GB402332A - Improvements in or relating to colour printing - Google Patents

Abstract

402,332. Photo-mechanical printing- surfaces. NADIN, A., 22, Hill Top, Hampstead Garden Suburb, London. April 29, 1933, No. 12527. [Class 98 (ii).] A colour printing process for use in newspaper or other high speed printing work consists in superimposing prints in selected colours by a number of half-tone blocks each of the complete subject but adapted to produce prints of different strengths. From the original subject a half-tone block is prepared photographically in the ordinary manner to produce a print in black or dark colour, and one or more " ghost half-tone blocks for printing in lighter colours are prepared in exactly the same way but in a form adapted to produce faint prints. These " ghost " blocks may be produced by photographing the subject through a semi-transparent mask of frosted glass, tinted glass, or matt celluloid and parts of these blocks may be modified to give stronger or weaker prints by darkening or whitening corresponding parts of the mask, or by applying local patches of resist to the blocks during the etching operations.