Abstract
The first practicable photomechanical system—contact-screen photogravure—was invented in 1852 by W. H. F. Talbot of England. Many of the approaches introduced by Talbot are still used in current practice: contact cross-line “master” and “working” screens: metal plate etching through a bichromated gelatin emulsion: etching with ferric chloride solutions of different concentrations: and selective local etching for “retouching” purposes.
To provide the tiny image ink-holding components in the printing plate, Talbot used fine gauze fabrics for the contact cross-line screens and fine resin particles (aquatint) applied as a powder or liquid. He also experimented with contact screens of ruled lines on paper: scored cartilage: waxed paper with scribed lines: aquatint pattern on paper and a blackened film with uniform grid of clear circular openings.