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SPECIMEN OF THREE-COLOR WORK. 
 
 Engraved and printed by the Chicago Colortype Company, 120^-1215 Roscoe St., Chicago 
 
A MANUAL 
 
 PHOTO-ENGRAVING 
 
 CONTAINING PRACTICAL INSTRUCTIONS 
 FOR PRODUCING 
 
 PHOTO -ENGRAVED PLATES 
 
 RELIEF -LINE AND HALF-TONE 
 
 WITH 
 
 CHAPTERS ON DRY PLATE DEVELOPMENT AND 
 HALF-TONE COLOR WORK. 
 
 By H. JENKINS. 
 
 CHICAGO : 
 
 The Inland Printer Company, 
 
 1896. 
 
Copyright, 1896, 
 
 BY 
 
 The Inland Printer Company, 
 Chicago, Illinois. 
 
 Press of 
 
 The Henry' O. Shepard Co, : 
 
 Chicago. 
 
 THEGfm ;i . l k 
 LIBRARY 
 
PREFACE. 
 
 IN preparing - this work, it has been my aim to 
 present such information that a person inex- 
 perienced in photographic operations might be 
 enabled to obtain from it an intelligent conception 
 of the methods used for making line and half-tone 
 engravings. 
 
 If therefore details have been entered into which 
 may to some seem superfluous, it should be remem- 
 bered that what may appear self-evident to the 
 expert may often be perplexing to the novice unless 
 clearly explained. 
 
 While entering thus into detail regarding the 
 processes treated of, I have avoided the discussion 
 of obsolete and untried methods, and have endeav- 
 ored to make the descriptions as brief as possible 
 without sacrificing clearness. 
 
 The methods described are those used in the reg- 
 ular engraving establishments, and I believe that 
 with careful study and properly directed effort, the 
 beginner will obtain satisfactory results. 
 
 (3) 
 
4 PREFACE. 
 
 In addition to the chapters devoted to the 
 engraving- processes I have prepared a chapter on 
 the development of the gelatine dry plate, as a work 
 of this nature would seem incomplete without some 
 information on that subject. 
 
 The excellent photographs from which a num- 
 ber of the half-tone plates were made were the 
 work of Mr. A. C. Pack, of the Randall studio, 
 Ann Arbor. 
 
 H. JENKINS. 
 
 Chicago, October 1, 1896. 
 
CONTENTS. 
 
 PAGE 
 
 Chapter I. Introductory 7 
 
 Chapter II. The Apparatus Required 9 
 
 Chapter III. The Shop Arrangement 23 
 
 Chapter IV. Negative Making 29 
 
 General Principles — Chemicals. 
 
 Chapter V. Negative Making 39 
 
 Line Negatives. 
 
 Chapter VI. Negative Making 49 
 
 Half-tone Negatives. 
 
 Chapter VII. Negative Making 62 
 
 Causes of Defects in Collodion Negatives — Care 
 of Silver Bath. 
 
 Chapter VIII. Reversing Negatives 66 
 
 Chapter IX. Etching 69 
 
 Line Work. 
 
 Chapter X. Etching 81 
 
 Half-tone Work — The Enamel Process. 
 
 Chapter XI. Finishing and Mounting Plates 87 
 
 (5) 
 
b CONTENTS. 
 
 PAGE 
 
 Chapter XII. Drawings — Photo-Lithogravure . . . 90 
 
 Chapter XIII. Development of Gelatine Dry 
 
 Plates , 96 
 
 Chapter XIV. Orthochromatic Plates 105 
 
 Color Work. 
 
 Chapter XV. Printing Half-tone Plates ... 114 
 
 Appendix. Tables of Weights and Measures 122 
 
 Valuable Formula; — Printing Methods — Etched 
 Embossing- Plates — Other Useful Informa- 
 tion. 
 
MANUAL OF PHOTO-ENGRAVING. 
 
 CHAPTER I. 
 INTRODUCTORY; 
 
 A COMPARISON of the periodicals of several 
 years ago and those published today reveals 
 to the observer a marked difference in the number 
 and quality of the illustrations. In the former we 
 find but few cuts, and those engraved on wood, 
 often in an indifferent manner. In the magazines 
 and newspapers of the present, however, nearly 
 every page exhibits one or more illustrations of 
 most artistic character. 
 
 While wood cuts are still used to a considerable 
 extent for general illustrative purposes, the major- 
 ity of the engravings are at present produced by 
 the now well-known processes of engraving by aid 
 of photography. The several advantages which 
 photo-engraving possesses over wood engraving 
 have created a demand which has steadily increased 
 and opened avenues of employment to many who 
 have taken up this branch of work as a profession. 
 A cut which formerly would have required several 
 days to produce can now be turned out in a few 
 
 (7) 
 
o MANUAL OF PHOTO-ENGKAVING. 
 
 hours, and will have reproduced all of the features 
 of the original copy to exactness, while its cost is 
 but a fraction of that for wood engraving". 
 
 While there are several methods of engraving 
 which depend upon photography for their existence, 
 the term "photo-engraving" is usually applied only 
 to relief plates in line and half-tone, and to a de- 
 scription of this class of work the following pages 
 will be devoted. 
 
 To the inexperienced, photography often seems 
 to be a mysterious and difficult art, but the manip- 
 ulations described hereafter will with proper study 
 become remarkably simple when the results attain- 
 able are considered. 
 
 The production of a photo-engraved plate in- 
 cludes several stages as follows : 
 
 1. The making of a negative. 
 
 2. The printing of the image on the metal. 
 
 3. The etching. 
 
 4. The finishing and blocking. 
 
 In regular establishments separate departments 
 are devoted to each branch, every employe being a 
 specialist in his line. 
 
 A description of the details which are included 
 in each of the various stages will, however, be given, 
 that the reader may obtain a general knowledge 
 of the art. 
 
HALF-TONE— 150-LINE SCREEN. 
 
MANUAL OF PHOTO-ENGRAVING. 
 
 CHAPTER II. 
 
 THE APPARATUS REQUIRED. 
 
 THE apparatus required for making- photo- 
 engravings will vary in completeness with 
 the amount and quality of work to be turned out. 
 For the experimenter or the establishment which 
 devotes but a small department to the work, an 
 equipment of hig-h grade and larg-e capacity would 
 be out of the question. For larg-e shops, however, 
 which are established with a view to commanding - a 
 large patronage, where rapidity of production and 
 a uniformly excellent quality of work are impor- 
 tant matters of consideration, it is essential that 
 the apparatus be of the most approved pattern, 
 and that each department be fully equipped. 
 
 The capacity of the apparatus should be deter- 
 mined by the size of plates demanded. The aver- 
 age engraving- establishment will find an equipment 
 for producing- plates 14 by 17 inches in dimensions 
 ample. The demand for half-tone plates is usually 
 for sizes under 10 by 12 inches, and many shops 
 are not provided with facilities for plates larg-er 
 than that size. Line plates are also, as a rule, of 
 dimensions smaller than this, but provision should 
 be made for work of as larg-e dimensions as the 
 funds available will permit, and the prospective 
 order may require. 
 
10 MANUAL OF PHOTO-ENGRAVING. 
 
 The article of the greatest importance, in con- 
 nection with the outfit, is 
 
 THE LENS. 
 
 This should be selected with a view to its fulfill- 
 ing- the special requirements of this class of work. 
 It should be of the rectilinear type, so that all 
 straight lines in the copy will be reproduced with- 
 out distortion. It should cut clearly all portions of 
 the copy, and its design should be such that it may 
 possess rapidity. There are several lenses on the 
 market which fulfill these requirements — the Rapid 
 Rectilinear Dallmeyer, the Steinheil and Swift 
 being popular among operators. 
 
 THE CAMERA. 
 
 In selecting the camera it is advisable to obtain 
 the form known as the enlarging, copying and 
 reducing camera, as its construction possesses sev- 
 eral advantages over the ordinary copying camera. 
 
 For half-tone work it should be provided with 
 the adjustable screen plateholder, which enables 
 the kit to be dispensed with for holding the screen 
 and sensitive plate. It is so constructed that the 
 separation of screen and plate can be adjusted 
 accurately and easily to any desired degree, and 
 different sizes of screen and plates can be used. 
 
 This plateholder has displaced the kit in all 
 leading shops, but for those who may desire to 
 use the kit, details of construction will be given 
 further on. 
 
MANUAL OF PHOTO-ENGRAVING. 
 
 11 
 
 CAMERA STAND. 
 
 The camera should be provided with a stand, 
 which may be in the form of a long- table or bench 
 to stand on the floor, or it may be swung- from the 
 ceiling - , this condition being necessary if the build- 
 ing is subject to vibrations from the running* of 
 machinery or other causes. It consists essentially 
 of an oblong- frame upon which the camera will 
 
 CAMERA AND SWING 
 
 slide readily, the frame being suspended from a 
 beam of the same leng-th, ropes or strips of metal 
 running- from the ends of the beam and attached to 
 each end of the frame in an inverted V shape. 
 The beam being suspended from the ceiling-, carries 
 the frame upon which the camera is placed. At 
 one end of the frame the copy board is fastened, 
 and should be in a position perpendicular to the 
 bed, and should be arranged to slide from ri^ht to 
 
12 MANUAL OF PHOTO-ENGRAVING. 
 
 left when desired. The length of bed will vary 
 according - to the capacity of the camera. For a 
 10 by 12 camera, ten feet; 11 by 14, twelve feet; 
 and for a 14 by 17 camera fourteen feet are good 
 proportions. Such a bed can be easily constructed 
 of ordinary scantling, or can be purchased from 
 dealers in photo-engravers 1 supplies. 
 
 SILVER BATH. 
 
 The silver bath is almost invariably kept in a 
 glass vessel of special form, which, when holding 
 
 the bath for use, should 
 be kept in a ''light- 
 tight " box, with a cover. 
 It is important that a 
 bath of ample capacity 
 be provided, as such a 
 one will require less at- 
 tention than a small one 
 and save the operator an- 
 noying delays. In all 
 well equipped shops two 
 
 SILVER BATH. 01 " m0re batllS ^ P 1 " " 
 
 vided for each operator, 
 that one may be used while another is being 
 rectified. 
 
 EVAPORATING DISH. 
 
 For evaporating the alcohol from the bath, a 
 porcelain evaporating dish is required. It should 
 be of ample capacity to hold the silver solution from 
 the bath, with room to spare. As an accessory, it 
 
MANUAL OF PHOTO-ENGRAVING. 
 
 13 
 
 is well to have an iron dish to hold sand in which 
 the porcelain dish can rest while heating-. 
 
 TRAYS. 
 
 For line etching- there should be one or more 
 large trays or "tubs" so arranged that they may 
 rock at the will of the etcher. These tubs are 
 
 made of wood, sealed water-tight and usually pro- 
 tected by a coating of impermeable varnish. For 
 developing prints on zinc, any ordinary sheet metal 
 tray will serve the pur- 
 pose. For half-tone 
 etching porcelain or rub- 
 ber trays may be used. 
 
 PRINTING FRAMES. 
 
 For printing on 
 metal there are special 
 frames, so constructed 
 that equal contact with 
 the negatives can be obtained for all parts of the 
 metal plates. For making silver prints the ordi- 
 nary photographer's printing frame is used. 
 
 GLASSWARE. 
 
 For measuring solutions, several graduates of 
 a capacity of from eight to sixteen ounces each 
 
 PRINTING FRAME. 
 
14 
 
 MANUAL OF PHOTOENGRAVING. 
 
 should be purchased. There should also be a large 
 funnel for filtering- the baths and several smaller 
 ones for collodion, printing 
 solutions, etc. 
 
 An important article is the 
 actino-hydrometer for testing 
 the strength of the silver 
 bath. 
 
 Various sizes of plate 
 glass, as required, should be 
 provided for negative making 
 and for turning negatives 
 upon. For the latter purpose 
 the glass is usually obtained 
 of one-fourth inch in thick- 
 ness, to more readily stand the pressure in the 
 printing frame. 
 
 Vials for hold- 
 ing collodion, 
 large bottles for 
 filtering the bath 
 into, and smaller 
 ones for solutions 
 are also necessi- 
 ties. 
 
 ROLLERS. 
 
 For inking line 
 plates, composi- 
 tion rollers are 
 used. These 
 should be of the kind known as "hard" rollers, 
 as they more readily take and distribute the ink. 
 
 GRADUATE. 
 
 COLLODION VIAL. 
 
MANUAL OF PHOTO-ENGRAVING. 
 
 15 
 
 An excellent roller for this purpose can also be 
 made from white rubber, such as is used for clothes 
 wringers. For inking- the plate after etching-, a 
 leather-covered roller is usually used. 
 
 MISCELLANEOUS ARTICLES. 
 
 Besides the articles described above, there are 
 other essentials, as follows : Gas stoves, for heating 
 and drying- plates ; squeeg-ees, for smoothing- down 
 neg-ative films — these are simply strips of white 
 rubber fastened to a strip of wood ; scales, for 
 weighing - dry chem- 
 icals ; negative racks ; 
 brushes for etching- — 
 bristle for line etch- 
 ing-, and soft for half- 
 tone ; inking- slab for 
 rolling ink upon — a 
 smooth sheet of stone, 
 zinc or glass will an- 
 swer the purpose ; pli- 
 ers, for holding plates 
 while burning in ; zinc hook, for cutting zinc plates ; 
 small camel's-hair brushes, for spotting and paint- 
 ing in on plates ; egg beater ; hammers ; nails ; 
 scraping tools, for cleaning spaces on zinc ; engrav- 
 ers' tools, for tooling plates after etching ; files, for 
 smoothing edges of metal ; calipers, punches, etc. 
 
 MACHINERY FOR FINISHING. 
 
 For a well equipped shop there are several 
 machines which are essential. Small concerns are 
 
 NEGATIVE RACK. 
 
16 MANUAL OF PHOTO-ENGRAVING. 
 
 often operated with but a small equipment of 
 machinery, but for large establishments the outfit 
 of necessary machinery is in many cases a very 
 extensive affair. 
 
 The routing- machine is the most important item 
 in this department, and is used for deepening - and 
 cleaning out the spaces in zinc etchings, making a 
 bevel around half-tones, etc. These machines can 
 be obtained in various sizes according to the dimen- 
 sions of plates to be routed. 
 
 A circular saw is also an essential piece of 
 machinery, for sawing metal plates, blocks, etc. 
 
 The trimmer, as its name indicates, is used for 
 trimming the edges of blocks after the plates are 
 mounted. 
 
 The shoot board is used for a similar purpose 
 and is generally substituted for trimmer in small 
 shops. 
 
 The Daniel's planer is used for making mounted 
 blocks type-high. It is an expensive machine, and 
 for small establishments the shaving machine oper- 
 ated by hand can be used instead. 
 
 A drill is often of use for various purposes, and 
 is necessary in mounting half-tone plates from the 
 back. 
 
 The beveling machine is used for beveling the 
 edges of plates. 
 
 The buffing - machine is used for polishing metal. 
 It is not found, as a rule, in small shops, as the 
 metal can be polished by hand. 
 
 For taking proofs, a printing press is required, 
 and for the engraving establishment the hand press 
 
to' 
 
 . ! ' 
 
 Jfc&HjTfitt* 6 ?'' 
 
 *L M 
 
 i 'fey | «W$ ; j 
 
 1 i«n \ .ft-f i 
 
 WIIHf^ |; 
 
 ZINC ETCHING — CRAYON EFFECT. 
 From sketch by Frank Holme. 
 
MANUAL OF PHOTO-ENGRAVING. IT 
 
 known as the "Franklin" or "Washing-ton" type 
 is best. 
 
 The mounting- slab is simply a smooth-surfaced 
 block of iron upon which the cuts are placed when 
 being blocked. 
 
 A detailed description of the above mentioned 
 machinery is not given here, on account of the 
 various designs on the market, and as manufac- 
 turers are always ready to send to inquirers 
 descriptions of all latest improvements. 
 
 THE WHIRLEK. 
 
 In coating plates for half-tones with the enamel 
 solution it is necessary, in order to obtain an even 
 coating, that a rapid whirling motion be given 
 while the solution is in the fluid condition on the 
 plate. 
 
 A number of devices can be used for this pur- 
 pose. A common form, sold by the supply houses, 
 consists of a handwheel mounted in a horizontal 
 position on a board and connected by means of a 
 belt with a table similarly mounted at the other 
 end of the board, the table being provided with 
 clamps to fasten the plate. Upon revolving the 
 handwheel the table is caused to revolve also, thus 
 spreading the solution in an even coating over the 
 plate. 
 
 A much better whirler, however, can be con- 
 structed by means of an ordinary drill stock, as 
 follows : To the bottom of a shelf placed at a 
 convenient height fasten the drill stock as shown 
 in Fig. A. Then at a machine shop obtain a 
 
18 
 
 MANUAL OF PHOTOENGRAVING. 
 
 strip of iron about three-fourths of an inch or an 
 inch in width, one-sixteenth of an inch in thick- 
 ness, and twelve or fifteen inches long - , and to its 
 center have fastened a round stem. Fig. B. Also 
 have made two strips about four or five inches 
 
 I 
 
 j£i_ 
 
 <-°-. 
 
 »-u 
 
 C 
 
 J 5. 
 
 WHIRLER. 
 
 long- with apertures cut at each end, those at one 
 end of a size and shape to admit the ends of the 
 other strips. Have one of the ends of each of 
 the latter strips bent over, and a hole drilled to 
 admit a thumbscrew, as shown in the cut, Fig. C. 
 The long strip is fastened in the chuck of the 
 drill by means of the stem and the two short strips 
 are slipped over the ends, as shown in Fig. C. A 
 gas stove should be placed under the whirler to 
 warm the plate and accelerate the drying of the 
 coating. 
 
MANUAL OF PHOTO-ENGRAVING. 
 
 19 
 
 The use of this whirler will be explained in 
 a later chapter. 
 
 THE KIT. 
 
 Before the advent of the plateholder mentioned 
 in a preceding- paragraph, the kit was used by 
 operators to hold the screen and sensitized plate 
 during exposure, and is yet used by those who do 
 not wish to incur the extra expense of the holder. 
 
 IL.fl 
 
 r ' 
 
 
 c 
 
 
 ' ; 
 
 The kit is simply a rectangular frame so con- 
 structed that when placed in the plateholder of the 
 
20 MANUAL OF PHOTO-ENGRAVING. 
 
 camera the negative plate will occupy the position 
 of the ground glass and the screen be held in front 
 of it. Its construction can be understood by an ex- 
 amination of the illustration. A is a frame made 
 of strips of cherry, walnut or other suitable wood, 
 about one inch wide, one-eighth inch thick and of 
 lengths required by the size of screen. The ends 
 should be mortised and glued strongly together. 
 On the opposite side of this frame is fastened a 
 second frame of strips, one-half inch wide and one- 
 fourth inch thick, and so placed that the inner 
 edges of this frame will be flush with the inner 
 edges of the other. The ends of this second frame 
 should be fastened in a similar manner to those of 
 the first. To the longest sides of this second 
 frame should be fastened springs, which may con- 
 sist simply of elastic curved strips of brass or 
 steel, the springs being fastened at one end so that 
 they can be moved so as to allow the other end to 
 press upon the screen when in position. These 
 sides of the second frame should be thin in the cen- 
 ter so that the springs will not interfere with the 
 slide. Across the corners of the kit between the 
 frames of which it is composed are placed four cor- 
 ner pieces to separate screen and plate. These are 
 often of silver but may also be made of wood, and 
 should be no thicker than to prevent contact of 
 screen and plate, and should be set into the first 
 frame so as to be flush with the side next the 
 second frame. 
 
 In the diagram, A represents the first frame ; 
 B, the second, with a view of one edge of the sides 
 
HALF-TONE— 120-LINE SCREEN. 
 
.MANUAL OF PHOTO-ENGRAVING. -1 
 
 containing- the springs ; C, the kit complete, with 
 corners. 
 
 The kit should be made of a size to readily 
 admit the screen used, negative glass of the same 
 size being used also. It should be thoroughly cov- 
 ered with shellac varnish, to prevent the silver 
 destroying the wood. 
 
 The use of the kit will be explained in the chap- 
 ter on half-tone negative making. 
 
 THE SCREEN PLATE. 
 
 The screen plate is, of course, absolutely nec- 
 essary in half-tone negative making. The size 
 obtained should be governed by the size of the 
 half-tone plates which the establishment expects 
 to make. 
 
 The description of the screen and its uses will 
 also be given in a later chapter. 
 
 CHEMICALS. 
 
 The chemicals required for making the collo- 
 dion negatives and for the etching operations are 
 as follows : 
 
 Alcohol (grain). Iron sulphate (ferrous). 
 
