Silver halide photographic emulsion and a process for the preparation thereof
US4686178A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 1986 |
| Grant date | Aug 11, 1987 |
| Priority date | — |
| Expiry date | Feb 3, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2001/0357
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A process for preparing a monodisperse core/shell type silver halide photographic emulsion comprising silver halide grains wherein the average silver iodide content in the grains is 0.5 to 10 mole % and each of the grains comprises a core portion having no silver iodide. The silver halide grains are caused to grow from seed crystals having substantially no twin crystal by supplying silver ions and halide ions in the presence of protective colloid. The supplying speeds of silver ions and halide ions are gradually increased as the grains grow and the supply of iodide ions in the halide ions is made before the completion of supply of silver ions. The content of ammonia contained in liquid phase emulsion is fixed to the value that is 0.3 normal or more and pAg is fixed to the value that is less than 8 for the supply of iodide ions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.