Direct positive dimethine cyanine dyes containing 1-aryl-2-heteroaryl indole nucleus
US4839271A · kind A · utility
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3Claims
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Key dates
| Filing date | Jun 26, 1987 |
| Grant date | Jun 13, 1989 |
| Priority date | — |
| Expiry date | Jun 26, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/141
- 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.