 Alcohol (wood). Iron perchloride. 
 
 Ether (sulphuric). Potassium permanganate. 
 
 Gun cotton. Iodine. 
 
 Ammonium iodide. Silver nitrate. 
 
 Cadmium iodide. Turpentine. 
 
 Potassium iodide. Ammonia (strong). 
 
 Potassium bromide. Castor oil. 
 
 Potassium cyanide (fused) Ammonium sulphide. 
 
 Ammonium bichromate. Eosine. 
 
 Strontium chloride. Le Page's liquid glue. 
 
22 MANUAL OF PHOTO-ENGRAVING. 
 
 Calcium chloride. Rubber cement. 
 
 Mercuric chloride. Transfer etching ink. 
 
 Ammonium chloride. Lye. 
 
 Acetic acid. Dragon's blood. 
 
 Nitric acid (Com.). Sodium bicarbonate. 
 
 Nitric acid (C. P.). Absorbent cotton. 
 
 Chromic acid. Charcoal blocks. 
 Copper sulphate. 
 
 Ordinary charcoal will not answer the purpose 
 of polishing - the metal. The most suitable is that 
 used by jewelers for soldering- purposes and is 
 obtained in blocks of about 3 by 4 inches. 
 
 To insure success most of the chemicals men- 
 tioned above should be chemically pure. They 
 should be kept in bottles corked or stoppered to 
 prevent evaporation or deterioration. The bottles 
 should be plainly labeled to prevent errors when 
 the contents are wanted for use. 
 
MANUAL OF PHOTO-ENGRAVING. 
 
 23 
 
 CHAPTER III. 
 SHOP ARRANGEMENT. 
 
 IT is a difficult matter to prescribe a set plan for 
 the arrangement of a photo-engraving- estab- 
 lishment, as there is such great variation in the 
 size and relative positions of rooms which may be 
 selected for occupation, and as large shops require 
 more extensive accommodations and special features 
 which need not enter into the equipment of smaller 
 concerns. 
 
 There are general principles, however, which 
 can be applied in fitting up any shop, and the 
 
 a s a 
 
 nu 
 
 a 
 
 i] 
 
 SHOP ARRANGEMENT. 
 
 accompanying diagram is given to represent an 
 arrangement for a shop of moderate size. 
 
24 MANUAL OF PHOTO-ENGRAVING. 
 
 THE OPERATING ROOMS. 
 
 A is the room for the half-tone, and B for the 
 line operating - . One room is often used for two or 
 more cameras, but it is advisable, if possible, to 
 provide separate apartments for the cameras, thus 
 avoiding - interference of one operator with another. 
 1 and 4 are the darkrooms. These may be con- 
 structed with walls of ordinary flooring joined to 
 be light-tight. They should contain sinks 3 and 5, 
 over each of which should be placed a tap for wash- 
 ing the negatives. At the right of the sink there 
 should be placed a shelf for holding the bottles of 
 developer and other solutions. Other shelves 
 should also be provided for holding stock solutions, 
 and other accessories. Above the sink there should 
 be a window containing a light of orange glass, 
 and arranged to slide open readily at the will of 
 the operator. If dry plates are to be developed, 
 arrangement should be made to close up the yellow 
 light and substitute the ruby light required for 
 dry-plate work. 
 
 The silver bath should be placed in a receptacle 
 at the back of the darkroom, the bath holders 
 being placed at such a level as to permit the con- 
 venient lowering of the plate into it. Above, or 
 at one side of the silver baths, a shelf should be 
 located upon which the plateholder can rest. 
 
 The darkroom should be of dimensions large 
 enough to give ample room, and should be free from 
 cracks and openings through which light might 
 pass. 2 and 6 are benches for holding negative 
 racks and other articles. 
 
VIGNETTED HALF-TONE — i 75-LINE SCREEN. 
 From wash drawing- by C. W. Traver. 
 
MANUAL OF PHOTO-ENGRAVING. 25 
 
 The location of the cameras should be such as 
 to be convenient to the darkroom, and they should 
 be swung- at a height to be most convenient for the 
 operator to manipulate. 
 
 The illumination of the copy is an important 
 factor in producing - negatives, and provision should 
 be made for obtaining the best facilities. The 
 light can be obtained either from a skylight, or by 
 means of electric lamps. In many shops both 
 means are provided, the light being obtained from 
 the skylight during the bright hours of the day, 
 and from the lamps at other times. The skylight 
 should be as large as convenient, to furnish an 
 ample volume of light. The lamps should be arc 
 lamps, and should be swung, one on each side of 
 the camera stand, near the copy board, in such a 
 manner that they may be readily raised or lowered. 
 They may, if desired, be arranged with movable 
 stands, instead of being swung. Two lamps 
 should be used, as a more uniform illumination can 
 be obtained from two than from one, and reflections 
 are avoided. The lamps should be wired to burn 
 independently of each other, and the current fur- 
 nished should be uniform, to prevent, as far as pos- 
 sible, flickering and variation in the intensity of 
 the light. Reflectors are generally used to concen- 
 trate the light on the copy, and are of various 
 forms. One can be made readily from an oblong 
 piece of tin, by bending it to make its section semi- 
 circular, the edges being bent to fit around the 
 sides of the lamp. The inner surface may be 
 painted white, or, better, etched off with nitric 
 3 
 
26 MANUAL OF PHOTO-ENGRAVING. 
 
 acid, which will prevent reflections being- cast on 
 the copy. 
 
 A shelf should be built outside of one of the 
 windows to give facilities for sunning the silver 
 bath. A gas stove should be placed on one of the 
 benches, for evaporating the bath, heating nega- 
 tives, etc. 
 
 ETCHING ROOM. 
 
 C is the etching room, which for convenience is 
 located next to the operating rooms. 7 is a sink of 
 ample capacity where the metal may be polished, 
 glass washed, and negatives turned. 8 is a shelf 
 for holding glass and other articles. 9 and 10 are 
 rooms for sensitizing metal, one being designed for 
 line and one for half-tone work. They should be 
 furnished with benches, shelving, and gas stoves. 
 The illumination should be subdued, to prevent the 
 action of light on the plates before printing, but 
 not to such an extent as is necessary for the dark- 
 rooms for negative making. 
 
 The construction, arrangement, and care of 
 these rooms should be such as to prevent the 
 accumulation of dust, which will cause spots in the 
 coating of the plates. This remark will also apply 
 to the darkrooms, 1 and 4. 
 
 In the room used for coating the line plates a 
 bench and slab may be provided for rolling up the 
 plates. 11 is a bench for general purposes, such as 
 cutting zinc upon, holding negatives for printing, 
 etc. 12 is the powder box to contain the dragon's 
 blood for the line etchings. In some shops an 
 
MANUAL OF PHOTO-ENGRAVING. 27 
 
 open box is used, but it is better to have a closet 
 built around it to prevent the powder from being- 
 carried about the room. 13 is a bench for a gas 
 stove for burning in the plates. 14 and 16 are 
 etching tubs, placed near the windows, to obtain 
 ample light. 15 is a sink or a bench to hold a tray 
 of water to rinse the plates after etching. 17 is 
 a shelf placed outside of the window for printing 
 by daylight. An electric lamp should also be pro- 
 vided for the printing. 
 
 THE FINISHING ROOM. 
 
 D is the finishing room in which numbers 18 to 
 23 represent the several machines. 24 and 25 are 
 benches for mounting the plates upon, for holding 
 tools, material, etc. 
 
 The machinery should be operated from a line 
 of shafting which should be provided with belt 
 shifters, that any machine may be started or 
 stopped as desired. If the building is equipped 
 with a power plant the shafting may be operated 
 by a belt running from some other line. If the 
 place is not thus equipped the power may be ob- 
 tained from a gas engine or electric motor. 
 
 E represents the office. 
 
 In large establishments the half-tone etching is 
 often done in a room separate from that used for 
 line etching, but such an arrangement need not be 
 considered as necessary. 
 
 In selecting a location for a shop it is important 
 to obtain one where there will be an ample supply 
 of running - water at all times and where there are 
 
28 MANUAL OF PHOTO-ENGRAVING. 
 
 a number of windows, as it is desirable to have 
 plenty of lig-ht. 
 
 In fitting- up the shop economy should sometimes 
 be sacrificed to completeness and convenience, as 
 future results ma}' at times justify an outlay which 
 mig-ht at first seem to be extravagant. 
 
 The above description is intended to give only 
 general directions for the shop arrangement. 
 Special situations will require various departures 
 from this plan. 
 
MANUAL OF PHOTO-ENGRAVING. 29 
 
 CHAPTER IV. 
 NEGATIVE MAKING. 
 
 GENERAL PRINCIPLES CHEMICALS. 
 
 THE production of a photographic negative, as 
 described hereafter, depends upon the fact 
 that certain salts of silver are so acted upon by cer- 
 tain of the component rays of white light as to be 
 changed in structure. The salts which have been 
 found to be thus sensitive are the iodide, bromide 
 and chloride of silver, each producing results some- 
 what different from the others and being often 
 combined in certain proportions to obtain the qual- 
 ities of all in the resulting negative. As intimated 
 above, not all of the rays which together form 
 white light are effective in making a change in 
 these silver salts, and it is this condition also which 
 renders photography possible, for the compounds 
 can be prepared for use in a room from which the 
 ''actinic" rays (as those which affect the salts are 
 called), are excluded, the plate being afterwards 
 properly exposed to the action of the "actinic" 
 light, and the operation is then completed by the 
 aid of the "non-actinic" illumination. 
 
 For convenience, it is customary (and, in fact, 
 essential) to use some substance to hold the salts 
 and form a film over the surface upon which the 
 
30 MANUAL OF PHOTO-ENGRAVING. 
 
 negative image is to be produced. Collodion and 
 gelatine are the substances now universally em- 
 ployed for this purpose in practical work. It is not 
 customary in making the sensitive plate to add 
 directly to the collodion or gelatine the required 
 salts of silver. It has been found to be more 
 advantageous to mix with these solutions the cor- 
 responding salts of other elements, and then sub- 
 mit them to the action of nitrate of silver, which 
 will cause the desired sensitive salts of silver to be 
 formed and leave the nitrates of these elements as a 
 by-product, which in certain cases is removed by 
 washing or precipitation. For instance, if we use 
 bromide of ammonium, the action of the nitrate of 
 silver will be to form bromide of silver and nitrate 
 of ammonium, and as stated above, the nitrate is 
 merely a by-product, having no value as a sensitive 
 agent. In the wet collodion process we prepare an 
 insensitive solution, containing the proper salts, 
 and use this solution to form a film upon which the 
 silver nitrate is afterwards allowed to act to form 
 the sensitive salts of silver, the collodion acting 
 merely as a support to hold the salts. In the gela- 
 tine process the silver nitrate is added to the solu- 
 tion, thus directly forming the sensitive compounds 
 within it, which, being held suspended in a finely 
 divided condition, are said to be in a state of 
 emulsion. 
 
 If, now, we have spread over a plate of glass, or 
 other suitable substance, a coating in which the sen- 
 sitive salts of silver have been formed, we will have 
 a film which, upon exposure to light containing 
 
ZINC ETCHING — ORDINARY OUTLINE NEWSPAPER CUT. 
 From drawing by A. B. Shults. 
 
MANUAL OF PHOTO-ENGRAVING. 31 
 
 actinic rays, will have certain changes produced in 
 its sensitive constituents. If the whole plate is 
 exposed, it is evident that the change will be uni- 
 form over the whole surface, but if only certain 
 portions are exposed, the change will take place in 
 only those parts and the intensity of the change 
 will be proportionate to the intensity of the action 
 of the light upon them. If, therefore, such a plate 
 is exposed in a camera properly focused upon some 
 object, the rays of light reflected from the object 
 will affect the sensitive salts in the film and produce 
 an image corresponding in its parts to the various 
 portions of the object. If, however, the plate is 
 examined after exposure, there will be no visible 
 image to be detected. The appearance will be 
 exactly the same as it was before exposure. To 
 bring out the image it is necessary to treat the 
 impressed salts with some substance which will so 
 act as to cause metallic silver to be deposited upon 
 the affected portions. This process is termed 
 "development," the agents employed being called 
 " developers." Various compounds are used for 
 the purpose, such as pyrogallol, eikonogen, ferrous 
 oxalate and ferrous sulphate, the latter being used 
 in the development of collodion wet plates. When 
 a collodion wet plate is acted upon by the developer, 
 the free silver nitrate which remains upon the sur- 
 face of the plate is decomposed, the metallic silver 
 being deposited upon the impressed portions of the 
 film. While in the emulsion the silver salts are 
 themselves decomposed. 
 
 The developers are invariably used in the form 
 
32 MANUAL OF PHOTO-ENGRAVING. 
 
 of a solution, and when flowed over the surface of 
 a plate those parts of the image which correspond 
 to the white parts of the object appear first, then 
 the parts corresponding- to the half-tones, and 
 finally the details in the shadows. The light 
 reflected from the whites most strongly affect the 
 film, and therefore the deposit of silver will be most 
 dense in those parts of it which correspond to the 
 white portions of the object, the deposit in other 
 portions being dense in proportion to the effect of 
 the light reflected from the corresponding parts of 
 the object, while those parts of the film upon which 
 the blacks are produced will be unaffected, as the 
 black portions have practically no actinic effect 
 upon the silver salts. 
 
 The process of development has an important 
 place in the production of the negative, for any 
 carelessness or ignorance in manipulation may ruin 
 what with proper treatment might result in a 
 negative of excellent quality. In the wet collodion 
 process the developer is simply flowed over the 
 plate as it is held in the hand, the operation being 
 simpler and more mechanical than the development 
 of the gelatine plate. In the development of a 
 gelatine negative the plate is placed in a tray and 
 the developer allowed to act until the desired effect 
 is obtained, it being necessary to vary the propor- 
 tions of the developer if the plates have been over 
 or under exposed. 
 
 After the negative has been developed, those 
 parts which have not been acted upon by the light 
 will retain the same appearance that they had 
 
MANUAL OF PHOTO-ENGRAVING. 33 
 
 before development, and as the unreduced salts are 
 of no value they must be removed. To accomplish 
 this the plate is treated with a solution which will 
 dissolve out these salts, and the negative is then 
 said to be "fixed." The substances usually em- 
 ployed to fix a negative are cyanide of potassium 
 or hyposulphite of soda, in solution. The action is 
 a chemical one, the corresponding- salt of silver 
 being - formed and dissolved in the solution contain- 
 ing an excess of the fixing agent. The result is 
 that we have an image on the plate, dark in the 
 portions corresponding to the high lights of the 
 object, with practically clear glass in the parts cor- 
 responding to the blacks, and if the object is one 
 with intermediate tints or half-tones, there will be 
 gradations in the negative to correspond. 
 
 To be of use in photo-engraving the negative 
 must be very intense, that is, the parts affected by 
 light must be opaque, while the lines must be as 
 clear glass. This result is obtained by a further 
 treatment of the film after fixing, and the method 
 will be described in the next chapter. 
 
 Upon the time which the plate is exposed in the 
 camera depends to a great degree the quality of the 
 resulting negative. The best results are obtained 
 only when the exposure has been of a duration of 
 time suited to the conditions. The area of dia- 
 phragm, amount of reduction of copy, intensity of 
 illumination, etc., each has an influence in deter- 
 mining the necessary time. 
 
 In making negatives for photo-engravings the 
 wet collodion process is at the present time almost 
 
34 MANUAL OF PHOTO-ENGRAVING. 
 
 universally employed, although some excellent 
 results may be obtained with dry plates made for 
 the purpose. In the wet process the plate is made 
 by flowing - over a sheet of glass a collodion contain- 
 ing" in solution certain iodides, bromides, or chlo- 
 rides, or combinations of such salts. The plate is 
 then subjected to the action of silver nitrate in 
 solution, which causes the sensitive silver salts to 
 be formed as explained above. The plate is 
 exposed and developed while wet, and if the ma- 
 nipulations are properly carried out the most 
 desirable results can be obtained. 
 
 THE COLLODION. 
 
 Various formula? for the collodion can be em- 
 ployed, but the following, which is known to many 
 operators, is one of the best, and is an excellent 
 one for either line or half-tone work : 
 
 Alcohol 8 ounces 
 
 Ether 10 
 
 Iodide of ammonium 30 grains 
 
 " " cadmium 50 " 
 
 Chloride of calcium 10 " 
 
 " " strontium 10 " 
 
 Gun cotton 80 " 
 
 Either of the chlorides may be omitted. The 
 gun cotton should be easily soluble. Anthony's 
 Red Label is recommended. 
 
 To prepare the collodion dissolve the gun cotton 
 in the ether and six ounces of the alcohol. Then 
 put the remaining two ounces of the alcohol in a 
 clean mortar and add each salt separately, and 
 grind with the pestle until dissolved. After all of 
 
HALF-TONE— 150-LINE SCREEN. 
 
MANUAL OF PHOTO-ENGRAVING. 35 
 
 the salts have been added and dissolved, pour the 
 solution into the solution of gun cotton and shake 
 well. This collodion will usually be found to work 
 well in a few hours after making - , but should it fail 
 to work clearly add a few flakes of iodine to turn 
 toward a red color. Before using - , the collodion 
 should be filtered through a tuft of absorbent cot- 
 ton placed in the neck of a clean, dry funnel which 
 should be provided for this purpose alone. The 
 collodion bottle should also be kept tightly corked, 
 as the ether rapidly evaporates, leaving the col- 
 lodion thick. 
 
 THE SILVER BATH. 
 
 To prepare the silver bath, dissolve crystals of 
 silver nitrate in water until the actino-hydrometer 
 will, when floated in it, register 40. Distilled or 
 clean rain water should be used if obtainable, but 
 ordinary water as obtained from the faucets can 
 generally be used. In any case the bath after mix- 
 ing should be placed in the sun for a day or two 
 until it becomes perfectly clear, as any organic 
 matter will be acted upon by the nitrate and be 
 precipitated. After sunning, the bath should be 
 carefully filtered, and, in order that it may give 
 clear images, a few drops of pure nitric acid added 
 until blue litmus paper will be turned red if placed 
 in the solution. 
 
 The bath is now placed in its holder, but must be 
 " iodized" before good results can be obtained with 
 it. If a collodionized plate is sensitized in it now, 
 the plate when taken from the bath will look thin 
 and be of a light bluish color, and will give a weak, 
 
36 MANUAL OF PHOTO-ENGRAVING. 
 
 thin image. This is due to the fact that in a fresh 
 bath the silver salts when formed in the film are 
 dissolved out by the silver solution. To prevent 
 this the bath must be supplied with iodides. The 
 best method is to place in the bath a collodionized 
 plate as large as the holder will take and let it 
 remain several hours until the salts are dissolved 
 out of its film into the bath. If necessary, this 
 operation should be repeated, until the plates when 
 taken from the bath will have a rich, creamy 
 appearance, and give images of the desired 
 strength. The methods for caring for the bath 
 solution will be given in Chapter VII. 
 
 THE DEVELOPER. 
 
 The developer for these plates is a solution of 
 ferrous sulphate, which may be dissolved in various 
 proportions. The following will be found to give 
 good general results : 
 
 Ferrous sulphate 4 l /i ounces 
 
 Acetic acid 3 to 2> l / 2 " / 3 
 
 Water 48 " 1^%J^ 
 
 Alcohol 2y 2 " or q. s. 
 
 The crystals of iron should be finely ground in 
 a mortar and then thoroughly dissolved. The de- 
 veloper may be made up by measuring its strength 
 by the hydrometer, in which case it should register 
 20, and to each 20 ounces there may be added \ l /> 
 ounces acetic acid, and alcohol in sufficient quantity 
 to make the solution flow readily. The action of 
 the sulphate is to reduce the silver, as explained in 
 a preceding paragraph, the acid being used to 
 retard its action and keep the image clear. Were 
 
MANUAL OF PHOTO-ENGRAVING. 37 
 
 the iron allowed to act alone it would cause a rapid 
 reduction over the entire plate and veil the image. 
 The alcohol is used to cause the developer to flow 
 readily over the plate, for after the bath has been 
 used for a time it takes alcohol from the plates, 
 causing - the developer to flow in streaks, the addi- 
 tion of alcohol to the developer aiding- it to flow in 
 an even sheet. 
 
 FIXING SOLUTION. 
 
 Cyanide of potassium. Water. 
 
 Make in solution strong enough to dissolve the 
 unreduced salts. Some operators use a saturated 
 solution, others prefer to use it more dilute. Hypo- 
 sulphite of soda may be substituted for the cyanide, 
 but the cyanide is recommended. 
 
 INTENSIFYING SOLUTIONS. 
 
