BROMOIL PRINTING
AND
BROMOIL TRANSFER

BY
DR. EMIL MAYER
PRESIDENT OF THE VIENNA CLUB OF AMATEUR PHOTOGRAPHERS

AUTHORIZED TRANSLATION
FROM THE SEVENTH GERMAN EDITION

BY
FRANK ROY FRAPRIE, S.M., F.R.P.S.
EDITOR OF AMERICAN PHOTOGRAPHY

AMERICAN PHOTOGRAPHIC PUBLISHING CO.,
BOSTON 17, MASSACHUSETTS
1923

Copyright, 1923
BY AMERICAN PHOTOGRAPHIC PUBLISHING CO.

Manufactured in the United States of America
Electrotyped and printed, March, 1923

THE PLIMPTON PRESS
NORWOOD·MASS·U·S·A

PREFACE

The bromoil process has always been one in which it has seemed difficult to attain success. Though many books and articles on the subject have been published, every writer seems to give different directions and every experimenter to have difficulty in following them. The consequence is that almost every successful experimenter with this process has developed methods of his own and has frequently been unable to impart them to others. One reason for this has been that each make of bromide paper varies in its characteristics from the others and that methods, which are successful with one, do not always succeed with another. Various bleaching solutions have been described, and, as the bleaching solution has two functions—bleaching and tanning, which progress with different speeds at different temperatures—a lack of attention on this point has doubtless been a frequent cause of unsuccess. Little attention has also been paid to the necessity for observing the temperature of the water used for soaking the print. The author of the present book has investigated these various points very carefully, and for the first time, perhaps, has brought to the attention of the photographic reader the need for an accurate knowledge of the effect of these different variables.

In the following book he describes only a single method of work, without variations until the process is learned, though he does describe various methods of work which may be used to vary results by the experienced worker. His method of instruction is logical and based on accepted educational principles. He describes one step at a time fully and carefully, explains the reasons for adopting it, and then proceeds to the next step in like manner. We feel sure that every reader, who will be reasonably careful in his methods of work and will follow these instructions literally, will learn how to make a good bromoil print. After attaining success in this way, the variations may be tried, if desired.

While the author gives instructions for testing out papers to see if they are suitable, it may be advisable to record here the results of some American and English workers. H. G. Cleveland in American Photography for February, 1923, recommends, in addition to the papers specially marked by their makers as bromoil grades, the following: Eastman Portrait Bromide; P. M. C., Nos. 7 and 8; and Wellington, Cream Crayon Smooth, Rough, or Extra Rough. He suggests that a rough test may be made of a new brand of paper by placing a small test strip in water at 120° to 140° Fahrenheit for a few minutes and then scraping the emulsion surface with a knife blade. If the coating is entirely soft and jelly-like, it will probably be suitable for the process. If it is tough and leathery, it will be unsuitable, and, if a portion of the coating is soft but the other portion tough, then it will also be unsuitable. His experience is that Wellington Bromoil paper is entirely suitable for the process. Chris J. Symes in The British Journal of Photography for December 1, 1922, recommends for bromoil the following English papers: Kodak Royal, white and toned; Vitegas, specially prepared for bromoil; Barnet Cream Crayon Natural Surface, Rough Ordinary and Tiger Tongue. For transfer, he has found the following suitable: Kodak Royal, white and toned; Kodak Velvet; Barnet Smooth Ordinary; and Barnet Semi-matt Card.

The reader who is interested in bromoil transfer, will find the directions of Mr. Guttmann on this process slightly different from those of Dr. Mayer in minor points, but the worker who is far enough advanced to essay this difficult process will be able to recognize these discrepancies and choose the process which seems more useful to himself.

Metal etcher’s presses for transfer are sold at comparatively high prices in the United States, but second hand ones may often be found in the larger cities. Small wooden mangles with maple rolls may be had at fairly low prices from dealers in laundry supplies, and have been found to be useful.

Following the style of the German original, italics have been freely used for the purpose of calling attention to the most important stages of the process, rather than for the ordinary purposes of emphasis.

Grateful acknowledgment is made to Mr. E. J. Wall for assistance in the first draft of the translation, and also in revision of the proofs.

Frank Roy Fraprie.

Boston, February, 1923.

CONTENTS

BROMOIL PRINTING AND BROMOIL TRANSFER

PRELIMINARY REMARKS

We all know what great progress photography has made in the last few years. The most obvious sign of this advance is the fact that it has gradually escaped from the practice of literal reproduction of the objects seen by the lens, and slowly attained to the rank of a recognized means of artistic expression, so that it can justly be considered as a new branch which has grown out of the old tree of reproductive art. This pleasing development may primarily be ascribed to the fact that the practice of photography, which was originally confined almost exclusively to professional workers, has gradually spread and has become a means of recreation to the multitude in their leisure hours. It was the amateur who demanded new methods and apparatus and thus gave a new impulse to photographic manufacturing. Improvements of the most fundamental character were made in optical apparatus, in the construction of cameras of the most varied types, and in the fabrication of plates and films. An extraordinary number of novelties has appeared in these lines in the course of time; modern photographic apparatus makes possible the solution of problems which would not have been attempted a few years ago, and improvements are still appearing.

The situation in the matter of printing processes is quite different. We are provided with apparatus and sensitive material for the production of the photographic negative, in a perfection which leaves nothing to be desired. To produce a print from the negative, however, we had until recently no positive processes which were not well-known to previous generations. This may be confirmed by a glance at any photographic textbook written around 1880. The various printing processes, platinum, bromide, carbon, and gum, which were until recently the alpha and omega of printing technique, had been known for decades. Compared with the methods for the production of negatives, printing methods showed practically no advance; they remained in complete stagnation. We can scarcely consider as an exception certain new methods brought forward in recent years, which proved unsuccessful and quickly disappeared from practice.

These facts can only be explained by remembering that the positive processes, which were available to photographers and with which they had to be satisfied, were rather numerous and offered a considerable variety of effects. Nevertheless, a single characteristic was common to all previously known photographic printing processes—their inflexibility. Each of these processes, in spite of its individual peculiarities, could do nothing more than exactly reproduce the negative which was to be printed. It was possible to produce certain modifications of the negative image as a whole, by printing it darker or lighter, or by using a harder or softer working process. Changes on the negative itself for the purpose of giving a more artistic rendering must, however, always be very carefully thought out in advance and effected by retouching, often difficult and not within the power of every photographer, or by other methods which change the negative itself. If such modifications of the negative proved unsuccessful, it was irreparably lost; if they succeeded, the plate, as a rule, could no longer be used in any different manner. The possibility of undertaking radical changes which might realize the artistic intentions of the worker on the print itself, in order to save the negative, and especially of planning and carrying out the deviations from the original negative, which expressed the worker’s artistic feelings, during the printing, was not afforded by any previously known printing methods. A single exception was found in gum printing, if the production of the image was divided into a series of partial printings. Each of these phases, however, was in itself incapable of modification except for the possibility of doing a certain small amount of retouching; nevertheless, by means of efficient management of the single printings and by properly combining them, beautiful artistic effects could be obtained. This, however, required an extraordinary amount of practice and skill, and a very considerable expenditure of time, and it must also be remembered that the failure of one of the last printings often destroyed all the previous work. Also, in gum printing, to have a reasonable expectation of success, the work must be thought out from the very beginning and carried out in exact accordance with a plan from which it was scarcely possible to deviate during the work, even when it became apparent that the desired result could not be satisfactorily obtained.

The possibility of planning results during the course of the printing and carrying them out directly on the print itself did not previously exist.

The first process to bring us nearer to this ideal and make possible a freer method of working was oil printing. The technique of this process consisted in sensitizing paper which had been coated with a layer of gelatine, by means of a solution of potassium bichromate, and of printing it under the negative. The yellowish image was then washed out; the bichromate had, however, produced various degrees of tanning of the gelatine, corresponding to the various densities of the silver deposit in the negative. The lighter portions, which had been protected from the action of light by the dense parts of the negative, retained their original power of swelling and could therefore later absorb water. The shadows, however, corresponding to the transparent parts of the negative, were tanned, had lost their absorptive power, and had become incapable of taking up water. Consequently, the high lights swelled up fully in water, the shadows remained unchanged, and the middle tones showed various degrees of swelling corresponding to the gradation of the negative. If the print was blotted off and greasy inks spread upon it by means of a properly shaped brush, the inks were entirely repelled by the swollen high lights which had absorbed water, and completely retained by the fully tanned shadows, while the middle tones, in proportion to the amount of tanning, retained or repelled the greasy ink more or less completely.

In this process, for the first time, there was found a possibility of changing various parts of the image absolutely at the worker’s will, even during the progress of the work. By the use of harder or softer inks it was possible to color the swollen high lights more deeply, or to hold back the shadows so that they did not take up all the ink that was possible. It was possible to leave certain parts of the print entirely untouched and work up other parts to the highest degree; in short, oil printing opened the way to free artistic handling of the print.

Thus, the oil process was the first photographic printing process in which we were completely emancipated from the previous inflexibility which ruled in all printing.

Nevertheless, a number of disadvantages attach to oil printing which hinder its general use. The most important shortcoming of this process is that bichromated gelatine as a printing medium can only reproduce a comparatively short scale of tone values. The production of prints from contrasty negatives is therefore impossible, for the shadows are much overprinted before details appear in the high lights, or on the other hand, there is no detail in the lights if the shadows are fully printed. This difficulty can be only partly overcome by the most skilful use of inks of various consistency. It is indeed possible to ink up the lights by the use of very soft ink, but this does not replace the missing details; and overprinted shadows, which it is tried to improve by keeping down the quantity of ink applied, appear empty. Thus it happens that most of the oil prints yet exhibited show a certain muddy family likeness, which, at first, when the process was new, was considered to be advantageous on account of the novelty of the effect, but later received deserved criticism. A second disadvantage of the oil print is the fact that it is not possible to observe the progress of the printing on the bichromated gelatine film. The brownish image on a yellow background is very deceiving, and it is usually necessary to determine the proper amount of printing for each individual negative by actual experiment, and to make additional prints by means of a photometer.

Another inconvenience of other previously known printing processes, to which oil printing is also subject, comes from the fact that the great majority of negatives are now made with small cameras. On account of the extraordinary perfection of modern objectives, the small negatives produced by modern hand cameras can be enlarged practically without limit. The advantages of a portable camera are so considerable that large and heavy tripod cameras have practically gone out of use, except for certain special purposes. On the other hand, however, direct prints from small negatives are, as a rule, entirely unsatisfactory from an artistic standpoint. If we desire to use any of the previously mentioned positive processes, including oil, to produce artistic effects, we must first make an enlarged negative. This requires, in the first place, the production of a glass transparency from the small negative, from which we may prepare the desired enlarged working negative.

Various workers held various views as to whether this requirement were a help or a hindrance, but it was universally accepted as a necessity. The way from the plate to the enlarged negative, nevertheless, always remained uncertain, tedious, and expensive. Simple as it may appear to be, it includes a whole series of stages where it is possible to come to grief. At every single step lurks the danger that undesired changes of gradation in the negative may result from inaccuracy in exposure and development, from the use of improperly chosen sensitive material, and from various other causes, and even if these factors are all correctly handled, there is still an unavoidable loss of detail. Therefore the path from the small original negative to the enlarged negative necessary in previously used processes is neither simple nor safe.

Naturally it was also necessary to travel this wearisome path in working the oil process, when it was desired to make large prints from small negatives.

When it was announced in England that Welborne Piper had discovered a process which started from a finished silver bromide print instead of from a gelatine film sensitized with bichromate, new vistas were opened. If the process should prove to be practically useful, we could consider that all the previously mentioned difficulties were overcome at a single stroke.

The principle of this process, bromoil printing, is the removal of the silver image from a finished silver bromide print by means of a bleaching solution while, simultaneously with the solution of the silver image, the gelatine film is tanned in such a way in relation to the previously present image that the portions of gelatine which represent the high lights of the image preserve their capability of swelling, while the shadows of the image are tanned.

Therefore the bromoil process is a modification of oil printing, based not upon a bichromated gelatine film, but upon a completed bromide print. This represents extraordinary progress. The two previously mentioned disadvantages of oil printing are completely avoided in the bromoil process. We now have at our command the far longer scale of tone values of bromide paper and we can use the great possibilities of modification allowed by the highly developed bromide process. The difficulties of printing are completely removed, for we have at our command a perfectly visible image as a starting point. A further advantage which can not be too highly estimated is inherent in the bromoil process: complete independence of the size of the original negative.

When I began my investigations in the field of bromoil printing, the process had, as far as practical value went, only a purely theoretical existence, as is the case in the early days of most photographic processes. The fact that it was possible to produce images on a bleached bromide print by the application of greasy inks was well established. The practical application of the process was absolutely uncertain and only occasionally were satisfactory results obtained. Most of the prints produced in this way were flat and muddy. It is easy to understand that the process could find no widespread popularity while it was so incompletely worked out. The researches, which I then began, showed that most bromide papers took up greasy inks after development by any method and subsequent bleaching of the image. The pictures thus obtained, however, were muddy, flat, and not amenable to control, and therefore were less satisfactory than the bromide prints from which I had started. During the course of my work, I have succeeded in obviating these difficulties, in the first place, by preparing a satisfactory bleaching solution, next, by determining what properties bromide paper must possess in order to give perfect bromoil prints, and, finally, by working out a series of other necessary conditions, which I have described in this book and which must be adhered to if the process is to work smoothly and certainly, and produce satisfactory results.

