Method for preparing a ready-to-use photographic bleaching solution
US5753423A · kind A · utility
4Cited by
5References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1996 |
| Grant date | May 19, 1998 |
| Priority date | — |
| Expiry date | Apr 29, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C7/42
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A ready-to-use bleaching or bleach-fixing solution can be prepared by mixing an aqueous solution of succinic acid, maleic acid or malic acid, and an aminopolycarboxylic acid ligand, adding a ferric salt to form a ferric ligand chelate, and adding a chemical base, such as ammonia, to provide a final pH of from 2.5 to 5.5. optionally, a portion of the chemical base can be added before the addition of the ferric salt.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.