Photographic emulsions and materials with reduced pressure sensitivity
US5439786A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1993 |
| Grant date | Aug 8, 1995 |
| Priority date | — |
| Expiry date | Jul 6, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C5/164
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is a negative-working, silver halide emulsion including monodispersed, non-twinned, non-tabular silver halide crystals having a core and a shell. The core has a first halide composition including silver chloride, silver bromide or silver chlorobromide containing at least 65% silver bromide. The shell has a second halide composition, different from the first composition, including silver chloride, silver bromide or silver chlorobromide, provided that: (a) the minimum difference in shell to core halide composition relative to the same halide, is as follows: (i) 0.5 mole % when the core is silver bromide, (ii) 10 mole % when the core is silver chloride, and (iii) 10 mole % when the core is silver chlorobromide; (b) the core represents from about 5 to about 50% of the total crystal volume; and (c) the shell contains no more than 50 mole % silver chloride. The emulsion also has a chemically sensitized surface, and substantially reduced black or white pressure sensitivity compared with homogeneous silver bromide or silver chlorobromide emulsions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.