 There are several methods of intensifying nega- 
 tives, but those most commonly used are the cop- 
 per and silver and the mercury intensifiers. The 
 former is generally favored. 
 
 COPPER AND SILVER METHOD. 
 
 1. Make a saturated solution of copper sul- 
 phate, and also one of bromide of potassium. 
 
 Place some of the copper solution in a wide- 
 mouthed bottle, and add to it some of the bromide 
 solution. Exact proportions are not necessary. 
 One part of the bromide solution to six or eight 
 parts of the copper will be about right. In making 
 the saturated solutions, it is well to use warm 
 water, as the salts will more readily dissolve. 
 
 2. Nitrate of silver. Water. 
 
 4 
 
38 MANUAL OF PHOTO-ENGRAVING. 
 
 Make a solution about 25 grains of the silver to 
 the ounce of water. It is not necessary in practice, 
 however, to measure the quantities exactly. The 
 operator will generally place a few crystals in the 
 bottle and dissolve in some water, adding- a few 
 more crystals if the solution acts too slowly. 
 
 3. Nitric acid. Water. 
 
 Make weak solution. About one part acid to 
 eight or nine parts water. 
 
 4. Ammonium sulphide. Water. 
 
 One part of the sulphide to about five or six 
 parts of water, to which a few drops of ammonia 
 may be added. Keep this solution covered. 
 
 MERCURY METHOD. 
 
 Mercuric chloride. Water. 
 
 Make a saturated solution. Some ammonium 
 chloride is usually added to cause greater satura- 
 tion. 
 
 In connection with this solution, solutions 3 and 
 4 given above are used. 
 
 CLEARING SOLUTION. 
 
 1. Place some iodine crystals in a bottle with 
 some crystals of iodide of potassium and add enough 
 water to make a deep red solution. The quantity 
 of iodide need not be as great as the quantity of 
 iodine used. 
 
 2. Cyanide of potassium. Water. 
 Make a very weak solution. 
 
 This solution is most readily prepared by taking 
 a small quantity of the stronger fixing solution, 
 and diluting it largely with water. 
 
ZINC ETCHINGS — FROM PEN DRAWINGS, GREATLY REDUCED. 
 Drawn by A. Cambersy. 
 
MANUAL OF PHOTOENGRAVING. 
 
 39 
 
 CHAPTER V. 
 NEGATIVE MAKING — LINE NEGATIVES. 
 
 IN making- negatives, the operator cannot exer- 
 cise too much care in every detail. The expe- 
 rienced hand knows too well that often carelessness 
 in what might seem to the uninitiated a trivial 
 matter may result in failure. 
 
 CLEANING THE GLASS. 
 
 The glass upon which the negative is to be made 
 must be scrupulously clean. To provide for this 
 there should be obtained two tubs, large trays, or 
 jars, into one of which a strong solution of lye 
 should be placed, and into the other a quantity of 
 nitric acid diluted with water. The glass should 
 first be allowed to soak for hours in the lye until 
 any particles of matter adhering to it are destroyed 
 or loosened. It should then be taken from it, 
 washed well to remove the lye and any dirt from it, 
 and placed to soak in the acid. When removed 
 from the acid it should be washed again and placed 
 in a negative rack to drain, or if desired for imme- 
 diate use it may be dried by rubbing with a clean 
 towel, and afterward with a piece of soft cotton 
 cloth. Before collodionizing it should be carefully 
 
40 MANUAL OF PHOTOENGRAVING. 
 
 dusted with a camel's-hair brush, to remove any 
 specks which might enter the bath or cause spots 
 in the film. A number of plates should be cleaned 
 at a time and kept in a negative rack for use. 
 Some operators albumenize the glass by flowing 
 over it after washing a solution of 1 ounce albu- 
 men in 8 or 10 ounces water, acidified with nitric 
 acid. The glass, after drying in a rack, is put 
 away with the albumenized sides all one way. 
 Such glass does not require an edging of rubber 
 before collodionizing. 
 
 FOCUSING. 
 
 Care should be exercised in focusing to obtain 
 absolute sharpness of the image on the ground 
 glass, as any blurring of the lines will render the 
 negative practically useless. Fasten the copy to 
 the board so that the image will occupy the center 
 of the ground glass, put a large stop in the lens, 
 and move the camera until the image, when per- 
 fectly sharp on the ground glass, is of the size 
 desired. In general, the focusing should be done 
 upon that part of the copy about midway between 
 the center and the edge, particularly if the copy is 
 one of large dimensions. 
 
 The lights should be so placed that the illumina- 
 tion of the copy will be as uniformly distributed as 
 possible. In photographing large copies by the 
 electric light, it is sometimes advantageous to move 
 the lights during exposure, to obtain an even illumi- 
 nation over the whole. In photographing tracings 
 or line drawings on thin paper, a sheet of white 
 
MANUAL OF PHOTO-ENGRAVING. -H 
 
 paper should be placed back of the copy. Copy 
 which is crumpled, or which cannot be made to lie 
 flat on the copy board, may be placed in an ordinary 
 printing- frame and photographed through the 
 glass. The cover glass in such a case should be 
 clear and well cleaned. 
 
 A small magnifying glass is often of service in 
 focusing to examine the lines of the image, espe- 
 cially if the ground glass is of coarse grain, or if 
 the reduction is great, or the lines of the copy 
 indistinct. With indistinct lines it often facilitates 
 accurate focusing to place a piece of newspaper or 
 other printed matter across the face of the copy, 
 and focus on that, removing it afterwards, of course. 
 After the focus is obtained, fasten the camera in 
 position by means of the set screws at the back, 
 take out the ground glass, remove the large stop 
 and substitute a small one. In photographing line 
 work it is necessary to use a small stop to obtain 
 clear lines, especially if the lines on the copy are 
 fine, or the reduction great. Having the copy 
 focused, the next operation is the 
 
 COLLODIONIZING AND SENSITIZING. 
 
 Having cleaned and dusted the plate, dip a small 
 brush (or a small stick, around one end of which a 
 tuft of cotton has been wrapped) into a solution of 
 rubber in benzine (see Chapter VIII), and run a 
 narrow strip of this around the edge of the plate. 
 The solvent will evaporate, leaving the rubber 
 around the edge, which will prevent the film slip- 
 ping from the plate. Now hold the plate by one 
 
42 
 
 MANUAL OF PHOTO-ENGRAVING. 
 
 corner in the left hand in a horizontal position, and 
 pour the collodion from the vial in a pool near the 
 upper right-hand corner D, as shown in diagram. 
 
 Use sufficient collodion to 
 cover the plate and move the 
 plate so that it will run first 
 up to D, then to C, then to 
 A, and finally to B, from 
 which it is to be drained 
 into the phial. While drain- 
 ing, the plate must be care- 
 fully rocked to obtain an 
 even coating. When the 
 collodion has become set, in- 
 vert the plate, place it on 
 the dipper and lower steadily into the silver bath. 
 Close the cover to the bath and let the plate remain 
 for several minutes, and it will then be ready for 
 exposure. 
 
 EXPOSURE. 
 
 Close the darkroom door and have the plate- 
 holder resting on its shelf in an upright position 
 and open to receive the plate. Then draw the 
 dipper holding the plate from the bath. If prop- 
 erly collodionized and sensitized the film should be 
 free from any spots or streaks and should have a 
 creamy appearance, with the silver solution on the 
 surface in an even sheet. If the solution lies over 
 the surface in greasy looking streaks, return the 
 plate to the bath at once, moving it around for a 
 moment in the solution, and let remain for several 
 minutes longer. When the plate is found ready to 
 
MANUAL OF PHOTO-ENGRAVING. 43 
 
 expose, let it drain for a minute or two, wipe the 
 back with a rag or tuft of cotton, then place in the 
 holder so that the film side will be toward the copy 
 when placed in the camera, close the back of the 
 holder and place it in the position of the ground 
 glass in the camera. 
 
 Having the cap on the lens and the lights prop- 
 erly placed, draw the slide from the holder, then 
 remove the cap from the lens. The time of expos- 
 ure must be a matter of experience, as it will vary 
 with the character of the lens, the intensity of illu- 
 mination, the amount of reduction of the copy, etc. 
 Short exposure gives broad lines, with lack of 
 intensity in the negative, and the resulting print 
 will be lacking in detail. Long exposure gives fine 
 lines, detail and density, but tends to fill the fine 
 lines. For blue or weak lines give as short an 
 exposure as practicable, for such lines tend to affect 
 the sensitive film, and if the exposure is lengthened, 
 the lines in the image will fill. Light blue lines 
 cannot be reproduced on the ordinary plate. When 
 the ground of the drawing is yellowish, give ample 
 exposure, as such a color does not readily affect 
 the film. 
 
 Shorten the exposure time in proportion as the 
 image is reduced in size. If the copy is brightly 
 illuminated it will require less time than when the 
 light is weak. When the exposure has been con- 
 sidered sufficient, replace the cap on the lens, return 
 the slide to the holder, and take the holder to the 
 darkroom. The plate is now ready for development. 
 
-±4 MANUAL OF PHOTO-ENGRAVING. 
 
 DEVELOPMENT. 
 
 This must of course be done by the non-actinic 
 light in the darkroom. To develop the image, hold 
 the plate horizontally in the left hand and flow the 
 developer from a beaker or graduate over the film 
 in one even wave ; then holding the solution on the 
 plate, keep moving* the plate gently to cause the 
 developer to flow from side to side. The negative 
 image will soon appear, and the time of its appear- 
 ance will indicate whether the exposure was prop- 
 erly timed. If the proper exposure was given, the 
 image will appear in a few seconds, the white 
 ground taking a dark appearance and the lines 
 retaining the color of the film before the developer 
 was applied. If, however, the image flashes up at 
 once and some or all of the lines become darkened, 
 it indicates over-exposure and the lines will be filled, 
 as the whole surface has been impressed and the 
 silver will be deposited to some extent on those 
 parts which should remain clear. 
 
 If, on the other hand, the image is slow in 
 appearing, and the details are brought up with dif- 
 ficulty, the plate has been under-exposed. If one 
 portion of the image appears before another, it in- 
 dicates uneven lighting of the copy, and when that 
 portion which appears first is sufficiently devel- 
 oped, it should be held to wash under the tap while 
 the developer is allowed to act upon the other por- 
 tions of the plate. Otherwise the fine lines in that 
 portion might fill by the time the other parts 
 become sufficiently developed. When the whole 
 
HALF-TONE FROM PHOTOGRAPH. 
 With and without background. 
 
MANUAL OF PHOTO-ENGRAVING. 45 
 
 image has attained the proper intensity, and the 
 details are visible, the plate should be immediately 
 washed under the tap to entirely remove the devel- 
 oper and unreduced silver solution. The remaining 
 operations can be performed by daylight. 
 
 FIXING. 
 
 Now flow the fixing solution over the film until 
 the unaffected portions are entirely dissolved, when 
 the lines should appear as clear glass. Then wash 
 the plate well again, and examine carefully to de- 
 termine if the film has proper density, if the lines 
 are fine enough, and if all are clear. Some expe- 
 rience will be required to detect these qualities. 
 If any of the lines are filled they will have a hazy 
 appearance, quite readily detected, but if not too 
 badly filled they can be cleared by a subsequent 
 operation explained below. If the plate is satisfac- 
 tory thus far, it must be intensified to make the 
 ground opaque, for in its present condition the 
 light would pass through the ground so readily as 
 to render the negative useless for obtaining a print 
 upon the metal. 
 
 INTENSIFICATION. 
 
 The intensification may be done with either the 
 copper and silver or the mercury intensifiers. To 
 intensify with the former, flow over the fixed and 
 washed negative the copper solution, until the film 
 becomes white, then wash well and flow with the 
 silver solution until it is blackened throughout, then 
 wash well again. It will usually be necessary to 
 repeat the process a second time, and sometimes 
 
46 MANUAL OF PHOTO-ENGRAVING. 
 
 even three or four times, if the exposure has been 
 short, but twice will as a rule be sufficient if the 
 exposure has been rightly timed. If any portion 
 of the ground should still appear thin, after the 
 other portions have become sufficiently dense, repeat 
 the operation on that part alone, to increase its 
 density. 
 
 If, after the entire ground has acquired the 
 proper density, the lines all appear sharp and 
 clear, additional blackness may be given to the film 
 by flowing with the ammonium sulphide solution 
 No. 4. Before using the solution No. 4, flow with 
 the dilute nitric acid solution No. 3, and rinse. 
 This will preserve clearness. Wash thoroughly 
 after blackening with the sulphide solution. If the 
 lines are at all veiled or closed, the sulphide is liable 
 to turn them yellow, and in such a case it should be 
 omitted. Additional density in the intensification 
 may at times be obtained by treating the film with 
 a dilute solution of iodide of potassium, after the 
 copper and before the silver is used. This turns 
 the film a lemon-yellow color. This treatment will, 
 however, sometimes cause a stain if the bath and 
 other chemicals are not in a clean condition. The 
 solution is made by dissolving a few crystals of 
 iodide of potassium in water. 
 
 CLEARING. 
 
 If, after intensifying with the copper and silver 
 solutions, any of the lines are filled, they must be 
 cleared. To do this, flow over the filled portions the 
 dark red solution of iodine and iodide of potassium, 
 
MANUAL OF PHOTOENGRAVING. 47 
 
 and rinse. Then carefully follow with the very 
 dilute solution of cyanide, applying- it until the 
 filled portions are cleared. If the cyanide solu- 
 tion is any too strong- it will dissolve the film also 
 and ruin the negative. During the operation the 
 water should be kept running from the tap and 
 immediately applied if the action shows any ten- 
 dency to proceed too far ; and at times it is to 
 advantage to let the water run over the plate, while 
 the cyanide is being applied, to cause the action to 
 proceed slowly. This treatment of the film will 
 cause it to become whitened. To blacken it, the 
 ammonium sulphide solution must be used as di- 
 rected above. 
 
 Instead of using the iodine solution strong and 
 the cyanide solution weak, some operators prefer 
 to dilute the former and use the latter strong, 
 intensifying again after the clearing. Instead of 
 using the solutions separately, they may be mixed 
 by adding cyanide to the iodine solution until the 
 color disappears, and diluting with water. The 
 solution is then applied until the lines are cleared. 
 If the lines are too badly filled it will be impossible 
 to clear them, and the negative will be worthless. 
 
 THE MERCURY METHOD. 
 
 Have the mercury solution in a tray and allow 
 the fixed negative to remain in it until bleached. 
 Then flow with the acid and sulphide solutions to 
 blacken. For greater density, place in the mer- 
 cury again until of a grayish color, and repeat 
 with the sulphide solution, washing well between 
 
48 MANUAL OF PHOTO-ENGRAVING. 
 
 each operation. The sulphide solution tends to 
 weaken the film, and in washing- the negative after 
 its use the water should not be allowed to run on it 
 with much force. Having obtained a negative with 
 clear lines and opaque ground, it may be dried 
 spontaneously or over heat and is then ready for 
 reversing, the operations for which will be de- 
 scribed in Chapter VIII. 
 
MANUAL OF PHOTOENGRAVING. 40 
 
 CHAPTER VI. 
 
 NEGATIVE MAKING — HALF-TONE 
 NEGATIVES. 
 
 IN making - negatives from line drawing's, as 
 described in last issue, there are no gradations 
 to be reproduced, but in obtaining negatives from 
 photographs and wash drawings we have every 
 gradation from solid blacks to pure whites, which 
 must be properly rendered. In order to obtain a 
 negative which will be suitable for reproducing 
 these gradations upon the metal plate, we break 
 up the negative image in such a manner that it will 
 be formed of dots and clear spaces, the size of the 
 dots varying to correspond with the different 
 shades in the copy. This is accomplished by plac- 
 ing in front of the sensitive plate when in the cam- 
 era a glass plate so ruled as to have alternating 
 parallel opaque lines and clear spaces. The light 
 passing through the clear spaces produces the 
 desired effect upon the sensitive film. 
 
 THE SCREEN-PLATE. 
 
 The ruled plate which is used for the purpose 
 described above is commonly called the screen- 
 plate. These plates may have lines ruled in only 
 one direction, or in several. The screen commonly 
 used has rulings in two directions, one set of lines 
 
50 MANUAL OF PHOTO-ENGRAVING. 
 
 crossing- the other at about right angles. Such 
 plates are made by sealing together two "single 
 line " screens, ruled in opposite directions, the 
 effect being to produce a network of the opaque 
 lines. Having such a cross-line screen-plate placed 
 in front of the sensitive plate during exposure, all 
 conditions being arranged to obtain the proper 
 results, the action of the light in passing through 
 the clear spaces is to so act upon the film that when 
 the plate is developed the image will be found to be 
 made up of opaque dots of varying size, those in 
 the whites being largest, the size decreasing as the 
 tints in the original grow darker until they prac- 
 tically disappear in the solid blacks. A print made 
 from such a negative will have separate black dots 
 in the high lights, which will increase in size as 
 the shadows deepen, running into solid lines, the 
 details in the shadows being formed of open dots, 
 which will decrease in size as the shades increase 
 in intensity, until they are absent in the blacks. 
 There is, therefore, a simple gradation correspond- 
 ing to the shades of the original, each shade being 
 composed of dots of a certain size. 
 
 A somewhat different effect than that obtained 
 with the ordinary single or double line screen may 
 be produced by using a screen having the clear 
 spaces of different sizes arranged in groups, and 
 also having the opaque obstructions differing in 
 sizes, and arranged in groups. The result with 
 such a screen is to obtain a printing surface made 
 up of groups of dots and lines, in which the indi- 
 vidual members differ from each other, but the 
 

 EFFECT OF "FOUR-LINE" SCREEN. 
 
MANUAL OF PHOTOENGRAVING. 
 
 51 
 
 MR. LEVY'S "FOUR-LINE" SCREEN. 
 
 geometrical arrangement being- similar throughout 
 the series. Mr. Levy has produced such a screen 
 with four sets of rulings, each set consisting of 
 parallel lines. Two of the sets are crossed at 
 right angles to each other, and the other two also 
 at right angles to each 
 other, and crossing the 
 first two at an angle 
 of forty-five degrees. 
 The apertures are, 
 therefore, in the form 
 of right-angled trian- 
 gles, but the intersec- 
 tions are so placed that 
 the apertures shall 
 vary in size, and there are also formed two dif- 
 ferent-sized obstructions to the light, one size by 
 the intersection of two lines, and the other by the 
 intersection of the four. 
 
 In the print obtained from the resulting nega- 
 tive made through such a screen, the high lights 
 will be formed of single dots corresponding to the 
 four-line intersections, and in the darker shades 
 a smaller dot, corresponding to the two-line inter- 
 section, will appear, thus forming two series of dots 
 which will run through the middle tints, increasing 
 in size as the shadows increase in intensity, until 
 they form continuous lines. The details in the 
 shadows will also consist of a series of open dots or 
 spaces corresponding to the clear apertures of the 
 screen, and as the shades deepen the dots repre- 
 senting the clear apertures will disappear in series, 
 
52 MANUAL OF PHOTO-ENGRAVING. 
 
 first those corresponding- to the smallest apertures, 
 then those corresponding - to the next size, and so on 
 until there will be but one series of open dots (those 
 corresponding to the largest aperture) in the 
 shades next in intensity to the solid blacks. With 
 such a screen the detail is more truly rendered, as 
 there is obtained more than one gradation of dots 
 for each shade in the half-tones. 
 
 THE NEGATIVE. 
 
 A half-tone negative properly made from a sub- 
 ject of good quality should have the dots so closed 
 in the whites that the clear spaces between them 
 shall be separated from each other, the dots de- 
 creasing in size as the tints in the original darken, 
 until they disappear in the solid blacks. The clear 
 spaces in the high lights should of course be of 
 such a size that the dots in the resulting print shall 
 be large enough to stand a sufficiently deep etch. 
 There are several factors which have an influence 
 in determining the quality of the negative, as 
 follows : 
 
 CHARACTER OF THE COPY. 
 
 The character of the copy determines to a great 
 degree the results obtainable. Many photographs 
 are entirely lacking in contrasts, while others are 
 as deficient in detail. The former will, of course, 
 require a treatment to obtain brilliancy in the half- 
 tone, while the latter will require manipulation to 
 obtain detail in the masses of shadow. The surface 
 upon which the drawing or photograph is made will 
 also sometimes cause difficulty in obtaining desirable 
 
MANUAL OF PHOTO-ENGRAVING. 53 
 
 effects. As a rule, smooth surfaces are to be pre- 
 ferred to work from, as the grain in rough surfaces 
 will often show to disadvantage in the reproduction. 
 The color or tone of the copy is another element to 
 be considered. The chocolate-brown tones, such as 
 were once obtained in albumen prints, give excel- 
 lent effects, while lilac and bluish tones tend to give 
 flat results. 
 
