Photothermographic composition of enhanced photosensitivity and a process for its preparation
US5843632A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 1997 |
| Grant date | Dec 1, 1998 |
| Priority date | — |
| Expiry date | Jun 27, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/49845
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photothermographic composition of enhanced photosensitivity is disclosed prepared by a process of (a) precipitating light-sensitive silver halide grains in the presence of a non-aqueous polymeric peptizer and (b) then combining the silver halide grains with a non-aqueous polymeric vehicle containing an oxidation-reduction image-forming combination comprised of an organic silver compound and a reducing agent for the organic silver compound. Light-sensitivity of the silver halide grains is enhanced by, prior to step (b), sensitizing the silver halide grains with a 1,1,3,3-tetra-substituted thiourea or selenourea having an acid dissociation constant of less than 7.0, the thiourea or selenourea being dissolved in an aqueous medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.