Direct positive dimethine cyanine dyes containing 1-aryl-2-heteroaryl indole nucleus
US4927933A · kind A · utility
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5References
3Claims
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Key dates
| Filing date | Jan 31, 1989 |
| Grant date | May 22, 1990 |
| Priority date | — |
| Expiry date | Jan 31, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/4853
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A fogged direct positive photographic silver halide emulsion containing a sensitizing amount of at least one cyanine dye defined above, e.g., cyanine dye containing a 1-phenylindole nucleus substituted in the 2-position with the 3-pyridyl group. The said cyanine dye is also covered. The dye useful in sensitizing the silver halide emulsion useful for fogged direct-positive films.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.