Method of processing silver dye bleaching materials and preparations suitable for the dye and silver bleaching
US4125402A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 12, 1977 |
| Grant date | Nov 14, 1978 |
| Priority date | — |
| Expiry date | Aug 12, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C7/28
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.