 ILLUMINATION OF THE COPY. 
 
 The illumination of the copy should be uniform, 
 and the lamps should burn without flickering or 
 variation in intensity. The lights should be placed 
 so that reflections on the copy will be avoided. 
 Large copies are more satisfactorily lighted from 
 the skylight than with electric lamps. With a 
 bright illumination a shorter exposure is required 
 than with one of less brilliancy. 
 
 SEPARATION OF SCREEN AND PLATE. 
 
 If the screen-plate could be placed during expo- 
 sure so that the ruled lines would be in contact with 
 the sensitive plate, it is plain that the result would 
 be merely a reproduction of the lines of the screen, 
 there being no variation in the size of the dots. In 
 order to obtain the required variation, it is neces- 
 sary to separate the screen and plate that there 
 may be a certain amount of diffraction of light 
 between them. The effect of such separation upon 
 the relative size of the dots will vary with the dis- 
 tance between the plates. The nearer they are 
 together, the less will be the variation, and conse- 
 quently the flatter will be the resulting negative. 
 
54 MANUAL OF PHOTO-ENGRAVING. 
 
 Therefore, to a certain extent, by varying - the 
 amount of separation, we may obtain detail or 
 contrast in the resulting - negative. When using 
 coarse screens, it will be found necessary to use 
 a wider separation than with a fine screen, to 
 obtain similar results, all other conditions being 
 the same. When the same screen is used for vari- 
 ous subjects, after a suitable separation has been 
 found to give proper rendering of good copies, it 
 will not usually be necessary to change the dis- 
 tance between screen and plate to obtain detail 
 or contrast, as these effects can be secured by 
 altering the area of the diaphragm, as will be ex- 
 plained. If a certain screen and plate are separated 
 to aid in obtaining contrast, the exposure time 
 should be somewhat less than that given when the 
 screen and plate are nearer to each other. To 
 increase the separation in the kit between screen 
 and plate, small pieces of cardboard are placed 
 between the screen and the corner pieces. 
 
 AREA OF DIAPHRAGM APERTURE. 
 
 Whether the half-tone negative shall have detail 
 or contrast depends to a great extent upon the 
 area of the aperture in the diaphragm used during 
 exposure. If the exposure is made with a small 
 aperture the resulting negative will, upon examina- 
 tion, be found to have the dots in the high lights 
 separated from each other, and the dots in the 
 shadows will be strong and approaching in size to 
 those in the high lights. The negative will there- 
 fore be made up of a network of clear lines, and a 
 
HALF-TONE FROM PHOTOGRAPH. 
 With ornamented background. 
 
MANUAL OF PHOTO-ENGRAVING. 55 
 
 print made from it would be formed of a similar 
 network of solid lines. The resulting - etching 
 would, therefore, give proofs gray and devoid of 
 contrasts. If, on the contrary, a large aperture is 
 used, the high lig-hts in the negative will be formed 
 of large dots, which will unite to form a network 
 of dark lines dotted with clear spaces, separated 
 from each other, while the dots will rapidly de- 
 crease in size as the depths in the shadows increase 
 in intensity, the blacks remaining as clear glass. 
 A print made from such a negative would have the 
 high lights made up of separate dots, the middle 
 tints would be formed of dark lines varying in 
 thickness, and the deep shadows would consist of 
 solid masses. An etching made from such a print 
 would give a "black and white" proof, and if the 
 area of aperture has been too large, detail will be 
 lost in many places where it should appear, the 
 gradations being buried in solid portions of black, 
 while the whites will appear "chalky," and if the 
 clear spaces in the negative have been too small, 
 the resulting dots in the print will not be of suffi- 
 cient size to stand a deep bite, rendering the plate 
 liable to smudg-e in the printing. 
 
 There is evidently a mean between the two 
 extremes, it being possible to find a diaphragm 
 having- an aperture with which a negative can be 
 made the print from which will have the dots in 
 the whites of sufficient size to allow a sufficiently 
 deep etch, and yet so separated that these high 
 lights will appear of the requisite clearness, the 
 dots and lines in the other portions being - of such 
 
56 MANUAL OF PHOTO-ENGRAVING. 
 
 dimensions that in the resulting- print we will have 
 a proper correspondence to the gradations in the 
 original. Not only may a single diaphragm be used 
 to accomplish the desired result, but during expo- 
 sure the area of the diaphragm may be changed, 
 using a small aperture during a part of the expo- 
 sure and a larger one for the balance, the small stop 
 producing the detail and the large one the union of 
 the dots in the whites. 
 
 It has been assumed in the above discussion that 
 the subject possesses the qualities of technical excel- 
 lence. If, however, a negative is to be made from a 
 copy which does not fulfill such conditions, the size 
 of the diaphragm aperture must be so selected as 
 to produce either detail or contrasts, as the case 
 may require. When the copy is one which has 
 abnormal contrast, a comparatively small stop will 
 cause dots to be formed in the shadows of the half- 
 tone and thus give detail, which will often be an 
 improvement. When, on the other hand, the copy 
 does not have sufficient brilliancy, the use of a 
 larger stop will bring out the contrasts. The 
 degree of detail or contrast to be thus produced to 
 obtain the best effects is, of course, a matter of 
 judgment on the part of the operator. The larger 
 the stop used the shorter should be the time of 
 exposure. 
 
 SHAPE OF THE DIAPHRAGM APERTURE. 
 
 While diaphragms having round apertures, as 
 usually supplied with lenses, have been generally 
 used by operators, those having other shapes may 
 
MANUAL OF PHOTO-ENGRAVING. 
 
 57 
 
 be used, the form of the dot being - determined by 
 the form of the aperture. Mr. Levy, of Philadel- 
 phia, has investigated the effect of various forms of 
 the aperture upon the shape of the dot in the nega- 
 tive, and states as a principle that each transparent 
 space in the screen acts during exposure as a pin- 
 hole lens, and causes an image of the shape of the 
 aperture to be formed upon the sensitive film. 
 From this it appears that if we use a round aper- 
 ture, the dots in the negative will be round, a 
 square aperture will produce square dots, a trian- 
 gular aperture triangular dots, etc. It has been 
 found that the dot formed by the use of a square 
 diaphragm will be stronger than the round dot, 
 and will require a shorter exposure time to pro- 
 duce, as it is plain that square dots will close up in 
 
 LEVY DIAPHRAGMS. 
 
 the whites in less time than round ones. Mr. Levy 
 has invented several forms of diaphragms, three of 
 which are shown here, the first form having a 
 
58 MANUAL OF PHOTOENGRAVING. 
 
 square aperture with two corners extended, the 
 second having- the four corners extended, and the 
 third having - a multiple aperture of four square 
 openings, the center being closed. These dia- 
 phragms may be made separate from each other, 
 but by an ingenious mechanical arrangement may 
 be combined, and the size and form of the opening 
 may be altered at will to be square or to have 
 either of the two forms illustrated above, a scale 
 on the lens tube indicating the size of the aperture 
 in terms of the focal length of the lens, and also 
 the length of the projecting corners, or the extent 
 to which the center is inclosed if the second form is 
 used. The diaphragms having the apertures thus 
 formed are recommended for use in making nega- 
 tives from flat originals, as the light in passing 
 through such apertures acts more intensely upon 
 the high lights than upon the shadows, thus pro- 
 ducing more brilliant effects than can be obtained 
 with the ordinary forms of aperture. For subjects 
 having the proper contrasts to produce a brilliant 
 negative the square aperture alone may be used 
 during the exposure, but for flat originals the 
 inventor recommends the consecutive use of the 
 square aperture, then the one with four corners 
 extended, and finally the one with the multiple 
 apertures. 
 
 EXPOSURE TIME. 
 
 The exposure time in making half-tone nega- 
 tives must be determined by the conditions as enu- 
 merated above. If all the conditions are properly 
 
MANUAL OF PHOTO-ENGRAVING. 59 
 
 adjusted and the exposure time is insufficient the 
 dots will not be sufficiently closed, and if the time 
 given is too long- the clear spaces will either be 
 filled or so small that the dots in the print would 
 not be large enough to stand a deep bite. 
 
 MANIPULATIONS. 
 
 First see that the screen is clean. A soft, clean 
 cotton cloth will be found useful in polishing it, and 
 any spots and streaks must be removed from its 
 surface, or they will be reproduced in the negative. 
 Breathing upon the surface while rubbing will aid 
 in removing any streaks. When clean, place it in 
 the kit and close the springs upon it ; then place 
 the kit in the plateholder so that the screen will 
 be between the lens and sensitive plate during ex- 
 posure. The operations of developing, fixing and 
 intensifying are similar to those described for line 
 negatives. To expose, the plate after being sensi- 
 tized is placed in the kit behind the screen, the 
 plateholder being then placed in the camera. Dur- 
 ing exposure one size of diaphragm may be used, 
 or the size may be varied to suit the conditions. 
 Upon this point the judgment and experience of 
 the operator must be used. After exposure the 
 plate is developed until the details appear, and 
 then fixed. After fixing it should be examined to 
 determine if the proper qualities have been ob- 
 tained. If the dots are widely separated in the 
 high lights, and the shadows are filled with strong 
 dots, the resulting print will be gray and flat. If 
 the dots in the high lights are closed up, and the 
 6 
 
60 MANUAL OF PHOTO-ENGRAVING. 
 
 details in the shadows are lacking - , the print would 
 be too brilliant, and would in many cases have dots 
 too small to allow the etching- to be carried to a 
 sufficient depth. In either case the exposure should 
 be repeated, and the size of aperture and exposure 
 time increased or diminished as required to obtain 
 the proper gradation. The beginner should use 
 but one size of diaphragm during anyone exposure 
 until he becomes familiar with the effects produced 
 by the different sizes of the apertures. 
 
 The intensification of the negative increases 
 the size of the dots, so that a properly exposed 
 negative need not usually have the stipple in the 
 whites quite closed before intensifying - , as that 
 opeiation will close them up unless too much sepa- 
 rated, and leave a strong - open space. In some 
 cases, however, a slight union of the dots will 
 not cause the clear spaces to be too small after 
 intensifying - . A little experience will enable the 
 size of the dots to be properly judged. A small 
 magnifying - glass is of service in examining the 
 negative. 
 
 Having obtained a negative in which the grada- 
 tion appears to be correct, it must be intensified, 
 the process being the same as described for line 
 negatives. If the copper and silver process is used 
 the ammonium sulphide need not be applied, as the 
 two solutions alone will be sufficient for a properly 
 exposed negative. One "dip" may close the stipple 
 sufficiently, or it may require two, and at times 
 three. Washing should, of course, be thorough 
 after each operation. For properly made half-tone 
 
MANUAL OF PHOTO-ENGRAVING. 61 
 
 negatives no such clearing- process as described for 
 line negatives is necessary. After intensification, 
 the negative is dried and prepared for printing 
 from. An intelligent application of the principles 
 stated in the preceding paragraphs will enable the 
 operator to produce negatives of good quality. 
 
62 MANUAL OF PHOTO-ENGRAVING. 
 
 CHAPTER VII. 
 
 NEGATIVE MAKING — CAUSES OF DE- 
 FECTS IN COLLODION NEGATIVES — 
 CARE OF SILVER BATH. 
 
 THERE are various defects which are liable to 
 occur in the making - of collodion negatives, 
 which may be due to faults in the chemicals, or lack 
 of care in manipulation. The following" are the 
 most common : 
 
 Fog - , by which is meant a filling up, or deposit, 
 in those portions of the image which should remain 
 clear. It may be caused by : 
 
 Actinic light entering camera, plateholder or 
 darkroom, and striking the sensitive plate. 
 
 Insufficient acid in developer or in bath. 
 
 An unripened collodion. 
 
 Over-exposure. 
 
 Over-development. 
 
 Developer too strong or too warm. 
 
 Fumes of chemicals. 
 
 Transparent spots in the film may be caused 
 by: 
 
 Dust in the collodion, in the bath, or on the 
 plate. 
 
 Excess of iodides in the bath. 
 
MANUAL OF PHOTO-ENGRAVING. 63 
 
 Undissolved salts in the collodion. 
 
 Streaks in the film may be due to : 
 
 Improper flowing of the collodion. 
 
 Scum on surface of bath. 
 
 Bubbles or specks of dust floating- in collodion. 
 
 Removing plate from bath too soon. 
 
 Alcohol in the bath, in which case the streaks 
 will be rather broad and wavy, and run in the direc- 
 tion of the dip. 
 
 Developer containing insufficient alcohol. 
 
 Developer striking film with too much force. 
 
 Developer too strong. 
 
 Collodion too thick, or over-iodized. 
 
 Dirty plates. 
 
 Dirty plateholder, which will sometimes cause 
 blotches like "oyster shells." 
 =— Thin images may be caused by : 
 
 A weak or insufficiently iodized bath. 
 
 Under-exposure. 
 
 Poor lighting of copy. 
 
 Blurred images may be caused by : 
 
 Improper focusing. 
 
 Camera being jarred during exposure. 
 
 Uneven density of film may be caused by : 
 
 Uneven lighting of copy. 
 
 Uneven coating of collodion. 
 
 CARE OF THE SILVER BATH. 
 
 To obtain uniformly good negatives requires 
 that the silver bath be kept in proper condition. 
 Every well-regulated establishment has several 
 
•34 MANUAL OF PHOTO-ENGRAVING. 
 
 baths, so that when one needs rectifying- another 
 can be used without causing - delay. The following 
 rules will, if followed, keep the bath in proper 
 order : 
 
 1. Keep it covered. 
 
 2. Isolate it from other chemicals. 
 
 3. Keep the hands clean while dipping plates or 
 handling the bath. 
 
 4. Skim the top every morning with a strip of 
 clean paper. 
 
 5. Filter often through absorbent cotton. 
 
 6. Keep the strength up. It does not waste 
 silver to do so. Some clean saturated solution 
 can be added to the bath occasionally when it is 
 in use. 
 
 7. When the bath becomes charged with alcohol 
 boil it down. By putting some water in the vessel 
 in which it is boiled, and pouring the bath into it, 
 some of the iodide will be precipitated, and aid in 
 keeping the bath from becoming over-iodized. Then 
 place over heat and let it steam until the odor of 
 alcohol is entirely gone. It is generally best to let 
 it boil down to a small volume. Then test with the 
 hydrometer, and if necessary add clean water to 
 make it register 50. Then filter well, and it is 
 ready for use again. If it fails to work clear, add 
 a few drops of nitric acid C. P. 
 
 8. To remove organic impurities add to the bath 
 enough permanganate of potassium solution to turn 
 pink, and place in a clean bottle in the sun for sev- 
 eral hours, and filter. 
 
 9. Matter in suspension can usually be removed 
 
HALF-TONE — 35-LINE SCREEN. 
 
MANUAL OF PHOTO-ENGRAVING. 65 
 
 by neutralizing- the bath with bicarbonate of soda, 
 and sunning - . Filter and acidify ag-ain.' 
 
 10. If the bath becomes over-iodized, pour it 
 into some clean water to precipitate the iodide, 
 filter, and boil down to required streng-th. If the 
 bath is evaporated at proper intervals, and the 
 iodide removed as directed in paragraph 7, it will 
 not become over-iodized. 
 
6Q MANUAL OF PHOTOENGRAVING. 
 
 CHAPTER VIII. 
 
 REVERSING NEGATIVES. 
 
 In order that the proof from the etching - may 
 appear unreversed as regards right and left, it is 
 necessary to reverse the negative before obtaining 
 the print from it. There are four methods by 
 which this may be done, as follows : 
 
 1. The sensitive plate may be so placed in the 
 holder that the glass side will be turned toward the 
 copy, allowance being made in focusing - for the 
 thickness of the glass. The springs of the plate- 
 holder must be specially arranged to hold the plate 
 when this method is used. 
 
 2. The image may be taken from the reflection 
 of the copy in a mirror, or what amounts to the 
 same thing. 
 
 3. By having - a glass prism with silvered hy- 
 pothenuse arrang-ed to fasten to the front of the 
 lens, the rays of light being - reflected from it 
 through the lens and onto the sensitive plate. A 
 modification of this arrangement has the prism as 
 a fixed part of the lens. 
 
 4. By stripping the film from the glass support 
 and placing in a reversed position. The two 
 methods last mentioned are those usually employed. 
 
MANUAL OF PHOTO-ENGRAVING. 67 
 
 The construction of the prism suggests its method 
 of use. 
 
 For turning- the collodion film it must be coated 
 with the following- solutions : 
 
 RUBBER SOLUTION. 
 Rubber cement. 
 Benzine, naphtha, or benzole. 
 
 Add sufficient of the solvent to the cement to 
 make a thin solution. 
 
 PLAIN COLLODION. 
 
 Alcohol . 6 ounces 
 
 Ether 6 ounces 
 
 Gun cotton 120 grains 
 
 Castor oil 1% to 2 drams 
 
 When the film of the negative is dry and cold, 
 flow over it the rubber solution, and place in the 
 negative rack until dry. AVhen the rubber is dry, 
 flow the collodion over the film, and also let dry. 
 The collodion may be set fire to while it is wet 
 and burned off, if desired, but this sometimes 
 causes a blistering of the film. After the collo- 
 dion is dry, cut the film to the desired size around 
 the image. If the cut is to be rectangular, the 
 negative should be placed on a board or table with 
 a straight edge, and a T-square and triangle be 
 used in cutting the lines. If the board has two 
 edges at right angles to each other, the T-square 
 alone will answer the purpose. After the film is 
 cut let the negative rest in a tray of water until the 
 film is loosened, then lift one corner with a knife 
 until it mav be taken between the thumb and finger 
 
68 MANUAL OF PHOTO-ENGRAVING. 
 
 of one hand, raise from the glass, take hold of the 
 adjacent corner also, and strip from glass and lay 
 the film in reverse upon a second sheet of clean 
 glass wet with water. Then lay upon the film a 
 sheet of wet paper, and rub the squeegee over it 
 in various directions to remove all of the water. 
 After this is done, hold face down over the gas 
 stove until the paper begins to dry, then remove it 
 and heat the film, to thoroughly dry it, and place in 
 rack to cool. 
 
 If the film refuses to strip from the glass after 
 soaking in the water, or if an albumen substratum 
 has been used under the original collodion film, 
 place the plate to soak in a solution of acetic acid. 
 Curling of the film after transfer is sometimes 
 caused by insufficient oil in the collodion. Should 
 the film fail to adhere to the glass after stripping, 
 flow under it a thin gum-arabic solution, squeegee 
 and dry as usual. Flowing the collodion or rubber 
 over the plate while warm will cause bubbling. 
 The collodion will at times bubble also on a cold 
 plate. This may be remedied usually by flowing 
 some ether over it when it has just set. It is cus- 
 tomary in engraving establishments to turn several 
 negatives upon one sheet of glass and print all 
 together on the same sheet of metal. Negatives 
 made with the prism will require varnishing before 
 being used to print from. 
 
MANUAL OF PHOTO-ENGRAVING. 69 
 
 CHAPTER IX. 
 
 ETCHING — LINE WORK. 
 
 CERTAIN organic solutions or mixtures con- 
 taining- a bichromate will, when reduced to a 
 dry state, be so affected by actinic light as to become 
 insoluble. Upon this principle depends the opera- 
 tions for making etched plates as described here- 
 after. If a metal plate is coated with such a 
 solution, the solution being allowed to dry in a film 
 upon the plate, and then exposed to light under a 
 negative, the light will pass through the clear por- 
 tions of the negative and render the coating under 
 those portions insoluble, the other portions of the 
 coating remaining soluble, as they are protected 
 by the opaque parts of the negative. These solu- 
 ble parts can then be removed, leaving the metal 
 bare between the lines of the image formed by the 
 parts of the coating affected by light. The image 
 being, by certain operations, rendered impermeable, 
 a solution can be applied to the plate which will 
 etch the metal away around these lines, and thus 
 leave the image in relief. 
 
 PREPARATION OF THE METAL. 
 
 The metals commonly used for the purpose of 
 making these plates are copper and zinc, the latter 
 
70 MANUAL OF PHOTO-ENGRAVING. 
 
 being - used universally for commercial work in line 
 etching - , while the former is used principally in 
 making half-tone plates. The metal may be pol- 
 ished by machine or by hand, the latter method 
 being used in most establishments of moderate size. 
 To polish the metal by hand a board should be fitted 
 in an inclined position in the sink so that water 
 from the tap can run upon it when desired, a couple 
 of nails being driven at the lower portion to hold 
 the metal in position when lying upon the board. 
 
