MAKING INTAGLIO PLATES By Elmer Latham

The method by which a photogravure plate is produced, is probably the least understood of all of the many photo-processes of reproduction. This is chiefly on account of the difficulty of the process, which is not an easy matter to explain in detail, and also on account of the secrecy with which all plate makers guard their processes.

The reproduction of a mezzotint or line-engraved print, when made by a good photogravure process, produces in most cases a print which cannot be detected from the original. The originator of the process was probably Fox Talbot, an Englishman. The writer has seen one of his prints, made between 1855 and 1860, which was a very creditable piece of work. Dujardin of Paris took up Talbot's process, and after much modification, succeeded in developing a successful process which he is working to-day. All photogravure plate makers of the present time have more or less copied the process of Fox Talbot.

There are three different methods of making these plates known to the writer. The reader probably knows that a photogravure plate is not a relief plate, but an intaglio, and is printed on an etching-press in the same manner as an etching and requires special skill in printing on the part of the printer to produce the best results. I will give a brief explanation of the three different processes.

The first is known as the transfer process. In this process a reversed photographic negative is made from the copy, from which a positive or "transparency" is made, either by contact or in the camera. A piece of carbon paper is then coated lightly with gelatine, sensitized with bichromate of potassium and allowed to dry. The paper is then placed in contact with the positive and printed in daylight until the image is imprinted on the gelatine coating of the paper, such portions of which as have received the most exposure from the action of light becoming quite insoluble. A copper plate, cleaned so that it is free from grease, is introduced into a large box into which has been blown a very finely powdered resin, which is allowed to settle somewhat before putting in the plate. The plate is allowed to remain in the box until a fine deposit of resin has settled all over it. It is then carefully removed and heated over a gas burner until the resin adheres firmly to the plate. The resin is melted only to such a point that it forms a fine grain all over the plate, leaving interstices of bare copper between. The paper, on the gelatine surface of which the picture is printed, is now placed in a tray of warm water, and the parts of the image which have had the least exposure are thereby dissolved and washed away, the image being thus fully developed on the paper. This is placed in contact with the grained plate, which has been placed in the tray of water, and firmly squeezed in contact with the plate. The paper is stripped off, leaving the gelatine film on the copper. The plate is now removed from the tray and dried, and is then ready for etching, which is accomplished by placing the plate successively in several baths of acid of different strengths until the desired results are obtained. This process gives a shallow plate, of not great wearing quality, and, as a rule, requires a great deal of work by the engraver to bring the plate up to anything like the copy. The light tints come out very soft and smooth, but the black tones etch "flat" and lose all detail. These blacks must be put in by hand. The poor wearing qualities of these plates make them undesirable in cases where a large edition has to be printed.

The next process is the "deposited" plate used by "Goupil" of Paris, in which copper is deposited by electricity upon a swelled gelatine film which has had a grain formed upon its surface chemically or otherwise. The deposition has to be continued until the plate has acquired the necessary thickness, which takes about three weeks; and this is a long time to wait in these days, when a publisher usually expects his order executed in ten days. These plates are practically hand made. The process gives a plate that could not possibly be used without a great deal of retouching by an expert engraver. Goupil turns out a beautiful plate, due principally to his large force of engravers, one man working on a particular part of the plate, then passing it on to another who does some other portion, and so on, until the plate is finished. In this way each engraver becomes exceedingly skilful in one thing. Line engraving is reproduced by this process exceedingly well, but such plates, like the transfer process, are shallow and give out soon in the printing.

The last process that I have to deal with is the one I am working myself. In this process the plates are made in two or more etchings, according to the requirements of the subject which is to be reproduced. This method produces a plate of great depth both in the light and black tints, and on account of the small amount of hand-work required after the plate is etched, the copy is followed very closely. With a good positive and favorable conditions, quite frequently a plate is made upon which the retoucher needs to do no work at all, and a more faithful reproduction is made than by any of the other methods that I have mentioned. After a good positive is procured, the copper plate is cleaned, and a sensitized solution of gelatine is flowed over the plate, dried down, and then printed under the positive, with a short exposure. The plate is grained as in the transfer process, and is then etched.

This first etching, on account of the short exposure, goes over the plate in about three minutes, and is simply intended to get the light tints. The plate is again cleaned off and coated, this time in a different manner, and given a much longer exposure under the positive. The next etching takes about three hours, which gives the blacks great depth. Comparing this with the transfer plate which has an etching of from fifteen to twenty minutes, the reason for the difference in the wearing qualities of the plate is quite evident. This process, whether used by myself or others, I feel free to say is the best one that has ever been worked, inasmuch as it gives a far more faithful reproduction than any of the others with a minimum of work by the retoucher.

