Ciba-geigy Ag

Ciba-geiby Ag

Max Marthaler

John Lenoir

Christoph Chylewski

Ekkehard Kramp

Gerald Jan

Matthias Schellenberg

Herbert Mollet

Alfred Oetiker

Robert Schaller

A method for processing exposed silver dye-bleach materials using novel preparations for combined dye bleaching and silver bleaching is described. In addition to a strong acid, a water-soluble iodide, a water-soluble oxidizing agent, an antioxidant and, if desired, a bleaching accelerator, these preparations also contain a mixture of 1,4- or 1,2-diazines as bleach catalysts. This mixture consists either of at least two bleach catalysts with redox potentials between +105 mV and -30 mV, the difference between the redox potentials of the catalysts being at least 15 mV, or of at least one bleach catalyst with a redox potential between +60 mV and -30 mV and at least one bleach catalyst with a redox potential between -30 mV and -100 mV, the difference between the redox potentials of the catalysts likewise being at least 15 mV. When exposed dye-bleach materials are processed using these preparations, images with improved color quality are obtained.

Method for processing silver dye-bleach materials

A process is described for the prevention of darkening and the formation of a sediment in photographic developer solutions which contain a silver halide developer, a water-soluble silver halide solvent and organic sulfur compounds. The organic sulfur compounds are a combination of (a) an organic thiol compound or thione compound capable of tautomerism and (b) a Bunte salt which contains groups conferring solubility in water. Developer solutions which contain the indicated combination of sulfur compounds are outstandingly stable.

Process for the prevention of darkening and the formation of a sediment

The present invention provides a new process for the production of masked subtractive positive color images by the silver dye bleach process, which comprises the steps of exposure, silver developing, dye-bleaching, silver-bleaching and fixing. The photographic material used contains, in at least two layers, one image-wise bleachable dye per layer, the absorption maximum of the dye corresponding in each case to one of the three primary colors red, green and blue and a silver halide emulsion layer sensitive in a specific spectral region being allocated to each dye, wherein this material (a) in at least one layer contains a dye, the undesired secondary color density of which is to be compensated, and a silver halide emulsion containing silver iodide is allocated to this dye, in the same layer and/or an adjacent layer, (b) in at least one further layer contains at least one further dye, the main color density of which corresponds to a secondary color density, which is to be compensated, of the first dye, and also a silver halide emulsion free from iodide ions, (c) contains a further layer which is adjacent to layer (b) and contains colloidal nuclei which are able, under reducing conditions, to deposit metallic silver from soluble silver complexes, and also contains an insensitive iodide-free silver halide emulsion which is not spectrally sensitized, and optionally a stabilizer, and (d) containing a separating layer, which does not contain any of the dyes of the layer or layers (a), between the layer or layers (a) and the layer (c). The silver developing bath with which the material is treated contains ligands which form water-soluble and diffusible silver complexes with silver.

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

A process for developing photographic silver halide material, which has been exposed image-wise is provided. The aqueous developer preparation used contains a developer compound for the silver halide, a water-soluble solvent for the silver halide and an aliphatic, cycloaliphatic, aromatic or heterocyclic di- or trisulphide. These preparations remain clear over a long period of time during which they do not lose their effectiveness by becoming turbid or by sedimentation of silver. They are of special advantage in continuously operated photographic developing processes.

Photographic developing process

The present invention relates to a process for the production of masked subtractive positive color images in accordance with the silver dye bleach process. In the material to be processed

The present invention relates to a new method for processing silver dye bleach material. The process measures of this method, consisting of (1) silver developing, (2) dye bleaching, (3) silver bleaching, (4) silver fixing are carried out in the sequence (1) to (4) with appropriate preparations. The silver bleaching (3) preparation contains (a) a strong acid, (b) a water-soluble iodide, (c) a water-soluble oxidizing agent, (d) a diazine compound and (e) an anti-oxidant. An excellent and rapid bleaching is achieved.

Method for processing silver dye bleach materials

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.

The invention relates to a dye bleach preparation which contains in addition to an acid, a water-soluble iodide and optionally a dye bleach catalyst at least one bifunctional sulphur compound having a sufficient solubility in the preparation and a low vapor pressure and containing at least one HS-group and at least one oxygen, nitrogen, phosphorus or additional sulphur atom, the sulphur atom of each HS-group being separated from the next oxygen, sulphur, nitrogen and phosphorus atom present in the molecule by at least three carbon atoms.

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Marly, Switzerland

Max Marthaler