used in the different processes distinct, for, should a piece of paper be accidentally used for drying a finished picture that had previously been employed in absorbing some of the sensitive solution, it would infallibly spoil it. 15. Water, — It has been recommended that the photographer should always use distilled water : this, in a great many of the processes, is not at all essen- tial. Common water generally contains muriate of soda, and some sulphates, &c.,in solution ; and there- fore, in making a solution of nitrate of silver, or in diluting a solution, we should avoid using it ; for it will of course precipitate the silver in the state of chloride ; rain or distilled water must be used in this case, although, where we cannot possibly get either, common water may be used, by allowing the precipitate to settle. The only consequence is, that the solution will be rendered very slightly weaker by the precipitation of a small amount of silver. In all the other manipulations required, common water answers very well, and has this advantage, — the photographer need not be sparing in its amount, and the picture may have a thorougli washing without much expense. Distilled water may be obtained of any chemist, or the amateur may readily distil it himself. 10 PHOTOGENIC MANIPULATION. Fig. 2. represents a convenient and economical still for the purpose. The whole is made of tinned iron, and can be used on a common fire, a is the body, holding about a gallon of water, which is introduced at the opening 6, which is then stopped by a cork. The tube d connects the neck of the still with the worm tub or refrigeratory e, which is filled with cold water, a supply being kept up through the funnel c, the hot water is drawn off through the cock / ; the different joints are rendered tight by lute, or, in the absence of it, some stiff paste spread on a piece of tape, and put round them answers very well. The distilled water is condensed in the worm, and passing off at the pipe is collected and preserved for use in a glass bottle. A glass retort connected with a Liebig's condenser forms a very convenient apparatus for distilling water, and may be heated either by an argand lamp, gas-light, or small chauffer. 16. Brushes y and Methods of applying the Solu- Hons, — The general method of applying solutions to the paper is by means of a brush, and for certain processes MATERIALS AND APPARATUS. 11 answers very well. They should be made of a soft mate- rial, and not bound with metal, for this has an injurious action upon several of the solutions ; they may be ob- tained constructed purposely for the photographer. Each brush should be kept for its own particular solu- tion ; that used for applying the nitrate of silver must not be used for the iodide of potassium, or any muriate, &c. ; and they should always be well washed after using. In the absence of proper brushes, the solu- tions may be very readily applied by a sponge tied to the end of a piece of wood. This is an economical plan and good, inasmuch as, when contaminated in any way, it may readily be replaced ; the only disadvantage is, that it is apt to disturb the surface of the paper. The brush used for applying the gallo-nitrate of silver in the calotype process is soon destroyed, and requires extreme care in washing, to remove all the gallo-nitrate, after each time of using ; the smallest quantity left in the brush being enough to spoil a clean solution. Old gallo-nitrate appears to act in a similar way to yeast, a very minute quantity sets up a decomposition in a clean and perfectly fresh solution. An instructive experiment on this point is the following : — expose a drop of gallo- nitrate of silver to sunshine, until it begins to darken, then take it into a dark room, and allow it to fall into fresh and clear gallo-nitrate that has not been exposed to light, and it will be found to become rapidly dis- coloured. [This, according to modern scientific par- lance, would be called catalysis, or, action by presence; i. e,y some phenomena we don't know much about, and give it a name instead of an explanation,] This action 12 PHOTOGENIC MANIPULATION. we have just mentioned is the great source of failures in the calotype process, and too much care cannot be taken to keep the brushes, &c., perfectly clean. A method of applying the solution, which removes this difficulty to a great extent, is to pour the liquid into a flat porcelain dish (fig. 5), or, what is better, upon the surface of a piece of plate glass, previously adjusted by set screws so as to be perfectly level, and then carefully to apply the paper so as to take up a certain amount of the moisture ; this will become very easy after a few trials. After laying the paper upon the solution, the finger should be gently passed over the surface so as to press out any bubbles of air that might interfere, care being taken not to draw any of the liquid over the back of the paper. Before floating the paper on the solution, about a quarter of an inch in breadth at one edge should be folded upwards, so as to enable the paper to be lifted without staining the fingers ; this part should, however, be previously moistened a little, so as to make the expansion of the paper uniform with that wetted by the solution. 17. It is sometimes an advantage, and particularly in preparing positive (§ 30) paper, when using a shallow earthenware dish, to draw the paper over the edge in taking it out of the solution ; this will draw off the superfluous moisture, and leave an evenly moistened surface. Both the plate glass and the earthenware vessel should be well washed after each operation, and care should be taken that they do not get scratched ; if so, it will be found that the gallo-nitrate will often remain in these scratches, and on pouring a fresh sola- APPARATUS AND MATERIALS. 13 tion on the plate, and applying the paper, it will be found to be stained something in the same style that bookbinders call marbling." 18. Chemicals — Nitrate of Silver. — This should be crystallized, and not the fused lunar caustic, the latter often being considerably adulterated with various sub- stances ; it generally contains both nitrate of copper and nitrate of potash ; it is a little lower in price, but the crystallized salt will be found to be more economical in use. Any contamination with copper will be readily de- tected by the salt being deliquescent, and the pictures produced will be found not to be permanent. Another matter to be attended to is this : — nitrate of silver very often contains a quantity of free nitric acid : this may be readily detected by the smell, and it may be remedied by dissolving in distilled water, and driving it off by heat. In doing so, the salt will recrystallize, and a great quantity of the acid will have been driven off with the water. The other chemicals required in the ordinary pro- cesses are, — iodide of potassium, bromide of potassium, and gallic acid. Acetic Acid. — The strength of this acid should be known ; it is generally sold containing very variable quantities of real acid. Chloride of Sodium, — Common salt is an impure chloride of sodium, but answers very well. Various other chlorides have been used, such as the chloride of barium, strontium, calcium, &c., and which we shall refer to presently. Hyposulphite of Soda.~T\\h should be pure, and 14 PHOTOGENIC MANIPULATION. free from sulpliuret of sodium. We give a method b'y which it may be prepared : one ounce of sublimed sul- phur is to be mixed with one ounce and a half of lime, previously slaked by the addition of hot water, and the mixture put into a clean earthen vessel. Three quarts of water are added, and the whole is to be boiled for two hours. The clear liquid may then be filtered off into several wide basins or dishes, and allowed to re- main freely exposed to air. When just made, the liquor is of a deep yellow colour, but by exposure to air it will become quite colourless. The time of exposure varies according to the strength of the solution, and the amount of persulphuret of calcium contained in it. This liquid, when colourless, is a solution of the hypo- sulphite of lime ; it should be filtered before use. The hyposulphite of soda may be made by adding common carbonate of soda; a white precipitate will fall, which is carbonate of lime, and hyposulphite of soda will re- main in solution. The bottle containing this solution should be lightly stoppered, otherwise sulphuret of so- dium is sometimes formed. 19. Different Methods of Preparing Photographic Paper. — If we brush a solution of nitrate of silver, having about 100 grains of the salt dissolved in an ounce of water, over a piece of paper, and allow it to dry, we shall have a paper moderately sensitive to light ; about one hour's good sunshine will com- pletely blacken it. This paper will serve very well for copying lace, leaves, ferns, &c. ; and there is this ad- vantage in using it, the picture can be fixed by soaking in hot water. The experimentalist will find very diffe- APPARATUS AND MATERIALS. 15 rent effects in using different sorts of paper. A highly- sized paper answers best with the simple nitrate of sil- ver ; it appears to combine with the size, and form a sensitive surface. By soaking in hot water, all the un- decomposed nitrate of silver and size is dissolved out together : but, however, this is far from being the best or most economical process. 20. Papers prepared tuitk the Chloride of Silver* — If we form a solution of nitrate of silver, and then add to it a solution of chloride of sodium, a white bulky preci- pitate will fall, which consists of chloride of silver, whilst there will remain in the solution nitrate of soda. The following diagram will roughly explain this interchange of substances. Common Salt. Chlorine. Sodium. Chloride \ / Nitrate of J> of Silver. / \ Soda. Silver. Nitric Acid. V ^ > Nitrate of Silver. From this it will be evident that if we wash paper over, first, with chloride of sodium, and allow it to dry, and then wash it over with nitrate of silver, the above interchange will take place, and the insoluble chloride vAW be precipitated in the pores of the paper. This forms an extremely sensitive surface, when a little excess of nitrate of silver is present ; hence, in giving the fol- lowing proportions for sensitive papers, care has been 16 PHOTOGENIC MANIPULATION. taken to allow this excess to be present, for it is a curious fact, but well worthy of attention, as it is of importance in the calotype process, that neither the chloride, iodide, nor bromide of silver, are sensitive to light when perfectly pure and free from organic mat- ter. We shall now give the proportions for forming the chloride papers. 21, Dissolve 60 grains of common salt in 3 ounces of water, (it is not necessary it should be distilled water), then weigh 60 grains of nitrate of silver, and dissolve this in one ounce of distilled ivater ; dip a sheet of good writing-paper in the solution of common salt, absorb the superfluous moisture by bibulous paper, or a clean dry cloth, and then allow it to dry ; then brush over the surface the solution of nitrate of silver, — this must be done rapidly and evenly. Should any part of the paper not have been touched by the brush, that part must not be filled in separately, but the whole sheet must be brushed over again very regularly ; care must be taken that the solution should be evenly spread over the whole surface alike, otherwise part of the paper will exhibit black patches on exposure to light, before the other part is sensibly darkened. The silver solution maybe applied by means of the porcelain dish, as explained (§ 16.) ; this paper should be allowed to dry in the dark, and when dry will be ready for use. These proportions may be varied according to the colours wished to be obtained in the finished drawing; it will be found, by using an excess of salt, that the paper will not be very sensitive, and it will darken to a disagreeable light slate colour, and there v/ill be no depth in the pic- APPARATUS AND MATERIALS. 