Effect of Sulphur Sensitization on the Delayed Formation of Latent Image Specks

Presented in part at the International Congress of Photographic Science at Cologne, 10-17 September 1986.

Abstract

The phenomenon of the delayed formation of latent image specks in sulphur sensitized emulsions with cubic and octahedral grains was studied. The degree of delayed formation changed only a little with sensitization level and then increased slightly at the highest level, while sensitivity increased gradually at first and then decreased. Development rate measurements revealed that the degree of dispersion of the silver specks increased with sensitization level. Conditions where the dispersion was large did not enhance the delayed formation process. The rate of delayed formation was measured and the kinetics are discussed. The rate constant at the optimum exposure region was decreased by sulphur sensitization but then increased at the highest sensitization level. The rate constant in the low exposure region did not change with level of sensitization. The product of the numbers of latent sub-image specks and single silver atom species was estimated from the rate constants. It decreased with sensitization and this was interpreted as a decrease in the number of single silver atom species produced by sulphur sensitization. Characteristics which differentiate single silver atom species from other silver specks were suggested.

Notes

Presented in part at the International Congress of Photographic Science at Cologne, 10-17 September 1986.