 If the metal is obtained polished from the deal- 
 ers, it will be necessary to use the charcoal only to 
 prepare the surface for coating. If it is unpolished 
 it should first be rubbed with pumice stone or 
 Scotch hone until the roughness is removed, and 
 then finished with the charcoal. If the pumice 
 stone is used, its polishing surface should first be 
 ground flat and smooth, otherwise it will scratch 
 the metal. While being polished the metal should 
 be kept wet from the tap, being rubbed in one 
 direction only with the pumice stone or hone and 
 in the transverse direction with the charcoal, 
 the end of the charcoal being used. If any flaws 
 are detected in the surface of the metal they must 
 be removed by punching from the back as described 
 below. Place a pair of calipers so that one point 
 shall be directly over the flaw, the other being 
 directly under it. Press the latter against the back 
 of the plate so as to leave a scratch, the end of 
 which will indicate the location of the flaw. Then 
 turn the plate face down upon a polished iron slab, 
 place the end of a punch over the flaw as indicated 
 
VIGNETTED HALF-TONE FROM WASH DRAWING. 
 Drawn by J. C. Leyendecker. 
 
 By courtesy E. A. Weeks & Co., Chicago. 
 
MANUAL OF PHOTO-ENGRAVING. 71 
 
 and strike the other end of the punch with the 
 hammer, which will bring- the flaw up to the sur- 
 face. Then polish again until the surface of the 
 plate is free from scratches and pits. The condi- 
 tion of the finished surface will depend largely upon 
 the charcoal. Some charcoal is gritty and leaves 
 scratches which, if deep enough, would show in the 
 etching. Such grittiness can often be removed by 
 soaking the charcoal in water or the jar of dilute 
 acid. 
 
 LINE ETCHING. 
 
 SENSITIZING SOLUTION. 
 
 Albumen from fresh egg 1 ounce 
 
 Water 8 ounces 
 
 Bichromate of ammonium 15 to 20 grains. 
 
 Dissolve the bichromate in the water, add to the 
 albumen and beat up well with the egg-beater in a 
 bowl or mortar. Filter until clean. Some etchers 
 add a few drops of ammonia to the solution. 
 
 COATING THE PLATE. 
 
 Having polished the plate, file the roughness 
 from the edges, wash it, let some water remain on 
 the surface, and carry it to the room used for coat- 
 ing and drain the water off. Then pour some of 
 the sensitizing solution to cover the plate and drain 
 it off at one corner, repeating two or three times, 
 draining at different corners to equalize the coat- 
 ing. Specks of dirt or bubbles should be removed. 
 
 Then hold the plate over the gas stove and 
 warm until dry, keeping it slightly inclined to allow 
 7 
 
72 MANUAL OF PHOTO-ENGRAVING. 
 
 any surplus fluid to drain. A little practice will 
 enable an even coating- to be obtained. When the 
 plate is dry, allow it to cool in the dark and it is 
 then ready for printing - . 
 
 PRINTING. 
 
 See that the heavy glass which is used for the 
 bed plate in the printing frame is clean, and also 
 the back of the negative. Any grit between the 
 two will sometimes cause them to crack when the 
 pressure is brought to bear. Also see that there 
 is no grit in the rabbet of the frame. Then place 
 the negative, film side up, upon the bed plate, and 
 carefully place the coated plate face down upon it. 
 Place the back of the frame upon the metal (usually 
 with a pad of felt or some folded papers between), 
 lay the bars across and fasten at the ends, and 
 turn the screws until sufficient pressure is obtained 
 to make contact between the plate and negative. 
 Then place the plate in the light to print. If in 
 sunlight, support the frame so that the rays will 
 strike directly upon the face. If the electric light 
 is used, give half of the exposure while the frame 
 rests upon its side, then turn it to rest upon the 
 opposite side, and give the balance of the exposure. 
 If the negative is a large one, keep the light swing- 
 ing, to equally illuminate the whole surface. Do 
 not allow the printing frame glass to become too 
 hot, or it will crack. The exposure time will ,T ary 
 from one to three minutes in the sunlight and from 
 three to ten minutes in the electric light. It will 
 require but little experience to judge of it properly. 
 
MANUAL OF PHOTO-ENGRAVING. <•> 
 
 ROLLING UP AND DEVELOPING. 
 
 After the plate has been sufficiently printed it 
 must be rolled up with transfer ink to obtain the 
 image. Upon the slab provided for the purpose, 
 place a little of the ink, and with a knife spread it 
 in a line across one end ; then with the composition 
 roller distribute it in an even coating - over the slab. 
 (Lifting- the roller from the slab while rolling will 
 aid in obtaining an even coating.) If any particles 
 of hardened ink or other matter cling to the roller, 
 remove them with turpentine and a rag. When the 
 roller has an even coating of the ink on it, roll it 
 over the face of the zinc until it also is evenly 
 coated. The ink on the zinc should not be too 
 thick ; the metal should appear faintly through it. 
 If the ink should be too thick on the metal, clean 
 the roller with turpentine, and when dry roll it 
 over the zinc and it will remove a good deal of the 
 ink. The ink coating should be heavy enough, of 
 course, to absorb enough dragon's blood and form 
 sufficient resist to the acid when burned in. 
 
 In cold weather the ink will sometimes refuse to 
 distribute properly under the roller. In such a 
 case wet it with a few drops of turpentine, or warm 
 the slab, and this difficulty will be removed. The 
 roller should be kept free from dirt, and in starting 
 work for the day the slab and roller should be 
 cleaned with turpentine and fresh ink used. A 
 little experience will enable the worker to judge 
 when the plate is properly rolled up. When the 
 proper coating of ink is obtained upon the metal, 
 
<4 MANUAL OF PHOTO-ENGRAVING. 
 
 place the plate in a tray of clean water (or hold it 
 under the tap) and rub the surface carefully with a 
 tuft of wet absorbent cotton. The parts of the 
 coating - which were not affected by the light will 
 rub away, leaving - the image in black lines. If the 
 exposure has been properly timed, the lines will all 
 remain unbroken upon a clean ground of metal. If 
 the plate was under-exposed, many of the lines will 
 rub away, and if over-exposed the ink will cling to 
 parts from which it should separate. In such a 
 case a few drops of ammonia added to the water in 
 the tray will often enable it to be removed. Rub 
 the image with the cotton until all of the lines are 
 clean and sharp, being careful to see that the spaces 
 are free from any adhering ink. Then dry the 
 plate by draining and warming over the gas stove. 
 By patting it before warming with a piece of damp 
 chamois skin, rolled into a pad, the surplus water is 
 readily removed. 
 
 READY FOR ETCHING. 
 
 AFTER ROUTING. 
 
 With a camel's -hair brush paint in with the 
 transfer ink, wet with turpentine, any parts of the 
 
MANUAL OF PHOTO-ENGRAVING. 75 
 
 lines which may be broken, and also the largest 
 open spaces as shown in the cut, one being - the 
 appearance of the plate when thus painted in, and 
 the other the appearance after routing- and finish- 
 ing. 
 
 The painting in of these spaces supports the 
 roller and prevents smudging in the subsequent 
 rolling. 
 
 POWDERING AND ETCHING. 
 
 After the plate has been thus painted, it is ready 
 for powdering. Have some dragon's blood in the 
 powder box, and dump it upon the surface of the 
 plate, and then brush off the surplus with a broad 
 soft brush, finishing with a tuft of dry cotton until 
 the metal spaces are clean. The dragon's blood 
 will adhere to the ink. The plate is now held over 
 the gas stove and heated until the powder incorpo- 
 rates with the ink, as shown by its turning a rather 
 glossy black. There are two grades of dragon's 
 blood, one a dark red color, the other lighter in 
 color. The latter will burn in more readily than 
 the other, and form a strong resist. After the 
 plate is thus heated paint the back with asphalt 
 varnish, cool, and the image being now able to 
 resist the acid, the plate is ready for the first bite. 
 
 The acid used for this bite should not be very 
 strong. The proportions are not arbitrary. The 
 beginner, however, may take about two and one- 
 half parts of the commercial nitric acid to thirtv- 
 two parts of water, for the first etch. Place this 
 in the etching tub and immerse the plate in it. 
 
7G 
 
 MANUAL OF PHOTO-ENGRAVING. 
 
 Then rock the tub, and as the action of the acid 
 proceeds, keep the plate clean by brushing - with the 
 bristle brush used for the purpose. This bite need 
 not be deep. Three to five minutes will be suffi- 
 cient, when the metal will be found so etched away 
 as to leave a line in slight relief. Then remove the 
 plate from the acid, rinse, dry off the surplus 
 water with a towel or the damp chamois, and warm 
 over the stove. Before continuing the etching- the 
 sides of the lines must be protected to prevent the 
 acid attacking them and causing breaks. This is 
 usually done by "powdering four ways," as fol- 
 lows : Take the plate to the powder box, and dump 
 some of the dragon's blood on it, then beginning at 
 one edg*e of the plate pass the brush over it from 
 that side to the side opposite, so that the powder 
 will be brushed against the sides of the lines. 
 
 <r 
 
 v 
 
 A 
 
 For instance, in above diagram, if the brush is 
 started at the side D, brush in direction indicated 
 by the arrow A toward side B. Hold the brush 
 
ZINC ETCHING — CRAYON EFFECT. 
 From sketch by Frank Holme. 
 
MANUAL OF PHOTO-ENGRAVING. '» < 
 
 upright, and brush in even sweeps without lifting- 
 from one extreme edge to the other. When the 
 spaces between the lines are clean, and the lines all 
 "covered," heat the plate again to cause the pow- 
 der to adhere to the lines, and, when cool, powder 
 in a similar manner in the direction of arrow B, 
 moving the brush from A to C, and heat again. 
 Repeat the powdering in the remaining two direc- 
 tions, heating after each, and if properly done the 
 powder will adhere so as to protect the lines on all 
 sides. 
 
 When cool, the plate is ready for the second 
 bite. The etching is proceeded with the same as at 
 first, the time being increased somewhat, and when 
 it has been carried far enough the plate is again 
 rinsed, dried and powdered as before, and placed in 
 the bath to etch again, the strength of bath and 
 time being increased. When the action has again 
 proceeded sufficiently, it is removed from the acid 
 and prepared for the fourth bite. This may be 
 done by simply powdering again as for the other 
 bites, but it is customary with many etchers to roll 
 the plate up again to form a thick coating of ink 
 over the tops of the lines before powdering for the 
 fourth bite, so that the ink will run down the sides 
 of the lines during the heating and form a more 
 impermeable coating. This rolling up is best done 
 with the leather-covered roller. After this rolling 
 up the plate is powdered again and given the fourth 
 bite. The four bites will, as a rule, be all that are 
 necessary for the ordinary work, and the plate can 
 be cleaned, routed and mounted. 
 
78 MANUAL OF PHOTO-ENGRAVING. 
 
 A "clean bite" may, however, be given to 
 remove the "shoulder" from the lines. During 
 the operation of powdering- and etching, the lines 
 are not always etched straight down, but are 
 formed in steps which, if prominent, will print up 
 and make a broad line in the resulting proof. To 
 remove this "shoulder " to a certain extent the ink 
 and powder are first removed from the plate after 
 heating and flowing with lye or alcohol, using a stiff 
 scrubbing brush. A coating of ink is then rolled 
 over the top of the lines and powdered and heated 
 so that while the top will be protected the sides 
 will remain bare. The plate is then placed in a 
 weak solution of acid and etched for a few moments, 
 the effect being to etch away some of the shoulder 
 and give a sharper line. This must be done with 
 great care. After cleaning, the plate is ready for 
 the finisher. 
 
 The strength of acid and time of etching for 
 each bite cannot be stated arbitrarily. They 
 depend largely upon the character of the etching, 
 some lines not being able to stand the action as 
 long as others, and it requires some experience to 
 judge when the biting has proceeded far enough, 
 the object being to allow the acid to act as far as 
 possible without undercutting or breaking the lines. 
 The experienced etcher does not, as a rule, measure 
 his acid, and judges by appearance of the lines 
 when the operation must cease. The beginner, 
 however, may commence by using the following 
 proportions for the solution and times for biting : 
 
MANUAL OF PHOTO-ENGRAVING. 79 
 
 First bite — 2)4 parts acid to 32 parts water. 
 
 Etch two to three minutes. 
 Second bite • — 2**2 parts acid to 32 parts water. 
 
 Etch five to six minutes. 
 Third bite — 3^2 parts acid to 32 parts water. 
 
 Etch eight to ten minutes. 
 Fourth bite — • 5 to 8 parts acid to 32 parts water. 
 
 Etch ten to twelve minutes. 
 
 The beginner should start with subjects having 
 strong lines, and should carefully watch the action 
 until he has acquired such experience that he can 
 etch without timing the bites. For regular work 
 four bites is usually sufficient, but some plates may 
 be given five and others will require only three, 
 the latter being the case when the lines are close 
 together. In many establishments the clean bite is 
 omitted, care being taken to powder the plate clean 
 so that no excess of powder will cling to the lines 
 and form a large shoulder. For a clean, deep job 
 the plate may have the spaces routed before the 
 last bite. 
 
 In powdering the plate, the brushing need not 
 be confined to only the four directions. Some etch- 
 ers apply it in various ways until the lines are suf- 
 ficiently protected. No powder should be allowed 
 to remain on the open spaces, and to prevent ex- 
 cessive shoulder no more than enough to protect 
 the lines should be left adhering to them. How- 
 ever, where an extra strong bite is to be given it is 
 sometimes well to powder twice around the plate. 
 After the second or third bite the small spaces will 
 
80 MANUAL OF PHOTO-ENGRAVING. 
 
 fill with the powder, but the lines being- close 
 tog-ether, great depth is not required as in the 
 wider spaces. Should any of the powder adhere 
 to the open spaces, causing- roug-hness, a knife or 
 scraper can be used to clean them. After the fin- 
 ishing- etch has been given, the coating- should be 
 removed from the plate by scrubbing with lye, and 
 the plate delivered to the router. Alcohol will also 
 remove the coating-, but is more expensive than lye. 
 
VIGNETTED HALF-TONE — i 33-LINE SCREEN. 
 From wash drawing by J. C. Leyendecker. 
 
 By courtesy Northern Trust Company, Chicago. 
 
MANUAL OF PHOTO-ENGRAVING. 81 
 
 CHAPTER X. 
 ETCHING — HALF-TONE WORK. 
 
 THE ENAMEL PROCESS. 
 
 SENSITIZING SOLUTION. . 
 
 A. — Albumen from fresh eggs 5 ounces ^-- 2. 
 
 Water 2 ounces / 
 
 B. — Bichromate ammonia 140 grains 
 
 Water 2 ounces — / 
 
 Ammonia a few drops - — 
 
 C. — Le Page's liquid glue 5 ounces 
 
 Water 3 to 4 ounces. / -^_ — ■2- 
 
 Beat up the eggs with the water, then add the 
 solutions B and C, and mix all together thoroughly. 
 The solution must then be filtered several times 
 through sponge or absorbent cotton until free from 
 specks and bubbles. Make also a solution of eosine 
 (red shade) by dissolving some of the powder in 
 hot water and keep in a tray for use. 
 
 MANIPULATIONS. 
 
 Have the copper polished and the surface hold- 
 ing a film of water, take it to the darkroom, drain 
 off the water and flow the plate with some of the 
 enamel solution, draining the surplus off at one 
 corner, then flow once or twice again and drain, 
 removing any specks or bubbles with a small 
 brush or stick. Having the solution clean on the 
 plate, put it in the whirler face down, having one 
 
82 MANUAL OF PHOTO-ENGRAVING. 
 
 corner in the opening- in one of the clamps and the 
 opposite corner in the opening- of the other, the 
 clamps being so placed that the plate will be cen- 
 tered. Then turn the hand wheel of the drill so 
 that the plate will be given a rapid whirling motion 
 which will spread the solution evenly over the sur- 
 face. The gas stove under the whirler should be 
 burning so as to warm the plate and dry the coat- 
 ing. The plate need not be heated excessively. 
 Enough to dry it will be sufficient. If it is not 
 convenient to have a stove under the whirler, the 
 plate may be whirled cold until the solution is 
 partially dried, and then removed from the whirler 
 and heated to dry. 
 
 If the coating upon examination now appears 
 clean upon the plate, let the plate remain in the 
 dark until cold, and then expose under a half-tone 
 negative as directed for exposing line plates. 
 When it is considered as sufficiently printed, re- 
 move it from the frame, place in the solution of 
 eosine for a moment, then wash under the tap. 
 The image will appear of a brilliant red color, and 
 should be washed until the details are all clear. 
 The eosine solution is simply to color the image to 
 render it clearly visible during development. Some 
 etchers omit it, but its use enables the development 
 of the details to be more readily watched. If the 
 plate has been properly exposed the dots and lines 
 of the image will correspond with the clear spaces 
 in the negative, and if the negative is one of good 
 quality, the details will be open and the high lights 
 will be clear with dots strong" enough to allow the 
 
MANUAL OF PHOTO-ENGRAVING. 83 
 
 proper depth of etch. These dots should be 
 square and may be separate from each other, or 
 just touching- at the corners, but the union should 
 not be so strong- as to prevent the separation of 
 the dots in etching, for the best effects are obtained 
 when the high lights are composed of separate 
 stipple. If formed of lines the proofs will be too 
 dark. If the print has been over-exposed, the 
 details will be filled and the dots in the whites will 
 probably run into heavy lines. If under-exposed, 
 the dots in the whites will be too small to stand the 
 etching, and some will perhaps be washed away in 
 developing, while the image will be weak. When a"" 
 properly exposed print has been obtained and 
 developed it should be flowed several times, after 
 being taken from the tap, with grain or wood 
 alcohol to remove the water, and then dried spon- 
 taneously, or the alcohol may be ignited and 
 burned off. 
 
 The print must then be burned in, which is 
 done by holding the plate by means of a pair of 
 pincers over a strong, steady heat, until the coat- 
 ing becomes of a chocolate brown or black color. 
 Then let cool and rub with a dilute solution of 
 chromic acid, which will clean the copper and 
 enable any spots to be readily detected. The plate 
 must now be spotted, that is, any stipple which is 
 missing must be replaced by some substance which 
 resists the etching fluid. Either asphalt or the 
 transfer ink may be used for this purpose. A 
 small camel's-hair brush should be obtained, and 
 some of the asphalt being placed upon it, the brush 
 8 
 
84 MANUAL OF PHOTO-ENGRAVING. 
 
 is drawn to a point and touched to the spots from 
 which the stipple is missing, and also any portions 
 of the image which it is desired shall appear solid 
 black are painted in. If the ink is used, the plate 
 is powdered with dragon's blood, which is brushed 
 off with cotton, the plate then heated enough to 
 burn in the powder adhering to the spots of ink. 
 The back is then painted with asphalt varnish, and 
 the plate cooled. It is then ready to etch. 
 
 For the etching fluid prepare a strong solution 
 of perchloride of iron, place it in a tray, immerse 
 the plate in it and brush the face of the plate with 
 the etching brush. The plate can now be allowed 
 to rest in the solution, being brushed occasionally 
 to clean the face from the sediment which results 
 from the chemical action. The tray may, if de- 
 sired, be rocked, but this is not necessary. Exam- 
 ine the plate at intervals, and when the dots in the 
 high lights appear to have had as much etching as 
 they will stand, brush the plate and wash immedi- 
 ately under the tap. If upon further examination 
 the dots appear large enough to stand more, 
 return the plate to the solution and continue the 
 etching. When finally the action has proceeded 
 far enough, rinse the plate, clean with solution of 
 chromic acid, rinse again, clean the asphalt from 
 the back with turpentine, dry and prove. 
 
 ETCHING VIGNETTES. 
 
 Very pretty effects can often be obtained by 
 etching a vignette or blended border around the 
 image. The plate is first etched in the ordinary 
 
^Ffagf 
 
 ZINC ETCHING. 
 From pencil and pen drawing - by Farny. 
 
 Copyrighted. 
 
 By courtesy The Ault & Wiborg Co., Cincinnati, Ohio. 
 
MANUAL OF PHOTO-ENGRAVING. 85 
 
 manner, and given a bite deep enough for printing-. 
 It is then dried and the face painted in solid with 
 the asphalt or transfer ink, the edge of the paint 
 not being carried to the edge of the plate, so that a 
 ground of stipple is left around the painted por- 
 tion. The plate is then returned to the etching 
 solution and etched a few moments to reduce the 
 stipple in size. It is then rinsed and dried and 
 painted again, the paint this time being extended a 
 little further. Another bite is then given to reduce 
 the size of the remaining stipple, and the opera- 
 tions are repeated. When the desired number of 
 tints are obtained, the plate is finally etched until 
 the remaining border of stipple is broken away. 
 The face is then cleaned with turpentine or alcohol 
 as the case may require, and the edge routed and 
 trimmed with the hand tool. The edges of the 
 paint should be wavy and may require a little artis- 
 tic taste to produce the desired effect. A proof 
 from such a plate will have a border formed of a 
 gradation of tints, blending from dark to light. It 
 requires some practice to obtain an artistic effect, 
 as the edges of the tints must not be too pro- 
 nounced. Three or four and even as many as five 
 tints may be obtained by skillful etching. 
 
