United States Patent
US Patent 4288535: Process for preparing silver halide photographic…
US 4288535 · granted 1981-09-08
| Patent Number | 4288535 |
|---|---|
| Title | Process for preparing silver halide photographic emulsions |
| Filed | 1980-05-19 |
| Granted | 1981-09-08 |
| Inventor(s) | Hideo Kanisawa, Tamio Kitahata, Hideo Horie |
| Assignee | Konica Minolta Inc |
| CPC Classification | G03C1/08, G03C1/005, G03C1/00 |
| Number of Claims | 1 |
Abstract
A process for preparing silver halide emulsions having high sensitivity and contrast by adding water-soluble iridium compounds during precipitation or physical ripening and adding water-soluble iodide compounds and sulfer sensitizers during chemical ripening.
Claims Summary
1. A process for preparing a silver halide photographic emulsion which process comprises adding a water-soluble iridium compound in an amount of 10-7 to 10-4 mole per mole of the silver halide at the stage of precipitation of silver halide grains or physical ripening thereof, and adding a water-soluble iodide in an amount of 10-4 to 10-2 mole per mole of the silver halide and a sulfur sensitizer at the stage of chemical ripening thereof.