Sensitivity and Chemical Sensitization of Silver Bromide Grain Faces of Different Crystallographic Index

Abstract

It has been observed that unsensitized silver bromide grains of cubo-oclahedral shape form latent-image specks preferentially on the cubic faces for all levels and intensities of exposure. Sulphur sen itization of such grains leads to an increase in number of latent-image specks and to a shift in the preferred sites of lalent-image formation to octahedral faces. Reduction sensitization increases the number of latent-image specks on cubic faces but has no influence on speck location. The reduction centres are located on the edges of grains and can be bleached by heavy exposures. Latent-image specks are formed on all faces when unsensitized grains are exposed in halogen acceptor. If exposure of the grains is continued with the acceptor removed there is preferential bleaching of those specks formed on octahedl al faces during the first exposure.Broad interpretations of these observations are offered based on consideration of the surface structures of silver bromide and sensitization mechanisms.