Ciba-geigy Ag

Carlo Boragine

Thomas Stauner

Remon Hagen

Herbert Mollet

Armin Meyer

Rainer Kitzing

Alfred Oetiker

A process for the production of a photographic color image by the silver dye bleach process, using a photographic material which comprises, on a base, at least one light-sensitive silver halide emulsion layer, which can contain a diffusion-resistant bleachable image dye, and immediately above this layer, on the side facing the light source, a silver halide-free layer containing a diffusion-resistant, bleachable image dye. The process gives very sharp photographic color images.

Process for the production of a photographic color image by the silver

Production of masked positive color images by the silver dye bleach process, by exposing a photographic material for the silver dye bleach process, silver developing, dye-bleaching, silver-bleaching and fixing, optionally, the step of silver-bleaching is carried out in a combined treatment bath together with dye-bleaching and/or fixing. A photographic material is used which contains (a) in at least one layer, at least one first bleachable image dye, which has at least one undesired color density which is to be compensated, (b) in the layer or layers (a) and/or in a layer adjacent to the said layer or layers (a), an iodide-containing silver halide emulsion allocated to the said dye or to each of the said dyes, (c) in at least one further layer, at least, in each case, a second dye, the main color density of which corresponds to the secondary color density of the first dye or dyes which is to be compensated, (d) in the layer or layers (c) and/or in a layer or layers adjacent to the said layer or layers (c), a silver halide emulsion which is free from iodide or has a low iodide content compared with the emulsion mentioned under (b) and is allocated to the said dye or dyes, and (e) in at least one layer (c) and/or in at least one further layer which is adjacent to the layer or layers (c) and which is separated from one or more layers (a) by at least one interlayer, a fogged silver halide emulsion which is free from iodide or has a low iodide content, is spontaneously developable to maximum density without exposure and contains a development retarder. Developing is carried out in a developer solution which does not contain any silver complexing agents. The resulting color images display outstanding color reproduction.

Process for the production of masked positive color images by the silver

The present invention relates a process for crosslinking hydrophilic colloids, especially gelatine. The colloid is crosslinked with a water-soluble organic crosslinking agent which is allowed to act in a system consisting of at least two colloid layers. At least one layer contains the crosslinking agent and at least one layer which is free from crosslinking agents contains an aprotic solvent.

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Villars-sur-Glane, Switzerland

Carlo Boragine