Some plate makers claim to make all their plates without any retouching, which cannot be done. As I have mentioned before, occasionally a plate can be made as good as the copy without hand-work. But to say that any chemical process gives such results continually, or that a plate cannot be improved by a skilful retoucher is, to say the least, misleading. All of the different processes are very sensitive to atmospheric influences, and no small amount of chemical as well as mechanical skill is required to keep things running smoothly; and at certain times the best of operators are at a loss to remedy some slight fault that may upset things temporarily. Photogravure making is based upon a foundation of small details, that must be looked after with the utmost care, and the neglect of any one of which means failure at the end. So it may be surmised that at times the operator has trouble of his own.

Every maker of plates, no matter which process he uses, has his individual ways of doing things, so that except in a general way no two processes are operated alike. This gives an individuality to each man's work, and an expert can easily tell one from another. For high-class illustrations, no other photographic process can compare with photogravure, and no doubt it will be many years before anything will be found to excel or even equal it. Much experimenting has been done with other methods, but the results have always been inferior, and I think it is safe to predict that the photogravure will always be popular.

Etchings, mezzotints, and steel engravings are still occasionally used in the illustration of fine books, and brief descriptions of how they are made will be of interest.

An etching is usually made on a copper plate. The plate being covered with a thin coating of wax, the artist works on it with an etching point, sketching his subject on the plate in fine lines as he would in making a pen-and-ink drawing, but cutting his lines through to the copper. The plate is then "walled in" with a high rim of wax, forming a sort of tray of the plate. Into this tray is poured a diluted solution of nitric acid, which etches, or "bites," into the uncovered lines on the plate. Some artists give a plate a short "bite," as the etching is called, for the light lines, then cover these portions of the plate with wax and give the plate successive "bites," stopping out each part as it gains its required depth. Others remove the coating and "prove" the plate by taking a print from it after each "bite,"—each of these prints being known as a "state of the plate" and showing what is still required to be done. In the work of an etcher like Whistler the impressions of the "first state," "second state," etc., are of considerable interest, as they show the progress of the man's work, but, except as an object of interest or as a curiosity, these prints can have no real value as they are unfinished work, simply showing the various stages in the making of a work of art.

A mezzotint is also usually made on a copper plate. A texture, or groundwork, is worked on the copper plate with a tool resembling a cabinet maker's toothed plane iron, except it is rounded at the end. The teeth are very fine, ranging from forty to one hundred and twenty to the inch in different tools. This tool is called a "Bercier," or "rocker." The rounded edge allows the tool to be rocked across the plate, the rocking motion causing the teeth to form indentations in the copper. The rocking has to be continued until the surface of the plate is completely covered, and it then presents an appearance like velvet. Rocking in from forty to sixty directions is necessary to cover the plate properly. The durability of a mezzotint plate depends entirely upon the pressure put upon the rocker, and the depth to which it penetrates the copper. After the ground is thus laid, the outline is sketched in on the rocked surface, which takes the pencil easily, and then with steel scrapers and burnishers the light and middle tints are worked down, leaving undisturbed the portions of the surface where the strongest blacks are to be. From time to time, a print is taken from the plate, to note the progress of the work, which advances slowly to the finish. On account of the length of time necessary for the laying of the ground and the scraping of the plate, many artists hesitate to attempt mezzotint plates. There are very few men in this country to-day who do mezzotint engraving, which, considering the results to be obtained, seems somewhat surprising.

For flesh tones, drapery, and landscapes it has no equal. The velvety richness of the blacks, the beautiful gradations of the middle tones, and the extreme delicacy of the light tints give the artist a power of expression not obtainable by any other method of engraving. Besides this, as the engraving is done on the bare copper, the artist can see at all times the progress of his work without having to take off the wax ground as he must in making an etching. This is a great advantage, for as the effect of each stroke can be plainly seen on the plate, the element of uncertainty which always attends the production of an etching is entirely eliminated, and it is then simply a question of skill with the scraper. The difficulty of obtaining rockers is one great drawback. I doubt if one could be obtained in New York to-day. The teeth have to be very accurately cut, and a perfect tool has a value to an engraver that cannot well be estimated. The lack of demand has prevented their manufacture in this country, but they could be made here by any fine tool maker.

Steel engravings are still used to some extent in this country, although only in portrait work. A wax ground is laid on the plate as in etching. A tracing is made from the photograph, from which the picture is to be made, and is then transferred to the wax ground. The engraver then follows the lines of the tracing with an etching point, the hair, head, and outline of the features being gone over carefully. Then the plate is etched with weak nitric acid. If the face is to be "stippled," it is covered with fine dots made by a graver directly on the surface of the metal after the plate has been etched and the wax cleaned off. If the face is to be a mezzotint, that part of the work is all rocked over, and then scraped down within the etched outline, when the flesh is modelled as in a regular mezzotint. The drapery, background, etc., is usually done by a ruling machine with fine or coarse, waved or straight lines, as the texture may require. These lines are ruled through a coating of wax, and then, by etching and stopping out, the required results are obtained.

This method of engraving is also giving place to process work, and in a few years more the steel engraved portrait will probably be a thing of the past.[Back to Contents]