Ciba-geigy Ag

Ciba-geigy Corporation

Herbert Mollet

Dieter Wyrsch

Matthias Schellenberg

Max Marthaler

Christoph Chylewski

Carlo Boragine

Alfred Oetiker

Negative color images are produced by the silver dye bleach process, by exposure of a photographic silver dye bleach material, silver developing, dye bleaching, silver bleaching and fixing, the silver bleaching being optionally carried out simultaneously with the dye bleaching and/or the fixing, in a single treatment bath. The photographic material consists of a support with at least one layer assembly of three layers in each case, each layer assembly containing, as viewed from the same side as the incident light:

Process for the production of negative color images by the silver dye

Production of masked positive color images by the silver dye bleach process, by exposure of a photographic material for the silver dye bleach process, silver developing, dye bleaching, silver bleaching and fixing, optionally the silver bleaching is carried out simultaneously with the dye bleaching and/or the fixing, in a single processing bath. The photographic material used contains

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

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

A method of processing silver dye bleaching materials is provided wherein a combined aqueous dye and silver bleaching bath is used which contains a strong acid, a water-soluble iodide, a dye bleaching catalyst, a water-soluble oxidant and an antioxidizing agent, wherein the antioxidizing agent is an alkali metal, alkaline earth metal or ammonium bisulphite adduct of an organic carbonyl compound. The dye and silver bleaching can also be carried out in separate baths and then the aqueous dye bleaching bath contains a strong acid, a water-soluble iodide, a dye bleaching catalyst and the antioxidizing agent, which is again said bisulphite adduct. The strongly acid baths which contain as antioxidizing agents the bisulphite adducts are stable over a lengthy period of time, exert a lasting antioxidizing action and are free of offensive odors.

Method of processing silver dye bleaching materials and preparations

The present invention relates to a simplified method for processing silver dye bleach material by (1) silver developing, (2) dye and silver bleaching (3) silver fixing and (4) soaking. The sequence (1), (2), (3), (4) is followed and the bleaching bath (2) contains (a) a strong acid, (b) a water-soluble iodide, (c) a water-soluble oxidizing agent (d) an antioxidant and (e) a dye bleach catalyst.

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Tentlingen, Switzerland

Herbert Mollet