Homogeneous photographic color developing concentrate
US6228567A · kind A · utility
7Cited by
10References
12Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 7, 2000 |
| Grant date | May 8, 2001 |
| Priority date | — |
| Expiry date | Apr 7, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C5/266
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A homogeneous color developing concentrate comprises a color developing agent in free base form, an antioxidant for the color developing agent and a water-miscible or water-soluble hydroxy-substituted, straight-chain organic solvent. This concentrate is prepared in a unique manner, namely by combining the noted components and removing the sulfate anions commonly present in color developing agents by precipitation with alkali metal ions. The concentrate can be used to prepare photographic processing concentrates and working strength solutions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.