17 ture ; a less proportion of salt will give a very sensitive surface having a dark-slate colour, a still less quantity gives a great depth and blackness in the drawing, and a smaller quantity will give a rich bronze colour, and so on, passing through all the shades of brown until we come to a very red brick colour having little depth. These principles will serve to guide the ama- teur, who will thus be enabled to vary the colours, and obtain any tone of picture his taste may dictate. The same rules will also hold good with the bromide paper, which we shall now give directions for preparing. 22. Bromide Paper, — Dissolve 60 grains of bromideX^ of potassium, and soak the paper in the solution ; absorb the superfluous moisture, and then wash it over with a solution of nitrate of silver having 100 grains to the ounce, observing the same precautions as with the chloride paper ; if required to be very sensitive, it may receive a larger quantity of silver. This is a very sensi- tive paper, and M. Biot says, he thinks nothing can be found more sensitive to light than the bromide of silver. 23. The fluoride, tartrate, benzoate, and iodide of sil- ver, have all been used, and they all modify the colour and the quickness of the picture very considerably ; and, in preparing the chloride papers, it will be found that the results will vary considerably by using different chlorides: — viz. the chloride of barium, used in the same proportion as the other chlorides, gives rise to a picture having a deep red ground ; the chloride of cal* cium, the chloride of lime, muriate of ammonia, muriate of iron, and the chlorate of potash, recommended by Mr, Cooper, the vapours of muriatic acid, recommended PART I. c 18 PHOTOGENIC MANIPULATION. by Dr. Schafhaeutl, and a great number of others, all modify the results considerably. y 24. But the best kind of photographic paper is that prepared with the ammonia nitrate of silver, and used upon a paper before spoken of (§ 12.), made by Nash ; a single wash of this solution, of the strength of 30 grains to the ounce of water, being sufficient to obtain a very sensitive surface, and will give a picture of a beautiful tone. The preparation of this ammonia nitrate, which requires a little care, I give below : — 25. Dissolve 30 grains of nitrate of silver in one ounce of distilled water, then cautiously add, drop by drop, strong solution of ammonia (liquor ammonice)^ until a precipitate of oxide of silver which is at first formed, is re-dissolved. Care should be taken that no more ammonia be added than is just sufficient to effect this, for if more be used, the paper will be almost insen- sible to light; it is better to adopt the precaution of not entirely re-dissolving the precipitate, but to allow a little cloudiness in the liquid; this will settle in a few hours, and the liquid become quite clear. 26. In preparing these papers, the experimenter should be cautious not to touch the prepared surface with his fingers; this generally gives rise, on exposure to light, to annoying representations of the markings of the skin, from the communication of organic mat- ter, which, as already stated, quickens the action of light. It is also a necessary precaution to mark the prepared side of the paper. The ammonia nitrate paper, and indeed all the very sensitive papers, should not be made more than a few hours before they are required for use; theybecomeyellowaud discoloured by long keeping. APPARATUS AND MATERIALS. 19 27. Making the Photograph, — We have now de- scribed several methods by which paper may be prepared in such a way that it will very quickly blackea all over, if exposed to light ; but it will be obvious that, if we shaded any part and exposed the other, the part covered would still remain white, and the whiteness would correspond to the form of the body shading it. If a leaf be placed upon a sheet of such prepared paper, and exposed to sunshine, the paper will become black all around the leaf, but underneath it, it will not have been blackened, except partially, under those parts of the leaf less opaque than the rest. The light will shine through these parts with different degrees of intensity, and there will be a corresponding marking ; the fibres of the leaf will shade more light than some of the other parts, and therefore will remain white ; but it is necessary, in order to obtain a perfect copy of the leaf, that no other lighl should get to the paper under the leaf, than what would shine through the more transparent parts. For this. Fig. 3. 20 PHOTOGENIC MANIPULATION. purpose, it is necesary that the object to be copied should be pressed close to the paper. — An apparatus contrived for this purpose is shown in Fig. 3. It consists of a thick piece of plate glass fitting into a frame ; upon this glass, the object to be copied is placed, and over this the sheet of prepared paper ; the board D is then laid over the paper, and the requisite pressure applied by means of a cross piece with a screw E. These frames are sometimes supplied with a sliding cover of wood C, by which the paper can be exposed to light when convenient. 28. A more simple form of pressure-frame is shown at Fig. 4; this consists simply of a piece of board Figs. 4. and 5. covered with soft flannel, upon which is laid the pre- pared paper, and then the object to be copied ; a piece of thick plate glass is then laid over this, and screwed down by means of four thumb screw^s, attach- ed to pieces of narrow wood fixed across each end of the glass. In copying an object which has thick parts, as the stems and thick fibres of plants, it is requisite to press the paper over them close to the glass ; this is done by putting a thick piece of flannel or a soft cushion in the pressure-frame beneath the paper, or the stems may some- times require paring down with a penknife when too thick. 29. Engravings may be beautifully copied by this process, particularly when they are moderately strong APPARATUS AND MATERIALS. 21 in light and shade : they should be placed with the printed side downwards. Ferns form exceedingly beautiful objects. Sea-weeds, feathers, wings of in- sects, and paintings on glass, serve to diversify the specimens. They should all be pressed as closely as possible to the glass, otherwise there will be a want of proper definition in the photograph. Engravings should be chosen which have been printed upon even and uniform paper; for, in copying the engraving, we also copy all the defects of the paper : they should also have no writing or printing upon the back, for this would also be copied. 30. In the first copy of a print by this process, the light and shade will not be true to nature; the dark parts of the picture will obstruct the greatest amount of light, consequently the paper will remain white underneath these shadows, while the white parts of the print will allow the light to shine through ; therefore the photographic paper will be darkened just in pro- portion to the light and shade, but in an opposite manner. This is what is technically called a negative photograph ; and in order to obtain the light and shade true to nature, or a 'positive photograph, we must place the negative copy, (of course, having previously fixed it) upon another piece of prepared paper, and expose this arrangement again to sunshine; this will again reverse the light and shade, and this copy will, there- fore, be correct. 31. A pretty method of multiplying designs is the following : — Cover a piece of glass with a coating of black varnish, and then with a steel point remove the varnish, according to any design you may wish to mul- 22 PHOTOGENIC MANIPULATION. tiply ; a piece of photographic paper placed under- neath this will, of course, be blackened where the varnish has been removed, and an exact copy of the design will be made; in Avhich way any number of copies can of course be made; but this requires some artistic skill ; nevertheless we have seen some very beautiful spe- cimens produced in this manner. Instead of the glass, a piece of ordinary photographic paper may be blackened all over, by exposure to the sun, and then submitted to the fixing process (§ 36). we should then prepare a solution of cyanide of potassium moderately strong; and with a quill pen dipped into this, trace any design we may wish to have multiplied : this will remove the blackened surface, or in other words, dis- solve the oxide of silver from the paper; it should then be washed in water and dried, when it may be used as a negative, and any number of positive (§ 30) pictures may be produced from it. 32. Time of Exposure. — This will, of course, vary with the degree of sensitiveness imparted to the paper, and the degree of capacity in the objects to be copied, the strength of the light, &c.; but the operator will easily determine this in a few trials. It is as well to make the impression rather darker than you wish it to be when finished ; for the fixing process hereafter described (§ 34.) will render the photograph a shade or two lighter. It is sometimes an advantage to render the engraving, or negative photograph, more transparent; this may be done by warming it, and then rubbing it over with white wax, and absorbing the excess by bibu- lous paper; or it may be covered with Canada balsam, APPARATUS AND MATERIALS. 23 or boiled linseed oil. These substances, however, have a tendency to make the paper yellow, unless used very sparingly, and which effect would just defeat the object we had in view in waxing them, viz. — to .obtain a copy from them more quickly. 33. On the Chemical Change produced, — We will now briefly notice the change which has been set up by the action of the light, and for this pur- pose will relate a very instructive experiment made by Mr. Hunt, which will give a clear view of the subject. That gentleman prepared some very pure chloride of silver, and placed it in a glass tube containing a little pure distilled water ; the tube was then hermetically sealed, and exposed to light; the consequence was, that the chloride became darkened, or in other words, it was decomposed into its elements, viz. silver and chlorine; the dark powder being silver and oxide of silver in a state of minute division, and the chlorine formed a solution in the water. This was proved, by breaking the tube and pouring off the water ; a solution of nitrate of silver was then added, when an immediate precipitate of white chloride of silver took place ; this was collected and weighed. A little dilute nitric acid was then added to the darkened chloride; this dissolved any silver that might be present; and it was found, on calculation, to be exactly equivalent to the amount of chlorine found in the distilled water. We could not resist giving this experiment, it being so exceedingly neat, and to the purpose. The first action in these papers, when exposed to light, is this, — that the chlorine, 24 PHOTOGENIC MANIPULATION. bromine, or nitric acid, with which the silver is com- bined, is set free, and dark oxide of silver is left in the paper. A still greater exposure to light sets free the oxygen, and metallic silver is left ; this forms the dark parts of the picture, and the undecomposed chloride of silver the lighter parts. We have, therefore, a com- plete picture, but which would not bear exposure to the light ; for this would act on the remaining chloride in the lighter parts of the picture, and darken it; our picture would, therefore, disappear, and we should have a mere black sheet of paper. The object with the photo- grapher will, therefore, now be, to remove this chloride of silver from the unsunned parts, without injury to the oxide of silver in the shadows. This we shall consider in describing the 34. Fixing Process. — It is known to chemists that the chloride of silver is soluble in a solution of ammonia; we may, therefore, dissolve the undecomposed chloride out of the paper by this agent; and it does so very effec- tually ; but, unfortunately, it also has the property of dissolving oxide of silver. We shall, therefore, have our picture moderately well fixed by soaking in ammonia ; but without great care, the oxide of silver forming the shadows will also be dissolved out. The ammonia used as a fixing agent should be rather weak. 35, Common salt has been recommended by Mr. Fox Talbot to fix the photograph. In this case, the action is also by dissolving out the chloride of silver, that substance being soluble in chloride of sodium or common salt ; it is probable, however, that this sub- stance also acts, to a certain extent, by getting rid of APPARATUS AND MATERIALS. 