Calcium ion stable photographic color developing composition and method of use
US6503696B2 · kind B2 · utility
0Cited by
18References
20Claims
0Family size
Assignee
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Key dates
| Filing date | Mar 12, 2001 |
| Grant date | Jan 7, 2003 |
| Priority date | — |
| Expiry date | Mar 12, 2021 |
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 a specific polyphosphonic acid sequestering agent. The composition also comprises a color developing agent in free base form and an antioxidant for the color developing agent. The calcium ion sequestering agent is morpholinomethanediphosphonic acid or a salt thereof. This sequestering agent can be used alone to control calcium ion precipitates, or in combination with a polyaminopolyphonic acid or salt thereof. 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.