Abstract: It was shown that bismuth ion doping has a great desensitizing effect on the photographic behavior of silver halide emulsion microcrystals. But so far the mechanism of its desensitizing effect has not been illustrated yet. An attempt was made to correlate the ionic conductivity, electronic conductivity of silver halide microcrystals and their photographic behavior. The-dielectric results suggest that the desensitizing effect of bismuth could be attributed to the fact that bismuth acts as a pretty sum of shallow electron traps, leading to the formation of highly dispersed latent image specks with lower catalytic activity.The present experimental results can be used to establish the Bi content allowed to contain in the main raw materials, e. g. silver nitrate and gelatin used in photographic industry and to strengthen HIRF in making some special films.

Key words: photographic chemistry, silver halide, ionic conductivity, electronic conductivity, dopping effect