25 any excess of nitrate of silver, by converting the whole into a chloride, — the chloride being almost insensible to light, without free nitrate of silver being present, as before stated (§ 20.); however, organic mat- ter is always present, which, as well as free nitrate of silver, determines the blackening action of light. Pho- tographs soaked in a solution of common salt are therefore but imperfectly fixed ; they should always be washed in abundance of water after immersion in the solution of salt. Iodide and bromide of potassium may be also used with hke success, the rationale being the same. 36. But the best substance to use is a salt called the hyposulphite of soda, and by proper precautions pic- tures may be perfectly fixed by it. The photograph should be placed in a flat porcelain dish, Fig. 5, and wetted throughout with cold water ; a quantity of hot water should then be poured upon it and allov/ed to remain a little time, which will shortly become milky from the quantity of muriates and sul- phates contained in ordinary water (§ 20) : this should then be poured ofF, and a fresh quantity of hot water placed in the dish ; it may now be allowed to stand in a shaded place until quite cold, and the photograph then rinsed with a little common water, and pressed be- tween folds of blotting paper. It is now moderately well fixed, but not perfectly ; all the size and nitrate of silver will have been dissolved out of it ; a solution of hyposulphate of soda should then be prepared, having about a quarter of an ounce of the salt dis- solved in a pint of water ; a little of this should then 26 PHOTOGENIC MANIPULATION. be poured into a flat dish, and the photograph gently laid with its back upon the surface of the solution, taking care the face is not touched by it ; the solution will gradually permeate the paper, and a red appearance will be given to the drawing ; the solution should tlien be quickly made to run over the surface, and the pic- ture withdrawn and placed in a vessel of cold water. The advantage of allowing the hyposulphite to act upon the back of the picture is this, that the greater part of the silver will be dissolved without injuring the photograph, whereas, if it had been wholly immersed, the solution would have acted considerably upon the drawing. This will be found to be more particularly the case with weak impressions, or those which have been produced by feeble light. The photograph may be allowed to remain in cold water a considerable time, or until the water is quite taste- less in which it is soaked. The hyposulphite of silver is extremely soluble, and it is a curious fact that it has an extremely sweet taste. It is an advantage to press all the water out of the paper once or twice before putting it into fresh water, as it is quite necessary to get rid of ajl this hyposulphite of silver, for if any remains it gives rise to the formation of sulphuret of silver, which inevi- tably spoils the photograph, — hot water immediately gives rise to the formation of this substance. It is as well to remind the amateur that, from the extreme solubility of the hyposulphite of silver, a great quantity of water is required rather than long soaking; the paper may be dried by pressure between clean bibulous paper. 37. Application, — Mr. Fox Talbot has patented a CAMERA PICTURES. 27 great number of applications of this new art, and has exercised great ingenuity in anticipating some purposes to which it may be applied ; one plan he has recorded in his specification is printing by photography, for which purpose, he directs that a number of letters should be cut out and waxed, or rendered transparent by some of the methods now in use ; these should be sorted and cemented on a sheet of paper in the order in which we wish them ; a copy is obtained from this, which is of course a negative, and any number of positives may be taken from the negative picture. Photography has been applied as a means of making the designs upon blocks of wood for woodcuts and for calico printing ; for this purpose the surface of the block is washed over with the solutions in the same way as they are directed to be applied to paper, and they may undergo the same processes in fixing. It has also been stated that an Italian gentleman has applied photography to delineating figures upon a lithographic stone with great success, and the pictures are stated to be produced with great rapidity, but the process has not been made known. It is a curious and interesting fact, that nearly all paper photographs may be rendered invisible, and again restored at pleasure. If a photographic picture, prepared by any of these methods and fixed as directed, be dipped into a solution of corrosive sublimate (the strength of the solution is of no material consequence), the picture is observed gradually to fade, and after a time, varying according to the strength of the solution, it will entirely disappear. It may thus be preserved 28 PHOTOGENIC MANIPULATION. for an indefinite length of time as an apparently blank piece of paper, but can at once be restored by washing it with hyposulphite of soda, the rapidity with which its restoration is effected is almost marvellous. CAMERA PICTURES. 38. We have hitherto described the most simple kind of photographs, — those produced by direct radiation through the object to be copied ; but the most interest- ing and important variety of sun pictures are those produced by light, reflected from the object to be copied upon the prepared surface ; in order to produce these results, the manipulation is a little more complicated, and requires a more expensive apparatus : but the effects produced are well worth the little additional trouble and expense. We allude to the method of obtaining views and portraits from nature by means of the Camera Obscura, an instrument which it is neces- sary to describe at some length, as upon its perfection a good deal of the success of the amateur will depend. 39. Caviera Obscura. — This instrument has hitherto been described in optical treatises as little more than a philosophical plaything; the requirements of photogra- phy have, however, induced opticians to make modi- fications in its construction, and almost every optician has altered it to suit his own particular fancy ; but we shall only describe those forms of the instrument quite adapted for the purpose, and which have been tested by us, and found practically the most useful and con- venient for the photographic processes on paper. CAMERA PICTURES. 29 40, Fig. 6. represents the most simple and inexpen- sive form of the apparatus ; it consists of a wooden box A, having at one end a meniscus or concavo-convex lens screwed into a sliding brass tube B, so as to be able to push it toward or away from a piece of dimmed glass C which is enclosed in a frame, and made to slide into a groove at the other end of the box. On pointing the camera at any object, there will be a reduced represen- tation of it on the ground glass C, more or less clear ; but this image may be rendered quite distinct by ad- 30 PHOTOGENIC MANIPULATION. justing the distance of the lens from the ground glass, D represents the sliding frame for holding the prepared paper, this fits into the same groove in the camera as the ground glass, and is provided with a sliding door E, so that the light can be made to fall on the prepared paper after its introduction into the camera ; the paper is affixed by one or two morsels of wafer upon the door F, of the frame. 41. Portable Camera, — Fig. 7. represents a much more complete and convenient form of camera ; the Fig. 7. sides of the box, A, are hinged together, and so contrived that, upon taking out the back and front, the box folds into a very small compass, and the whole can be packed into the box, B ; the slide for containing the paper is also very convenient, inasmuch as it is so con- trived that two pieces of prepared paper may be enclosed and exposed to light in succession, it is shown CAMERA PICTURES. 31 in a a. The pieces of prepared paper are laid, the prepared side downwards, upon the squares of glass a a, having a piece of black paper interposed between the two, to prevent the light acting upon one, whilst the other is being impressioned ; the two halves of the slide are then folded together, and secured by a brass clasp at each side. Upon reference to Fig. 6. it will be seen that one slide is represented as drawn upwards, this would let the light act upon one piece of paper ; this shut down, the frame turned round in the camera box, and the other drawn up, would then uncover the other piece. 42. But a very convenient and useful modification in this camera, is the sliding front, h ; the part of the camera front bearing the lens is made to slide in a dove- tail in the other part of the front, so that the operator is able to raise or depress the lens to the extent of about one inch or one inch and a half. In raising or depressing the lens, we also raise or lower the horizontal line of the landscape (or other object at which the camera is pointed) upon the ground glass; now, as will be seen in our directions for taking views, it is absolutely essential in order to obtain correct perspective — for example, in copying a building — that we should not raise the camera at an angle, but that it should be perfectly horizontal. Now, supposing the operator to be standing on the ground, it will be found that if the camera is horizontal, one-half of the picture will be occupied by the object we wish to have represented, and the other half by the foreground, which we could just do as well without, and it is very probable the effect of the picture will be spoiled, by some of the upper part of the object not being represented. Now this difficulty 32 PHOTOGENIC MANIPULATION. is completely overcome in this case, by raising the object-glass" a little higher, when part of the ground will be cut off, and the whole of our object represented, without having to move the camera out of its hori- zontal position ; consequently, the true perspective will be retained. 43. As some little care is required in the construction of a camera, it may be as well to make the reader acquainted with two or three points to be attended to, and some of the optical principles on which its use depends. Fig. 8. represents the lens, and the directions of the Fig. 8. rays of light in forming the image. If we hold a double convex lens opposite any object, we shall find that an inverted image of that object will be formed on a piece of paper held behind it ; but the lens being doubly convex, the rays which pass through it will go to the same distance from every part of its surface, therefore the image a will be found in the same curve as the lens A. This may be corrected to a great extent by using a lens of the periscopic form ; this was first suggested by Dr. Wollaston : by this means the rays a A, h B, are rendered longer than the central rays, c, c. This lens, when used in the camera, should have the concave side towards the object, and in order still more to reduce the error of figure, a small diaphragm CAMERA PICTURES. 