"Now we possess a granular picture having all the true qualities required in a photo-engraved plate, or, rather, such as will give a reverse in metal having these qualities. The steel or zinc plate is then to be exposed to light to completely harden the mixture all over, and is then treated exactly as in my other engraving process; that is, pressed into soft metal by hydraulic pressure, electrotyped, and then the surface is aciercised or coated with steel. The dark parts are thus represented by a coarse grain, the middle tints by a medium grain, and the finest shades by the most infinitesimal particles, thus meeting all requirements necessary to a successful photo engraving process."
This process was taken up by a Frenchman and claimed by him as his own invention. The chief difficulty with it was that the plates before being perfect require the work of a skillful engraver, sometimes for weeks. They were therefore very costly, six dollars per square inch being charged for the making of the plate alone.
Klic's process, 1886, was the next important improvement in photogravure or intaglio printing, and since then many other processes and improvements have been introduced by Obernetter, Waterhouse, Colls, Zuccato, Sawyer and others.
In the following chapters Mr. H. R. Blaney gives a working description of the process as practiced to-day by many of the leading firms in this and other countries. This originally appeared in the columns of THE PHOTOGRAPHIC TIMES, but I have made many additions that I have imagined may be of value to the student. A dividing line will be found between Mr. Blaney's writings and my own additions.
Any negative may be used for photogravure, that is, taken from nature, or from a painting or engraving, provided it is reversed, and, in the case of paintings, should, in addition, be on an orthochromatic plate. The negative should be soft and brilliant, well exposed, and not hard or under-exposed. A reversed negative is always necessary if the print from the copper plate is required to be similar in regard to right and left, or if no other means are to be taken, to reverse the image upon the copper plate. Professionals use stripping plates especially made for this purpose for small work, or the reversed negative may be made in the copying camera. A fairly good reversed negative can be made by contact in the printing frame from an albumen print from the original negative, the print made transparent with white wax by being placed on a piece of warm, clean metal and the wax rubbed over the face. To have the negative reversed, the print should first be placed, face out, against the glass of the printing frame, with its back against the sensitive surface of the transparency plate, the back closed in and exposed to a large lamp for about five seconds. Every care must be taken that you use the best of negatives, carefully retouched if necessary, as the professional photographic etchers have informed me that (from their standpoint) the success of the whole process depends on the quality of the original negative and the care taken in artistic retouching.