Selenium and iridium doped emulsions with improved properties
US5164292A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 27, 1990 |
| Grant date | Nov 17, 1992 |
| Priority date | — |
| Expiry date | Dec 27, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/43
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The invention is generally accomplished by forming a silver halide emulsion and during precipitation adding iridium and selenium in an amount effective to decrease reciprocity failure with substantially no decrease in speed. In a preferred form, a photographic element is formed comprising of bromoiodide emulsion having about 3 to about 88 nanograms of iridium per square meter of silver halide grain surface area and about 42 to about 487 nanograms of selenium per square meter of silver halide grain surface area. It is also preferred that the iridium and selenium be added at a point after the precipitation has proceeeded to a point wherein at least half of the silver to be added is present.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.