Silver chloride emulsions of modified crystal habit and processes for their preparation
US4400463A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 1982 |
| Grant date | Aug 23, 1983 |
| Priority date | — |
| Expiry date | Sep 30, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/43
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Radiation-sensitive photographic emulsions are disclosed comprised of a dispersing medium and silver halide grains the halide content of which is at least 50 mole percent chloride, based on silver. The silver halide grains include tabular grains having a thickness of less than 0.5 micron, a diameter of at least 0.6 micron, and an average aspect ratio greater than 8:1 which account for at least 50 percent of the total projected area of the silver halide grains. The tabular grains have two opposed substantially parallel major crystal faces lying in {111} crystal planes and exhibiting at least one of the following features: (1) at least one peripheral edge lying parallel to a <211> crystallographic vector lying in the plane of one of the major faces and (2) bromide and/or iodide incorporated in a central grain region. The tabular grains are formed in the presence of an aminoazaindene and a peptizer having a thioether linkage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.