The bromoil process, which is now completely mastered, offers, in brief, the following advantages:

Simplicity, certainty and controllability of the printing material;

Independence of the size of the negative and easy production of enlarged artistic prints;

Freedom in the choice of basic stock and its surface;

The possibility of freely producing on the print any desired deviations from the negative, during the work;

Full mastery of the tone values without dependence on those of the negative;

Independence of daylight, both in printing and in working up the print;

The possibility of the most radical alterations of the print as a whole and in part during the work;

Freedom of choice of colors;

The possibility of preparing polychromatic prints with any desired choice of colors, and complete freedom in the handling of the colors;

The possibility of comprehensive and harmonious modifications of the finished print;

The possibility of producing prints on any desired kind of non-sensitized paper by the method of transfer.

The description of working methods will be divided into the following phases:

CHAPTER I
PRODUCTION OF THE BROMIDE PRINT

Failures in the bromoil process in the great majority of cases can be ascribed to the fact that the basic bromide print was not satisfactory. Therefore the method of preparation of the bromide print or enlargement deserves the most careful consideration, for the bromide print is the most important factor in the preparation of a bromoil print. The beginner, especially, can not proceed too carefully in making his bromide print.

Because of the extraordinary importance of this point, we must first define what is here meant by a perfect bromide print.

In deciding how to produce a satisfactory bromide print as a basis for a bromoil, we must exclude from consideration esthetic or artistic grounds.

The bromide print must be technically absolutely perfect, that is, it must have absolutely clean high lights, well graded middle tones, and dense shadows. Especial stress must be laid on the brilliancy of the high lights. It is best to compare these high lights with an edge of the paper which has not been exposed and is not fogged or, even better, with the back of the paper. The highest lights should show scarcely a trace of a silver precipitate and must therefore be almost as white as the paper itself. Negatives which do not allow of the production of prints as perfect as this should not be used while the bromoil process is being learned.

This apparently superfluous definition of a perfect bromide print has to be given in this way, because it only too often occurs in practice that the worker himself is not clear as to what is meant by the expression, perfect bromide print. This may be partly ascribed to the fact that the silver bromide process—whether rightly or wrongly need not be determined here—has not been properly appreciated among amateurs who are striving for artistic results. Bromide printing has frequently been considered not to be satisfactory as an artistic means of expression, and has therefore been considerably neglected. In many quarters it is considered as just good enough for beginners.

Nevertheless, the bromide process is per se an uncommonly flexible method and gives, even with a very considerable amount of overexposure or underexposure, that is, even when very badly handled, results which are considered usable. It is even possible that an improperly made bromide print, one for instance, which is soft and foggy, might in some circles be considered as esthetically more interesting than a perfect print. This is an undeniable advantage of the process. It may also become a danger, if an imperfect bromide print is used as a starting point in the bromoil process. If anyone is not sure on this point, let him compare his own bromide prints with such samples as are frequently shown by manufacturers in window displays and sample books. He will then see what richness of tones and wealth of gradation are inherent in the process. If, however, an imperfect silver bromide print is used as a starting point for a bromoil, it can not be expected that the latter will display all the possibilities of this process. If the bromide print is muddy, the work of inking will be difficult, and it will be impossible to obtain clean high lights. If it is underexposed and too contrasty, it can not be expected that the bromoil will show details in the high lights which were lacking in the bromide print. If the worker himself does not know that his silver bromide print is faulty, he is inclined to ascribe the difficulties which he finds in making the bromoil print and his dissatisfaction with the results, to the bromoil process itself. Most of the unsatisfactory results in bromoil work must be ascribed to the imperfect quality of the bromide print which is used, and this is the more important as this lack is not perceptible to the eye after the bleaching is completed. Whoever, therefore, desires to successfully practice bromoil printing, must first decide impartially and critically whether he actually knows how to make bromide prints, and must acquire full mastery of this process.

The technically perfect bromide print made from a properly graded negative can, as will later be described, have its gradations changed in the bromoil process without any difficulty, and thus be made softer or more contrasty. The advanced bromoil printer who is a thorough master of the technique of the process will therefore easily be able to work even with poor negatives; when making his bromide prints from such negatives, he will consider the ideas which he intends to incorporate in the bromoil print and will make his bromide print harder or softer than the negative and at the same time retain the necessary cleanness of the high lights.

The best starting point for a bromoil print, however, especially for the beginner, is and must be a bromide print as nearly perfect as possible.

A suggestion for the certain obtaining of such prints may be added here. When we are working with a negative with strong high lights, judgment as to the freedom of the bromide print from fog by comparison with an unexposed edge is not difficult. This is not the case with negatives which show no well marked high lights. In such cases it is advisable to determine what is underexposure by making test strips in which details in the high lights and middle tones are lacking and, working from this point, determine by gradual increase of exposure the correct time which gives a perfectly clean print.

The Choice of the Paper.—One of the most important problems is to find a suitable paper for the process. Not all of the bromide papers which are on the market will give satisfactory results. It is only possible to use papers whose swelling power has not been too completely removed in process of manufacture by the use of hardeners. The principle of the bromoil process is that a tanning of the gelatine shall occur simultaneously with the bleaching of the silver bromide image. As we have already remarked, this does not affect the high lights and leaves them still absorbent, while the shadows are tanned and therefore become incapable of taking up water. The half-tones are tanned or hardened to an intermediate degree and therefore can take up a certain amount of water. Therefore, in place of the vanished silver image, we get a totally or partially invisible tanned image in the gelatine film.

The variously hardened parts of the gelatine film, corresponding to the various portions of the vanished bromide image, display the property acquired through different degrees of tanning by the fact that the portions of the gelatine which remain unhardened and which correspond to the high lights of the silver image formerly present, absorb water greedily. Consequently they swell up and acquire a certain shininess, because of their water content; in addition they generally rise above the other parts of the gelatine film, which contain little or no water, and give a certain amount of relief when they are fully swelled. The portions of the film in which the deep shadows of the bromide image lay are completely tanned through, can therefore take up no water, and remain matt and sunken. This graded swelling of the gelatine film becomes more apparent, the higher the temperature of the water in which the film is swollen.

If, however, the paper was strongly tanned in the process of manufacture, the gelatine has already lost all or most of its swelling power before it is printed and, although the bleaching solution in such cases can indeed remove the silver image, it can no longer develop the differences of absorptive power which are necessary for a bromoil print; for, although the bleaching solution can harden an untanned gelatine layer, it cannot bring back the lost power of swelling to a film which is already hardened through and through.

Therefore bromide papers which have already been very thoroughly hardened in manufacture show no trace of relief after bleaching, and very slight, if any, shininess in the lights. This is the case especially with those white, smooth, matt, heavyweight papers which are especially used for postcard printing. When such papers are taken out of the solutions, as a rule, these run off quickly and leave an almost dry surface. It is generally not possible to make satisfactory bromoil prints on such papers. It is true that the image can be inked by protracted labor; it is, however, muddy and flat and, as a rule, cannot be essentially improved even by the use of very warm water. Other types of bromide paper which have not been so thoroughly hardened may show no relief after bleaching, yet, after the surface water has been removed, they do show a certain small amount of shininess in the high lights when carefully inspected sidewise. With such papers the necessary differences of swelling can generally be developed if, as will later be more completely described, they are soaked in very warm water or in an ammoniacal solution. It is rare to find in commerce silver bromide papers which have not been hardened at all, or only very slightly hardened, in their manufacture. Such papers, because their films are very susceptible to mechanical injury, are not likely to stand the wear and tear of the various baths. On the other hand, as a rule, they usually produce a strong relief even in cold water, and therefore tend to produce hard prints. The greatest adaptability for bromoil printing may be anticipated from bromide papers which are moderately hardened during manufacture.

To determine whether a given brand of bromide paper is suitable for bromoil work, an unexposed sheet of the paper should be dipped in water at a temperature of about 30° C. (86° F.) and the behavior of the gelatine film observed. If this swells up considerably and becomes slippery and shiny, the paper has the necessary swelling power and can be used with success.

On account of the great variety of bromide papers which are on the market, we have a very wide choice as regards the thickness and color of the paper and the structure of its surface. It may be remarked here that papers of any desired surface, even rough and coarse grained papers, can be used for bromoil printing, as easily as papers with a smooth surface. The difficulties experienced with very rough surfaced papers in some other processes do not exist in bromoil. Because of the elasticity of its hairs, the brush carries the ink as easily into the hollows of the surface as to its high points.

The thickness of the paper is of no importance in bromoil printing, except that the handling of the thicker papers is easier, because they lie flatter during the work and distort less on drying; also, as a rule, thick papers are easier to ink.

Gaslight papers can also be used if their gelatine films satisfy the above mentioned requirements. Therefore we have the widest possible choice in the printing materials for bromoil.

A great number of bromide papers of different manufacturers are well suited for bromoil printing; it is, however, advisable to make a preliminary investigation as to the amount of hardening they have undergone, for it occasionally happens that different emulsions of the same brand show quite different grades of hardening, so that on one occasion it is possible to make bromoil prints on them without the least difficulty, while the same paper at another time may absolutely refuse to take the ink. On account of the great popularity of the bromoil process in recent years, it can be easily understood that some manufacturers might seek a wider sale for their products by claiming for them a special suitability for this process. It is therefore a wise precaution to previously test even those brands which are advertised as specially adapted for bromoil printing, and not to depend too much on such claims.

Development.—The processes of tanning in the film of a bromide print, produced by the bleaching of the silver image, which will be described later, are of an extremely subtle nature. We must therefore endeavor to avoid all causes for damage in this process and especially everything which tends to harden the whole film even to the slightest degree. Any tanning, which affects the whole gelatine film, has the same effect as general fog in a negative. It is well known that almost all the developers used in photography have more or less tendency to harden the gelatine film. A very considerable damage to the bromoil print through the use of a tanning developer might naturally be imperceptible to the eye. Yet this may at times manifest itself in a very undesirable and disturbing form, especially when the bromide paper has been so much hardened in manufacture that it possesses only just the necessary qualification for bromoil printing. It may then happen that the last remainder of swelling capacity can be taken from the paper by the use of a tanning developer. However desirable it might be and however it might simplify the process to be able to use any desired developer in producing the bromide print, to avoid trouble it must be observed that the use of developers which tan the film may seriously influence the result, even though it is possible to get some kind of prints in many cases. If the worker is absolutely sure that the bromide paper which he is using is not strongly hardened and is therefore well suited for bromoil printing, he may undertake development with any one of the ordinary developers which he prefers.

The developers, which do not exercise a hardening influence on the gelatine, are the iron developer and amidol (diamidophenol hydrochloride). As the iron developer is not really suited to this purpose on account of certain unpleasant qualities inherent in it, it is advisable to use amidol for the development of bromide paper for bromoil printing whenever possible, and the best developer is composed as follows:

The sodium sulphite is first dissolved in water, and the easiest way is to pour the necessary quantity of water into a developing dish and sprinkle the pulverized or granular dry sodium sulphite into it while the dish is constantly rocked; solution takes place almost instantly under these conditions. Larger lumps, which would stick to the bottom of the dish, must be immediately stirred up. As soon as the sodium sulphite is dissolved, the amidol should be added and this will also dissolve immediately. The addition should be made in the order described, for, if the amidol is dissolved first, the solution is often turbid. If dry sodium sulphite is not available, double the quantity of crystallized sulphite may be used.

The amidol developer should be freshly prepared each time that it is used, as it does not keep in solution. The measurement of the quantities of amidol and sulphite given above does not need to be made with the most painstaking care, as small variations in the quantities are unimportant.

In using amidol developer the greatest care must be taken to avoid allowing amidol powder, in even the smallest quantity, to come into contact with the bleached print ready for bromoil printing. Even the finest particles of amidol, although invisible to the naked eye, will produce yellowish brown spots on the gelatine which penetrate through the film and into the paper itself. These dots and spots, especially if, as is usual, they occur in large numbers, will make the print completely useless, and it is impossible to remove them.

If amidol developer is not available, any other developer which is desired may be used. As we have already stated, however, certain possibilities of failure are to be anticipated, but will not necessarily occur.

Every effort should be made to produce a bromide print as perfect as possible, with clean high lights.

The best bromide prints or enlargements for bromoil printing are those which are correctly exposed, but are not developed out to the greatest possible density. A print which is thus fully developed is very satisfactory as a bromide but offers certain difficulties in bromoil printing, which will be described later. Therefore the development should be stopped as soon as the lights show full detail without any fog, but before the shadows have reached full density. The deepest shadows should then be of a deep greyish black, but should not be clogged up. When a bromide print is properly exposed, there is sufficient time between the appearance of the details in the lights and the attainment of the deepest possible black in the shadows to easily select the proper moment for cessation of development. It is, however, desirable not to go beyond this stage of development, for the reason that a very dense silver deposit distributed completely through the gelatine emulsion to the paper support is not easily bleached out. When this difficulty occurs, the bleaching solution is generally, but incorrectly, blamed for it. If, in spite of this difficulty, complete bleaching is attained, the shadows of the image usually retain a yellowish color which cannot be removed by the baths which follow the bleaching. If it is intended to ink up the whole surface of such a print, this discoloration of the shadows is not important, for it will be completely covered by the ink. But if the print is to be treated in a sketchy manner, and some parts of its surface are not to be inked, this cannot be successfully done on account of the yellowish coloring of the shadows.

Underexposure must be carefully avoided, for details which are not present in the bromide print will, of course, not appear in the bromoil print.

Overexposure will occasionally give usable results, if the development of the overexposed print is stopped at the proper point. In such cases, we must usually expect some deposit in the high lights and consequently a certain fogging of the image, though this can often be overcome, at least partly, by swelling the print at a higher temperature. Perfect prints cannot be expected, if the basic print is lacking in quality. If the overexposure is not too great, the print can be improved to a certain extent by clearing it in very dilute Farmer’s reducer. Treatment with this reducer has no deleterious effect on the later processes. The Farmer’s reducer should only be used for a slight clearing up of too dark parts of the bromide print; for this purpose the parts of the moist print which are to be reduced should be gone over with a brush dipped in very dilute reducer and immediately plunged into plenty of water, to avoid any spreading of the reducer into other parts of the image.

