GB1314441A - Material and a process for the production of colour corrected reproductions - Google Patents

Abstract

1314441 Colour corrected reproductions of multi-colour originals AGFA - GEVAERT AG 28 April 1970 [29 April 1969] 20292/70 Heading G2C The invention comprises a duplicate material having a red-sensitive silver halide emulsion layer which contains at least one cyan colour coupler, a green-sensitive silver halide emulsion layer which contains at least one magenta colour coupler, and a blue-sensitive silver halide emulsion layer which contains at least one yellow colour coupler, in which the colour coupler or couplers in at least one of the layers is or are so chosen that the image dye produced upon colour reversal processing has equal side densities, and a process for the production of colour duplicates from a multi-coloured original by means of a photographic colour reversal process which comprises producing a black and white masking image from the colour original, registering this with the original, exposing a multi-layered colour photographic duplicate material as defined above, in which the photographic material for the production of the black and white mask comprises one or more silver halide emulsion layers each of which corresponds to a silver halide emulsion layer of the duplicate material in which the image dye with equal side absorption is produced upon colour reversal processing, such that its spectral sensitivity is complementary to the main absorption of the image dye, and its gradation is numerically equal, but negative in sign, to the side absorption of this image dye, based on the grey equivalent colour density 1, and colour reversal processing the exposed duplicate material. In a modification of the process the black and white mask material may contain a mixture of two silver halide emulsions in the form of a single silver halide emulsion layer, in which the spectral sensitivity of one emulsion is complementary to the main absorption of one image dye and the spectral sensitivity of the other emulsion is complementary to the main absorption of another image dye of the duplicate material which is to be corrected, whereby the sensitivity ratio of the two emulsions corresponds to the gradation ratio of the corresponding two-layered material. The dye of the magenta partial image and the dye of the cyan partial image pairwise may have equal side absorptions. At least one of the silver halide emulsion layers of the duplicate material may contain a mixture of at least two colour couplers has essentially identical main absorptions but different side absorption, the colour couplers being mixed in such a ratio that the sum of the side absorptions of the colour coupler mixture is equal in the two thirds of the spectrum outside the main absorption.