GELATINE PROCESS.
FOR THE REPRODUCTION OF DRAWINGS IN LINE IN RELIEF, SUITABLE FOR PRINTING AT THE TYPE PRESS.
This is a more delicate and sensitive method of obtaining a relief block. It is called the “gelatine,” or “Gillot” process.
The drawing is photographed to the required size (as before), and the negative laid upon a glass plate (previously coated with a mixture of gelatine and bichromate of potash). The part of this thin, sensitive film not exposed to the light is absorbent, and when immersed in water swells up. The part exposed to the light, i.e., the lines of the drawing, remains near the surface of the glass. Thus we have a sunk mould from which a metal cast can be taken, leaving the lines in relief as in the zinc process. In skilful hands this process admits of more delicate gradations, and pale, uncertain lines can be reproduced with tolerable fidelity. There is no process yet invented which gives better results from a pen-and-ink drawing for the type press.
Reproductions of pencil, chalk, and charcoal are also possible by this process; but they are not suited for it, and there is generally too much working up by hand on the block to suit rapid printing. These blocks when completed have a copper surface. The blocks take longer to make, and are about double the price of the photo-zinc process. The cost varies from 9d. to 1/6 the square inch.
M. Gillot, in Paris, may be said to be the inventor or perfector of this process, now used by many photo engravers in London, notably by Mr. Alfred Dawson, of Hogarth Works, Chiswick.
HALF-TONE PROCESS.
FOR THE REPRODUCTION OF WASH DRAWINGS, PHOTOGRAPHS, ETC., BY THE SCREENED PHOTO-ZINC RELIEF PROCESS.