Developing fog should naturally be avoided as much as possible. Fogging of the bromide print is caused by the formation of a more or less dense silver precipitate without any relation to the image over the whole surface of the print. As the bleacher takes effect wherever metallic silver is present in the film, the result in such cases is a general tanning of the film, which is detrimental to the production of the necessary differences in swelling power in the gelatine. The tanned gelatine image is then also fogged.

Consequently the best results may be obtained from very brilliant, but not excessively developed, bromide prints.

We must also avoid falling into the opposite extreme in the development of the bromide print, by getting too thin prints lacking in contrast. In prints which are too thin, only a very small quantity of metallic silver has been reduced in the development, and this lies wholly on the surface of the film. Such prints usually show full detail, but the contrasts between the lights and the shadows are too small. Since the tanning produced by the later bleaching occurs because of the presence of metallic silver in the film, and since its intensity depends on the quantity of this silver, we cannot obtain the necessary difference in swelling power by bleaching the film of prints which are too thin because of insufficient development. The result is a weak tanned image in the gelatine film; bromoil prints thus produced can consequently only exhibit a very short scale of tone values, and this cannot be essentially lengthened by the use of the bromoil process alone. Such bromide prints may find a special application in combination transfers, which will be described later. It is also possible, under certain circumstances, to use incomplete development as a method for producing soft bromoil prints from contrasty negatives.

Control of the Silver Bromide Print.—Although in bromoil printing the most various renderings can be obtained from a perfect bromide print, by variation of the temperature of swelling and by proper handling of the inking, it is also possible, under some circumstances, to vary the final result by proper treatment during the making of the bromide print, especially when we are not dealing with normal negatives. If, for instance, we have to deal with a very thin negative, it is possible that even the extreme possibilities offered by the bromoil process are not sufficient to insure the attainment of the desired modulation, for, as will later appear, the possibility of increasing the difference in swelling in the film is limited by the limited resisting power of the gelatine. In such cases, we must take advantage of the accumulation of all possible aids and therefore, in making the bromide print, do all that is possible in order to bring out desired objects, which are only indicated in the negative and do not show sufficient detail.

Therefore, if we desire to increase the contrast of the negative in the final print, we should use a harder working paper and add potassium bromide to the developer.

If we desire to get soft prints from a contrasty negative, we may use different methods. The simplest way is the use of a very rapid and consequently soft working paper. Ordinarily, however, this method is not sufficiently helpful. We must therefore also use suitable methods in later steps of the process, such as making the difference in swelling in the gelatine layer as small as possible in order to bring down the contrast, or inking up with soft inks.

A very reliable process for the production of soft prints or enlargements, even from contrasty negatives, is the following: the proper exposure for the densest portions of the negative should be first determined by means of a trial strip; then a full sized sheet of paper is exposed for exactly the time which has been determined, soaked in water until it is perfectly limp, and then placed in the developer. As soon as the first outlines of the image appear, the print is placed in a dish of pure water and allowed to lie there, film down. As soon as development has ceased, the print is taken out of water, dipped into the developer for an instant, and then immediately put back into the water. This method requires considerable time for full development, but produces prints or enlargements of especial softness. In this process, the developer which is absorbed by the film is soon exhausted in reducing the heavy deposit in the shadows, so that their development ceases, while enough developer still remains unexhausted in the other portions of the image to keep on developing. With very dense negatives, developer warmed to 25° C. (77° F.) can be used for the production of soft prints, but it must be very much diluted and carefully used, for development proceeds very quickly. Very soft prints may also be obtained by bathing the exposed bromide prints for about two minutes in a one per cent solution of potassium bichromate before development. This solution is thoroughly washed out of the print, and it is then developed.

Yet with very hard negatives all these remedies frequently fail, because the high lights are almost completely opaque to light because of their density. In such cases the negative itself must be improved. The ammonium persulphate reducer usually recommended for such plates, which acts more strongly on the lights than on the shadows, is, however, too uncertain in its action and may imperil the negative. It is better to adopt Eder’s chlorizing method, which enables one to improve too contrasty negatives in a convenient and certain manner. The principle of this process is as follows: the metallic silver of the negative is converted into silver chloride, which is again developed. This redevelopment is accomplished in such a way that the silver chloride on the surface of the film is first reduced to metallic silver; if development is continued, the reduction is continued to the bottom of the film. The delicate details, lying on the surface of the film, are thus first developed, while development of the overdense high lights, in which the silver deposit extends right through to the glass, is finished only after some time. It is therefore possible to stop development at the instant at which the shadows and half-tones are completely redeveloped, while the overdense high lights are, for instance, only half developed, and therefore only half consist of metallic silver, the lower half being still silver chloride. If the development is interrupted at this stage and the negative placed in a fixing bath, the still undeveloped silver chloride is dissolved. The shadows and half-tones thus retain their original values, and only the overdense deposits in the shadows are reduced. If the development is not stopped at this stage, but is carried through to completion, the negative is obtained unaltered, and the process can be repeated. If the second development is stopped too soon, the negative may be endangered and a very thin negative, lacking in contrasts, obtained.

The practical application of the chlorizing process is effected by bleaching the negative in the following solution:

As soon as the negative is completely bleached, which should be judged not only by transmitted light but also by examination from the glass side, it should be well washed and immersed in a slow-acting developer. All these processes can be carried out in daylight, and the second development of the negative is best controlled by frequent examination of the glass side. Development should be stopped when the shadows and half-tones are blackened, and there is still a whitish film of silver chloride in the high lights. Observation of the negative by looking through it is not advisable, for the negative very soon appears dense by transmitted light, because the metallic silver formed in development masks the silver chloride. As soon as the development is considered to have gone far enough, the plate should be rinsed and then fixed and washed in the usual manner. After a few trials, the judgment of the correct stage at which to stop development presents no difficulty.

I ordinarily use the chlorizing process in the following way, which practically excludes any possibility of failure: the negative is completely bleached in the solution just mentioned, and then washed for five minutes. It is then developed in any desired developer until it shows by transmitted light practically the same density, though in a brownish color, as it had before chlorizing. It is then rinsed off, placed in a solution of hypo, not stronger than two per cent, and carefully watched by light passing through the plate; it is taken out as soon as the desired stage is reached, well washed, and dried. In this modification of the chlorizing process the condition of the plate can be observed at every stage. The final negative, to be sure, does not consist of pure metallic silver, but as a rule of a combination of silver and silver chloride; but such negatives are sufficiently permanent for making prints and enlargements on bromide paper.

It is also advisable to lessen the harsh contrasts in a normal negative, either by masking the more transparent parts on the glass side, or by holding them back in printing or enlarging. Briefly, every possible means should be employed in order to obtain as good and harmonious a bromide print as possible.

The beginner is strongly recommended, however, in his first trials with bromoil, to start as far as possible with normal negatives and correct, and especially very clean, bromide prints. The use of this process for the improvement of the results from difficult negatives should be left for more expert workers.

It is often desired to provide landscapes with clouds, and this can be easily attained if enlargements are used as the basis for bromoil prints. Acceptable results are given by a process, which has often been recommended. This is, after blocking out the sky on the negative, to enlarge the landscape, develop the print and again place it while still wet on the enlarging screen and expose for the clouds, disregarding the existing image, and then develop the clouds.

I might describe here another process for obtaining clouds, because it is especially suitable for the bromoil process. If there is no object in the negative which is cut by the upper edge of the plate, it is extremely easy to introduce clouds into such a landscape, and at the same time lengthen out the picture at the top. A cloud negative suitable for the landscape is chosen, and the relative exposures for the landscape and clouds found as accurately as possible by test strips. The landscape negative is then focused on the enlarging screen so that there is plenty of paper above the upper edge of the plate, and then the exposure is made while the upper part of the paper is covered with a card, which is kept moving constantly between the light source and the enlarging screen, so that the upper edge of the plate is not imaged on the screen. After the exposure is finished, the paper is shifted down on the screen until the upper edge of the paper comes at the place which was previously occupied by the edge of the plate, the landscape negative is changed for the cloud negative, and the clouds are exposed on the upper and hitherto unexposed part of the enlarging paper, while the landscape is protected from exposure by means of a piece of card, shaped like the previous one for the sky, and continually moved to avoid a sharp line of separation. In the subsequent development a perfectly uniform picture is obtained, in which there should be no visible trace of its compound nature.

Obviously, in the preparation of the bromoil print, it is advisable to employ to the utmost the many possibilities which bromide printing offers. Thus too thin parts of a negative may be held back by proper blocking out on the back and numerous other possible modifications, which have been described in textbooks and technical journals, but which cannot be further dealt with here, may be profitably employed.

Fixation.—The developed bromide print should be well rinsed and fixed in the usual way. If the rinsing is omitted or is too superficial, complete or partial reduction phenomena may occur in the fixing bath, and make the print unusable.

The bromide print should be left in the hypo solution for about 10 minutes, and care should be taken, if several prints are simultaneously treated, that they do not stick to one another. Then should follow thorough washing for removal of the hypo; if traces of hypo remain in the film, the subsequent bleaching is rendered more difficult, as the image does not disappear but only turns brownish. While it is feasible to subject the bromide print to the bleaching process, as soon as it comes from the washing, an intermediate drying is an advantage; for the gelatine gains greater resistance by this drying.

CHAPTER II
THE REMOVAL OF THE SILVER IMAGE

Bleaching.—The bleaching process has the purpose of making the bromide print, correctly prepared according to the previously described method, suitable for the bromoil process. To this end the silver image must be made to disappear and in its place that condition of the gelatine produced which renders it possible for it to take up the greasy ink. The bleaching solution has, therefore, two functions: it must remove the metallic silver, imbedded in the gelatine film, which forms the bromide image, and at the same time cause a tanning of the gelatine film corresponding to the image that disappears. In the place of the silver image there then exists an invisible tanned image in the gelatine film.

There are a large number of chemical compounds known to photographic technique, which enable us to dissolve out the metallic silver imbedded in the gelatine film. Such are, for example, the many reducers which have found practical application. Many of these chemicals also cause changes in the gelatine simultaneously with the solution of the silver. But not one of the hitherto known bleaching solutions possesses the double power required of it: solution of the silver image and corresponding tanning of the film. Some produce too great a tanning which acts upon the whole film, and the result in inking-up is muddy flat prints, which do not lend themselves to artistic modification. With other bleaching solutions a differential tanning of the gelatine is produced, but at the same time they so alter the surface of the gelatine that it becomes glossy all over, and only takes even soft inks with difficulty.

My experiments have led to the compounding of a bleach which completely fulfils the requirements set for it; the silver image is quickly and completely removed, while simultaneously a tanning of the film, strictly analogous to the disappearing image, is effected; easier and more certain inking-up is rendered possible, and besides this the advantage is obtained that the differences of relief, produced in the gelatine by the bleaching process, can be influenced to a wide degree by varying the temperature of the water. The composition of this bleaching solution, which prepares the gelatine film in the most perfect manner for the bromoil print, is as follows, three stock solutions being required:

A concentrated bleach is made by mixing:

To every 100 ccm of this mixture should be added 10 drops of pure hydrochloric acid (10 drops to 3½ oz.). This concentrated bleach will keep indefinitely and should be diluted before use with three to four times its volume of water. The use of a more concentrated solution is not advisable, as irregularities frequently occur in consequence of too rapid bleaching, especially towards the margins of the prints.

The color of the concentrated bleach is green, or when diluted, yellowish; the solution must be absolutely clear. When the stock solutions are mixed there is usually some cloudiness, but this is cleared up by the hydrochloric acid. By standing for a long time at low temperatures a precipitate is sometimes formed, but this is of no moment. The compounding of this bleach should be made with the greatest accuracy. Inaccuracies or modifications in its composition are serious, because although the solution does not lose in bleaching power, yet the invisible tanning action is then often not completed in the desired manner. Too great an addition of hydrochloric acid for example, accelerates the process of bleaching, but the inking-up of prints thus bleached is frequently difficult. If the bleaching of the shadows of the bromide prints goes on slowly, the reason as a rule lies in the fact that the prints were overdeveloped and have an excessively dense silver deposit.

The bromide prints should be immersed in this bleaching solution, after previous soaking in cold water. If they have been correctly made, the image rapidly grows weaker and after a few minutes its greyish-black color changes into a pale citron yellow. If the bromide print was developed too far, the bleaching takes rather longer, as the shadows, developed right through to the base, require a lengthy period for solution. If several prints are to be bleached at once, the best procedure is to place one print in the solution and turn it film side down when the first traces of bleaching are noticeable. Then the next print should be immersed with the film up and by thus proceeding gradually it is possible to bleach a large number of sheets simultaneously in the one dish. Continual movement will prevent the formation of air bells. If air bells adhere to the film, they protect those places from the action of the bleach and dark points or spots of unchanged metallic silver remain, the subsequent bleaching of which naturally prolongs the process. The same applies to prints which lie on top of one another.

With too slow bleaching, the hydrochloric acid may be gradually increased, at the most to double that prescribed; one should not hasten the bleaching process by warming the solution. The bleaching is rapidly effected in warm solutions; yet generally the film of moderately hardened papers is so altered that they swell up too much even in cold water and take the ink badly or not at all. The dilute bleaching solution will keep and may be used repeatedly as long as it acts; when it becomes exhausted, the slowing up of the bleaching cannot be hastened by the addition of hydrochloric acid. The chemical reactions in the bleaching bath are, according to Dr. P. R. von Schrott, as follows:

2CuBr₂ + Ag₂ = 2AgBr + Cu₂Br₂

The cuprous bromide, Cu₂Br₂, which is formed, reduces the bichromate as follows:

3Cu₂Br₂ + 6CrO₃ = 3CuBr₂ + 3CuCrO₄ + Cr₂O₃.CrO₃

It sometimes happens that bromide prints, in spite of long immersion in the bleaching solution, apparently will not bleach and only change their color to brown.