33 should be placed in front of the lens. The diagram, Fig. 9, represents this arrangement, and the position of the stop is shown at a, when it will be seen that it just admits the rays of light from the object, and no more. If a stop, having the same opening^ had been placed farther in advance of the lens, it is evident that it must have cut off some of the rays of light from the Fig. 9. upper and lower parts of the figure, or if the tube had been made longer, the same effect would have taken place ; this is a very common fault in the construction of cameras, and should therefore be attended to. 44. By using a small opening in front of the lens, we are enabled to cover a greater extent of surface, and more correctly, than by using a larger opening, but it is at the sacrifice of light ; for the larger the opening we employ there will of course be a greater amount of light upon the prepared surface, and we shall obtain a picture more quickly ; but in order to obtain the greatest amount of distinctness, we must employ a very small opening. It is better that the operator should have two or three sizes, of about half, three- * fourths, and one inch and a quarter in diameter : and supposing the lens to be nine inches in focal length, we PART I. D 34 PHOTOGENIC MANIPULATION. shall be enabled, by having an opening of about three- fourths of an inch, to cover a surface of nearly five inches square. As a general rule, with a moderately small opening, a lens will cover a square surface of about six-tenths of its focal length ; that is, supposing a lens to be of twenty inches focus, it will enable us to have our prepared paper six-tenths of twenty inches square = twelve inches square. This is a general rule ; for, of course, if the object is very close to the glass, the distance of the paper from the lens will have to be increased, and instead of twenty inches focal length, it may be twenty-five or twenty-six, and the size of the paper may be increased in proportion. 45. Another important matter to be attended to, is what is called Chromatic Aberration, Fig. 10. Fig, 10. y z .... Let a represent a ray of white light falling on the lens L; it will not pass through colourless, but will suffer decomposition into the primitive colours of which white light is composed. Now all these colours have a different degree of refrangibility, or are differently bent out of their straight course ; therefore all these colours will have a different focal distance for the image a, a ; the visual focus, or that of the yellow ray, being at 2/, whilst the focus for the violet rays will be at v, and for ^ the red at z. Now, it has been stated (§ 5.), that the CAMERA PICTURES. 35 rays by which the photographic image is produced are the violet, whilst those which act most intensely on the organ of vision are the yellow. It will therefore be evident, that, when we adjust the focus of the camera, we shall obtain the focus of the yellow ray, whilst the image produced by the violet rays will not be properly dis- tinct ; it is necessary, therefore, after having obtained the best visual focus, to push the lens a little nearer the paper so as to get the violet rays to act on the paper. This distance is about one-thirtieth of the whole focal length of the object glass, with a moderate-sized open- \ ing ; of course, with a smaller diaphragm the chromatic 'I aberration will be a little less, but as a general rule to the photographer, the lens should be pushed in one- thirtieth of the focal distance, after having obtained a distinct and v/ell-defined image. The instrument- makers generally mark on the brass tube containing the lens, a scale which indicates at once the proper focus. 46. Lenses are made with a combination of glasses, in which this chromatic aberration is overcome ; but there is this disadvantage attending them, that in achromatizing a periscopic lens, we increase the error of figure, and therefore cannot cover so large a field ; however, for the more delicate operation of the Daguerreotype where extent of surface is not so much an object as minuteness of detail, an achromatic lens is preferable. A great amount of attention has been paid to this point, and combinations of lenses are now made beautifully achromatic, but the expense is enormously increased, and for the processes on paper we can recommend, from our own experience, a single D 2 36 PHOTOGENIC MANIPULATION. meniscus lens, and believe that, if properly adjusted to the chemical focus, equally as good pictures may be produced by it as by a more expensive form. CALOTYPE. 47. We are indebted to Mr. Fox Talbot for the dis- covery of this process, by which a paper may be pre- pared of an extraordinary degree of sensitiveness. The sensitive papers before described may be used in the camera, but they require such an enormous time to pro- duce an image, that on this account they are all but useless, two or three hours being in general neces- sary for exposure before an image is produced ; whilst in the calotype, in a very few seconds, the paper re- ceives the impression. Before, however, describing the process, we shall enumerate the apparatus required. Two or three flat porcelain dishes for holding the solutions of iodide of potassium, nitrate of silver, hypo- sulphite of soda, distilled water, &c. Fig. 5. A sheet of plate glass, supported upon adjusting screws, to apply the gallo-nitrate. Camel or badger hair brushes. A steam apparatus for developing the picture, shown at Fig. 12 ; or, in the absence of this apparatus, a basin of hot water will do very well. A graduated glass to measure out the gallo-nitrate ; this should not be made too narrow, but should admit of being readily cleaned ; this cleaning being absolutely essential after every time of using, inattention to which will cause many failures. CALOTYPE. 37 A board for laying the paper upon whilst applying the solutions. 48. Preparation of the Iodized Paper, — ^The paper having been selected with the precautions before stated (§ 10.), it should be laid upon the board, having two or three sheets of blotting paper underneath it, so as to absorb any moisture that may by chance get over the side of the paper ; it should be held by the finger at one corner and washed over by candle-light with a solution of nitrate of silver, having about 20 grains of the salt dissolved in one ounce of distilled water ; this should be allowed to dry at a little distance from the fire, and then altogether immersed in a solution com- posed as follows : — Dissolve in a pint of water 250 grains iodide of potassium, 125 ,5 chloride of sodium (common salt), 125 „ bromide of potassium. It may be allowed to remain for about half a minute in this solution, so as to insure the whole of the pre- viously applied nitrate of silver being converted into the mixed iodide, chloride, and bromide of silver, for should there be any free nitrate of silver left in the paper, it will be liable to darken spontaneously, and the operator will be annoyed by finding that upon applying the gallo-nitrate to excite the paper, it will blacken all over ; at the same time, care should be taken that it does not remain too long in the solution, for if it should, the iodide of silver being very soluble in iodide of potassium, the whole will be dissolved out. 49. The object of the operator in this part of the 38 PHOTOGENIC MANIPULATION. process being to leave an iodide of silver in the pores of the paper, perfectly free from impurity, it is necessary, after the paper has been immersed in the iodide of potassium, to remove the excess of this salt and a nitrate of potass, which is formed, by well washing in common water. For this purpose the operator should provide himself with three or four large vessels of water, and after the first piece of paper has been immersed in the iodide of potassium, it should be placed in vessel No. 1 and gently agitated, and left until the next piece of paper is ready for washing, when the first iodized piece should be removed into vessel No. 2, and the second piece of paper submitted to the same wash- ing and agitation as the first, and so on, until the first prepared piece has passed through three or four vessels of water, when it should be taken out and the super- fluous moisture removed by clean blotting-paper, and then left to dry spontaneously ; the paper should then be preserved from the light in a portfolio until required for use. 50. We have sometimes found it an advantage when washing the paper, to let a drop of the water from the paper fall into a solution of nitrate of silver ; if there should be a precipitate, it will indicate that the whole of the iodide has not been washed out ; but should there be no precipitate, the operator may consider that the soluble salts have all been removed. This is a useful test in one or two respects, first, because the paper should not be washed more than is absolutely necessary, for it has a tendency to make the paper woolly, which will then print imperfectly ; secondly, it CALOTYPE. 39 is essential that the whole of the iodide should be removed, for if not, the amateur will find that the requisite degree of sensitiveness to light will not be ob- tained, for it will convert the excess of nitrate we add in order to make the paper sensitive, into iodide of silver, which, when pure, is absolutely insensible to light, as already stated. (§ 20.) 51. Applying the Sensitive Mixture.*^Th\s consists in the application to the iodized paper of a mixed solution of gallic acid and of nitrate of silver, called by Mr. Fox Talbot, Gallo-nitrate. It is prepared as follows : — we give the formulte as originally published by Mr. Fox Talbot, for we believe, after all the modifications which have been made, that his proportions are the best. — Dissolve 100 grains of crystallized nitrate of silver, in two ounces of distilled water, to which is added one- sixth of its volume of strong acetic acid (which will be two and two-thirds of a drachm) ; this solution should be kept in a bottle excluded from the light. Now make a saturated solution of gallic acid in cold distilled water, the quantity dissolved is very small ; when re- quired for use, the two liquids should be mixed together in equal quantities, and then poured upon the plate glass; having adjusted it by the set screws, so that the solution will not run off, the sheet of iodized paper should then be carefully applied to the wet surface, and the air bubbles gently pressed out by passing the finger over the back of the paper. As soon as the paper has ceased to curl upwards, it should be removed from the glass, and very gently pressed between folds of blotting-paper, but only just enough to remove any 40 PHOTOGENIC MANIPULATION. shining patches of moisture on the surface, and then placed at once in the frame of the camera, for it is now extremely sensitive, and should be used directly, for with this strength of solution the paper almost immediately blackens spontaneously. To obviate this, Mr. Fox Talbot directs that the paper should be immersed for an instant under water, after the application of tlie gallo-nitrate, and then blotted off. It is evident that this is equivalent to using a more dilute solution ; it is, therefore, better, instead of using the solution so strong as Mr, Fox Talbot recommends, to dikite it twenty or thirty times its bulk with water, and then apply this to the paper, when it will be found to preserve its whiteness for ten or twelve hours, if care- fully excluded from light. As a general rule, the longer we wish to keep paper after the sensitive solution is ap- plied, the more the gallo-nitrate should be diluted ; but when we wish for very sensitive paper, the dilution should not be more than three or four times the bulk of the mixed liquids. Another matter must be at- tended to carefully if we wish to obtain clean and clear pictures : — if the acetic acid we use be of the greatest possible strength, or the crystallizable acid, then the amount stated to be added by Mr. Fox Talbot is the proper quantity ; but if weaker, then we must add a larger quantity ; for Mr. Cundell has pointed out (Phil. Mag. No. CXCII.) that one great cause of the failure of calotypists, is in having their paper blackened all over, or becoming of a dirty colour by the absence of the requisite quantity of this acid. The operator may^ therefore, be sure that if his paper becomes discoloured CALOTYPE. 