 The "Full Tone" or "High Light" process by 
 which plates are produced with certain parts of the 
 ground free from stipple is done by simply painting 
 in the plate, leaving those parts unprotected, then 
 etching until the stipple breaks away. The parts 
 are then deepened, and finished with the tool. In 
 printing, to bring up any portion of the plate 
 
86 MANUAL OF PHOTO-ENGRAVING. 
 
 heavy, shade the other portions after they have 
 been exposed sufficiently, and allow the light to act 
 longer upon that part. 
 
 In etching - , avoid excessive brushing". Use the 
 brush only occasionally to clean the plate, unless it 
 is desired to etch out some part especially light. 
 To obtain a better idea of the actual depth of the 
 etching than can be determined by the appearance 
 of a stipple, scratch off with a knife some of the 
 enamel on the margin of the plate. The scratch 
 will etch down and the depth can be felt with the 
 
 X finger nail. The proportions given for makings v 
 the enamel solution are not arbitrary. Different 
 amounts of the constituents can be used if desired. 
 An excess of glue will cause a tendency to fill in 
 the print, while a solution which is too thin will 
 peel from the plate in etching. 
 
 Half-tone etching may also be done by the albu- 
 men process, using the same solution as for line 
 work which is generally used for half-tones on 
 soft zinc which will not stand the heat in burning 
 in the enamel solution. 
 
MANUAL OF PHOTO-ENGRAVING. 87 
 
 CHAPTER XI. 
 
 FINISHING AND MOUNTING PLATES. 
 
 A FTER the etching- of the line plate is finished it 
 /\ is tacked to a board and placed in the routing- 
 machine, and all the larger open spaces deepened 
 with the routing tool. If several negatives have 
 been printed on one sheet of zinc, each image is cut 
 out, a thin border of zinc being left around it. The 
 cut is then fastened to a block by tacks driven 
 through the routed spaces and around the edge, 
 and the block planed type-high. Any burr remain- 
 ing on the lines is then removed with a hand tool, 
 and the plate is ready for proving. 
 
 In mounting a half-tone cut, a beveled edge may 
 be formed around the cut with the routing or bevel- 
 ing machines, and the plate fastened to the block 
 by tacks driven through this edge. Another 
 method is to mount the plate from the back as 
 follows : Saw the margin of metal from around 
 the image, leaving enough" for a black line (if the 
 line is wanted), and bevel the edge with a file, 
 removing the burr from both sides. Clean the 
 back of the plate and scrape the surface bright in 
 several places, leaving several deep scratches in the 
 places thus brightened, then upon each place drop 
 some hydrochloric acid, and lay a thin piece of 
 
88 MANUAL OF PHOTO-ENGRAVING. 
 
 solder upon it. Upon the solder set a small screw 
 and direct the flame of a blowpipe upon the solder 
 until it melts and forms around the head of the 
 screw, holding- the screw in position by any conven- 
 ient tool. The solder should not be too large or it 
 will form too larg-e a mass when melted. Having 
 thus soldered screws to the several points, which 
 should be evenly distributed over the plate, set the 
 plate screws down upon the wood block, length of 
 the plate with the grain of the wood, lay another 
 block upon the face of the plate and strike it with 
 the hammer, so that the screw will leave marks 
 upon the face of the first block. Then with a one- 
 fourth inch drill, drill holes through the block at 
 these points, after which insert a countersink drill 
 in the chuck and with it drill from each side of the 
 block into the holes made by the one-fourth drill, 
 letting the countersink go below the surface of the 
 block on each side. Sandpaper the face of the 
 block and place the plate on it so that the screws 
 will sink into the corresponding holes, allowing the 
 plate to rest flat upon the surface of the block. 
 Then protecting the face of the plate with another 
 block clamp it tight, and with a small ladle pour 
 melted type metal into the holes on the opposite 
 side, not allowing it to come to the surface of the 
 block. When it is cool the plate will be firmly 
 fastened to the block. 
 
 Saw the block around the metal, leaving a small 
 margin of wood and then it is ready to trim. Place 
 the block on the trimmer, having the gauge set so 
 that the knives will just catch one edge, and pass 
 

 HALF-TONE — 150-LINE SCREEN. 
 
MANUAL OF PHOTO-ENGRAVING. 89 
 
 the table back and forth, giving the gauge screw a 
 slight turn each time until the wood is trimmed up 
 to the metal. If the plate is so placed that the 
 wood will not trim parallel to the edge of the plate, 
 place a piece of folded paper between the block 
 and gauge to cause the part at which the wood 
 is thickest to be moved farther toward the knives. 
 Trim each edge, running the block through slowly 
 when making the last cuts, and then make it type- 
 high in the planer. If the type metal should be 
 found to come to the surface of the block it should 
 be routed down. In mounting line and half-tone 
 cuts together, if the plates are not of the same 
 thickness the thinner ones must be underlaid to 
 bring their surfaces to the level of the thickest 
 plate. Cherry wood is usually used for blocking 
 plates, metal blocks being used for those from 
 which stereotypes are to be made, such as line 
 plates for newspaper work. 
 
 The first proofs from half-tone plates will often 
 show black spots. In such a case the plate is given 
 to the engraver who tools them out. The half-tone 
 may often be improved also by having certain parts 
 burnished to make those parts in the proof appear 
 darker. For fine magazine work it has become 
 customary to use the tool very extensively upon 
 half-tone plates, many of them being given the 
 appearance of fine wood engravings. The tool is 
 also often used to vignette portraits and to clear 
 away the stipple in places where it is desired to 
 have clear whites in the proof. 
 
90 MANUAL OF PHOTO-ENGRAVING. 
 
 CHAPTER XII. 
 
 DRAWINGS — PHOTO-LITHOGRAVURE. 
 
 THE line drawing's for reproduction should be 
 made with black ink and the lines should all 
 be sharp and bold. Gray and fine lines are ex- 
 tremely difficult to reproduce, especially if the 
 reduction is great. To make drawings rapidly and 
 accurately, a common "wrinkle" is to draw the 
 lines over a silver print, the photographic image 
 being afterwards bleached out, leaving the draw- 
 ing alone on the paper. 
 
 The method is as follows : Obtain some plain 
 salted paper and sensitize it by brushing over the 
 surface a tuft of absorbent cotton wet with a solu- 
 tion of silver nitrate. Dry in the dark and expose 
 under an ordinary negative made from the copy 
 to be reproduced until the image shows a dark red 
 or purple. Wash, then place in a dilute solution 
 of acetic acid for several minutes until the image 
 is fixed. Wash again, then dry and make the 
 drawing over it with Higgins' waterproof ink. 
 When this is dry, flow over the print a saturated 
 solution of mercuric chloride in alcohol, or in about 
 equal parts of alcohol and water. The red image 
 will be removed, leaving the drawing, after which 
 
MANUAL OF PHOTO-ENGRAVING. 91 
 
 the paper should be rinsed and dried, being - then 
 ready for the photographer. 
 
 Another method to obtain the outlines of the 
 drawing is to make a ferrotype, or "tintype," and 
 over this to place a sheet of thin transparent gela- 
 tine or celluloid, the outlines being scratched in 
 with a point. Powdered graphite or other pigment 
 is then dusted over the gelatine and adheres to the 
 lines. By placing the gelatine over a sheet of 
 paper, line side down, and rubbing it, the lines will 
 be transferred to the paper. The ferrotype is 
 made in the same manner as a wet plate, the sheet 
 of metal being substituted for the glass. 
 
 In drawings for colorwork it is often desired to 
 have the part of the drawing for each color made 
 separate. The whole drawing is first made in the 
 colors as they are to appear in the original, then 
 tissue paper is placed over it and the outlines for 
 one color drawn upon it. The back of the paper is 
 then covered with some pigment (rubbing a blue 
 pencil over it is the easiest way), laid back down on 
 another piece of paper or card, and the lines traced 
 over, thus transferring them. That portion of the 
 drawing is then finished up as desired and the 
 others obtained in a similar manner. "Scratch 
 board " is generally used for making drawings 
 upon, as it has a smooth surface with no grain to 
 appear in the reproduction, and alterations can be 
 made upon it without altering the character of the 
 surface. 
 
92 
 
 MANUAL OF PHOTO-ENGRAVING. 
 
MANUAL OF PHOTO-EXGK AYIXG. 93 
 
 PHOTO-LITHOGRAVURE. 
 
 Bv the term photo-lithogravure, as used here, is 
 meant the reproduction of line drawings containing 
 tints of lines or dots. 
 
 The method largely used for placing- these tints 
 upon the copy is known as the Ben Day process. 
 
 The apparatus consists of a film of gelatine 
 mounted in a frame, the form of the tints being so 
 placed in relief upon it that when rolled up with 
 ink they can be readily transferred to the copy by 
 placing the film above it and pressing upon it with a 
 burnisher or other convenient instrument. Similar 
 results, however, may be obtained by the following 
 method. 
 
 The necessary apparatus is simply several plates 
 ruled to form tints of lines or dots, some examples 
 of which are shown. 
 
 These rulings are made upon plates of stereo- 
 metal mounted on blocks of wood to be type high. 
 We will now consider the application of the method 
 as shown in the example (page 92). First there was 
 drawn the outline of the letters with the curves 
 and scrolls forming- the skeleton of the drawing. 
 
94 MANUAL OF PHOTO-ENGRAVING. 
 
 The tints were then all put in as follows : Take the 
 dotted tint around the numbers 141, 143, 145, which 
 also appears at the upper portion of the plate near 
 the name Marvin. A sheet of smooth tissue paper 
 was tightly stretched over the face of the drawing-, 
 being- pasted around three edges. Then the outline 
 of the tint was drawn with a pencil. After this 
 was done a card was slipped under the tissue and the 
 tissue cut out with a sharp knife on the lines just 
 drawn, the card being then removed, leaving the 
 space on the drawing bare where the tint was to be 
 placed. The drawing was then placed on the bed 
 of a hand press, the tint block rolled up with ink 
 and placed face down upon it. The pressure being 
 then brought to bear leaves the dots on the face of 
 the drawing in the open space, the other parts of 
 the drawing being protected by the tissue. This 
 sheet of tissue being then removed another one is 
 put on, the outlines for another tint drawn and cut 
 out, the tint block being rolled up and the impres- 
 sion being taken as before, leaving another tint on 
 the drawing, and so on for the remaining tints. 
 
 To get the cross-line tints, two impressions are 
 taken from a single-lined plate, the position of the 
 plate for the second impression being at right 
 angles to the first position. In making a shade 
 line around letters where it is desired to have a 
 white space between the letter and the shading, the 
 tint may be allowed to run up to the letter when 
 the impression is made, the white space being 
 scraped out afterwards. When letters which are 
 to appear white are to be protected while the 
 
MANUAL OF PHOTOENGRAVING. 95 
 
 impression is being- made, tissue cut out to fit the 
 letters are pasted on them at two or three points, 
 the paste being- removed afterwards. When the 
 tints are all inserted in the drawings the reproduc- 
 tion is made in the camera as usual. This process 
 gives results similar to those obtained in litho- 
 graphing, and very handsome effects can be 
 obtained by running the tints in colors. 
 
'•Hi MANUAL OF PHOTO-ENGRAVING. 
 
 CHAPTER XIII. 
 
 DEVELOPMENT OF GELATINE DRY 
 PLATES. 
 
 GENERAL PRINCIPLES. 
 
 IN the development of the gelatine dry plates the 
 reduction of silver to form the image is ob- 
 tained by an agent which decomposes the silver 
 salts affected by lig"ht. Combined with this ag-ent 
 several others are usually used, each of which has 
 a special influence in determining- the result. 
 
 Besides the reducing agent we will have, there- 
 fore, the following components in the solution. An 
 alkali, usually sodium carbonate (sal soda). The 
 action of the alkali is to render the film more easily 
 permeable, and to increase the affinity of the 
 reducing agent for oxygen, thus increasing its 
 reductive powers, causing the reduction to take 
 place in the parts least affected by light before 
 great density has been obtained in the high lights. 
 Detail is therefore obtained in the middle tones, 
 producing an image full of gradation, and should 
 the proportion of alkali be too great, the reduction 
 of the silver will be rapid, and take place over the 
 entire surface, causing fog. If there is an excess 
 
ZINC ETCHING — BLACK AND WHITE EFFECT. 
 Drawn b}- John Sloan. 
 
MANUAL OF PHOTOENGRAVING. 97 
 
 of alkali, yet not sufficient to cause fog - , the details 
 will develop too rapidly and be so strong- when the 
 proper density in the high lights has been reached, 
 that the negative will be too flat and wanting in 
 contrast. 
 
 To prevent the reducing agent from absorbing 
 oxygen from the air, a sulphite, usually sodium 
 sulphite, is added to the developer. Having a 
 greater affinity for oxygen than the reducing 
 agent, it takes up the oxygen, thus preventing the 
 decomposition of the reagent, and also preventing 
 stain. 
 
 To prevent the too rapid action of the reagent 
 and to preserve clearness, a restrainer, usually 
 bromide of potassium, is used. The action of the 
 restrainer is more energetic upon the middle tones 
 than upon the high lights, and when by over-ex- 
 posure, or excess of alkali, these portions tend to 
 develop too rapidly, it is used to retard the action 
 until the high lights have gained in intensity, thus 
 obtaining contrast, where desired, and preventing 
 fog from any excess of alkali. 
 
 An excess of the restrainer acts, therefore, like 
 an excess of the reducing agent to produce hard-' 
 ness and contrasts. 
 
 It is evident that we may mix the developer in 
 proportions to promote detail or contrasts, or that 
 we may manipulate it so that one constituent will 
 retard the action of another to any desired extent. 
 There are certain proportions, however, of the 
 constituents entering into the composition which 
 may make what we may term a normal developer, 
 
98 MANUAL OF PHOTO-ENGRAVING. 
 
 that is, a developer which when applied to a prop- 
 erly exposed plate will bring- out the gradations 
 and intensity in proper order, producing- a negative 
 of the best technical quality. 
 
 As stated in a preceding chapter, the time of 
 exposure is a matter of no less importance than the 
 development of the negative, for while with skillful 
 manipulation good results may be obtained from 
 the plate slightly under or over exposed, it is only 
 with correct exposure that the best effects are 
 produced. 
 
 The exposure time of the gelatine plate is much 
 shorter than for the collodion, varying from a small 
 fraction of a second to several seconds (or perhaps 
 under special conditions to an extended time i. 
 
 A correct exposure properly developed will yield 
 a negative having gradations to render the details 
 in the subject, but will preserve the contrasts suffi- 
 ciently to avoid flatness in the resulting print. 
 
 Over-exposure tends to produce negatives full of 
 detail, yielding prints without brilliancy. 
 
 Under-exposure tends to produce negatives with 
 strong contrasts, lacking in detail, the resulting 
 print being hard. 
 
 The treatment for over or under exposed plates 
 will be given below. 
 
 Various reducing agents may be used in the 
 development of gelatine plates, but pyrogallol is 
 considered the standard by the majority of profes- 
 sional photographers. 
 
MANUAL OF PHOTO-ENGRAVING. 99 
 
 PYRO DEVELOPER. 
 
 Prepare stock solutions as follows : 
 
 A. — Sodium sulphite, 40 by actino-h3 r drometer ; and 
 
 B. — Sal soda, 20 b3 r actino-hydrometer. 
 
 C. — Bromide of potassium, 1 part to 9 or 10 parts water. 
 
 For convenience these solutions may be made up 
 in quantities. 
 
 To prepare the developer, take one part ot the 
 sulphite solution A, one part of the alkaline solution 
 B, and two parts of water, then add 2 1 /i grains of 
 pyro for each ounce of the resulting - solution. Then 
 add a few drops of the bromide solution C. 
 
 In cold weather enougri heat may be applied to 
 the water to just remove the chill, but it must not 
 be warm. 
 
 In hot weather increase the proportion of water 
 to 2) 2 or 3 parts, and keep the solution cold by 
 placing - ice in it. 
 
 FIXING BATH (CRAMER). 
 
 A. — Water 1 quart 
 
 Sulphite soda 4 ounces 
 
 Sulphuric acid l / 2 ounce 
 
 Chrome alum 3 ounces 
 
 B.^Water 3 quarts 
 
 Hyposulphite soda 32 ounces 
 
 Dissolve A and B separately and mix. In cold 
 weather use one-half the quantity of A. 
 
 DEVELOPMENT. 
 
 In the development of the plate, the points to be 
 considered are : First, the time in which the imag-e 
 
100 MANUAL OF PHOTO-ENGRAVING. 
 
 appears ; second, the contrasts ; third, the detail ; 
 fourth, the intensity. An intellig-ent judgment of 
 these will enable the operator to determine whether 
 the exposure has been of the proper duration, and 
 conduct the development accordingly. 
 
 Place the plates in a clean tray, which should be 
 kept for this purpose alone, and flow the developer 
 over them in an even wave, using - enough to cover 
 the plates. Then rock the tray to cause the de- 
 veloper to flow from side to side. If the exposure 
 has been properly timed the high lights of the 
 image will appear first, then the gradations in the 
 middle tones, those corresponding to the lighter 
 shades first, being followed by the darker shades, 
 then the details in the shadows. When all the 
 gradations have thus appeared in proper order, 
 the development is continued until the proper 
 intensity is reached, which is determined by the 
 appearance of the plate when held up to the red 
 light. Only experience will enable the intensity 
 to be properly judged. Some papers will require 
 a denser negative than others. 
 
 If the exposure time has been too short, the 
 imag-e will be late in appearing as compared to 
 the normal, and the details in the half-tones and 
 shadows will hang back, and if the development is 
 carried on as for proper exposures the high lights 
 will gain the desired intensity before the details 
 will come out, thus producing a hard negative 
 devoid of detail. In such a case simply place the 
 plate in a tray containing developer diluted with 
 water. The development will then take place 
 
VIGNETTED HALF-TONE, HIGH-LIGHT EFFECT — 100-LINE SCREEN. 
 From wash drawing- by W. L. Wells. 
 
MANUAL OF PHOTO-ENGRAVING. 101 
 
 slowly, the details having- time to appear before 
 the high lights assume any great intensity. 
 
 When the details have properly appeared, the 
 plate can, if necessary, be returned to the normal 
 developer until the proper intensity is obtained. 
 
 Some operators place under-timed plates in a 
 developer to which an excess of alkali has been 
 added, but such forcing of detail will seldom yield a 
 good negative, and there is great liability to fog. 
 
 If there is any detail which can be brought out 
 the method given above will do it. A badly under- 
 timed plate will, of course, never produce a good 
 negative. 
 
 If the plate has been over-exposed, the image 
 rapidly appears, the details coming up with the 
 high lights, and the negative will be flat. In such 
 a case it should be placed in a tray containing nor- 
 mal developer to which there has been added more 
 of the bromide solution. The restrainer will cause 
 the reduction in the portions least affected by the 
 light to be retarded, while the high lights will gain 
 in intensity, thus producing contrasts. 
 
 When a number of plates are developed in suc- 
 cession the developer will deteriorate, and should 
 be replaced by fresh as occasion may demand. 
 
 During development, the plate should be exam- 
 ined from time to time by holding it between the 
 eye and the red light, and when the proper inten- 
 sity has been obtained it should be rinsed for a 
 moment under the tap and placed in the fixing bath, 
 in which it should remain for five or ten minutes 
 after the white color has left the film. 
 
102 MANUAL OF PHOTO-ENGRAVING. 
 
 After fixing - , it should be washed in running- 
 water for at least two hours to remove the hypo 
 from the film. 
 
 When taken from the water, the ball of the 
 hand may be passed over the face of the negative 
 to remove any sediment from the water, the plate 
 being then placed in the rack to dry. 
 
 Instead of using dry pyro, it is customary with 
 many operators to have a pyro solution, various 
 formulae being given by platemakers. The above 
 formula? with dry pyro, however, will give results 
 second to none. 
 
 A number of other reducing agents are on the 
 market, some of which dispense with the use of an 
 alkali, but for all-around work with all brands of 
 plates pyro continues as a standard. 
 
 Among the other agents which have gained in 
 favor metol is one of the best, giving excellent 
 results. This developer may be prepared as fol- 
 lows : 
 
 Make stock solutions of sal soda at 30, and sul- 
 phite at 60 by the hydrometer. 
 
