Process for the preparation of silver halide emulsions containing dispersed clumps of fine grains
US5976778A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 1998 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Oct 27, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/44
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A process of preparing a radiation-sensitive silver halide emulsion is disclosed in which the silver halide grains form dispersed clumps. A population of fine silver halide grains is precipitated at higher concentrations than previously taught for preparing this type of an emulsion by employing a peptizer limited in amount, limited in methionine content, or both. Following formation of the grains, they are aggregated into clumps by the addition of a surfactant, optionally assisted by the adding iodide, increasing pH or both. The grain clumps are stabilized against further aggregation by adding a high methionine peptizer and optionally assisted by the precipitation of additional silver halide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.