Figures 4, 5, 6, and 7, as well as some others, are zinc etchings reproduced from Mr. Mörch’s work. With them more effort has been made to secure half-tone by a variety and quantity, or filling, in of lines. The example below was made by using the objects (ferns) themselves as the negative, without any interposition from photography, and shows one of the possible applications of zinc etching. It is delicate work and is very beautiful when carefully done. An example of true half-tone, obtained in the manner described in Part II., is the one which follows. It was made by Mr. F. E. Ives, the earliest inventor of a half-tone process, several years ago. The larger examples of half-tone work which appear in this book are made after the most modern fashion and formulæ, as described in Part II., and will serve well to show what the worker in this fascinating process may expect to reach after patient and persistent experiment. When we look upon Fig. 1 and see the very best that zinc {118} etching could do a few years ago, and compare it with the Mosstype and other half-tone pictures now possible, we may well wonder at the growth of the art.
It has been attained by the careful and persistent plodding of a few. Many a method has been discarded for a newcomer, and there is no telling what may come next. Photography has about revolutionized the illustration of books and magazines, and has made the newspaper far more attractive than it was a few years ago. It has made the faces of almost every renowned individual familiar in every land and in every household, and the attractions of every known country have been so pictured by it that every intelligent child is familiar with them. It has been said that process-engraving has supplanted wood-engraving. This is not so. How many newspapers were illustrated before process-engraving was made available? How many works of the old masters and gems of the old museums abroad were made familiar to the lovers of pictures everywhere, by wood-engraving? Instead of coming into the arts to take the place of another, photo-engraving has made a place for itself and a market for itself. Moreover, it is refining and educating the masses by creating a love for art, where before its advent, there was very little feeling for the beautiful. Its accomplishments have been marvellous, and yet they have hardly begun. The good photography has done in bringing the wood-engraver up to his duty in following the artist in every line and light and shade, it will augment by teaching him how to secure the loveliest effects of nature. It will make way for more wood-engraving as well as for more process-pictures if you choose to call them such.
PART III. PHOTO-ENGRAVING ON COPPER.
CHAPTER I. SUBJECTS IN LINE.
In printing from copper plates, the ink, instead of being spread on the surface of the plate by means of a flexible roller as in ordinary type printing, is smeared over the previously warmed plate and thereby forced into the deep parts of the plate. Then, after the surface is polished, the paper picks out the ink from these cavities and so forms the picture. Therefore, instead of using a negative for producing the resist, a transparency is required; and for the production of subjects in line, the transparency must fulfil all the conditions laid down as required in a negative for the production of prints for zinc etching and for photo-litho. transfers, and must be from a subject in line or in stipple.
The negative is made the exact size required, by the wet collodion process (the lens being used without the reversing mirror). This negative is intensified by immersion in the bichloride of mercury solution, and after well washing is blackened by the application of ammonia, as directed in Part I. of this book, under the head of photographic manipulation.
The negative must be varnished, and the margin outside the actual subject required to be shown in the copper plate, must be masked by means of strips of tin-foil cut perfectly straight and laid in position squarely and symmetrically. The object is to make this margin appear in the transparency as perfectly clear glass.
The masked negative is next placed in the carrier of the dark slide, film up; then a couple of thicknesses of blotting paper about the eighth of an inch square are laid on the extreme corners of the negative. Upon these pieces of blotting paper a sensitive wet collodion plate is placed face down. The little squares of blotting paper serve to prevent the sensitive plate from touching the negative. {120}
The camera, with the lens out of focus, should be pointed to a large sheet of white paper; insert the dark slide, draw the shutter, uncap the lens, and the light reflected from the white sheet through the lens, through the negative upon the sensitive plate, will result, after development, in a transparent positive of the negative.
The time of exposure will, of course, vary and can only be found by experiment. The operations of development, etc., are carried on as for a negative.