The reason for this usually unimportant phenomenon is, as a rule, that such prints have not been sufficiently washed and still contain hypo.

It may also happen that prints which have lain on top of each other in washing are badly washed in parts; then the image bleaches, but the film shows dark patches or streaks at those places which still contain hypo. Such apparently unbleached prints should be left for about 10 minutes in the bleaching solution; the disturbing coloration, whether of the whole picture or only of parts, disappears completely in the subsequent baths, even when the image had apparently remained at full strength.

If such a print, apparently not bleached or spotty, is immersed in the sulphuric acid bath mentioned below, the discoloration of the film is quickly removed by its action; the print then often passes through a phase in which it appears to be a negative, the secondary image becoming visible on the yellow ground, and then bleaches out completely. With such prints it may also happen that it is only noticed after removal of the stain that unbleached traces of the silver image still remain. Then the bleaching must be repeated.

If the color of the bromide print only changes to brown even after protracted immersion in the bleaching solution, otherwise retaining full gradation, and remaining unchanged even in the sulphuric acid bath, though it bleaches out in the hypo, the print cannot be inked. The reason for this difficulty is improper composition of the bleaching solution, or occasionally improper development and fixation of the bromide print. It may also be due to excessive use of the bleaching solution; 3 to 4 ccm (50 to 70 minims) of concentrated bleaching solution should be allowed for every 13 by 18 cm (5 by 7) print.

Obviously all these processes may be carried out by diffused daylight. The bleached-out prints should be repeatedly washed, until the drainings are quite clear, and should then be immersed in the following bath:

In this bath any remaining color disappears quickly and completely, and prints, which have apparently wholly or partially resisted bleaching, are also very rapidly decolorized in this bath. Any spots and streaks also disappear. If, however, there is anything left, then the bleaching was not complete, and unreduced metallic silver remains in the film. After the sulphuric acid bath the prints should show the pure color of the paper base; the film side ought to be hardly different from the back in color. With prints that have been overdeveloped, a certain slight variation of color remains in the film, which, however, in no wise prejudices the inking-up. If there are still some spots, they are usually due to a slight precipitate lying on the surface of the film, which can be easily swabbed off. When this point of colorlessness is reached, and it usually requires only a few minutes, it is useless to leave the prints longer in the acid bath. They should be washed in repeated changes of water and immersed in the following fixing bath:

The use of this fixing bath is essential and is based on the following considerations. During the bleaching process a secondary silver bromide image is formed in the gelatine film. This secondary image is not visible on white and yellowish bromide papers, because it is whitish-grey. If a bleached print, which has not been fixed, is exposed for a long time to daylight a distinctly visible blue-grey image is formed, which naturally is troublesome in the further operations. This secondary image of silver bromide is completely removed, however, by the fixing bath.

The ordinary acid fixing baths can also be used without disadvantage for fixing. If the sulphuric acid is not sufficiently washed out, decomposition of the fixing bath may ensue, which will be made apparent by the unpleasant smell, and which is prejudicial to the action of the bath. Care should be taken that the prints do not stick to one another in the fixing bath and that they are thoroughly fixed out, as the secondary bromide image that is not removed will make its appearance in insufficiently fixed places and may cause darker patches.

Washing then completes the preliminary preparation of the prints.

For the sake of completeness it should be mentioned that the prints may be immersed in the bleaching solution in the darkroom after the first development, and can be fixed after the solution of the silver image. This shortened process is, however, uncertain and can not be recommended.

The Intermediate Drying.—After the bleaching process outlined in the previous section the print must be dried without fail. While drying after the development and fixation of the bromide print is advisable but not absolutely necessary, the intermediate drying after bleaching is of the greatest importance. It is possible that the later operations may be successful in spite of neglect of this recommendation. As a rule, however, various mishaps occur when the intermediate drying is omitted. In many cases the ink can only be caused to adhere with difficulty, in others, not at all; sometimes the inking will proceed up to a certain point and then suddenly completely stop. Sometimes the image appears as a negative, that is to say, the ink is taken up by the high lights and rejected by the shadows. All these failures will be obviated by the intermediate drying at this stage. Whether this intermediate drying takes place rapidly or slowly is practically immaterial; naturally it ought not to be so prolonged that the gelatine suffers.

The prints thus prepared can either be again soaked in water and immediately worked up, or kept and treated at any time. It is very convenient, especially for an amateur, to have a stock of such ready prepared and dry prints, because he is then in a position to work when he finds time and opportunity. The prints, prepared and dried as has been described, will keep indefinitely. With correct treatment there can be seen on the gelatine film of the dry print scarcely a trace of the bleached-out image; only in the very deepest shadows a slight coloration of the film, tending to grey, can sometimes be noticed. It is advisable, therefore, to mark the print on the paper side before bleaching, as otherwise it is subsequently difficult to distinguish this.

Before we go any further, the whole preliminary process is summarized once more:

• Development,
• Fixation,
• Washing,
• Bleaching,
• Short washing,
• Sulphuric acid bath,
• Short washing,
• Fixation,
• Washing,
• Intermediate drying.

CHAPTER III
THE INKING-UP

The Production of the Differential Swelling.—In the chapter on the bleaching we fully explained the processes which take place in the gelatine film under the action of the bleaching solution, and that the most important result of the bleaching process, aside from the disappearance of the silver image, is the formation of different degrees of swelling corresponding to the primary image, which in their totality form the tanned image produced in place of the photochemical image by the bleaching.

For the success of the bromoil print, it is now of the utmost importance that the different capabilities of swelling, now latent in the gelatine film, should be satisfactorily utilized. It is obviously possible to produce this swelling in very different degrees. The colder the water used for the swelling, the smaller the difference between the lights and shadows, while the warmer the water the more this difference is accentuated. If, for example, a print prepared for the bromoil process is placed in cold water and allowed to swell for some minutes, the existing capacity for swelling will only be excited to a slight degree. The high lights of the invisible image only take up a little water, and when dry are differentiated from the shadows under oblique visual examination by a very delicate gloss or not at all. If this picture is now worked-up with greasy ink, a print is obtained with a short scale of gradation, and its tone values are usually less satisfactory than those of the original bromide print. If, on the other hand, the print is placed in very warm water, the swelling of the gelatine reaches a maximum. The high lights are very much swollen, even the half-tones are somewhat raised, and the shadows, which do not absorb water, appear sunken. The result of the swelling in such warm water in this case is the formation of a very pronounced relief, that is not only visible, but is almost perceptible to the touch. If such a picture is inked up, a bromoil print is obtained, the contrasts of which are much stronger than those of the original bromide print. Between these two extremes there is obviously a whole series of intermediate stages, the suitable employment of which permits of the most varied gradations.

As already mentioned, the capacity for swelling of the different makes of bromide papers is not the same in baths of the same temperature. This fact, however, argues neither for nor against the usefulness of the various bromide papers. It makes necessary, to be sure, a certain care in the use of a paper, the qualities of which are unknown. If one has to deal with such a paper, the prepared print should first be soaked in quite cold water; it should then be removed from the water, placed on a support, dried in the manner to be later described, and examined by oblique illumination as to whether the high lights show by a slight gloss that they have absorbed water. This will be the case if the image shows well swollen high lights; if they are not present, it will hardly be possible to find distinctly glossy places. In any case one may begin with the inking-up, prepared, as will be explained later, to increase the swelling if necessary during the inking-up by immersion in warm water. If on the other hand, the print, when taken from the cold water, distinctly shows places where differences of swelling are shown by a gloss or even a delicate relief in the film, the work may be proceeded with, without further trouble.

Under any circumstance one should be careful at first in the production of the differential swelling. There should rather be no relief than too pronounced a one; for differences of swelling that are too small can be easily and satisfactorily increased during the work; on the other hand it is scarcely possible again to reduce too strong a relief. While learning, or when using an unfamiliar brand of paper, it is therefore advisable to allow the sheet to swell first in cold water and to carefully begin the inking-up. Only if this is not satisfactory, should a warmer bath be used and the inking again tried. This method is, however, dealt with more fully in the section of Chapter III, entitled “Different Methods of Working” ([page 85]).

The Properties of the Relief and its Influence on the Character of the Picture.—In order that the following explanations may be understood, an important property of the prepared and dried gelatine film must be mentioned.

The film of the prepared print, in which the differences of swelling necessary for the formation of the bromoil print are latent, develops variations of relief when it is placed in water. Then the untanned high lights absorb water, as already described, while the hardened shadows do not absorb it. The result of this process is the formation of those swellings, which, when they have attained a certain degree, are characterized by the formation of a relief.

A definite degree of swelling corresponds to a definite temperature of water. This swelling disappears again if the film is dried. The gelatine has, however, acquired the property of again attaining the same degree of swelling when immersed in water at any time after drying, even if the temperature of this water be a good deal lower. A print, for example, on which a certain relief has been produced in water at 35° C. (95° F.) and which has given up this water again because of drying, again attains the same relief if immersed in ordinary tap water at 10° C. (50° F.). If, however, this print after drying is immersed in water at 40° C. (104° F.), that is in hotter water than that first used, a still higher relief is obtained, and again in a similar manner, after drying, it will attain this higher relief when immersed in water at any lower temperature.

The degree of swelling that is once attained can, therefore, so far as the resistance of the gelatine film will permit, be increased, but it cannot be reduced, if the print as a whole is not subjected to a tanning, as with formaldehyde, a process that is not easily controllable. This peculiarity of gelatine makes it necessary to go to work carefully in the formation of the relief, so as not to carry the latter too far. If the work is begun on a too low relief this can be easily increased to the necessary height, as will be shown later, absolutely without any regard to any inking up that may have been done. On the other hand, if the formation of the relief has once been carried too far, as a rule the print can not be used, although reduction of the excessive swelling by a tanning agent may be attempted.

The property of the gelatine film, just described, offers a further convenience for the bromoil worker; for he can bring the bleached and dried print to the necessary degree of relief in water of suitable temperature, and, if he does not wish to work it up at once, it can be dried and laid aside until needed. In working-up such prints he is then, as a rule, relieved of the necessity of obtaining warm water.

The question how far the swelling of the film has to go or in other words what kind of a relief should exist, if any, in order to obtain a harmoniously graduated bromoil print, is extremely difficult to answer. A few practical trials quickly give the ability to judge this correctly. If a well-modulated negative is used, one in which the differences of gradation between the high lights and the shadows are not too great, the swollen gelatine film after drying should show a very delicate but still noticeable relief; yet the high lights of the print should scarcely be raised above the shadows, and should not show too marked a gloss.

The visibility of the relief is essentially determined by the character of the print. The more contrasty the bromide print was, the more easily are the different degrees of swelling made apparent by the formation of a visible relief. A picture with sharp outlines and great contrasts, such as an architectural study, easily gives a distinct relief visible in all its details. Pictures with softer gradation, as, for instance, delicate portraits, behave differently. One can not expect a striking relief in such prints. If this should be forced by warming the water, the bromoil print may easily attain an undesirable harshness. With portraits, one should therefore be satisfied when the outline of the profile against the background, the contours of the eyes and the mouth, are raised to a barely visible extent from the gelatine base. At the same time very dense parts, like a white collar, a lady’s light dress, lace, etc., may show a very distinct relief, even when the sharper lines of the face scarcely stand out in relief. Yet even in such cases the features can be recognized by the different gloss of the high lights and shadows under oblique observation. Naturally some attention must be paid here to the particular views of the operator. If strong contrasts are desired, greater differences of swelling must be used; if, on the other hand, softly modulated effects are sought, distinct relief must be avoided. In any case it is advisable not to attain this at once, but to get it as needed during the working-up by the use of water gradually increasing in temperature.

It must be laid down as an axiom that the efficiency of a relief should never be judged by the eye alone, but should always be carefully tested out by inking-up with the brush. The degree of swelling is correctly estimated at the first attempt when, in inking-up, the picture appears quite clearly after a little hopping, and this may happen if the character of the image is right, even though no relief could be seen.

The stronger the relief formed by warming the water, the more contrasty the bromoil print will be. Nevertheless there is a certain limit which should not be overstepped. If the print is warmed in the water bath so much that an excessive relief, which can almost be felt with the finger, is formed, in which deeply cut lines alternate with highly glazed places in relief, then the high lights are so saturated with water that under no circumstances will they take ink; even the softest inks will not adhere to them. Thus we obtain harsh highlights without details, while the deeply sunken shadows literally fill up with ink and become sooty. If the formation of the relief has been driven so far, it is not advisable to treat the print with ink.

The forcing of the relief to the extreme possible limit is only justified when working with a flat negative, in order to obtain as rich a gradation as possible from a flat print. Also, this should not be done all at once before the commencement of the inking-up, but effected gradually during the work. Working in this way, extraordinarily successful results can be obtained and the contrast of the bromoil print can be made far more rich than that of the original bromide print. The limit lies only in the resisting power of the gelatine film and the flatter the bromide print was the sooner this is reached.

The upper limit of temperature permissible for the water can hardly be defined; it depends entirely on the hardness of the gelatine film. It may happen that it is necessary gradually to go almost to the boiling point. Films that are hardened right through will withstand even boiling water without forming a relief.

If, in warming the print, the melting point of the gelatine is approached, those parts which are but slightly tanned, such as the high lights, and especially any unexposed edges, begin to show a granular structure, and finally, when the heating is carried further, to melt.

