The effect of doping [Fe(CN6]4- and [Ru(CN)6]4- on the photographic properties of the T-grain emulsion

Abstract

The effects of two dopants, K4[Fe(CN)6] and K4[Ru(CN)6], on the photographic properties of the iodobromide T-grain emulsion were studied in this paper. It was found that both the doping amount and the location within the grain had significant effects on the photographic properties of the emulsion. The doping by either [Fe(CN)6]4- or [Ru(CN)6]4- could increase the photographic sensitivity of the silver halide emulsion, indicating that they could form shallow electron traps in the silver halide crystal, effectively protecting the electrons from immediate recombination with the holes. The extent of the improvement varied with different dopants and the doping conditions. The sensitivity increased more if the location of the dopant was near the grain surface for [Fe(CN)6]4- and either near the surface or in the deep interior of the grain for [Ru(CN)6]4-. This study also indicated that iodide had an influence on the efficiency of the doping process. The chemical sensitization time could be prolonged and the formation of fog could be retarded by doping.