Photographic bleaching compositions and method of processing color reversal elements
US6365332B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 7, 2000 |
| Grant date | Apr 2, 2002 |
| Priority date | — |
| Expiry date | Sep 7, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/47
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Color reversal photographic elements can be effectively processed to provide positive color images using bleaching compositions in which the primary bleaching agent is a ferric complex of 1,3-propylenediaminetetraacetic acid or a salt thereof. Any potential precipitation of the bleaching agent is inhibited by the presence of at least 0.005 mol/l of an organic polyphosphonic acid, an aminopolysuccinic acid, or a polycarboxylic acid containing at least one hydroxy group as a compound. This compound can be added directly to the bleaching composition or introduced from carryover from a previous photoprocessing step, such as a prebleaching step using color reversal processing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.