In the development of the relief great care should be taken that no part of the print remains dry, and, if the film is placed face down, air bubbles should be avoided. If the print is placed face up in the dish, no part of it should project above the water, as it will then not absorb enough water; if the swelling has already taken place and a part of the film projects above the water (and this frequently happens, as the print, which at first lies on the bottom of the dish, after some time rises to the surface), the relief of the exposed parts goes down after some time, since the water evaporates from them into the air. Such insufficiently swollen parts, or those which have dried out, behave exactly as though they had been tanned more than the other parts of the surface. They have been able to absorb little or no water, or have lost the absorbed water by evaporation. They therefore take the ink, like the tanned shadows, far more readily than they would if they had retained the right amount of water, and far more ink adheres to them than should be the case and than adheres to the correctly swollen parts of the film. Thus patches of different form and size are formed at these places by the stronger adherence of the ink. Yet by renewed soaking of the print in the water these neglected places may be easily brought anew to the correct degree of swelling, and as far as concerns small spots caused by air bells, can be easily corrected. If larger patches of the film are insufficiently swollen, after the application of the ink they are usually much darker than the rest of the surface, and in such cases it is not always easy to obtain again the necessary evenness of the ink; it is then often necessary to ink up the whole print much more strongly than was originally planned, or to remove the whole film of ink.

Besides the warm water bath there is also another means at our command to produce the differences of swelling. This is the use of ammonia. A. & L. Lumière and Seyewetz, in a treatise published in 1913, on the resistance of gelatine to alkalis, found that cold solutions of ammonia did not attack gelatine but caused it to swell more.

If a bleached print is immersed in an aqueous one per cent solution of ammonia, the film attains in a very short time the highest degree of swelling of which it is capable, without the gelatine in the high lights being softened or damaged. The estimation of the height of the relief, which is so important for the successful carrying out of the inking, is scarcely possible with the ammonia bath, as it is extremely difficult to gauge its action. Therefore, it should only be used in those cases in which the highest swelling is absolutely necessary, as for instance, when using papers which have been strongly hardened in the manufacture, or with prints with very poor contrasts. A further application is with the transfer process, in which on the one hand it permits of the use of very soft inks and on the other hand enables one to keep the gelatine very resistant. Full details on the transfer of bromoil prints will be found in a later chapter. In very extreme cases, one may try to combine the action of the warm water and the ammonia bath, and use a warm ammonia bath. The ½ to 3 per cent solution of sodium carbonate recommended by E. Guttmann acts even more energetically than the ammonia solution.

As is obvious from the foregoing remarks, it will be as well to work usually with water baths and leave the ammonia bath for a last resource, the more so as in the swelling of prints in this bath certain troublesome phenomena may appear, which do not occur when using the water baths. Sometimes the bleached image reappears in the ammonia bath in a brown color; sometimes small white spots appear on the prints which will not take the ink and which, as can be determined by examining them by transmitted light, also exist in the substance of the paper; finally the gelatine film sometimes swells all over, so that the ink is not taken up anywhere. Prints which are failures in consequence of the use of the ammonia bath, should be dried and can be again treated in a warm water bath.

The Utensils.—For the application of the ink the following are required:

Brushes.—A best quality oil-printing brush with very elastic hairs cut on the slant, the so-called stag’s-foot brush, should be used. To apply the ink, a brush should be used with a working surface of from 1½ to 2½ cm (⅝ to 1¼ in.) diameter; by diameter is meant the length of the longer axis of the elliptical surface produced by the slanting cut of the brush. For working-up very small surfaces or for placing accents of color, a brush of about ½ cm (³⁄₁₆ in.) measurement should be used. In certain cases still smaller brushes may be useful. Such brushes are only used for working up details; they are only aids for special work. For the application of the ink generally, only the larger brushes should be used. It is far more difficult to apply the ink evenly with small brushes than with the larger ones, so that their use may cause needless discouragement.

The application of the ink is effected by placing the whole working surface of the brush charged with ink on the print, and then slowly lifting it up; this results in a deposition of ink corresponding to the working surface of the brush used. The smaller the brush the more often it must be applied, and therefore, the greater the probability of irregular inking, especially in those parts where the brush marks overlap. Also small brushes are handled less conveniently than larger ones and smear easily. The first thing to do in inking a bromoil is to obtain a good, even, thin film over the whole surface, to get a general impression of the whole effect. Only then is one in a position to judge how the tone values should be varied. The use of too small a brush unduly protracts this first operation and makes it difficult.

The brushes should be elastic but not too soft. Too soft brushes smear, that is to say, they deposit the ink in a thicker layer at their edges than in the middle and produce elliptical rings of ink, which must always be evened out by hopping.

In determining the size of the brush, the size of the bromoil print must be taken into account. Generally it is easier to work with brushes of from 1½ to 2½ cm (⅝ to 1¼ in.) in diameter. For large sizes up to 30 × 40 cm (12 × 16 in.) brushes of even 4 or 5 cm (1½ or 2 in.) may be used. Such brushes are not cheap, but are practically indestructible, if they are properly cleaned every time after use. The brushes are sold in tubular paper cases; these latter should be preserved and the brushes, after cleaning, put back into them, so that they are covered and the hairs do not get ruffled.

In order to preserve the brushes and keep them in good working order, they must be cleaned as soon as the work is finished, otherwise the ink left in them sets and makes the hairs brittle.

Brushes of long swine bristles with cut ends may also be used; with these especially, clean prints are quickly attained. They are superior to hair brushes of poor grade.

The cleaning of the brushes is best effected as follows: Pour into a deep dish a readily volatile fat solvent, such as benzol, trichlorethylene, carbon tetrachloride (carbona), etc.; but not turpentine, for if this be used the brushes cannot be used sometimes for days. Dip the brush into the liquid and press out the solvent on the edges of the dish, and stroke the brush vigorously on a piece of lintless linen, which should be used for this purpose only. The solvent can be used, ignoring the opacity which it soon assumes, as long as it will dissolve the ink. Only the hairs of the brush should be dipped in the solvent, but not the binding, as in some cases the cement with which they are fastened may be attacked.

The Inks.—Theoretically, any ink prepared with a fatty medium is suitable for bromoil printing. In order to give satisfactory results, the inks must satisfy two conditions: they must have the correct consistency and their medium must be soluble in benzol. As regards the consistency of the ink it should be noted that the prepared film in its swollen condition, that is when the lights are saturated with water, absolutely repels greasy inks only when this swelling attains the highest possible degree; a case which one seldom needs and which will usually have to be avoided. If this swelling is not carried to the limit, the high lights, in spite of the water they hold, will take up the greasy ink, yet usually only when the ink is very soft. The swollen high lights thus repel ink of thicker consistency, while they take the softer inks more easily in proportion as they become thinner. That the tanned shadows also take hard ink is natural, for they do not contain, or contain only to a very small extent, the water which repels the ink. From these considerations it follows that in many cases satisfactory results cannot be obtained by using ink of only one consistency.

The hard or heavy ink should have about the consistency of table butter, and it should be possible to spread it into an even smooth film on a glass plate with light pressure. The soft or light ink should have about the thickness of honey and should spread under the knife without noticeable pressure.

Collotype or copper-plate printing inks of various makes are frequently usable. As a rule, however, they must be tested as to their usefulness for our process; their consistency is frequently too hard, and sometimes they are not taken up by the film or cannot be distributed well, even when they are considerable diluted with linseed oil varnish, in spite of an apparently correct consistency.

The nature of the ink is not only influenced by the greasy substance used as a medium, but also by the material of the coloring matter itself. This is why many inks, in spite of their apparent softness, work tenaciously or “short,” while sometimes inks of hard consistency smear.

If occasionally the dilution of an ink of too hard consistency appears necessary, this is best effected with linseed oil varnish, which, however, should not contain any driers. If the work has been begun with a stiff ink of a certain shade and it is desired to retain this tone to the end, it is advisable not to use a thin ink for dilution, but to thin down the stiff ink with varnish.

Inks of too hard nature are not practicable. Such were necessary in the oil-printing process. In the bromoil process, which is much less sensitive to the consistency of the ink, their use merely means a needless loss of time. An ink of correct consistency is easily taken up and produces quick drawing without smearing, while too hard inks are difficult to apply and soon refuse to take if they are not diluted.

It is extremely simple and advantageous to prepare the inks oneself, as outlined by E. Guttmann in Chapter VIII, [p. 177]. The process recommended by him is to place the powdered colors on a matt glass plate and rub up with varnish by means of a muller or pestle. This procedure is considerably facilitated, if, according to my suggestion, a few drops of a readily volatile oil-solvent be added. The ink is thus immediately liquefied and can be quickly and perfectly rubbed up. The solvent evaporates during the grinding, which is much easier than in the old way, and the ink again acquires the desired character without suffering in any way.

As a palette for the ink the best thing is a piece of waxed or parchment paper, fastened on a white support, such as a card. Such a palette has the advantage that after use it can be discarded without cleaning. Moreover the color value of the ink can be fairly easily determined on it. If necessary old negatives, or other glass, may be used as a palette, and their use also makes cleaning unnecessary, which is an unpleasant and messy job.

A small quantity of ink should be taken and distributed as thinly and evenly as possible on the palette. A thick layer is not convenient, as then the brush takes up too much ink and too much is deposited at a time on the bromoil print. The film of ink should show as smooth and uniform a surface as possible; thicker ridges should be avoided, because the brush is thus more strongly inked in spots and therefore transfers the ink unevenly to the print. The distributed ink should be perfectly homogeneous and flexible. A thin layer of ink sets to a skin on its surface after a short time and then cannot be used.

This setting also takes place in the body of the ink and becomes evident by the formation of a delicate skin or hard crumbly particles on the surface of the ink. These must always be removed; such hardened inks can only with difficulty be distributed on the palette. Finally it should be mentioned that hard inks may be slightly softened by warming.

The Support.—A stout glass plate or drawing board should be used as a support, and inclined at an angle of about 30 degrees by propping up at the top; a damp and elastic pad must be placed on the glass or board. This pad is not for the purpose of keeping the print damp during the working-up, as is usually stated; on the one hand this is superfluous in view of the possibility of repeated soaking, which is to be described later, and on the other hand it would not produce the desired result. It is erroneous to suppose that the water which passes from the damp support to the paper side can equalize the loss of water which the film suffers by evaporation from its surface. The pad should, therefore, only be so damp that the bromoil print adheres firmly to it, when under the brush. The pad should absorb and hold moisture; but this should not be imparted to the brush when it touches the pad in working-up the edges, otherwise water will be carried on to the print and cause spots. For this reason damp blotting paper or filter papers should be absolutely rejected for the pad. If such papers are used for the damp pad, the brush, which in working the edges must inevitably touch them, will not only take up water but also the paper fibers and, transferring them to the print, cause trouble. Moreover, sheets of paper in a damp state are difficult to lay smooth and are scarcely usable.

The best material for the pad is the copying sheets used for copying books, which consist of two layers of linen with an intermediate film of rubber. Such sheets have the advantage that when damp they always remain flat and smooth. A damp piece of linen, doubled and smoothed out, is also simple and certain. The pad must lie absolutely flat, because any ridges become most unpleasantly visible in inking-up, particularly with thin papers, as the brush always slips from the highest parts of the ridges and causes inequalities in the print.

Removal of the Water from the Surface of the Print.—After the prepared print is removed from the water and laid on the pad, the water adherent to its surface must be removed. This is best effected in the following way: Take a large, absorbent, lintless cloth, spread it smoothly over the print, and press it gently with the flat of the hand. By repeating this, the water is easily removed without endangering the film; whether the drying is complete can be judged by examining it obliquely. The freedom of the cloth, used for drying the print, from fluff and lint is of great importance. If the cloth gives up fibers to the surface of the print, these cannot be seen at first. In inking-up, innumerable minute dark spots and lines appear on the film, as the deposited fibers take the ink very strongly and thus suddenly become visible. It is frequently erroneously assumed that such troublesome defects come from the brush. This is seldom the case; on close examination these fibers will be seen to be particles of the textile material. When possible, linen that has been frequently washed should be used for the drying.

When the water is to be removed from a print that has already been inked and again soaked, care should be taken that the cloth is freed from any folds by damping and subsequent drying, for such folds can, when pressed on the print, damage the film of ink. Although this is not of material importance, as such faults can be easily evened out by hopping, yet these small precautions avoid unnecessary trouble. Sidewise or wiping movements of the cloth should be carefully avoided, especially if the print has already been inked, because the ink is unnecessarily smeared by the wiping. After removal of the cloth one should make sure by examining the print obliquely that the water has been completely removed from the surface.

It is advisable to keep several cloths ready for drying off the film, for this will have to be done fairly frequently during the work. Care should be taken to remove most carefully every trace of water; water which is picked up by the brush causes spots, for the drops of water in the brush keep the ink away from the points of contact. In such cases it will be seen that white spots make their appearance in different parts of the print, continuously shifting their position during the work. By perfect drying off, these phenomena, which are in any case not necessarily important as regards the final result, can be avoided. In drying off a print already inked-up, the cloth will as a rule remove some ink from the surface; such cloths should not be used again until they have been washed, because they may transfer ink to a place where it is not wanted.

The Brush Work.—The prepared print, lying flat on the pad, and with its surface freed from adherent water, should now be inked up.

Before beginning the application of the ink a little stiff ink, at least as large as the working surface of the brush, should be placed in a corner of the palette. This should be spread out flat, thin and free from ridges; then the knife should be wiped and a little soft ink spread in another place.

The brush should now be pressed down on the hard ink already distributed on the glass plate, and the ink dabbed very carefully from the brush on a clean place of the palette. One should never go with the brush direct from the ink itself to the print, as this will form a spot which it is difficult to work out. It is of the greatest importance always to work with a brush that has been well dabbed out and in which the ink is evenly distributed. If the brush has not been sufficiently dabbed out it leaves on the print a quantity of small, much darker and usually linear particles of ink, which cannot be distributed or are only removable with difficulty. Such spots must then as a rule be removed by the method described on [page 72].

