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US 4,304,846 AGranted
Method for processing silver dye-bleach materials
AssigneeCiba-Geigy Corporation
InventorsMax Marthaler, Gerald Jan
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AssigneeCiba-Geigy Corporation
InventorsMax Marthaler, Gerald Jan
Estimating the term…
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.
A method for processing imagewise exposed silver dye-bleach materials comprising the process steps (1) silver developing, (2) dye bleaching and silver bleaching, (3) silver fixing and (4) washing, wherein for the combined dye bleaching and silver bleaching a preparation is applied which contains (a) a strong acid, (b) a water-soluble iodide, (c) a water-soluble oxodizing agent, (d) an antioxidant, (e) substituted or unsubstituted benzo- or pyrido-[c]-cinnolines, substituted or unsubstituted pyrazines and quinoxalines or quinoxalines containing additional fused 5-membered or 6-membered rings, as bleach catalysts, said component (e) is a mixture of at least one bleach catalyst (I) with a redox potential between +150 mV and -30 mV and (a.sub.1) at least one bleach catalyst of the same group or (a.sub.2) at least one bleach catalyst (II) with a redox potential between -30 and -125 mV, the difference between the redox potentials of the bleach catalysts being at least 15 mV.
A method for processing imagewise exposed silver dye-bleach materials comprising the process steps (1) silver developing, (2) dye bleaching and silver bleaching, (3) silver fixing and (4) washing, wherein for the combined dye bleaching and silver bleaching a preparation is applied which contains (a) a strong acid, (b) a water-soluble iodide, (c) a water-soluble oxidizing agent, (d) an antioxidant, (e) substituted or unsubstituted benzo- or pyrido-[c]-cinnolines, substituted or unsubstituted pyrazines and quinoxalines or quinoxalines containing additional fused 5-membered or 6-membered rings, as bleach catalysts and (f), a bleaching accelerator, said component (e) is a mixture of at least one bleach catalyst (I) with a redox potential between +150 mV and -30 mV and (a.sub.1) at least one bleach catalyst of the same group or (a.sub.2) at least one bleach catalyst (II) with a redox potential between -30 and 125 mV, the difference between the redox potentials of the bleach catalysts being at least 15 mV.
A aqueous preparation, for combined dye bleaching and silver bleaching, which contains (a) a strong acid, (b) a water soluble iodide, (c) a water-soluble oxidizing agent, (d) an antioxidant, (e) substituted or unsubstituted benzo- or pyrido-[c]-cinnolines, substituted or unsubstituted pyrazines and quinoxalines or quinoxalines containing additional fused 5-membered or 6-membered rings as bleach catalysts and (f) a bleaching accelerator wherein the bleach catalysts are a mixture of at least one bleach catalyst (I) with a redox potential between +105 mV and -30 mV and (a.sub.1) at least one bleach catalyst from the same group or (a.sub.2) at least one bleach catalyst (II) with a redox potential between -30 and +125 mV, the difference between the redox potentials of the bleach catalysts being at least 15 mV.
An aqueous preparation, for combined dye bleaching and silver bleaching, which contains (a) a strong acid, (b) a water-soluble iodide, (c) a water-soluble oxidizing agent, (d) an antioxidant, (e) substituted or unsubstituted benzo- or pyrido-[c]-cinnolines, substituted or unsubstituted pyrazines and quinoxalines or quinoxalines containing additional fused 5-membered or 6-membered rings, as bleach catalysts, wherein the bleach catalysts are a mixture of at least one bleach catalyst (I) with a redox potential between +105 mV and -30 mV and (a.sub.1) at least one bleach catalyst from the same group or (a.sub.2) at least one bleach catalyst (II) with a redox potential between -30 and 125 mV, the difference between the redox potentials of the bleach catalysts being at least 15 mV.
Dependencies are inferred from the claim text.