41 when every care has been taken in the other parts of the process, that he has not got enough acetic acid in the solution. The tendency of this acid appears to be, to keep the white parts of the picture clean and white, but too much destroys the sensitiveness of the paper. 52. Exposure in the Camera, — The camera is to be placed upon some firm and steady support, and pointed at the object we wish to represent. A clear and distinct focus is then to be obtained upon the ground glass, and the tube afterwards pushed in a cer- tain distance to the chemical focus (§ 45.) ; the ground glass is then removed, and replaced by the frame con- taining the prepared paper, and the slide in front drawn up for a certain time, which depends entirely upon the amount of light existing at the time, the size of the diaphragm in front of the lens, the sensitiveness of the paper, and the colour of the object to be copied, &c. All these matters the amateur must determine by experience, and with a few trials of his apparatus he will easily determine the time. It varies from about half a minute to five minutes ; an exposure for a longer time seldom produces good results. The operator must bear in mind that any object of a yellow colour will take a much longer time than a white or blue, and when the light is yellow from clouds, or when near sun- set, the picture will also take much longer to be pro- duced. Generally, in views or buildings a much better effect is produced when the sun shines on the object for a few seconds, as we are about to withdraw the paper ; it sharpens and gives a much greater intensity 42 PHOTOGENIC MANIPULATION, to the lights, whilst, if there had been sunshine during the whole of the exposure, the shadows would have been very heavy. Portraits. — In copying the human face divine," two or three hints may not be unacceptable to the amateur. The sitter should be placed in an easy, na- tural position, and remain perfectly still during the operation. A very ludicrous effect is often given from an inattention to this, for it is obvfous, if a person as- sumes two or three positions during the exposure of the paper, there will be a corresponding number of images impressed, and we may thus have a representation of one or two additional noses, fingers, or eyes, or the nose or eye may have a greater breadth, or be consi- derably elongated ; to avoid this, a rest for the head should be made use of, one form of which is repre- sented (fig. 11) ; this is to be attached firmly to the back of the chair, and the person allowed to assume the desired position ; the rest should then be adjusted so that the arm having the curved piece of brass attached just touches the back of the head ; this will keep it sufficiently still for all the minute markings to be very accurately copied. In order to operate with success, the model should be well illuminated, but at the same time care should be taken to avoid the direct rays of the sun ; for this purpose a sort of canopy should be placed over the head, made of blue calico, so that the shade may fall beyond the feet; this will also prevent Fig. 11. CALOTYPE. 43 too much light falling on the forehead and the top of the shoulders ; too much light falling directly from above has the disadvantage of not shewing the eyes with distinctness, the shadows from the eyebrows and forehead falling on them. With respect to the proper backgrounds, those who undertake portraits will ar- range them according to their own tastes : some paint a landscape, library, or balcony roughly, and place it behind the sitter ; these look very well for a full length portrait, in a group : for a plain background, an old blanket gives a very even and uniform tint. As a general rule, the camera should be placed about the height of the eyes ; by this means, the upper or intel- lectual part of the head v;ill be slightly enlarged, the eyes may be directed towards the camera. 53. Views. — The operator must be very careful, when directing the camera to a building, &c. that it should be perfectly horizontal; for if the camera is pointed upwards, so as to take in the whole of the object, the picture will have a very bad effect, for the building will appear in the picture as if falling, and none of the perpendicular lines will be erect. Some have recommended that the operator should endeavour to have the camera placed at about one-third of the height of the building, but we think pictures have a more pleasing and natural effect if taken from the street, at about the height of the eye, so as to get the same angles in the picture we are generally accustomed to, in viewing any object. It is generally better to have the camera at about the distance of double the height of the object; of course, it must be left to the 44 PHOTOGENIC MANIPULATION". taste and management of the operator, as to the con- trasts, &c. in the picture. The object upon which we place more importance, and of which we desire the most clear representation, we should adjust the focus of the camera more clearly upon ; but should the landscape embrace various objects, at different distances, it will be necessary to use a very small opening in front of the object-glass, otherwise only one or two objects will be distinctly in focus, and the rest indistinct. 54. Developing the Picture, — When the paper has been exposed in the camera the requisite time, there is, to all appearance, seldom any impression, it being generally as blank as before, but the picture exists, though in a latent state. In order to render it visible, Mr. Fox Talbot directs that the paper should be again washed over with a solution of the gallo-nitrate of silver, and then exposed to a gentle heat. The best method of applying this gallo- nitrate, is to pour it, as before directed (§ 51), upon the piece of plate glass (taking care that it is thoroughly clean), and then apply the paper to the surface until Fig. 12. it is moderately wet ; any air bubbles should be pressed out, by passing the finger over it as before mentioned. The paper should then be held in front of the jet of steam, which should be allowed to act equally all over the paper, when the picture will slowly develope itself. Fig, 12 represents a convenient apparatus for the pur- pose. Should any part of the picture CALOTYPE. 45 not appear sufficiently distinct, the jet of steam may be allowed to play upon it for a short time longer than the other parts. The paper should not be allowed to be- come drij in this process, otherwise the heat will em- brown it, but it may be rewetted with the gallo-nitrate, and again exposed to heat. A very simple and very effectual plan is to develope the picture by means of the steam and heat arising from a basin of hot water — the picture should be held horizontally, and moved about over the steam. Some have recommended a dry heat, viz., by a vessel heated with hot water, but this plan is very apt to embrown the picture, the moisture being so soon evaporated, whereas with the steam, a considerable amount of water is condensed, and the paper is therefore kept moist. After the picture has obtained its greatest intensity, it should be agitated in a little common water — this being renewed once or twice— and it may, after a pressure between the folds of clean blotting paper, be submitted to the operation of 55, Fixing the Picture. — Mr. Fox Talbot originally directed that it should be immersed in a solution of bromide of potassium, containing 100 grains of that salt dissolved in ten ounces of distilled water. After remaining for a little time in this solution, it should be well washed in common water, and dried with blotting paper. But a much better plan is to immerse it in a solution of the hyposulphite of soda for a short time, and then wash it well in water, renewing it a number of times. It is better it should be soaked for three or four hours, and then dried with bibulous paper. (§ 36.) The following deviation from Mr. Fox Talbot's pro- 46 PHOTOGENIC MANIPULATION. cess answers extremely well when the paper is to be used and the image brought out immediately ; the pic- tures obtained by its means are generally very clean, and the light parts very white ; for portraits, and where great quickness is required, we have found it excellent. Apply to the paper a solution of nitrate of silver, containing 100 grains of that salt to 1 ounce of dis- tilled water. When nearly, but not quite, dry, dip it into a solution of iodide of potassium, of the strength of 25 grains of the salt to 1 ounce of distilled water, drain it, wash it, as before directed (§ 51.), and then allow it to dry. Now brush it over with aceto-nitrate of silver, made by dissolving 50 grains of nitrate of silver in 1 ounce of distilled water, to which is added one-sixth its volume of strong acetic acid. Dry it with bibulous paper, and it is now ready for receiving the image. When the impression has been received, it must be vi^ashed with a saturated solution of gallic acid, and exposed to a steam heat. (§ 54.) The image will be gradually brought out, and may be fixed with hypo- sulphite of soda. It will be observed that in this pro- cess the solutions of nitrate of silver and of gallic acid are not mixed before application to the paper, as in Mr. Talbot's process ; we therefore can use a brush for applying the solutions, which is sometimes an advan- tage ; of course, separate brushes must be used for the nitrate of silver and for the gallic acid. In preparing calotype paper, too much care cannot be taken, not only to prevent the daylight falling on it, but also to exclude, if possible, the strong glare of a candle or lamp. The candle should be removed some distance CALOTYPE. 47 from the paper, or a yellow screen should be placed around it. This must be particularly attended to when the paper is intended to be kept some time after 'the sensitive mixture has been applied, for the slightest im- pression of light will in a little time develope itself strongly, if not visibly ; it will make its appearance when the picture is brought out, giving the light parts a dirty appearance, or, very probably, the paper will blacken all over. 56. Obtaining the Positive Photograph, — The pic- ture just described, as being obtained in the camera, is a negative picture, similar to those we have mentioned in the description of the common photographic papers. {§ 30.) It is therefore necessary that a positive picture, or one with the lights and shades as they occur in nature, should be obtained ; this can be produced very quickly on the calotype paper, but it is unadvisable, as the tone of the picture is not so pleasant as that obtained by the common photographic processes. (§ 19.) The ammonio-nitrate paper is decidedly the best. The negative calotype picture should be laid, with its face downwards, upon a piece of dry ammonio- nitrate paper, and secured at two of the corners by morsels of wafer, and then placed in the pressure frame, Fig. 4, and exposed to light, until the necessary degree of intensity in the positive picture is produced. This can be readily ascertained by taking it out of the frame, and raising it gently, so as not to disturb its position, or draw it apart from the wafers ; the rest of the process with the positive picture being precisely the same as at (§ 34). 48 PHOTOGENIC MANIPULATION. 