The whole brush technique is based on the following principle: if the brush charged with ink is placed on the print and allowed to remain there for a moment, and then slowly lifted up, the ink remains on the image. If it is set down sharply and quickly lifted (the so-called “hopping”), it removes ink. In the first inking-up of a print, the swelling of which has been correctly carried out, the application of the ink may be effected by a gentle dabbing. A very thin film of ink is thus produced and almost simultaneously correctly distributed.

The brush should always be held by the extreme end between two fingers, never by the middle or near the hairs. The more lightly and more delicately the brush is managed the better it works.

It is best to begin the work at some characteristic place of the picture, which is well known to the worker; the ink should first be spread as delicately and evenly as possible on a small spot, avoiding, as far as possible, going over the same place twice with fresh ink. When the place selected has been covered with a light film of ink, the surface should be hopped over with light movements, when, with correct preparation of the print, the outlines will soon appear. A bromoil print correctly prepared, and with swelling suitable to the ink used, is easily recognizable by the fact that the image appears delicately but distinctly under the very first strokes of the brush. If this does not happen even after some time, either the degree of swelling of the print is too low or there is some fault in the preparation of the print, such as, for instance, unsuitable paper, a poor bromide print, errors in bleaching, etc. The longer the hopping continues, the more distinct the details should become. Then the application of the ink should be continued in places adjacent to those already worked up, until finally the whole surface of the print has been evenly gone over with ink and the image is visible in all its details, although still very thin and delicate. It is advisable to use a rough print from the negative as a guide.

Beginners usually make the mistake of jumping from one spot to another without filling up the intervening parts. This makes the work more difficult. Inking up should be carried out continuously by passing from those places already worked on to those not inked up. If it is noticed that the places which were first inked up appear too pale compared to their surroundings, since they have still too little ink, they should be inked up more strongly. Too dark spots should be evened out with the brush by removing the excess of ink and depositing it on the less inked parts. The amount of ink used on the print is very small; that which is first taken up by the brush lasts for a long time. It is not necessary to have frequent recourse to the ink spread on the palette by the knife, but is much better to take up, as long as possible, fresh ink from the spot on the palette on which the brush was dabbed.

On the other hand, however, every application of the brush to the print should actually deposit some ink on the print. If those parts touched by the brush do not increase in intensity, it must be determined whether the dark places on the palette from which ink is supposed to be taken, are actually giving up ink; for if the film of ink remaining on the palette is too thin, fresh ink must be deposited and distributed on it by the brush.

Care should be taken not to overload the brush with ink, for then the hairs stick together, distribute the ink badly on the print and, moreover, frequently leave large coherent particles of ink on the film, thus causing spots. As the brush is cut on the slant, it may happen that in dabbing out the brush on the palette and in the application of the ink to the print, the front and longer part of the brush is used more strongly. Then the ink collects at the back edge of the brush and causes spots when the brush is used more vigorously.

In many cases it is possible to complete the print with the hard ink alone. If it is noticed that the hard ink does not take well on the print and is removed again in lifting the brush, its consistency is too stiff for the work. One should not then continue to use it, but should soften the ink in the following manner: First place the brush in the hard ink and dab it out well in another place on the palette. Now dip the ends of the brush hairs carefully and very lightly into the soft ink and dab out the very small quantity of the soft ink taken up by the brush on the same spot, on which the hard ink has been previously distributed. There is thus formed on the palette as well as in the brush a mixture of the two inks. Now try carefully whether the now softened ink adheres well to the print, by placing the brush lightly on a light place of the print. If it leaves behind a light trace of ink without any trouble, the consistency is correct; but if this does not happen, the ink must be diluted again in the same way with the soft ink. If on the other hand the brush leaves behind a strong trace of ink from a light touch, the ink is too soft and requires the addition of some hard ink. It is not advisable to mix the soft and hard inks on the palette with the knife, as it is very difficult to strike the right consistency in this way.

This applies to all mixtures and dilutions of the ink which may be necessary in the course of the work, as in strengthening a colored ink with black, or in the preparation of any desired tint by admixture of different inks, and finally in softening inks with varnish. In all these cases mixing of the inks on the palette with the knife puts too much ink into use; also, as long as the ink is on the palette, one cannot estimate with the necessary exactitude either the tint or the consistency. The correct procedure is rather first to go with the brush to the first color and distribute this on a clean place, then set the same brush in the second color and make the mixture on the palette by dabbing. Then the mixture thus obtained should be tested as to its shade of consistency by gentle application to the print, and more of one or the other ink added in the same way with the brush. It should be noted that inks of a soft consistency go a very long way; the whole surface of the brush should never be dipped into such inks, but only the point of the brush. Softening of the inks with varnish should be effected in the same way.

When the first inking up is finished, the addition of ink of the same consistency is continued until the print is completed or will no longer take ink, which, as has already been pointed out, is known by the fact that the newly applied ink no longer adheres, but that the brush removes it from the print. Then one proceeds to a further dilution of the ink by taking more soft ink with the brush and adding it to that already mixed, and continues the work. The use of the unmixed soft ink is not even necessary in many cases. If, however, it proves to be necessary, it should be used, but with care, for a brush stroke which puts too much soft ink on any part of the print, especially in the shadows, causes a patch. The beginner will work most easily and successfully if he always keeps the applications of ink as delicate as possible and obtains depth only by a repeated and even coating of ink, fully distributed every time. If a place should still turn out to be too dark, one can try removing the excess of ink, if it be a hard one, with a clean brush. If a dark patch is formed by too vigorous application of a mixed or even a soft ink, another brush should be dipped into the hard ink, dabbed out, and the spot removed with this brush. Moreover, such places can as a rule be easily rectified after the second soaking of the print, which will be described presently. If the fault cannot be removed in this way, the ink must be partially or entirely removed, according to the instructions in Chapter III, [page 73], and the work begun anew. This should be done without hesitation by the learner if the application of the ink does not succeed as he desires; the prepared print can be used for practice like a school slate by washing it off after each attempt with a solvent of the greasy medium.

For the application and the hopping off of the ink for large areas of the print one should always use the whole working surface of the brush. Smaller surfaces or outlines should be worked up with the front edge of the slantingly-cut brush; in laying on the ink one should never continue with the point, because this bends and gives unpleasantly sharply defined ink edges. In order to cover a place with ink very thoroughly, one should hold the brush firmly, give it a slight twist and then raise it up straight and slowly. If it is desired to coat a whole print evenly with ink, it should be applied in stripes over the whole print, the brush being pushed forward and not necessarily completely lifted up from the surface. The brush is pressed down firmly, the pressure relaxed a little, the brush moved forward half its width, then pressed again, and so on. In this way with a little experience there may be produced perfectly even ink stripes which bring out the outlines of the image and which are made close together until the whole print has been gone over, when one begins with the hopping. With papers with marked structure these stripes are best made in the direction of the structure and not at right angles. Especial care should always be taken that the shadows of the print, which take the ink most easily, are not too strongly inked up, and one should try by light hopping to bring out all the desired details at the very first application of the ink. When the shadows have once taken too much ink, it is not easy to clear them up by brush work alone. The inking up of large deep shadows must always, therefore, be very carefully done. Such parts of the picture are the most strongly tanned and therefore take the ink very readily and hold it very tenaciously. They should therefore never be touched with a brush freshly charged with ink, but one should work on the heavier shadows only when the brush has given up the greater part of its ink to the less sensitive parts of the image. Even then it always contains enough ink for the darker parts of the print. The first application of ink in the shadows, especially, ought never to be heavy and cannot be kept too delicate. When the desired details in the shadows appear to be well defined, they should then be strengthened. But even this should not be effected by a single thick coating of ink, but by successive additions of thin ink films and hopping after each.

Especial emphasis must be laid on the statement that all details, which it is desired to have in the finished print, must be brought out by the first application of the ink. If parts of the image are strongly inked up before the desired details have appeared, it is difficult to develop these later. On the other hand, detail, which has been brought out in the first inking, cannot be suppressed by any further skilful application of ink, but only strengthened.

These phenomena can on the other hand be successfully used to prevent the appearance of undesirable details in the picture. If for artistic reasons one desires to suppress detail and work flatly, the parts in question should be inked up from the start more strongly and evenly, and the hopping be either entirely omitted or stopped before the details which are to be omitted are brought out.

For beginners especially, it is useful in applying the ink, as well as in hopping, to lift the brush after every few strokes and examine the results obtained, so as to decide on further procedure.

One should accustom oneself to examine the print from time to time at a certain distance, while it is being worked on; for the correct impression as to whether the tonal values are correctly chosen, can be gained only at a greater distance; it is then seen more easily and clearly whether or not individual parts of the print carry too much or too little ink.

Particular parts of the print, which one wishes to have more contrasty, should be gone over after the hopping with a wiping motion of the brush; the ink is thus removed from the raised parts of the relief. If one goes too far in this, the inking can be done over again in the usual way.

If it is desired to free a brush from the soft ink, it should be dipped into hard ink specially spread on the palette for this purpose, and dabbed out well on a clean place, and this operation repeated two or three times, using each time another part of the palette. At the end of this manipulation the brush will practically no longer contain anything but hard ink.

When one has once learnt the initial steps of brush technique, in the course of time one fails to notice the difference between the laying on and the hopping off of the ink. The hand in time acquires an instinctive handling of the brush, which takes care at once of both the application and the distribution of the ink; if the proper relation between the consistency of the ink and the degree of swelling of the gelatine has been hit upon, a simplified handling of the brush comes of itself, because then the application of the ink is especially easy.

When, with papers of rough surface, the grain of the paper remains white in the shadows, in spite of hopping, such places should be treated by going over them with the inked brush with light pressure with a rotary motion.

Practice teaches that there is always a definite consistency of ink which corresponds to a definite degree of swelling and with this the print may be executed from start to finish. If the operator has learnt by experience what ink consistency corresponds to the existing swelling of the film, he will prepare his ink of the suitable consistency, and is then in a position to carry out the work uninterruptedly without any new mixing of the ink.

It is a little difficult for the tyro to answer the question as to when the application of the ink should be stopped, that is to say, when the print may be looked upon as finished. There is frequently a temptation to consider the print finished when it is very delicate yet completely visible in all its details. The beginner often lacks the courage to apply more ink at this stage; he usually believes also that the print will take no more ink, because, as has been mentioned above, the part of the palette from which he has hitherto taken the ink, gives up no more. Such prints, which recall sketchy pencil drawings, deceive one during the work, but only satisfy later if this particular technique is suited to the character of the picture, which is certainly not always the case. One must therefore carefully consider during the work whether one should actually stop.

The second danger lies in the opposite direction, and is due to the fact that, led on by the constantly increasing vigor of the image, one cannot rightly decide when to stop. The danger here is that one is tempted by the vigor of some part of the picture to make the other parts also as strong in color, until by such continued action the print is immersed in the deepest gloom, which becomes still more gloomy after defatting the finished print. Such excess must be avoided as a rule. Experience and taste soon teach one to hit the happy mean.

The first, delicate and general application of ink, which may be considered as a guide print, is in many cases somewhat wearisome, especially when the picture has large areas of rich, deep shadows. With correct preliminary treatment of the print there are no real difficulties in the preparation of such a guide print. Yet the work, especially with large sizes, is really time-consuming and also offers, when considered from the artistic standpoint, but little interest, since the actual creative work of the operator only begins after the guide print is finished; only then is he in a position to actually give expression to his artistic feelings by suitable inking of the different parts.

Since, therefore, the work in the preparation of the guide print is actually quite mechanical, it is natural to make use of any means which enables one to facilitate and hasten this work.

For this there may be used, but only by the expert worker, a method based on the following considerations:

If an ink of suitable consistency is dissolved in a suitable solvent, such as benzol, carbon tetrachloride, trichlorethylene, etc., the pigment is very evenly disseminated in this solvent. If the latter again evaporates, the ink deposits in an even coating, unchanged in its nature.

It is therefore, possible, in the first application of the ink, to use such a solvent on the print and by its aid the wearisome mechanical work of the first inking may be rapidly and easily carried out.

In practice the method of procedure is as follows: there is first produced, on the print which is to be worked up, a relief which is vigorous enough to sufficiently develop all the detail in the shadows. An ink which is fairly stiff for this degree of swelling is chosen; the brush is first dipped in the solvent and then into the ink, which has been thinly spread on the palette. After a few dabbings on the palette the ink solution with which the brush is charged is spread on the print with a hopping motion and distributed with the same brush as evenly as possible. If the distribution becomes difficult in consequence of evaporation of the solvent, the brush should be again dipped in the solvent, and then the distribution can be easily completed. The film of ink thus obtained should be fairly thin, but must not be quite even.

After the complete evaporation of the solvent, the ink is worked up with a clean brush, with which the guide print can be finished without trouble and in the briefest time.

There are also other variations of this method of the application of dissolved inks. For instance, one may first apply some ink with the brush to the print and then distribute it with a second brush dipped in the solvent; one may also prepare a solution of the ink in a dish and paint it on the picture, or bathe the whole print in a solution of the ink. All these variants, especially the last two, have, however, certain disadvantages, so that the procedure first outlined is to be preferred.

After the guide print is prepared in this way, the further application of the ink is carried out in the normal manner.

The solvent is most conveniently chosen so that it is not too volatile, as for instance heavy benzol. But it ought not to contain any oil. When placed on the surface of the hand, it should evaporate fairly slowly, but without leaving any trace of grease.

Certain failures, which sometimes appear in this process, must be mentioned. If the film of ink is too thin, it can be repeated without further trouble in the same way, with rather more ink. If, on the other hand, too much ink is applied, a complete image is immediately formed without any possibility of the shadows being worked up. In this case the ink must be again removed by the solvent. If individual parts of the picture are too dark, from too much ink, it is sufficient to go over these parts with a brush dipped in the solvent, in order to clear them up.