 Take 20 ounces of each and add to it 40 ounces 
 of water in which y? ounce of metol has been dis- 
 solved. 
 
 In warm weather dilute with an equal quantity 
 of water. 
 
 The manipulation is the same as with pyro. 
 
 INTENSIFICATION. 
 
 If the development of the negative has not been 
 carried far enough it will be thin and require 
 
MANUAL OF PHOTO-ENGRAVING. 103 
 
 intensification. Various formula? may be used, but 
 those containing mercury are commonly employed. 
 
 Dissolve 2*2 ounces of iodide of potassium in 12 
 ounces of water and pour into it gradually a satu- 
 rated solution of bichloride of mercury. A red pre- 
 cipitate of mercuric iodide will be formed. The 
 mercury solution must be added until this precipi- 
 tate cannot be dissolved by shaking - . Avoid adding 
 any more mercury, however, than will make the 
 solution very slightly turbid. Then add 2 J j ounces 
 hyposulphite of soda, and when dissolved add water 
 to make up to 40 ounces. 
 
 For use, take one part of the above solution to 
 three parts of water and immerse the negative 
 after fixing and washing until sufficient density is 
 obtained. If the hypo has not been thoroughly 
 washed from the film, the intensifier will cause 
 stains. If over-intensified the density may be 
 reduced by leaving the negative in the fixing bath 
 for a short time. 
 
 REDUCTION. 
 
 Negatives which are too dense may be reduced 
 by a dilute solution of hypo to which a little of a 
 solution of potassium ferricyanide has been added. 
 
 The solutions may be made up of }4 ounce of 
 the salt to 8 ounces of water. Add a little of the 
 potassium solution to the hypo solution and im- 
 merse the negative until sufficiently reduced, then 
 remove and wash. 
 
104 MANUAL OF PHOTO-ENGRAVING. 
 
 CAUSES OF DEFECTS IN GELATINE NEGATIVES. 
 
 Fog. — White light entering- darkroom or cam- 
 era, over-exposure, excess of alkali in developer, 
 hypo or other chemicals in developer, developer too 
 warm. 
 
 Negative too thin. — If the shadows lack detail, 
 under-development ; if the shadows have detail, 
 weak developer, or exposure too great. 
 
 In tensity too great. — Over-development, reagent 
 in excess in developer, or warm developer. 
 
 Abnormal contrasts. — Under-exposure or devel- 
 oper too strong. 
 
 Frilling. — Solutions too warm, insufficient alum 
 in fixing bath or prolonged washing-. 
 
 Flatness. — Over-exposure or too much alkali in 
 developer. 
 
 Spots. — Dust or bubbles in developer. 
 
 Stains. — Developer oxidized, impure chemicals 
 or not enough sulphite in developer, deteriorated 
 fixing solution or insufficient fixing. 
 
 Streaks. — Developer allowed to flow unevenly 
 over plate when first applied, or fixing bath acid. 
 
 Crystals on negative. — Hypo not all removed 
 frjm film. 
 
ZINC ETCHING OF PORTRAIT— MEDALLION EFFECT. 
 From drawing by Jules M. Gaspare! . 
 
MANUAL OF PHOTO-ENGRAVING. 103 
 
 CHAPTER XIV. 
 
 ORTHOCHROMATIC PLATES — COLOR 
 WORK. 
 
 COLOR. 
 
 THE undulatory theory of light, which is now 
 accepted as explaining- most satisfactorily its 
 various phenomena, assumes that light is produced 
 by vibrations of the ether, an imponderable, color- 
 less, perfectly elastic fluid which is supposed to pen- 
 etrate all matter and occupy all space. The waves 
 of ether, being- generated by the source of light, 
 are transmitted from it in all directions, the vibra- 
 tions being transverse to the direction in which the 
 ray of light is moving. 
 
 The sensation of white light is not caused by 
 one set of vibrations, but by several, for if we pass 
 a ray of white light through a prism it will be 
 decomposed, and the result will be a series of colors 
 (the spectrum) which can be shown upon a screen, 
 each pure color being produced by ethereal waves 
 always of the same length but differing in length 
 from the waves which produce any of the other 
 colors. This decomposition of the white light is 
 caused by the refraction or bending of the rays as 
 they pass through the prism, each of the compo- 
 nent rays being bent at a different angle than any 
 10 
 
106 MANUAL OF PHOTO-ENGRAVING. 
 
 of the others. The waves which are the longest 
 and which produce the red sensation are refracted 
 least, and the shortest waves — those which produce 
 the violet sensation — are refracted most, the waves 
 producing- the intermediate colors being- refracted 
 more or less according to their relative lengths. 
 Besides the rays of the spectrum which affect the 
 eye, others exist which are not visible and which 
 can be detected by their chemical effect. 
 
 Pure colors — that is, colors which are produced 
 by only one set of vibrations — are to be found only 
 as spectral colors. They cannot be obtained from 
 any pigment, for no matter how nearly any pig- 
 ment may appear optically to approach a color of 
 the spectrum, spectroscopic analysis will show its 
 color to be produced by more than one set of vibra- 
 tions. 
 
 The red, green and blue-violet of the spectrum 
 are the fewest pure colors from which by combina- 
 tion in certain proportions of two or the three any 
 other color may be produced, and they are there- 
 fore termed primary colors. The sensation of 
 yellow, for instance, may be obtained by the com- 
 bined action of the pure red and green rays, purple 
 of red and blue or violet, while white light is pro- 
 duced by the combination in equal quantities of all 
 three primary rays. The proportions may be 
 varied to produce other colors. Lilac may be pro- 
 duced by the combination of blue and red, the blue 
 rays predominating, while orange may be obtained 
 by combining red and green, the red predominat- 
 ing. 
 
MANUAL OF PHOTO-ENGRAVING. 107 
 
 The color of any object (or pigment) depends 
 upon its properties of absorption or reflection of 
 the primary rays. If illuminated by white light 
 and all the rays are reflected, it is said to be white. 
 If all the rays are absorbed, it is said to be black, 
 and if some are absorbed and some reflected the 
 color will be determined by the reflected rays ; for 
 example, if the green and blue-violet rays are 
 absorbed and the red reflected, the object is said to 
 be red. Some objects, such as colored glass or 
 colored solutions, allow some rays to pass through 
 them, absorbing or reflecting others, and this prop- 
 erty is utilized in filtering out certain rays which 
 it is desired shall act upon the sensitive plate to 
 obtain certain results. 
 
 Two colors which combined produce white are 
 called complementary colors. Since the three pri- 
 mary colors combined produce white, it follows that 
 the color resulting from the combination of any 
 two of them is complementary to the other pri- 
 mary. Primary red and green give the sensation 
 of yellow, which is therefore complementary to the 
 primary blue. 
 
 ORTHOCHROMATIC PLATES. 
 
 If a negative is made from a colored object by 
 using an ordinary photographic plate, it will be 
 found that the true color values have not been 
 obtained in the negative — that is, the reds and 
 yellows will appear too dark in comparison with 
 their values in the original, while the blue will 
 
108 MANUAL OF PHOTO-ENGRAVING. 
 
 appear as white.* This is due to the fact that the 
 only visible rays of the spectrum which affect the 
 ordinary plate are the blue-violet rays, these being 
 the only rays absorbed (except the invisible rays 
 from beyond the violet, which are known as the 
 ultra-violet rays). 
 
 This defect in the plate may be remedied, how- 
 ever, by treating- the film with certain dyes which 
 may be added to the emulsion before the plate is 
 coated, or the coated plate may be bathed in a solu- 
 tion of the dye. If a plate thus prepared is exposed 
 to a colored object, a transparent yellow filter of the 
 proper intensity being - so placed that the light will 
 pass through it before acting - upon the plate, the 
 resulting - negative will show practically the true 
 color values, the blacks, reds and blues appearing 
 as dark parts in proportion to their relative inten- 
 sities, while the yellows will appear as light parts. 
 
 The use of the yellow filter is to cut off the 
 action of the blue-violet rays to which the plate, of 
 course, remains sensitive. 
 
 Such a negative is called orthochromatic, from 
 the Greek words meaning correct and color. 
 
 COLOR PLATES. 
 
 Instead of sensitizing and exposing the plate to 
 obtain the effect of all the colors, it may be ren- 
 dered sensitive to certain rays and others excluded 
 
 * The effect of a pure red or yellow would be practically the same as 
 black. That red and yellow pigments will usually have some action on the 
 plate is due to the fact that they reflect more or less blue-violet — no pig-men t, 
 as stated before; having 1 a pure color. 
 
VIGNETTED HALF-TONE —133-LINE SCREEN. 
 With tint background. 
 
MANUAL OF PHOTO-ENGRAVING. 109 
 
 during - exposure by means of a properly dyed color 
 filter. We can then make from any colored object 
 three negatives, one of which shall have been 
 affected by the red rays, one by the green and one 
 by the blue-violet. If, then, three printing plates 
 are made corresponding to these negatives and 
 printed in pigments of complementary colors, the 
 images being properly superposed, the result will 
 be a reproduction in the colors of the original. 
 Inks complementary in color are used because, to 
 produce the desired effect, there must be absorbed 
 from the white paper such primary rays as the 
 original absorbed from the white light which illu- 
 minated it, which will cause the proper rays to be 
 reflected to reproduce the colors of the original. 
 The quantity of the respective colors reflected 
 from the image will be equal in quantity to those 
 reflected from the original when the quantity 
 absorbed by the pigments from the white: ground 
 is equal to the quantity absorbed from the light by 
 the original. 
 
 Blue of the proper shade will absorb red, red 
 will absorb green, and yellow will absorb blue. 
 The printing plate corresponding to the " red neg- 
 ative " must be printed in blue, to the "green 
 negative" in red, and to the "blue negative" in 
 yellow. 
 
 The inks must, of course, be sufficiently trans- 
 parent to allow the passage of the proper rays.* 
 
 * Discrimination must, of course, be used in the selection of inks of the 
 proper shades. Of two pigments, for instance, both may be said to be blue, 
 and one have much greater red-absorbing properties than the other. 
 
110 MANUAL OF PHOTO-ENGRAVING. 
 
 To obtain any one of these negatives the coat- 
 ing of the plate must be sensitive to those rays bv 
 which it is to be affected, and the other rays to 
 which it will also be sensitive must be excluded bv 
 means of a color filter. 
 
 For the "blue-violet negative," corresponding 
 to the yellow-printing plate, an ordinary gelatino- 
 bromide plate may be used with a methyl violet 
 filter, which will prevent the action of the ultra- 
 violet rays which would interfere w T ith the ren- 
 dering of the true color values. 
 
 For the "green negative" (red-printing plate), 
 the orthochromatic (erythrosine-cyanine) plates as 
 prepared by dry-plate makers may be used with a 
 strong yellow filter, which will allow the green 
 rays to pass and cut out the blue-violet. 
 
 The "red negative" (blue-printing plate > may 
 be made with an ordinary plate treated with 
 cyanine, which renders the plate sensitive to all 
 rays except green. The cyanine solution may be 
 made by dissolving ten grains cyanine C. P. in 
 twenty ounces alcohol. The plate is dipped in this 
 for twenty or thirty seconds, rinsed in distilled 
 water, and dried in the dark. Any filter may be 
 used which will exclude blue-violet rays and admit 
 the red. Crysoidine orange will give good results. 
 
 Plates sensitized with cyanine are extremely 
 liable to fog and must be developed in almost 
 darkness. 
 
 In making any of the color negatives, exposure 
 and development must be correct or the color values 
 will not be rendered properly. 
 
MANUAL OF PHOTO-ENGRAVING. HI 
 
 The color filters must be correct, and their 
 qualities should be determined by examination with 
 the spectroscope, which shows the colors transmit- 
 ted. They may be made by coloring- collodion or 
 gelatine and coating- glass with it, or by placing a 
 colored solution in a glass cell. The glass plates 
 must have their sides parallel and free from irreg- 
 ularities or a blurred image will result. The color 
 screen may be placed in front of the lens or at the 
 back, the latter position being generally preferred. 
 
 Having obtained the three negatives, the next 
 step is to make from them three corresponding 
 positives, which may be made on either gelatine or 
 collodion plates, care being taken to not make the 
 positives too intense. 
 
 During the operations of making the negatives 
 and also the positives the camera must be firmly 
 fastened that no movement whatever shall occur, 
 for the slightest variation will render useless 
 results. 
 
 The positives must now be placed so that the 
 half-tone negatives for the printing plates can be 
 made from them by transmitted light, the camera 
 as before being fixed to avoid any movement. The 
 form of the diaphragm aperture is an important 
 consideration in making these negatives. If the 
 round or square aperture, such as used for ordi- 
 nary work, be employed, it is evident that the 
 superposition of the -images from the printing 
 plates would result in a moire effect ; but if aper- 
 tures of such a form be employed as will give in 
 each case, an effect, not of cross lines, but of a 
 
112 MANUAL OF PHOTO-ENGRAVING. 
 
 single set of parallel lines which when superposed 
 will cross the lines of the other images at the 
 proper angle, the moire effect will be avoided. In a 
 preceding chapter it was stated that the form of 
 aperture determined the shape of the dot in the 
 negative. If a slot-shaped aperture is used, its 
 sides being parallel to one of the sets of lines of the 
 screen, the resulting negative will be made up of 
 continuous lines running in one direction, due to the 
 joining- of the images of the aperture ; but if the 
 aperture be broadened in the middle so as to have 
 an elliptical form, the negative will be made up 
 of similarly shaped dots in the lighter portions, 
 the dots being ranged in parallel lines and joining 
 to form solid lines in the shadows. With the use 
 of properly shaped apertures in the diaphragms 
 we have a means, therefore, for obtaining proper 
 effects with a cross-line screen. 
 
 To cause the lines of the negative to run at the 
 desired angle in each case, the kit for holding the 
 positives may be arranged to revolve through any 
 number of degrees as required. The positives are 
 then placed successively in the kit and turned as 
 required to sixty degrees for the exposure. If the 
 positives are properly placed as regards right and 
 left, it will not, of course, be necessary to reverse 
 the negatives. 
 
 An examination of the color plates will show 
 the forms of the elements and their proper relation 
 to each other. 
 
 The operations should be so carried out that the 
 printing plates shall have quite open high lights, 
 
ZINC ETCHING— WITH GRAIN EFFECT. 
 Drawn by Fred Richardson. 
 
MANUAL OF PHOTO-ENGRAVING. 113 
 
 any parts which are desired to appear extra light 
 being - corrected with the tool. Perfect register is 
 essential in printing these plates to obtain correct 
 results. The yellow is printed first, the red super- 
 posed next, and the blue last. Plates mounted on 
 metal bases give much better results in printing 
 than if mounted on wood. 
 
11-1 MANUAL OF PHOTO-ENGRAVING. 
 
 CHAPTER XV. 
 
 PRINTING HALF-TONE PLATES. 
 
 PHOTO - MECHANICAL engraved printing- 
 plates have largely revolutionized pressroom 
 theories, and owing to the shallowness of the en- 
 graving and to the greater necessity of dependence 
 on the qualities of paper and ink, the judgment 
 and skill of the pressman is more than ever before 
 required to give life and brilliancy to cut work. 
 Unevenness in half-tone plates is a source of much 
 annoyance to the pressman. All plates should be 
 made perfectly level before etching and the great- 
 est uniformity should be observed in the grinding - 
 and polishing. 
 
 The following instructions for preparing half- 
 tone plates for printing obtains in one of the larg-e 
 establishments of America noted for the quality of 
 the half-tone work produced. Obtain all the cuts 
 on a certain piece of work from the composing 
 room before they are made up in the forms, and of 
 each cut have proofs taken on three different 
 weights of paper — 24 by 36, 60, 70 and 80 pounds 
 - — and then proceed to make cut underlays. Tak- 
 ing 1 one of the proofs on the 70-pound stock, care- 
 fully trim it all around, leaving a margin of one- 
 sixteenth of an inch of blank all around the print. 
 
-> % 
 
 - ^ 
 
MANUAL OF PHOTO-ENGRAVING. 115 
 
 Then cut out of the sheet all of the extreme high 
 lights, being careful to cut a little of the surround- 
 ing shadows with them, the purpose of this being 
 to prevent too much impression on the point of 
 division, which would have a tendency to bring up 
 the shallows. Then take a proof on the 80-pound 
 stock and remove from it the extreme blacks and 
 solids — always cutting a little inside the line — and 
 paste them on the 70-pound sheet already treated, 
 using common flour paste or mucilage. Then take 
 one of the proofs on 60-pound stock and cut out all 
 of the intermediate shades such as should appear 
 lighter or softer in the finished print. Take these 
 several proofs and paste them together, and this 
 would be called a four-ply cut overlay, excepting 
 that all of the pieces comprising it are cut a trifle 
 inside of the line. If the cut has more shade in it 
 than can be properly treated with three sheets, 
 take a 50-pound paper in place of the 60-pound and 
 add one sheet to the underlay, treating it in the 
 same way as the second sheet with the exception 
 that instead of cutting out the extreme solids 
 remove all the semi-dark shades as well and paste 
 them on. Having made the underlays in the man- 
 ner described, proceed to unmount the cuts from 
 their bases. In order to do this without injuring 
 or scratching them great care is required. The 
 tools which will be found to be the most advan- 
 tageous are a small hammer, a pair of pliers, and a 
 small chisel — this last should be about a quarter of 
 an inch in diameter at the shank and should have a 
 long tapering blade, and be about half an inch 
 11 
 
116 MANUAL OF PHOTO-ENGRAVING. 
 
 wide at the extremity of the blade. Some small 
 wire brads, such as are commonly used for mount- 
 ing- the plates, a prick punch, a small nail set, an 
 electrotyper's iron finishing- plate, and a pair of 
 plate calipers such as are used by electrotypers, 
 are the other requisites. Having- removed the 
 plate from the block, take the calipers and mark at 
 least two distinct points on the back of the plate in 
 order to be able to paste the underlay accurately in 
 position. This done, lay the cut face up on the 
 iron plate and with a small boxwood planer g-o 
 over the entire surface, taking- care to strike only 
 a moderate blow. Take the block thereafter, and 
 examine it carefully to see that it is free from 
 lumps and rough places and mount the cut on the 
 opposite side to that from which it was taken and 
 send it to the composing- room. 
 
 This method saves a great deal of time in the 
 final make-ready of the form, as it is only necessary 
 to even up the impression on the cut, and the under- 
 lay will throw the lig-hts and shades where they 
 should be without any further care on the part of 
 the pressman, and for long- runs will preserve the 
 cut much better than if a plan of overlaying- was 
 followed. It holds up to the rollers the dark parts 
 of the cut, properly supplying- them with ink and 
 protecting- the lig-hter and more delicate shades 
 from receiving- unnecessary pressure. 
 
 . The practice of many pressmen who obtain g-ood 
 results is to even up the cut by underlays, and then 
 proceed to make such overlays as the character of 
 the work will indicate to be the most suitable. To 
 
MANUAL OF PHOTO-ENGRAVING. 117 
 
 be successful in making- any kind of an overlay as 
 little paste as possible should be used, only sufficient 
 to compactly bind together the different portions of 
 the overlay, and to register each piece of paper over 
 the other with positive accuracy. For work of dif- 
 fering character the papers used in overlays vary. 
 Impressions of the cuts are taken, for instance, on 
 three grades of stock : One sheet, say of 10- 
 pound folio, one of double that thickness of super- 
 calendered, and one sheet of the stock upon which 
 the cut is to be printed. Sometimes the last sheet 
 mentioned is selected for the first treatment, which 
 consists in cutting away from it any large, light 
 backgrounds, and scraping down and slitting off 
 many of the light and medium tones, so as to throw 
 up the stronger ones and the solids. A sharp knife 
 and some degree of skill is necessary to handle a 
 sheet of paper in this way, but it is worth one's 
 while to acquire it, for it saves time and much past- 
 ing on of parts of overlays, besides giving a firmer 
 basis. 
 
 The sheet of supercalendered stock may now 
 be taken, and from it should be cut all the light 
 tints as well as some of the stronger ones. The 
 sheet is also used as the foundation on which to 
 paste the cut-out portions of the two other sheets. 
 
 The third sheet of thin folio should be used to 
 make overlays for such portions of strong solids 
 and shades as require them. These should be 
 pasted accurately in place on the supercalendered 
 sheet, and over them should be fastened the first 
 sheet treated. From this arrangement it will be 
 
118 MANUAL OF PHOTOENGRAVING. 
 
 apparent that the first sheet, the folio and the 
 supercalendered sheets press on the form in the 
 order named, and in their relative degree of pres- 
 sures. 
 
 WHY PLATES FILL UP WITH PICKS. 
 
