High contrast photographic silver halide material
US6383711B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 21, 2000 |
| Grant date | May 7, 2002 |
| Priority date | — |
| Expiry date | Aug 21, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/44
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A high contrast photographic material comprises a support bearing a silver halide emulsion layer, containing in the emulsion layer or in an adjacent hydrophilic layer, a hydrazide nucleating agent characterized in that the emulsion layer contains silver halide grains of octahedral character which are spectrally sensitized and silver halide grains which are not octahedral in character eg cubic.Preferably only the grains which are octahedral in character are spectrally sensitized.Preferably the emulsion layer or an adjacent hydrophilic colloid layer contains a booster compound eg an amine rendering the material developable in a developer solution having a pH below 11.Preferably both types of grain are chemically sensitized. The use of tabular grains as causer emulsions enhances the absorption characteristics of the dyes so that as well as providing high photographic sensitivity the dye peaks are broadened.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.