57. Mr. Fox Talbot has described a plan by which the tone of the positive picture is altered considerably. He directs that, after removal from the light, it should be placed in a weak solution of iodide of potassium. This will convert the whole of the free nitrate of silver into the yellow iodide of silver. It should then be im- mersed in a boiling solution of the hyposulphite of soda, — the yellow colour will be removed from the lights, and a very peculiar tone left on the picture. This is a very perfect method of fixing, the photograph seldom becoming dark, as is the case sometimes with other methods of fixing. 58. This method has also been applied by the same gentleman to fix the negative photographs ; the ne- gative picture should be immersed in a hot solution of the hyposulphite until the yellow colour disappears from the iodized paper, and be then washed as usual. This is stated by Mr. Talbot to produce better positive pictures, but in our hands it has not proved successful, the hot hyposulphite appears to injure the picture con- siderably. 59. The calotype process just described is exquisitely sensitive, very beautiful impressions from prints, leaves, ferns, and pieces of lace, may be produced in a few minutes by exposure to moonlight, a candle, or gas light, but for producing the same effect in sunshine a fraction of a second is sufficient. Some operators render the negative pictures transparent, this is some- times an advantage when we wish to print very quickly; it may be done as described (§ 32). Sir D. Brewster has proposed an important modifi- CALOTYPE. 49 cation of this method of obtaining positive photo- graphs. He states that the present mode gives a rough- ness of shade which destroys the softness of the picture. To obviate this he interposes a sheet of white paper without water-mark, and of uniform texture. The diffusion of the light thus occasioned shades off, as it were, all the sharp lines and points, and gives a higher degree of softness to the picture. Two, or even three sheets may be interposed in strong sun light. A similar effect may be obtained in a less degree by placing the back of the negative upon the positive paper, so as to cause the light to traverse the thick- ness of the negative, and this may be combined with one or more sheets of clean paper ; but this will be appropriate only for portraits, and it has the advan- tage (sometimes required) of making the individual look another way. To those," adds Sir David, who see the experiments above described for the first time, the effect is almost magical ; and when the nega- tive is removed, we see only a blank sheet of white paper, and our surprise is very great when, upon lifting this sheet, we discover beneath it a perfect picture, whi oil setms, as it were, to have passed through the opaque and iiapt i vuas m:- ^en.'* The calotypt; process has been much simplified by Mr, Huni, to whom we are indebted for ihe s^reater number of proceo. i 'yi paper at present iinown, and whose valuable researches ou tb/^ cli^^Tnieai efiocts of light have added so greatly to our knowledge of that mysterious agent. 60. Mr. Hunt has shown that the action of light on PART I. E 50 PHOTOGENIC MANIPULATION, nearly all the salts of silver may be hastened, and the effects developed by gallic acid, or other reducing agents, and he has given several formulse for producing pictures. We give one which we hav&ifound the best, but the principle is the same in all. An insoluble salt of silver is formed in the paper having a slight excess of the nitrate, this is exposed to light, and then brought out by a solution of gallic acid, or proto-sulphate of iron. The following Mr. Hunt calls FLUOROTYPE. 61. A sheet of paper is to be washed, first, with a solution of bromide of potassium, and then with the fluate of soda, or, which will be found the better plan^ the two salts may be united. The strength should be as follows : {Bromide of potassium, 20 grains. Distilled water, . . 1 fluid ounce. / Fluate of soda, . . 5 grains. 1^ Distilled water, . . 1 fluid ounce. Mix a small quantity of these solutions together when the papers are to be prepared, and wash them once over with the mixture, and w hen dry, apply a solution of nitrate of silver, sixt} grains to the ounce of water. These papers keep for some weelrs without injury, and become impressed with good Imao-es half rninute in the camera^ The impression is not sufficiently strong when removed from the camera for producing positive pictures, but may be rendered so by a secon- dary process. 62. The photograph should first be soaked in water FLUOROTYPE. 51 for a few minutes, and then placed upon a slab of por- celain, and a weak solution of the proto-sulphate of iron brushed over it ; the picture immediately acquires great intensity, and should then be stopped directly, or the blackening will extend all over [the paper ; it may be fixed by being soaked in water, and then dipped into a solution of hypo-sulphite of soda, and again soaked in water as in the other processes. 63. We find it is better to add to the proto-sulphate of iron a little acetic or sulphuric acid : this will be found to prevent the darkening of the lights of the picture to a great extent, and it will be found better not to pre- pare the paper long before it is required for use, this being one reason why the picture often becomes dusky on application of the proto-sulphate. Reasoning upon the principle that the action of light is to reduce the salts of silver in the paper to the metallic state, and that any substance which would reduce silver would also quicken the action of light, we were led to the fol- lowing experiment : The proto-chloride of tin possesses the property of reducing the salts both of silver and of gold ; a paper was prepared with the bromide of silver, and previously to exposing it to light, it was washed over with a very weak solution of the chloride of tin ; the action of light upon the paper was exceedingly en- ergetic ; it was almost instantaneously blackened, and a copy of a print was obtained in a few seconds; this was performed last summer. I have lately tried once or twice to repeat the experiment, but v/ithout success ; the paper being blackened in the dark spon- taneously. I hope, however, to have some leisure shortly, E 2 52 PHOTOGENIC MANIPULATION. and sliall endeavour to perfect the process, which gives a g'ood deal of promise. FERROTYPE OR ENERGIATYPE. 64. Mr. Hunt some little time ago announced a process, he at the time called the Energiatype, from an opinion of his, that the efTects produced were not by light, but resulted from a peculiar principle he de- nominated Energia; he has, however, since altered it to Ferrotype, which includes all the processes in which proto-sulphate of iron is used as a reducing agent. The original process was as follows : — a solution is prepared by dissolving two drachms of succinic acid, and five grains of common salt, in one fluid drachm and a half of distilled water, having previously added half a drachm of mucilage of gum arable ; this is applied to the paper, and when dry, is to be washed over with a solution of nitrate of silver, containing sixty grains to the ounce of water; it is allowed to dry in the dark, when it is fit for use. It may be preserved in a portfolio, and placed in the camera when wanted. The time necessary for exposure varies from two to eight minutes, but like the calotype no image is visible ; in order to bring out the dormant picture, it is necessary to wash it with a saturated solution of proto-sulphate of iron, to which has been added two drachms and a half of mucilage of gum arable ; we find it is an improvement in this process as well as in the Fluorotype, and, indeed, in all FERROTYPE OR ENERGIATYPE. 53 cases when the proto-sulphate of iron is used, to add to it a little acetic acid. 65. It is not essential to use the succinate of silver, for Mr. Hunt finds that the picture may be produced either with the benzoate, the bromide, the iodide, the arseniate, and, indeed, nearly any one of the salts of silver. The proto-sulphate of iron has this advantage, that pictures may be produced much quicker by its means than by any other method ; when used instead of gallic acid in developing an ordinary calotype picture, the quickness is extraordinary, and engravings, &c, may be copied absolutely instantaneously. 66. Mr. Hunt has modified this process in a very ingenious way ; he has taken advantage of the property possessed by the oils of cassia and of cloves in preci- pitating metallic silver, as in Drayton's process for silvering mirrors, but he finds that the silver will be precipitated more readily when the light has acted. The following is the process : — The paper, after having been submitted to the influence of light, is immersed in spirits of wine containing in solution a small quantity of the essential oils of cassia and of cloves, and as soon as the spirit has penetrated the paper, it is to be pressed between folds of blotting paper previously saturated with the same solution, and then pressed together between two pieces of plate glass ; in the course of an hour or two the picture will be developed very beautifully, and may be fixed in the ordinary way. * 54 PHOTOGENIC MANIPULATION, CHROMATYPE. 67. This is another process for which we are also indebted to Mr. Hunt, and it has this advantage, that it is a positive process ; that is, a copy of an engraving is produced at once, with the lights and shades correct; it is also one of the most simple and easily managed, and the pictures produced are very beautiful. The process was made known at the Meeting of the British Association, August 1843. One drachm of sulphate of copper is dissolved in half an ounce of distilled water, to which is added half an ounce of a saturated solution of bichromate of potash; this solution is applied to the surface of the paper, and, when dry, it is fit for use, and may be kept for any length of time without spoiling. When exposed to sunshine, the first change is to a dull brown, and if checked in this stage of the process we get a negative picture, but if the action of the light is continued, the browning gives way, and we have a positive yellow picture on a white ground. In either case, if the paper, when removed from the sunshine, is washed over with a solution of nitrate of silver, a very beautiful positive picture results. In practice, it will be found advan- tageous to allow the bleaching action to go on to some extent ; the picture resulting from this will be clearer and more defined than that which is procured when the action is checked at the brown stage. To fix these pictures it is necessary to remove the nitrate of silver, which is done by washing in pure water ; if the water CHROMATYPE. 55 contains any muriates the picture suffers, and long soaking in such water entirely destroys it, or if a few grains of common salt are added to the water the ap- parent destruction is very rapid. The picture is, how- ever, capable of restoration ; all that is necessary being to expose it to sunshine for a quarter of an hour, when it revives; but instead of being of a red colour, it becomes lilac, the shades of colour depending upon the quantity of salt used to decompose the chromate of silver which forms the shadow parts of the picture. 68. Mr. Hunt has since modified this process — we give his account : A neutral solution of the chloride of gold is mixed with an equal quantity of the solution of bichromate of potash. Paper washed with this solution, and exposed to light, speedily changes, first to a deep brown, and ultimately to a bluish-black. If an engraving is superposed, we have a negative copy, blue or brown, upon a yellow ground. If this photo- graph is placed in clean water, and allowed to remain in it for some hours, very singular changes take place. The yellow salt is all dissolved out, and those parts of the paper left beautifully white. All the dark portions of the paper become more decided in their character, and, according as the solarization has been prolonged or otherwise, or the light has been more or less intense, we have either crimson, blue, brown, or deep black negative photographs.'' 