 This comes from several causes, usually unsuit- 
 able rollers or rollers not set light enough to prop- 
 erly roll the delicate plate surfaces, and rollers not 
 cast true in the stocks. Inks that are too stiff or 
 too thin, or not sufficiently ground, or ground in 
 inferior oil or varnish, will also cause this trouble. 
 Washing the plates with either woolen or cotton 
 rags forces into the sharp openings of the half-tone 
 the flock from the rags, and this also causes 
 "picks." Half-tone work should be washed with 
 a good brush of medium fineness, and a clean cot- 
 ton rag should be used to lightly sponge up the 
 washing fluid — be it benzine, astral oil or turpen- 
 tine. In no case should rags alone be used to clean 
 these plates, nor should anything be carelessly, 
 harshly or hurriedly rubbed over their surfaces. 
 
 Defective coating on enameled paper, or what is 
 known as surfaced wood-cut paper, will produce 
 picks and fill-ups on half-tone plates ; and in such 
 cases an ink with a very slight tack should be used 
 to get fair working results ; but the form should 
 be washed off oftener than when better stock is 
 running. After making ready, and between long 
 stops, half-tone plates should be thoroughly cleaned 
 off, as by so doing clearer and more satisfactory 
 work can be turned out. 
 
wcr lous sir. zxsvu t 
 
 
 HALF-TONE MADE DIRECT FROM BOOK COVER. 
 
MANUAL OF PHOTO-ENGRAVING. 119 
 
 COLORS FOR HALF-TONE PRINTING.* 
 
 In every child's storehouse are treasured many 
 bits of color. This love of color, inborn, may 
 always be made of strong- appeal. The profusion 
 of illustration constitutes one of the greatest influ- 
 ences in every grade of publication — commercial, 
 scientific and literary. The form and detail being- 
 fixed by the subjects concerned, it remains only to 
 print them in such quality and strength of color as 
 shall be best. Since the greater portion of print- 
 ing- is confined to one color, this article is limited to 
 printing- in monotones. 
 
 Fitness to the subjects themselves controls the 
 choice of some colors. Fig-ures, particularly nudes, 
 require warm tones. It is not customary, how- 
 ever, to be restricted to such monotones as ap- 
 proach flesh tints. Browns, deep reds and rich 
 olives are all g-ood. Marines are the most limited 
 in rang-e of color, greens and blues being- g-enerally 
 used. Landscapes allow more license in color, all 
 of the autumnal tints being- possibilities. 
 
 Next to the subjects, the purposes and uses of 
 the print must be reg-arded. For permanent value, 
 simplicity of effect is of more importance than any 
 striking- contrasts which will, in time, prove a 
 detraction. The plain catalogue pag-e is made 
 attractive by some monotone which is at once deco- 
 rative and an approach to the true color of the 
 subject. Commercial printing-, such as catalogues 
 
 *From an article by Mr. Henry Lewis Johnson in The Inland Printer 
 the above suggestive notes on colors for half-tone printing are taken by 
 special permission. 
 
120 MANUAL OF PHOTO-ENGRAVING. 
 
 and placards, admits of stronger colors than are 
 used in bound volumes, purely illustrative. The 
 practical value of a catalogue illustration often 
 requires that all of the details be clearly shown, 
 and dark colors are necessary for this. In art 
 catalogues the reverse is found ; everything is 
 sacrificed to effect. 
 
 Black always shows the full strength and bril- 
 liancy of an engraving. Colors which approach 
 black in density possess most brilliancy and detail. 
 Browns, although good, are open to some preju- 
 dice, since for many years they have been used on 
 every fine programme, catalogue and specimen 
 print. An order for a " fancy job" has been syn- 
 onymous with brown ink. This color has one 
 practical advantage. Where the same plates are 
 used, year after year, in catalogues, the}* become 
 necessarily somewhat worn and battered. These 
 defects are largely obscured by this neutral color. 
 
 Blues are not much used in half-tone printing. 
 In their use all of the lights, which give contrast 
 and brilliancy to a picture, are lost. It is naturally 
 a color seldom used for landscapes. The slow dry- 
 ing qualities of the ink are an objection to its use 
 on programmes or any work which has to be bound 
 soon after printing. Blue-black, of the darkest 
 shades, is being largely used, giving marked bril- 
 liancy to the print. 
 
 Reds, in the richer carmine shades, are effective 
 but somewhat costly. They are difficult colors to 
 handle well, requiring very exact gradations to 
 avoid being crude. Yellow has some important 
 
ZINC ETCHING — INTENSE BLACK AND WHITE EFFECT. 
 Drawn bv J. C. Leyendecker. 
 
MANUAL OF PHOTO-ENGRAVING. 121 
 
 uses. Deep corn yellow is preferable to the canary 
 shade. Greens are good and are in great favor at 
 the present. Particularly rich effects are obtained 
 in deep shades of olive, yielding strength and 
 warmth. Such prints closely approach photograv- 
 ures in effect, having strength yet obscuring the 
 half-tone lines. Instead of primary browns, blues 
 and greens, each one is better for ordinary pur- 
 poses as it approaches black. 
 
 For the printer there is a practical, and, in- 
 deed, economical side to the use of colored inks. 
 By using the engraver's proof in black in making 
 ready, the print may be brought up to its proper 
 condition. The element of " rush " usually enters 
 in at this stage. Justice cannot be done to the cuts 
 in black, in long, hurried runs, as it is difficult to 
 maintain the color. A slight variation in the bril- 
 liancy of the print in an olive or brown does not 
 constitute the defect which it would in black. In 
 place of strained effects in descriptive lines and 
 text, the monotone is the desired decoration. 
 
 The use of monotones is an interesting and a 
 critical part of the work. For the simplest print 
 the requirements of color are exacting, and, suc- 
 cessfully handled, constitute a step in advance in the 
 art of printing. 
 
APPENDIX. 
 
 TABLES OF WEIGHTS AND MEASURES 
 INFORMATION FROM VARIOUS 
 SOURCES. 
 
 
 
 
 
 MEASURES. 
 
 
 
 
 
 
 
 
 
 LINEAL. 
 
 
 
 
 Mile. 
 
 Rods. 
 
 
 Yards. 
 
 Feet. 
 
 
 
 Inches. 
 
 1 = 
 
 320 
 
 = 
 
 17l 
 
 50 
 
 = 5280 
 
 
 = 
 
 63360 
 
 
 1 
 
 
 
 5', 
 1 
 
 = 16 
 
 = 3 
 
 1 
 
 SURFACE. 
 
 1 , 
 
 = 
 
 198 
 36 
 12 
 
 Acre. 
 
 Roods. 
 
 
 Sq. 
 
 Rods. 
 
 Sq. Yds. 
 
 
 Sq. Ft. 
 
 1 = 
 
 2560 
 
 = 
 
 io; 
 
 2400 
 
 = 3097600 
 
 = 
 
 27878400 
 
 
 1 
 
 = 
 
 
 160 
 
 = 4840 
 
 = 
 
 43560 
 
 
 
 
 
 1 
 
 VOLUME. 
 
 30' 
 
 1 
 
 4 = 
 
 272 < 4 
 9 
 
 Gallon. 
 
 Quarts 
 
 
 
 Pints. Gills 
 
 
 Cubic Inches. 
 
 : = 
 
 4 
 
 = 
 
 
 8 
 
 = 
 
 32 
 
 = 
 
 231 
 
 
 1 
 
 
 
 2 
 1 
 
 FLUIDS. 
 
 16 
 
 4 
 
 
 
 Gallon. 
 
 Pints. 
 
 Ounces. 
 
 Drams. 
 
 Minims. 
 
 Cubic Centim's. 
 
 1 = 
 
 8 = 
 
 
 128 
 
 = 
 
 1024 = 
 
 61440 
 
 = 3785435 
 
 
 1 = 
 
 
 16 
 
 = 
 
 128 = 
 
 7 
 
 '680 
 
 = 473179 
 
 
 
 
 1 
 
 = 
 
 II II 
 
 
 480 
 60 
 
 = 29574 
 = 3697 
 
 122 
 

 
 
 APPENDIX. 
 
 12. 
 
 
 
 
 WEIGHTS. 
 
 
 
 
 
 
 TROY. 
 
 
 Pound. 
 
 Ounces. 
 
 Penn; 
 
 1,-weij. 
 
 fht. Grains. 
 
 Grams. 
 
 1 = 
 
 12 = 
 
 
 240 
 
 5760 = 
 
 373.24 
 
 
 1 = 
 
 
 20 
 
 = 480 = 
 
 31.10 
 
 
 
 
 1 
 
 = 24 = 
 
 1.56 
 
 
 
 
 APOTHECARIES'. 
 
 
 Pound. 
 
 Ounces. 
 
 Drams 
 
 
 Scruples. Grains. 
 
 Grains. 
 
 1 
 
 = 12 = 
 
 96 
 
 = 
 
 288 = 5760 = 
 
 373 . 24 
 
 
 1 = 
 
 8 
 
 = 
 
 24 = 480 = 
 
 31.10 
 
 
 
 1 
 
 = 
 
 3 = 60 = 
 
 3.89 
 
 
 
 
 
 1 = 20 — 
 1 = 
 
 1.30 
 .06 
 
 
 
 
 AVOIRDUPOIS. 
 
 
 
 Pound. 
 
 Ounces. 
 
 Drams. Grams. 
 
 
 
 1 = 
 
 16 
 
 = 
 
 256 = 453.60 
 
 
 
 
 1 
 
 = 
 
 16 = 28.35 
 1 = 1.77 
 
 
 1 gram = 15.43 grains = .03215 troy ounces = .03527 
 
 avoirdupois ounces. 
 1 grain = .0648 grams. 
 1 pound avoirdupois = lyV? pounds troy = IjVi pounds 
 
 apothecaries'. 
 1 ounce avoirdupois = l T yv ounces troy = l T v 5 2 ounces 
 
 apothecaries'. 
 1 pound troy = 1 pound apothecaries'. 
 
 1 ounce " =1 ounce " 
 
 1 grain " =1 grain " 
 
 1 pennyweight " — § dram " 
 
 TO PREPARE PERCENTAGE SOLUTIONS. 
 
 For each fluid ounce of water take of the salt 4.557 grains 
 to make a 1 per cent solution, twice the amount for a 2 
 per cent solution, etc. 
 
 When stated in parts per 1,000, etc., for each fluid ounce 
 of water take of the salt 0.4557 to make 1 part in 1,000, twice 
 
- 
 
 roount to 
 
 I 
 
 PR] ::^:h : - 
 
 i . 
 
 Water 
 
 1 ... 1 ounce 
 - 
 
 Dis- - the paper 
 
 th soltridoi ; in dark 
 e. Then 
 
 - 
 - - - - - bleachec 
 
 - 
 
 ^ro- 
 - 7 may be 
 
 ~ibed in Cbar 
 
 - 
 
 - ' _ ~ 
 
 - . 
 Tar 1 . - 
 
 iron 123 % 
 
 Water . - 
 
 -- - - ■ 
 
 - 
 
 acid : ri::.; 
 
 I gTains 
 3 ounces 
 
 5 per cent solution of ferro- 
 sh and fix in 10 per cent solution 
 
 - 
 
APPENDIX. 125 
 
 ANOTHER PROCESS. 
 
 Water 300 cu. centim's 
 
 Gelatin 10 grams 
 
 Ferric chloride, in thick solution 20 cu. centim's 
 
 Tartaric acid 10 grams 
 
 Ferric sulphate 10 grams 
 
 When paper is dry, expose under negative and develop in 
 
 Gallic acid 20 grams 
 
 Alcohol 200 cu. centim's 
 
 Water 1 liter 
 
 and wash. 
 
 VARNISHES. 
 VARNISH FOR COLLODION NEGATIVES. 
 
 g Water 30 ounces 
 
 Borax \ l / 2 ounces 
 
 White shellac 4 ounces 
 
 Glycerine % ounce 
 
 Dissolve the borax in the water, then add the shellac and 
 warm the water, keeping it so until the shellac is dissolved, 
 then add the glycerine. 
 
 DEAD BLACK VARNISH. 
 
 Gum lac 30 grams 
 
 Alcohol 200 cu. centim's 
 
 Dissolve. 
 
 Lampblack 60 grams 
 
 Alcohol 40 cu. centim's 
 
 Dissolve and add to the gum solution. 
 
126 APPENDIX. 
 
 PLAIN PHOTOGRAPHIC PAPER. 
 
 It is an easy matter to prepare one's own paper and it 
 will keep for any length of time. All that is necessary is 
 to use a good quality linen paper and soak it in a weak siz- 
 ing of gelatin containing a chloride salt, so that when apply- 
 ing nitrate of silver afterward to this paper a chloride of 
 silver will be formed. The following is an excellent for- 
 mula: Take a smooth linen paper if it is to be used for pen- 
 and-ink work, or a rough paper like Whatman's drawing 
 paper if for wash work, and immerse it in a warm solution 
 of the following : 
 
 Water 1 ounce 
 
 Gelatin 12 grains 
 
 Chloride of ammonium 8 grains 
 
 When the paper is soaked with this liquid hang it up to dry. 
 It will keep indefinitely. To sensitize this paper use : 
 
 Water 1 ounce 
 
 Nitrate of silver 50 grains 
 
 Nitric acid 15 grains 
 
 CLEARING SOLUTION FOR HALF-TONE 
 NEGATIVES. 
 
 Engravers having trouble with negatives filling up in 
 the intensifying will find a clearing solution of great value. 
 Property used, it is one of the most valuable aids in secur- 
 ing perfect half-tone negatives. There are two ways of 
 using this clearing solution. The first is to prepare an 
 iodine solution : 
 
 Iodine in flakes 10 grains 
 
 Iodide of potassium 10 grains 
 
 Water 1 ounce 
 
 After the negative is intensified with bromide of copper and 
 nitrate of silver as usual, it should be examined with a 
 magnifying glass to determine how much clearing is neces- 
 sary. Then flow over the negative the iodine solution until 
 
12 
 
APPENDIX. 
 
 it has permeated through the film, wash well, leave the water 
 running, and flow over the iodized plate a very weak solu- 
 tion of cyanide of potassium. If it should appear to clear 
 the negative too quickly, thrust the negative immediately 
 under the running water. After washing examine with the 
 glass again, and proceed or stop clearing as judgment war- 
 rants. The majority of operators add cyanide solution to 
 the iodine solution until the latter becomes clear as' water, 
 and use it then as the clearing solution. 
 
 TWO SUGGESTIONS FOR DESIGNERS. 
 
 Wall paper of neat design may sometimes be used as a 
 background for a group of photographs to be reproduced in 
 half-tone, giving a better appearance than a plain ground, 
 and allowing the time of an artist to design a ground to 
 be saved. Good effects can also be obtained in some cases 
 by spreading glue over certain portions of a design and 
 sprinkling over the wet glue chips of metal from the router 
 or trimmer. 
 
 ETCHED EMBOSSING PLATES. 
 
 Plates for embossing can be made quite readily by zinc 
 etching, as follows: From the relief plate take an impres- 
 sion with black ink on thin white paper, as nearly trans- 
 parent and tough as can be obtained. Then dust over the 
 wet ink very finely powdered graphite or other opaque 
 powder to render the ink still more impervious to light. 
 Coat a thick zinc plate with the sensitive albumen solution, 
 place the paper in contact with it, insert in printing frame 
 and expose in same manner as with a negative. Then roll 
 up and develop as usual and the result will be an image 
 having the letters or design of exposed zinc with a ground 
 of transfer ink. The plate is then etched in the usual man- 
 ner, care being taken to protect the edges of the design 
 from breaking. If the relief plate is not at hand, make a 
 negative of the design and from this a positive, and use the 
 positive to obtain the print upon the zinc. To make the 
 
128 APPENDIX. 
 
 positive, place the negative in the kit in front of the copying- 
 camera, having the lens in the kit inside. Fasten a sheet of 
 white paper to the copy board and move the ground glass 
 until the image measures exactly the proper dimensions, 
 then proceed as in making an ordinary negative. A method 
 simpler than the above would be to transfer the image from 
 the relief plate to the zinc by means of the press, paint in 
 the ground well with transfer ink, and etch. 
 
 A SUBSTITUTE FOR GROUND GLASS. 
 
 There is scarcely any accident more aggravating to the 
 photo-engraver than the breaking of the camera ground 
 glass. As it is of frequent occurrence and it is difficult to 
 obtain glass ground fine enough for the purpose, it behooves 
 the photographer to be provided with the following varnish 
 which furnishes an excellent substitute for ground glass: 
 
 Sulphuric ether 4 ounces 
 
 Benzole 2 ounces 
 
 Alcohol J 2 ounce 
 
 Gum sandarac or damar 100 to 150 grains 
 
 If too much alcohol is used it will give a transparent 
 instead of a ground glass effect. Flow this varnish on a 
 sheet of plain glass like collodion. It dries quickly and 
 without heat, and should give an excellent imitation of 
 ground glass. In passing it might be said that if a little 
 gl3 r cerin is rubbed into the grain of an ordinary ground 
 glass it renders it much easier to focus on. It is best to rub 
 it over but a portion of the ground glass, say a strip from 
 the center to one edge. 
 
 PROVING COLOR PLATES. 
 
 Mr. J. H. Siedenburg, of New York, says The Inland 
 Printer, has devised the following- method of proving color 
 plates : In a worthless piece of zinc, saj- 10 by 12 in size. 
 } -inch holes are drilled in diagonal corners. Short pieces 
 of a steel needle are driven into these holes and soldered 
 
COMBINATION OF LINE AND HALF-TONE, ETCHED 
 TOGETHER ON ZINC. 
 
 Qg 
 
 he 
 on 
 i 11- 
 th 
 y. 
 
 „ .<- »t ^v- .uor- 
 
 ^vlh,\ America; m m cms country 
 Mla ton any British plans tor the acquisition 
 of Hawaii." 
 
 THE INLAND PRINTER. 
 The April number of the' Inland Printer 
 leads off with a cool and discriminating re- 
 view of tne work of Aubrey Beardsley, the 
 new eccentric illustrator, Mr. Way, the 
 critic, rightly distinguishes Beardsley's work 
 as oecoratioii, like that of the Japanese, 
 rather than illustration. There are articles 
 on "KeCKnt Type Designs," "Colored Ink 
 Fountains for Printing Presses," "Advan- 
 tage.-; of Type Written Copy," anil a score of 
 other subjects in which printers take delight, 
 besides less technical studies devoted to the 
 aesthetic sideof beck-making, and a profusion 
 of the best selected and most handsomely 
 printed full-page and marginal engravings. 
 
 ■po pn^KS RECEIVED. " 
 
 Ai 
 
 c 
 
 Bas 
 tak 
 bat 
 Bai 
 capt 
 
 W 
 
 east 
 cone 
 hous 
 si dei 
 
 $ ' Di( 
 Schc 
 
 HALF-TONE REPRODUCTION OF TYPE-MATTER. 
 
Appendix. 129 
 
 there, after which the upper ends of the needles are filed 
 to sharp points. This he calls the "ground plate." After 
 photographing - and etching the color plates, one of them 
 is taken and clamped securely to the center of the ground 
 plate ; ^-inch holes are drilled through the regular registry 
 points, which were, of course, on the cop}' and photo- 
 graphed on each plate. These holes are bored through 
 both the color plate and the ground plate. Now two block- 
 ing brads about ^Vinch thick are driven through the ground 
 plate holes from the back and cut off to height of thickness 
 of color plate. With nail set, punch the metal around the 
 brads to hold them rigid. When jVinch holes are bored in 
 the center of the registry points in the other color plates 
 they are all ready for proving. When the first color plate is 
 proved, the needle points in the ground plate puncture holes 
 in the proof, which are used to register the paper in the 
 subsequent printings, while the steel brads keep the plates 
 in register. 
 
 TO CHANGE THE READING ON ONE THERMOM- 
 ETER SCALE TO THAT ON ANOTHER. 
 
 Fahrenheit to Centigrade. — Subtract 32 from the Fahren- 
 heit reading and multiply the result by f. 
 
 Fahrenheit to Reaumur. — Subtract 32 from Fahrenheit 
 reading and multiply result by f. 
 
 Centigrade to Fahrenheit. — Multiply Centigrade reading 
 by | and add 32 to the result. 
 
 Centigrade to Reaumur. — Multiply the Centigrade read- 
 ing by |. 
 
 Reaumur to Fahrenheit. — Multiply the Reaumur reading 
 by | and add 32. 
 
 Reaumur to Centigrade. — Multiply the Reaumur reading 
 
 byf. 
 
>00<KH>0<><><K><K>0<><HKH><><KK><>00<KH><><XK>< 
 
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