Fixer additives used in combination with iron complex based bleaches to improve desilvering
US5434035A · kind A · utility
5Cited by
18References
22Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 29, 1993 |
| Grant date | Jul 18, 1995 |
| Priority date | — |
| Expiry date | Dec 29, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C7/42
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of treating a seasoned fixing solution comprising desilvering a fixing solution containing a chelating compound represented by Formula I EQU MOOC(CH.sub.2)m(X)p((CH.sub.2).sub.n COOM).sub.q (I) PA1 where X is N, or C--OH; PA1 n and m are independently 0, 1, or 2; PA1 if X is N then p is 0 or 1 and q is 1 or 2; PA1 if X is C-OH then p is 0, 1 or 2 and q is 1 or 2; and PA1 M is a cationic counterion; and PA1 further containing a carryover amount of a bleaching agent which is a complex of ferric ion and a tridentate or a tetradentate ligand.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.