69. A process with the bichromate of potash has also been announced by Mr. Mungo Ponton. Paper should be soaked in a saturated solution of the bichro- mate of potash, and then exposed to sunshine ; a delicate 56 THOTOGENIC MANIPULATION. bufF coloured negative picture upon a yellow ground will be the result. To fix these pictures, all that is necessary is to soak them in common water, when the yellow colour will disappear, and they will be per- fectly white, — this is a simple and easy process, the rationale of which appears to be this : — Bichromate of potash consists of chromic acid and potash ; under the influence of light the starch in the size of the paper and the chromic acid react upon one another, and it is very probable that the acid is partially reduced, for, with paper having very little size, the bichromate bears a much longer exposure. A knowledge of these facts has led to a pretty modification of this process by M. Edmund Becquerel : he directs that paper should be steeped, in a weak solution of iodine in alcohol and then copiously washed in water, it will then assume a beautiful blue tint ; if this tint be uniform the paper is deemed proper for the experiment, otherwise the ope- rator must size it himself with starch. It is afterwards to be steeped in accordance with Mr. Ponton's method, in a concentrated solution of bichromate of potash, and the superfluous moisture removed by bibulous paper and dried ; it is now ready for exposure to light ; in order to copy an engraving it will require a time vary- ing from one minute to fifteen according to the thick- ness of the paper of the engraving and the intensity of the light. After the exposure, wash the paper well and dry it ; when it is dry, steep it in a weak alcoholic solution of iodine, and when it has remained some time wash it in water and then dry it between the folds of blotting paper, but not before the fire, for the com- CIIRYSOTYPE. 57 pound of iodine and starch is discoloured at about 212° Fahrenheit. If it is thought that the copy is not suffi- ciently brought out, repeat the immersion several times ; by this means you may obtain any degree of intensity of tone that you may wish the picture to have. In this process the chromic acid seizes upon the starch over those parts which have been exposed to light. Now as starch possesses the property of forming with iodine a combination of a very fine blue, it is evident that on those parts of the paper which have not been impressed by the solar rays, the starch will not have combined with the chromic acid ; the iodine will therefore form the blue iodide of starch, and thus represent shade by shade. CHRYSOTYPE. 70. This is a process discovered by Sir John Herschel, in which iron and gold are used as photo- genic materials. Good paper is to be washed with a solution of the ammonio-citrate of iron, and dried, and afterwards washed over with a solution of the ferro- sesqui-cyanuret of potassium. This paper should be dried in a perfectly dark room, when it will be ready for use in the camera. After it has been exposed a short time, the picture may be developed by washing it with a neutral solution of gold, of such a strength as to ap- pear of the colour of sherry wine ; the image instantly becomes visible, and may be fixed by well washing in wa- ter, dried by blotting paper, and then washed in a weak solution of the iodide of potassium. Should the picture 58 PHOTOGENIC MANIPULATION. not have been well washed previously to the application of the iodide of potassium, the lights vAW become dis- coloured, but they will speedily whiten again sponta- neously. CYANOTYPE. 71. Sir John Herschel is also the originator of this process, or rather a number of processes, for it includes all pictures taken with salts of iron, particularly when in combination with cyanogen. Paper is washed over with a moderately strong solution of the ammonio- citrate of iron, and exposed in the ordinary way until a faint negative picture makes its appearance. A saturated solution of the common ferro-prussiate of potash, in which is dissolved a little gum arabic, is then to be rapidly passed over the paper when the nega- tive picture vanishes, and is replaced by a greenish-blue one, with a greenish-yellow ground. This picture re- quires no fixing. 72. Another method, which requires a longer expo- sure to the sunshine, but possesses this advantage — the lights of the picture are white, and the shadows of a beautiful blue. The following is the method of pre- paration : — Wash paper over with a solution of nitrate of mercury, and, when dry, with a saturated solution of sesqui-cyanuret of potassium. It is now ready for exposure, which should be continued until the required degree of intensity in the colour is produced. The picture may be fixed by soaking in cold water, to which a little alum has been added. CYANOTYPE. 59 73, A very interesting and curious process was dis- covered by Sir John Herschel^ by which latent pictures can be produced, which are capable of being de- veloped by the breath, or by a moist atmosphere. If solution of nitrate of silver, specific gravity 1*200, be added to ferro-tartaric acid, specific gravity 1*023, a precipitate falls, which may be again nearly redissolved by a gentle heat ; a yellow hquid is obtained, in which further addition of the nitrate causes no turbidness. When the total quantity of the nitrate solution amounts to one-half the bulk of the ferro-tartaric acid, it is enough. The liquid so prepared does not alter in the dark. The paper is to be spread over with this solu- tion and exposed wet to sunshine (but partially shaded) ; for a few seconds no impression seems to have been made, but by degrees, although with- drawn from the light, it developes itself spontane- ously, and at length becomes very intense. But if the paper be thoroughly dried in the dark, it pos- sesses the singular property of receiving a dormant or invisible picture, to produce which (if it be, for instance, an engraving which is to be copied) from thirty seconds to a minute's exposure to sunshine is requisite. It should not be continued longer than that time, as not only the ultimate effect is less striking, but a picture begins to be visibly developed, and which darkens spontaneously after it is withdrawn. But if the ex- posure be discontinued before this effect comes on, an invisible impression is the result ; to develope which, all that is necessary is to breathe upon it, when it imme- diately appears, and very speedily acquires an extra- 60 PHOTOGENIC MANIPULATION. ordinary intensity and sharpness, as if by magic. Instead of the breath, it may be subjected to the regu- lated action of aqueous vapour, by laying it in a blotting-paper book, of which some of the outer leaves have been damped by holding them over warm water. POSITIVE CALOTYPE. 74. At the second Meeting, at York, of the British Association, Professor Grove described a process by which positive pictures could be taken at once, without the trouble of having to make a negative in the first instance. Ordinary calotype paper is darkened till it assumes a deep brown colour, almost amounting to black ; it is then redipped in the ordinary solution of iodide of potassium, and dried. When required for use it is drawn over diluted nitric acid, one part acid, and two and a half parts water. In this state, those parts exposed to light are rapidly bleached, while the parts not exposed remain unchanged. It is fixed by washing in water, and subsequently in hyposulphite of soda, or bromide of potassium. Mr. Grove likewise described on the same occasion another process which promises, when carried out, to be of great utility. It is the conversion of a negative calotype into a positive one, and was thus stated : Let an ordinary calotype image or portrait be taken in the camera, and developed by gallic acid ; then drawn over iodide of potassium and dilute nitric acid and exposed, to full sunshine ; while bleachiug the dark parts, the light is redarkening the newly precipitated iodide in the CATALISS150TYPE. 61. lighter portions, and thus the negative picture is con- verted into a positive one. CATALISSISOTYPE. 15, The above name has been given to a process described by Dr. Wood: — The paper to be prepared is steeped in distilled water, to which has been added hydrochloric acid in the proportion of two drops of the former to three ounces of the latter; when well soaked, the moisture is to be lightly absorbed, and washed over with a mixture of half a drachm of syrup of ioduret of iron, in two and a half drachms of water, into which one or two drops of a solution of iodine may be dropped. It is now to be dried with bibulous paper, and washed over evenly with a solution of nitrate of silver, twelve grains of the salt to the ounce of water. It is now ready for the camera, the time of exposure varying from a second to half a minute, ac- cording to the degree of light. When removed from the camera no picture is visible, but if left in the dark it gradually developes itself, and ultimately becomes extremely perfect. It is fixed by washing first in water, and afterw^aids in a solution of bromide of potassium (twenty grains to an ounce), after which it must be again carefully washed and dried. 76. A process has been proposed by M. Gaudin, (which appears to be a modification of one men- tioned by Dr. Schafhaeutl and of Mr. Hunt's Ferro- type) : — The paper is exposed for a minute in the vapour of hydrochloric acid, after which a nearly .62 PHOTOGENIC MANIPULATION. saturated solution of nitrate of silver is to be brushed over its surface, and allowed to dry. The dry sheet is placed in the camera in the dark. On removal no trace of the image will be visible ; but upon wetting the paper with a nearly saturated solution of sulphate of iron, slightly acidified by the addition of a few drops of sulphuric acid, the picture is immediately developed. The time necessary for exposure in the camera is much about the same as for the calotype. To fix the picture, which is a negative one, it must be first washed in distilled water, and subsequently in distilled water, to which has been added ten per cent, of caustic ammonia. This is stated to be a good paper for obtaining positive pictures from negative ones ; for which purpose, however, the sulphate of iron need not be used. The paper should be exposed until the edges are blackened. ANTHOTYPE.* 77. This is a general name given to those methods of producing pictures, in which the coloured juices of plants are the photographic agents ; nearly the whole have been described by Sir John Herschel. The petals of the flowers should be crushed in a marble mortar, and the juice expressed by squeezing the pulp in a clean cloth. It should then be spread upon the paper with great care, so as to be perfectly uniform all over, and then dried by spontaneous evaporation. It is better to add a little alcohol, as it prevents the * From avOoQj a flower, and rvTrog, a picture. ANTHOTYPE. 