If, after evaporation of the solvent, great irregularities in the distribution of the ink are seen, as for instance, spots and streaks which cannot be easily worked out, the print should again be placed in water; after drying off, the evening-up may be carried out without difficulty.

If in hopping with the second clean brush the image does not appear at once without trouble, either the relief was too low, or the ink too soft, or the solvent contained oil.

The ink can obviously be placed on the bromoil print not only with the brush but with any other suitable ink carrier, such as rollers. Yet by this the process is rendered more mechanical and deprived of all those great advantages, which distinguish it from all other printing methods. Especially, the possibility of local treatment is mostly lost; the unlimited command of the tonal values and the structure of the ink can only be guaranteed by the use of the brush. The only offset to this loss is a gain in speed. Agility, however, is not sought after in artistic labors. If one wants to prepare a lot of prints quickly, it is better to use the bromide process, which is especially suitable for such a task, and thus save the trouble of the bleaching and the other processes necessary in making bromoil prints.

Resoaking of the Print During the Working-up.—Resoaking the print during the inking up, without regard to the existent film of ink, is one of the most important aids in the bromoil process.

This procedure is based on the following considerations: It has already been pointed out that the prepared gelatine film possesses the property of again assuming after drying the same degree of relief which was imparted to it by the warm water bath. When a swollen print is taken out of the water and placed on the pad for working up, evaporation immediately begins at the surface of the film; the gelatine, therefore, continuously gives up water to the surrounding air during the work, and more quickly in proportion as the air is drier and warmer. As has already been mentioned, the damp pad does not alter this, since the supply of water from the pad through the paper is not sufficient to restore the water content of the film. Therefore, while one inks up one part of the print, all other parts gradually lose their water; and since it is this water which renders the gelatine, after its tanning, capable of repelling or taking the greasy ink, the work gradually becomes more and more difficult. The gelatine film, which feels smooth when the film is removed from the water, especially in the high lights and any exposed margins, becomes gradually leathery. It may still take ink, but the distribution of this, and especially the development of the drawing and the details, become more and more difficult.

If, however, the print, which is partly or entirely inked up, is again placed in water and this time in cold water, the gelatine film very rapidly absorbs this and again attains the same degree of relief that it had at first. Sometimes it appears as though a marked clearing up of the image takes place in the water; the high lights become cleaner, and many details appear in the shadows which were not visible during the working-up. On the other hand, with some inks the picture appears to become weaker under the water. This, however, is only an illusion and is of no importance, as in drying, or in again going over the picture with the brush, the image again attains the previous depth and color and still greater clearness.

Here also, one must take care that the print is completely immersed and that no air bells adhere to the film, since those places to which the water does not have access do not reswell, and on further work may give rise to spots. In removing the print from the water the inked-up surface should not be touched with the fingers, or finger prints will remain in the ink. The print should therefore be taken hold of by the edges.

While the print is soaking in the water, the bringing out of the details, especially in the shadows, may be facilitated by stroking those parts with the tip of the finger or a swab of absorbent cotton. In the same way dirt which has collected on the surface during the work may be removed. In the latter case one may also use more vigorous friction, even though the ink film is thus removed, since the removal of the troublesome particles is more important than saving the thin film of ink, which can be easily renewed.

The print is then removed from the water, placed on the pad, and dried as previously by spreading over and pressing down a lintless cloth, although because of the film of ink any wiping action should be avoided. Then when the brush work is resumed, it can be completed in an extraordinarily easy manner.

It should be specially noted that the print must be worked up after this second soaking with the same brush as before, which need not be recharged with ink. Only after the print has been hopped in this way, should fresh ink be applied.

During the work, the bromoil print, as a rule, will scarcely retain the necessary degree of dampness longer than a quarter of an hour, and not this long in dry and warm weather.

The resoaking of the print should be undertaken without hesitation as often as any difficulty in the distribution of the ink is met with; for this saves a great part of the brush work, and almost automatically brings out contrasts and details. Especially while learning the process and later with more difficult prints, the work is most conveniently divided as follows: first application of the ink and distribution by hopping, as long as it is easy; resoaking the print; drying off and hopping anew with the brush not freshly charged with ink; second application of the ink and hopping of the ink now applied; another soaking, and so on. The operation may be repeated as often as desired without the film taking any harm.

Because of the possibility of always bringing the print to the correct degree of relief during the brush work by means of resoaking, there is absolutely no limit to the size of the bromoil print. One can simply finish a part of a print of any desired size and then, after another soaking, go on to the next part and so on until the whole print is inked.

If the relief of the film corresponds to the desires of the operator, the bromoil print may be finished completely in this way. If it is seen that the relief is not sufficient to give the desired modeling and contrast, the resoaking may be effected with warmer water than was used at first. Yet, until the worker has completely mastered the process, this should be done carefully and the temperature of the water gradually raised by adding hot water, in steps of not more than five degrees, until the requisite relief is attained. The use of a thermometer is here absolutely essential, for the estimation of the temperature of the water by the hand is quite unreliable and may lead to the greatest errors. This applies to all water baths used in the bromoil process. At this point it should be noted that a print, which on account of its characteristics has to be placed at the beginning in very hot water to attain the necessary relief, is usually covered with very tiny air bells, which can easily be overlooked; they must be removed by wiping under water so as to avoid troublesome spots.

If the relief of the whole print is satisfactory, but, because of the character of the negative, a few places in the deep shadows do not show the necessary details, the desired shadow detail might possibly be attained by increasing the whole relief, yet at the same time the relief in the rest of the image would be carried too far. In such cases, the places which should be relatively more swollen can be separately more highly swollen while the rest of the surface of the print retains the original relief, by pressing on them a cloth soaked in warm water or a suitably formed swab of absorbent cotton. A still stronger effect is obtained when such places are painted with a water-color brush charged with a one per cent solution of ammonia, either on the film or, after previously marking the outlines, on the back.

When the relief of the gelatine has been increased by soaking in water which is warmer than that used for the first bath, certain precautions must be observed in removing it from the water. It frequently happens, when using certain inks, that the water which runs from the film causes streaks and spots, and that evening these out is at least troublesome and frequently very difficult. This action, which does not occur when resoaking in a bath of the same or a lower temperature, is explained by the fact that the greasy medium of the ink is liquefied by the high temperature of the water, and runs down irregularly or mixes with the water and is carried off by it. There are thus formed on the film of ink marks which show the form of the streams of water which have run off. Such troubles may be avoided by bringing the support close to the dish in which the print is soaked, lifting the print out of the water as far as possible in a horizontal position and placing it in the same position on the support, and immediately spreading the previously dried cloth over it and carefully drying. By observing this precaution, the running off of the water from the film, which is the cause of this difficulty, is prevented. Any traces left by the cloth, used for drying off, can be easily evened out again by the brush.

By making use of this soaking of the print during the work, the bromoil printer is absolutely unlimited in the time used for his work and is not driven by any necessity for haste. He can continue his work in peace and without hurry, and devote himself to any particular part of his picture at will, without being afraid that other parts will meanwhile lose their capacity for being worked up.

The Removal of the Ink from the Surface.—If, in the application of the ink, a fault occurs, which for any reason cannot be corrected with the brush, or if one sees in the course of the work that the ink film is not satisfactory in tonal values or shading, the print would have to be discarded, if it were not possible to remove the ink without damage to the film. This is feasible, however, without any special difficulty; one need not, therefore, throw away such a print, but after removal of the ink can again ink it up, but this time with avoidance of the previous fault.

If there are only small faulty places, the ink may be removed from the print as it lies on the pad, as follows:

Cut a small piece of transparent, waxed paper, or, lacking this, of thin smooth white paper of approximately the shape of the overinked spot, but slightly larger, and place it on the faulty spot, turning up a little corner so as to be able to lift the paper again. Then rub with the finger tip carefully and pull off. The ink is thus removed from the bromoil print and transferred to the paper. If the removal is not complete, the operation is repeated with a second piece of waxed paper. If very small places, as, for instance, the eyes of a portrait, have to be dealt with, the rubbing should be done with a round stick, such as a penholder.

By inking again, the part that has been thus removed may be replaced without any trace of a correction.

If the whole film of ink is to be removed from a bromoil print, a soft dry cloth or better still a swab of absorbent cotton should be soaked in benzol or other solvent, and the picture washed with it. The medium of the ink is dissolved by the benzol and the ink taken up by the wiping cloth.

Every stroke must be made with a clean portion of the swab, which must frequently be soaked again with benzol, otherwise the ink dissolved by the benzol and taken up by the swab will be again put down on the paper. If, after washing with benzol some traces of ink still remain on the film, the print should be immersed in water, but only after the benzol has completely evaporated not only from the film but also from the fibers of the paper, and it should then be gently wiped with the finger. Even if the film still shows a slight tint after this, the working-up may be begun again successfully, since the traces of the previous inking disappear under the new application of ink.

This complete removal of the ink with benzol may also be repeatedly effected. Beginners can, therefore, use any prepared print several times for experiments. But experts should not think of washing an unsatisfactory print with benzol. Those who possess a transfer machine can remove the film of ink mechanically in the simplest way by transfer.

If it is desired to remove the ink from very small portions of the print, this is most easily effected by repeated use of art-gum, which should be sharpened to a point. After every application of the art-gum, a fresh surface of the gum must be used, so that the ink is not again transferred to the picture. It should be noted, however, that repeated use of the gum on the same spot may cause blisters.

Failures.—To assist the beginner, some possible failures will be here described.

It may happen that during the inking the print becomes covered with fibers and small hairs of the most different shapes. This phenomenon may sometimes become so troublesome that a successful print appears problematical. It is frequently incorrectly assumed that these impurities are caused entirely by the brush. Hairs that have fallen from the brush are always recognizable as such, for they are straight, relatively thick, lie entirely on the surface of the film, and can be easily removed. When there is an excessive appearance of fibers, they are due to the use of an unsuitable cloth for drying. The fibers are of the most different shapes, from dots to recurved and entangled lines.

From the fact that they always appear most strongly and frequently during the inking up, it is frequently erroneously assumed that they are caused by the brush used for the inking, or that dust is deposited from the air; this is not so. A dirty brush may be to blame; mostly, however, they are fibers of very different shapes, which are brought on to the damp and somewhat tacky gelatine film by the pressure of an unsuitable cloth, which is not free from lint, and they are held fast by the gelatine and torn from the cloth as this is lifted. At first these thin and almost transparent fibers are not visible. But they take the ink, and thus it happens that they seem to appear in ever increasing numbers during the inking. If individual fibers (which may come from an otherwise suitable cloth), or brush hairs that have fallen out, have to be removed, this is readily effected by art-gum, worked to a point with the fingers. With such a point long fibers can be very easily lifted from the film, while the tiny cloth fibers cling very firmly to the film. A small white spot, where the gum point has touched, remains, as this removed the ink also from the gelatine. Such points can be completely closed up by repeatedly going over them with the brush.

Single hairs or fibers lying on the surface may be allowed to remain, when they occur in places where for any reason one must not destroy the ink film; they can be very easily removed from the film with a sharp instrument in the after treatment of the finished print; usually they leave scarcely any mark.

If, on the other hand, the fibers have appeared in large numbers, the print should be immersed in water and one should try to remove them by gentle friction with the tip of the finger, which is generally successful, even if the film of ink is also removed at the same time. If, however, the fibers adhere so firmly that they cannot be removed in this way, which is particularly likely to happen in the shadows, the whole coating of ink must be removed in the manner outlined in the previous section, [page 73].

The only safeguard against the appearance of this difficulty is the use of a material as free from lint as possible for drying the film.

It may happen that the print takes the first hard ink instantly and very readily, but that even with long hopping clearness of the details is not obtained; the picture indeed shows up well, but remains muddy, as even the high lights retain the ink and become darker with further application of the ink. Then, as a rule, the requisite relief has not yet been attained, and the print must be placed in warmer water. If all the instructions for the development of the bromide print, the bleaching and the swelling have been adhered to, and success is still wanting, then the fault lies in the paper, which was hardened too much in manufacture. The bromoil process is based on the fact that the shadows are tanned more than the high lights, and that then the tanned places take up more ink than the untanned. If the whole film was completely hardened from the start, there cannot be more tanning added by the bleaching, and the ink will take everywhere, in the lights and in the shadows.

If the high lights of the picture completely repel any grade of ink, while this adheres thickly in the shadows, then the formation of the relief has been forced too far.

If the print takes the ink neither in the high lights nor the shadows, there is either a fault in the preliminary preparation, as, for instance, bleaching in too warm a solution, or one too strongly acidified, or the print has been acted on too energetically by the ammonia bath. In the last case the print may be dried and again swollen in water.

If large or small irregular spots which take the ink more strongly than the surrounding parts, are formed during the inking, the reason is either that the prints have lain one on top of the other in the preliminary baths, or the film has been prevented from swelling by air bubbles, or by having risen out of the water. Thus certain places are less well prepared or are not swollen, and therefore behave as though they had been more strongly tanned, that is to say, they take even the first ink strongly and stand out from their surroundings as spots and streaks. Sometimes such spots are improved by putting more ink on the print; if they are not of large area and are in the less important parts of the picture, they may be ignored, as they can be removed from the finished print without special trouble, as will be explained later. If, however, the spots have a large area, or occur in an important part of the picture, for instance, in the eyes of a portrait, it is preferable to stop further work. As a matter of fact, all such blemishes may be removed by after treatment of the print, but the trouble entailed by the correction of large faults is greater than the work of preparing a new print.

Sometimes darker spots or streaks of irregular outline show themselves during the work, which from their shape cannot be ascribed either to air bubbles or to partial sinking of the relief. Then there are probably irregularities in the gelatine coating, for which the preliminary treatment of the bromide print is not responsible.

If the print shows a satisfactory relief, but still takes the ink badly or not at all, the reason is in the incorrect composition of the bleaching solution, or the omission of the intermediate drying after bleaching.

