Sulfo-substituted carboxylates as buffers for photographic bleaches and bleach-fixes
US5783376A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 14, 1997 |
| Grant date | Jul 21, 1998 |
| Priority date | — |
| Expiry date | May 14, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/44
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A composition for bleaching or bleach-fixing a silver halide photographic material has a pH of from 2 to 9. The composition comprises a bleaching agent which is either a persulfate or polyvalent metal complex of an aminopolycarboxylic acid, and from 0.01 to 2M of a sulfo-substituted carboxylate represented by Formula I EQU (MO.sub.3 S).sub.n --R--(COOM).sub.m (I) PA1 wherein R is a benzene ring or a straight, branched or cyclic saturated aliphatic group having 2 to 8 carbon atoms; PA1 M is hydrogen or an organic or inorganic cation; and PA1 n is 1 to 7; PA1 with the proviso that if R is an aliphatic group, m is 2 to 4 and m and n combined cannot equal more than the number of carbon atoms in R plus two, and if R is a benzene ring, m is 2 to 5 and m and n combined cannot equal more than six.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.