63 paper from becoming changed by the air, which some- times occurs very quickly when this precaution is not taken. The following are some of the results which are mentioned by Sir John Herschel :— The flowers of the Corchorus*japonicus impart a fine yellow colour to paper, and, upon exposure to sun- light, in about half an hour it is rendered quite white. Common Ten Weeks' Stocks, — Papers prepared with the alcoholic extract of this flower are of a very bright red. and are sensibly decolorated in a few hours. The red poppy gives a very beautiful red colour, which is speedily bleached by the light, — and nearly all the coloured flowers yield materials which may be used to produce photographic pictures, — they are positives, and are more or less permanent ; and it is an extremely interesting study to observe the various effects pro- duced by different vegetable preparations. Dr. Draper and Mr. Hunt have followed out this subject in its more extended view, viz., the action of light upon plants, but they appear to difler in many of their results. Mr. Robert Hunt placed seeds under different coloured glasses; these seeds were found by him to ^rminate under the yellow glass, but were not found to '.e viiid i«leuii?h ; however, if removed, after germina- •on, and placed triidcT the bli : they grew and were -alLLy. Mr» Hunt has uczn commissioned by the • itish Association to pursue this subject* •'"rom the stigations of this gentleman, it is ceriain :. hat the ole of the carbon of a plant, and which constitutes Jie greater part of its solid matter, has been derived from the atmosphere in which it exists united with 64 PHOTOGENIC MANIPULATION, oxygen and carbonic acid. This carbonic acid is decom- posed by plants, when under the influence of light, into carbon and oxygen gas ; the plant assimilates the car- bon, and forms it into organized matter, and oxygen is liberated. Now this occurs just according, and in pro- portion, to the amount of light, or rather, to the quan- tity of actinic power existing at the time ; for it has been shewn, that under yellow, green, or red glasses, plants grow but very imperfectly ; or, in other words, they are unable to decompose the carbonic acid, in con- sequence of the absence of the chemical or blue rays. Every person must have noticed the sickly appearance of vegetation, if grown in a place where light is partially excluded ; the leaves are nearly white, and if the plant does flower and bear fruit, the leaves are pale and scentless, and the fruit insipid. We have familiar ex- amples of this when the gardener wishes to bleach celery or endive ; he covers up the plants with earth, light is excluded, and they become quite white ; the interior of a cabbage is white, and for a similar reason. These are interesting facts, for they shew how mutually de- pendent animals and plants are one on another. It h absolutely essential to animal life that die iLquisite quantity of oxygen should eXist in the air, which myriads of animals are continually etbsttauung, in order to keep up a process of oombuslion, the product of which is earbor'c acid; for on mbaung the oxygen from the air, it combiner, vv?lh the carbon contained in our bodies, and forms this noxious gas, which is exhaled, and deteriorates the atmosphere. Now, under the in- fluence of light, this carbonic acid is decomposed by ANTIIOTYPE. 65 the vegetable kingdom, and pure oxygen gas set free, to be again absorbed by animals. In the words of Mr. Hunt, It is not possible to conceive a more perfect or more beautiful system of harmonious arrangement than this. If the vegetable world was swept away, animal life would soon become extinct ; and if all animal ex- istence was brought to a close, the forest would fall, and the flowers of the field, which now clothe the earth with gladness, perish in the utterness of a lamentable decay." We have now conducted the reader through some of the most important and useful of the photographic processes on paper. The next part will be devoted entirely to a description of the Daguerreotype, Thermo- graphy, and other processes with metallic plates. F INDEX. Anthotype, § 77. Aberration, § 44. Chromatic, § 45. Ammonia, fixing Photographs by, § 34. Alchemists ; early History of Photography, § 2. ;' tinism, § 4, 5. pplying the Solutions, § 16. Acetic Acid, § 18. — Use of, § 51. Ammonio-nitrate Papers, § 24. Directions for prepar- ing, § 25. Applications of Photography, §37. Blotting Paper, § 14. Bromide of Potassium, § 18. Papers, § 22. Fixing by, § 35. brushes, use of, § 16. ^rewster's, Sir David, method of taking Positives, § 59. Catalissisotype, § 75. Cyanotype, § 71. Chrysotype, §70. Chromatype, § 67. — Modification of, § 68. Camera, § 39. Improved form of Slid- ing Front, § 42. Double Slide, § U. Camera, Optical, Principles of, § 43. Pictures, § 38. Chloride of Silver, § 20. Papers pre- pared by, § 20. Chloride of Sodium, Fixing by, $35. Chemical change in Photographic processes, § 33. Calotype, Simplification of, § 60. Positive, by Professor Grove, § 74. Davy, Sir H., and Mr. Wedg- wood, § 6. Distilled Water, § 15. Distilling, Apparatus for, § 15. Diaphragms, use of, § 43. Developing Calotype Pictures, § 54. Energiatype, process of, § 64. Energia, § 4, 5. Ferro-sesqui-cyanuret of Potas- sium, use of, § 72. Fixing Photographs, § 34. Calotypes, § 55. Fluorotype, § 61. Ferrotype, § 64. Grove's, Professor, Positive Ca- lotypes, § 74. Gaudin, M., process by, § 76. INDEX. Herschel's, Sir John, Chrysotype, process of, § 70. Cyanotype, § 71. Experiments on the Heat Rays, § 4. Hunt's, Mr. Robert, Chromatype, process of, § 67. • Energiatype, § 64. Fiuorotype, § 61. Experiment of, § 33. Hyposulphite of Soda, § 18. Fixing of Photographs by, § 36. of Silver, Solu- bility of, § 36. Horn Silver, § 2. Iodized Paper, Method of Mak- ing, § 48. Lenses, Remarks on, § 44, 45. Muriatic Acid, Vapour of, § 23, 76. Negative and Positive Photo- graph, § 30. Nitrate of Silver, Purity of, § 18. Niepce, Experiments of, § 7. Old Gallo-Nitrate, Property of, § 15. Oils of Cassia and Cloves, § 66. Papers for Photographs, ^ 10, 11. Paper, Bibulous, § 14. Bromide, § 22. Chloride, § 20. Protosulphate of Iron, § 62. Photography, Davy and Wedg- wood's Experiments in, § 6. Ponton, Mr. Mungo, Process of, § 69. Paper for, § 13. Photograph, Making the, § 27. ] Pressure Frames, § 27, 28. Positive Pictures, Method of ob- taining, § 56. Sir David Brewster's, § 59. Rays of Light, Different effects upon Chloride of Silver, § 3. Ritter's experi- ments on, § 3. Resins affected by Light, § 7. Scheele, Discov-ery of, § 3. Sensitive Mixture, application of, § 51. Talbot^ Calotype process of, § 47. Announcement of, § 8. Photographic Paper of, § 21. Time of Exposure, § 32. Wood's, Dr. Catalissisotype, 75. LIST OF PKICES OF THK APPARATUS AND MATERIALS DESCRIBED IN PART I. OP PHOTOGENIC MANIPULATION, REaUIRED FOR PRACTISING THE CALOTYPE AND OTHER PAPER PROCESSES. WHATMAN'S SUPERFINE SATIN POST PAPER, Folio, 2*. 6d. per quire. NASHE'S Ditto, 2*. 6d. per quire. White Bibulous Paper 2^. per quire. STILL WITH REFRIGERATORY, Complete for economically preparing Distilled Water. Fig. 2. 1 Gallon, IL Is. Od. 2 Gallon, 1/. 11*. 6d. BROAD CAMEL'S HAIR BRUSHES, li 2 2| 3 4 5 in. broad. 1*. 6d* 2s. 2s. 3d. 2d. 6d. 3s. 6d. 4s. 6d. SHALLOW PORCELAIN DISHES, For containing the Solutions. Fig. 5. 2fin.by4. 5 in. by 7. 7 in. by 9. 10 in. by 7i. 11 in. by 14. Is. Is. 6d. 2s. 2s. 6d. bs. 6d. PHOTOGENIC PRESSURE FRAMES. Fig. 4. Fig. 3. 4Jinby5i. 6 in. by 9. 8i in. by 11. 5*. 6d. 8s. 6d. lbs, BINDING SCREWS. G. G. Fig, 3, 3*. 6d. per pair. APPARATUS FOR DRYING THE PAPER, By means of Hot Water, 12^. and 14*. 2 STEAM APPARATUS. Fig. 12. 1^. 1*. Od. COMMON PHOTOGENIC CAMERAS. Fig. 6. IL 5s. Qd, to 21. 2s. Od. CUNDLE'S IMPROVED CAMERAS, As described Phil. Mag. No. 160, May 1841, for Pictures. 7 in. by 5. 21. Us. 6d. PORTABLE CAMERA. The Holders for the Paper being made circular, Pictures of a large size are taken. 8i in. by 6^. 41. 4s. PORTABLE CAMERA. Fig. 7. With Focusing Glass, two Improved Double Frames for Paper^ in Box, complete, 31. ISs. 6d. HEAD REST. piXlL TT .. 7*. 6d. Of an Improved form 1^. 5^. 0^?. PORTABLE TRIPOD STAND, With Mahogany Legs and Brass Ball and Socket, 1/. lis. 6d. PORTABLE TRIPOD STAND, With folding Legs, Box-wood Ball and Socket, and made very light, 21. 2s. Chemical Preparations required in practising the Photogenic Art. g ^ Pure Ammonia, per lb. . . . . • . • • • • ^ ^ Alcohol, per pint . . Acetic Acid, (crystallized) per oz. ^ ? Copper Sulphate, per oz. 0 3 Gallic Acid, per oz. . . . . . . • • • • ^ ^ Gold Chloride, (crystallized) „ Solution, per oz. ^ ^ Iron Protosulphate, per oz. . . . . • • • • 2 0 Ammonia Citrate, per oz. .. .. 0 9 Potassium Bromide, per oz. . . • . • • • • 5 0 ,, Iodide, per oz. .. 4 0 Potash Bi-Chromate, per oz. .. .. 16 Silver Nitrate, (crystallized) per oz. . . • • • • 5 0 Soda-Hyposulpliite, per lb. •• •• ^ ^ Succenic Acid, per oz. 5 0 Notv Publishing in Parts, each complete in itself , Price Is, MANIPULATIONS IN THE SCIENTIFIC AETS. The following are already published. Parts I. and II. ELECTROTYPE MANIPULATION, By Mr. CHARLES V. WALKER, EDITOR OF THE ELECTRICAL MAGAZINE, Sixteentfi Edition, These Two Parts may be had done up in cloth boards, Price 2s. Qd. " This little manual contains a most complete account of the whole process of Electrotype Manipulation. We have seldom, indeed, met with a work l»rofessing to give instruction in the manipulation of any art or process of mauuficture so practically useful as this small volume." — Civil Engineer and Architect's Journal, Part III. PHOTOGENIC MANIPULATION; Containing the Theory and Plain Instructions in the Art of PHOTOGRAPHY, Including, Calotype, Fluorotype, Ferrotype, Chromatype, Chry- sotype, Cyanotype, Catalissisotype, and Anthotype. By ROBERT J. BINGHAM, Chemical Assistant in the Laboratory of the London Institution. Part IV. PHOTOGENIC MANIPULATION ; Including Daguerreotype, Thermography and Electrical and Galvanic Impressions, By GEO. THOS. FISHER, Late Assistant in the Laboratory of the London Institution. *' One of the most comprehensive of the many treatises which have been published on the manipulation of the new arts of design." — Civil Engineer and Architect' s Journal. "A useful little manual, containing much practical instruction." — Athe- ncEum. ^% All the Apparatus and Materials described in these Works may be had wholesale or retail of the Publishers, PUBLISHED BY GEORGE KNIGHT AND SONS, FOSTER LANE, LONDON. 4 Just Published^ in Demy 8vo, Illustrated by a characteristic Frontispiece, and nearly 300 Woodcuts^ Price \\s, cloth, a new and greatly enlarged Edition of LECTUEES ON ELECTEICITY, COMPRISING GALVANISM, MAGNETISM, ELECTRO - MAGNETISM MAGNETO- AND THERMO- ELECTRICITY. By henry M. NOAD, Author of '* Lectures on Chemistry/' &c. &c. In these Lectures, Mr. Noad traces the progress of electrical science, from its earliest development to its latest discoveries, in a clear and comprehensive manner ; — it supplies, and that very efficiently, a vacuity that has for some time existed in scientific literature.'' — Artisan. ^* This is a very great improvement upon the former edition. Mr. Noad has made the best use of his time, and he now gives to the public a volume which is really a valuable compilation of the principal researches in electricity." — Literary Gazette, ** This work embraces every branch of science identified with electrical phenomena. We know of no other volume to which an inquirer can refer, for the best and latest information, with so much certainty of finding it." — Mechanics'' Magazine. ** A work much called for by the progress which has been made during the last few years in this interesting science. The author sets out with an historical sketch of electricity, and then proceeds to give a detail of the phenomena, which are experimentally evolved. We have seldom risen from the perusal of any work of science with more satisfaction." — Polytechnic Magazine, edited by Dr. Stone. These Lectures proceed through all the gradations of electri- city, atmospheric and voltaic ; magnetism, and electro-magnetism ; concluding with magneto- and thermo- electricity. The experi- ments are well illustrated with woodcuts ; and from the easy de- scription of their performance, the work is most valuable for the student and amateur, while it forms a most convenient text-book for the man of science." — Mining Journal, An able and popular compilation, on a subject of increasing interest, and very fully illustrated with woodcuts." — Athenaeum. A most complete treatise, which does great credit to the scientific acquirements and to the perseverance of the author." — The Lancet,