Abstract
The effects of hexachloroirridate on the photographic properties of silver halide emulsions were examined at various intensity exposures. The addition of a small amount of hexachloroirridate at the precipitation of silver halide extremely eliminates the high intensity law failure but does not influence on the characters at low intensity. When the addition of hexachloroirridate is carried out at after ripening or before coating, the elimination of high intensity law failure is not observed. It is considered that the effects of hexachloroirridate is due to positive hole trapping by trivalent irridium ion located in the silver halide crystals. The irridium (III) ion will instantaneously trap positive holes and inhibites the recombination of electrons with holes at the high intensity exposure.
