Calcium ion stable photographic color developing composition and method of use
US6416940B2 · kind B2 · utility
6Cited by
13References
15Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 10, 1999 |
| Grant date | Jul 9, 2002 |
| Priority date | — |
| Expiry date | Nov 10, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/21
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A color developing composition is stable in the presence of calcium ion because of the presence of two specific types of polyphosphonic acid sequestering agents. The composition also comprises a color developing agent in free base form and an antioxidant for the color developing agent. The mixture of sequestering agents includes a polyaminopolyphosphonic acid and either a hydroxyalkylidenediphosphonic acid or morpholinomethanediphosphonic acid. The composition can be used to provide images in various color photographic silver halide materials.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.