The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 08, 1981
Filed:
Feb. 04, 1980
Max Marthaler, Marly, CH;
Gerald Jan, Fribourg, CH;
Ciba-Geigy AG, Basel, CH;
Abstract
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.