Finally it may happen that the image appears almost as a negative during inking-up, since the high lights take the ink quicker than the shadows. This phenomenon appears when the intermediate drying after bleaching has been omitted, or if the work has been begun with too soft an ink. In such cases, if too much ink has not been applied, the fault can be corrected by further working-up with a hard ink. If this is of no use, all the ink must be removed from the faulty places in the manner already described.

If during the inking-up small irregular white spots in groups show themselves and shift their places, then there are drops of water in the brush or on the print. The print should be dried, the brush also, and the spots hopped dry and worked over.

Yellow or brown spots and patches, which often appear during the work, increasing in number and continually enlarging, or even penetrating through the film into the fiber of the paper, are to be ascribed to the fact that particles of amidol were deposited on the film before the soaking of the print. When these particles dissolve in water they cause the trouble just described. If there are merely scattered spots of this kind which have not penetrated the paper, they may be scraped out of the finished print and then retouched. The real remedy, however, is in keeping the amidol carefully closed and as far as possible not in the same room as the prepared prints.

Ink streaks, which a print treated with a soft ink shows when it is taken out of the warm water, only appear when the print is placed in a slanting or vertical position; they can be avoided by taking the print from the water and immediately bringing it into a horizontal position on the support and rapidly drying, so that the water cannot run off.

The failures caused by the use of the ammonia bath were described on [page 46].

Alteration of the Character of the Picture by the Inking.—If the inking is carried out exactly according to the previous instructions, which have been given chiefly for the benefit of beginners, the result will be a picture which, as regards gradation, will be like the original bromide print before it was bleached. The finished bromoil print, produced by a perfectly even application of ink over the whole picture by means of successive additions, each thoroughly worked over with the brush, differs from the original bromide print in coloration, structure, more extended gradation, and change in the character of its surface. As the worker is at liberty to stop at any desired stage of the work, he can obtain from the original bromide print, according to his taste, a delicate light-toned bromoil or a very rich and highly modulated print, or any intermediate stage between these two extremes.

Yet these possibilities by themselves alone would not justify the conversion of the original bromide print into a bromoil. The substitution of a new photographic positive process for an old one is only justified if the new process accomplishes something essentially different and above all something better. But absolutely uniform working over of the bleached bromide print with greasy inks does not completely fulfil this postulate. Mere changes of gradation of the whole picture or of its color can certainly be attained by simpler photographic methods. The extraordinary advantages of the bromoil process lie in other directions.

Bromoil printing, for instance, permits us to ink any individual part of the print more or less, or even not at all, at will; it is possible to give enormous brilliance and aerial perspective to the high lights; they may show when finished every tonal value represented in the negative; it is also possible to darken them to an extraordinary extent by the application of more or softer ink. On the other hand, the shadows may be kept perfectly light by omitting to ink them or by very delicate treatment, or, by successive applications of the ink, they may be strengthened to very great intensity and yet retain all their details.

The worker has wide opportunity for control in the local treatment of his prints. His dependence on the negative is limited to the drawing, while in the treatment of the tonal values he is absolute master. Most of the other positive processes are dependent on the negative for their extremes of depth and of delicacy; the bromoil process does not know this dependence. If it is desired to obtain a delicate picture from any negative, one uses only a little ink, and hops it off thoroughly; then there may be obtained from even the most contrasty negative a delicate print, but one thoroughly worked out in all its details. On the other hand, there is practically no limit to the continued application of ink; the film is still capable of taking up more ink, long after the limits of artistic pictorial effect have been passed. The result is that in the bromoil process vigor and depth of the shadows can be produced in any desired intensity. The most striking advantage of the process lies, however, in the possibility of changing the tonal values of any individual portion of the print at will.

If for example, a negative was used in making the original bromide print which had been taken without any attention to the requirements for getting correct tones, by suitable treatment in making the bromoil one can obtain an approximately correct print without special trouble, since one can, for instance, convert an absolutely clogged-up sky, which is pure white in the bromide print, to a suitable grey tone by the use of soft ink, and at the same time lighten foliage which is too dark; a flat print, wanting in plasticity, may be improved by making objects in the foreground more vigorous, and accentuating appropriate parts of the middle distance. It is easily possible to supply the lacking aerial perspective of certain kinds of prints. In portrait work in the bromoil process, skilful workmanship renders one absolutely independent of the nature of the background. A light background can be made dark, a dark one light. In portraits taken out of doors, the small details of the background that are out of focus or obtrusive may be omitted, toned down or completely remodeled. Unpleasing details of the clothing or the hair can be omitted or so far softened down that they are no longer disturbing. We are able to accentuate certain parts of the picture to make them dominant, while other parts of the image may be treated very sketchily; in short, the possibilities of control which this process offers are almost inexhaustible.

I will now try to outline the methods of carrying out some of these modifications, as far as is possible without practical demonstration.

The beginner is first of all recommended to use a proof print from the negative as a check, so that he may have a clear idea as to what changes he needs to make, and so that further, in carrying out his ideas, he does not change neighboring parts of the print which should remain unchanged. The simplest example of control is the lightening of the shadows. This is done by very careful application of the ink, which is stopped before the shadow parts become too dark. One should avoid touching such parts later with the brush, when it is charged with soft ink.

If light portions are to be made darker, the procedure depends upon the size of the parts involved. Extensive parts of the picture in high relief, as for instance the sky, should be gone over as evenly as possible with a suitable soft ink, and with this, simultaneously, by going lightly over the lighter places and applying it more heavily here and there, clouds may be put in. The evenness of the inking is of the greatest importance here, as it cannot later be hopped off very much; frequently in such cases the ink only lies on the surface, without adhering firmly; if left untouched, it combines intimately with the surface when the print is dry, but is easily removed by hopping. It is possible to change the outlines of neighboring parts of the image; if too dark edges are formed, they can be easily softened by after treatment of the finished print. In some cases it may be necessary to add considerable quantities of varnish or linseed oil to dilute the ink. The darkening of too light places may be also effected by dabbing ink with the brush on the finished dried print, which the print then naturally takes all over.

If tiny light patches are to be made darker, the point of the large brush, or if necessary of a very small brush should be used, avoiding any disturbance of surrounding parts, as far as possible. Such changes are difficult only when the bright spots that are to be worked out are in immediate contact with very dark parts. The process is much simpler when parts of the print of medium tones, which are surrounded by lighter parts, are to be darkened. If, for instance, the eyes of a portrait are to be darkened, ink should be applied to the whole of the eye with a small brush, and then hopped off. A tree trunk, which must be brought out in relief, should be covered throughout its whole length with soft ink, and the ink should then be worked over, by hopping it from the lighter toward the darker parts. In practice, the bringing together of neighboring tones, which differ considerably in value, can be easily effected by hopping off the ink from the darker parts with a brush that has not been freshly charged with ink, and depositing it on the lighter parts. The lightening of too dark places can also be attained by going over them with a perfectly clean brush that has not been dipped in the ink. Isolated high lights can be accentuated by touching them with a pointed water-color brush, dipped in water; then the film swells and repels the ink. Stained high lights or too dark middle tones may be lightened by wetting a brush of proper size by means of a wet cloth and then lightly hopping with this the places which are to be corrected. The brush picks up the color, but must be immediately cleaned by rubbing it on a clean portion of the palette, after which it may be again wet and used again. Clouds can be worked into dark parts of the sky in this way.

The Structure of the Ink.—Independently of the surface of the paper on which the work is done, the structure of the coating of ink can be influenced by the nature of the brush work. If a brush well charged with ink has its full surface placed firmly on the gelatine film and then slowly lifted up, an impression of the surface of the brush remains; the individual hairs or groups of hairs of the brush have each deposited a part of the ink that they had taken up, and a very coarse-grained spot of ink is produced. If we now hop, that is, dab with quick light blows of the brush, the ink begins to be distributed, since it is taken away from the lighter parts and taken up by the shadows. The drawing of the picture thus appears under the brush, at first with a very coarse grain and without many details. The longer one hops and thus distributes the ink, the finer becomes the grain, and it especially becomes much finer on the addition of softer ink. The bromoil printer hence has it completely within his power to limit the division of the ink to any desired coarseness of grain, assuming, of course, that he has suited the consistency of the ink to the degree of relief, and is therefore able to completely finish the print with the original ink without adding any softer. Prints may thus be prepared, which because of their coarse structure, resemble certain graphic methods. But, when this is intended, the application of the ink must be carried on as evenly as possible from the beginning, so that it needs very little hopping off, for any considerable amount of hopping unavoidably produces a finer grain. Even if the use of softer inks is necessary, a coarse structure can be obtained by suitable brush work. The longer, however, the ink is distributed by hopping, the finer becomes the structure of the ink film and the smoother the surface.

The most perfect smoothness is also attainable, if it is desired for any reason. For this a not too volatile solvent should be used, such as heavy benzol. The method of using this is as follows: when the print has been fully inked and is complete, though still somewhat coarse-grained, a cloth should be wet with the benzol, and the brush lightly pressed thereon and then passed quickly over the desired parts of the picture. At first a smeared spot is formed on the surface of the print; by continued gentle hopping the spot is gradually worked out, and by continued working we get a fineness of detail, equal to that of printing-out paper. It is true that even the highest lights acquire a delicate film of ink, so that a print treated in this way is somewhat low in key. If the hopping with the brush charged with benzol is not continued until the finest possible grain is attained, a misty effect may be produced, with some suppression of the finest details; a method which is frequently useful in the production of landscapes.

By suitable ink and brush technique the effect of any other known photographic printing process may be attained in bromoil printing, from the rich-in-detail gloss of collodio-chloride paper to the characteristic effects of gum-bichromate. Yet the far-reaching possibilities which bromoil places at our command really only begin where most of the other processes end.

Different Methods of Working.—In the following pages some of the different methods of technique, which the bromoil process permits, will be briefly sketched. Obviously, however, the description of these methods cannot be made complete without practical demonstration. Nor can all conceivable methods of working be mentioned, as individual treatment of the process can be varied in many ways.

We will first describe the method of working which is most suitable for the beginner, because it offers tolerable certainty to those who have not yet mastered the process.

The beginner, in order to obtain good results, must start with a bromide print as clean and well-modeled as possible, and its high lights should not be fogged in the least. He should place the print, bleached and prepared exactly according to the methods detailed in this book, in water at about 18° C. (65° F.), leave it there for a few minutes, dry its surface, and begin the application of the ink with the stiffer ink, which should be thinly applied and then worked over until the hopping brings out no further detail. If the drawing of the image does not quickly appear upon hopping the print, and the result is only a detailless patch of ink, the original temperature of the soaking bath must be increased. Then the print should be again immersed in the water, left for two minutes, and again dried. The work of hopping is now continued with the same brush with which the print was originally treated, and without its having been again put into the ink. As a rule the mere placing of the print in water again will have increased the contrasts, and new details will have appeared, which can be considerably accentuated by now going over with the brush. Only when the print has been again worked over, should fresh ink be carefully applied with the brush; this should then be distributed by hopping, and the print again soaked in water. The procedure thus outlined: application of the ink, hopping, soaking, going over it with the empty brush, fresh ink application, hopping, soaking, and so on, is continued as long as the print gains in strength and depth, without becoming dull or muddy. If, however, this point is reached, the inked print should be immersed in water at a rather higher temperature and left in it for some minutes. The print is then further treated with the brush, without fresh inking, and will soon become much clearer in the high lights. If the clearing thus obtained is not sufficient, the temperature of the water bath should be increased by a few degrees, but not more than 5° C. (9° F.) at a time. As the high lights become clearer it may happen that the stiff ink will no longer be taken up. Then it is necessary to soften it a little. This method of working will guarantee to the beginner the attainment of good results with tolerable certainty.

Hard Ink Technique (Coarse-grain Prints).—If it is desired to prepare a bromoil print of rough surface and coarser character, the worker must be able to finish the print exclusively with a relatively hard ink. For this it is necessary to determine by trial the temperature of the water bath at which the film of the print acquires a relief which is absolutely suitable for the stiff ink. When this degree of relief has been found, the print should be inked up strongly but evenly from the very start, so that one is not compelled to go over individual places several times with the brush. Thus the coarse structure of the ink is obtained. The use of hog’s bristle brushes is also efficacious in coarse-grained work.

Soft Ink Technique.—This method of working is used on the one hand for the preparation of low-toned misty effects, on the other hand to obtain fully and richly modeled prints. In the first case the bromide print should be correctly exposed, but not completely developed; while in the second case it should be thoroughly developed. The print is then, according to the choice of the operator, either brought at once to a fairly high relief, or only gradually raised to the same relief during the application of the ink. Then, in the course of inking, a point is soon reached at which the stiffer ink is repelled by the high lights and perhaps also by the lighter half-tones, and during the hopping is again taken up by the brush. Then the ink should be carefully softened with linseed oil or varnish, and the whole print gone over with the softer ink. Prints which are executed in the soft ink technique are characterized by a specially fine velvety surface after defatting.

Sketch Technique.—If one proposes to completely work up certain parts of a print and leave the rest treated in a sketchy manner, and possibly to omit some parts altogether, one should begin by working up the part which should stand out. Thus, in a portrait, the head should be first worked up; then proceed systematically, with the ink remaining in the brush, to sketch in the clothing and the background, and perhaps leave unimportant parts of the print completely untouched. To facilitate the work, disturbing details or a too prominent background may be removed or reduced on the bromide print, before bleaching, with dilute Farmer’s reducer. If, when the work is finished, the parts that have not been inked are visible through their relief and glossiness, these traces of the uninked picture completely disappear in drying, if the original bromide print was not developed too vigorously. If one contemplates producing a vignette, it is absolutely unnecessary to obtain this by the use of masks or vignetters when making the bromide print. The effects which result from the suitable treatment of the bromoil print are far more free and beautiful.