Photographic Sensitivity and Surface Potential of Silver Bromide

Abstract

AbstractTypical ensitization procedures have been applied to change ub tantially the photographic respon e of thin evaporated layers of pure silver bromide, which if untreated build up no surface image at all, but on ensitization yield normal characteri tic curves. The vacuum deposition of invisible but developable silver speck on the surface of untre:lled samples creates direct positive imaging due to bleaching by photoexcited holes. The dark conductance of layers with varied thickness subjected to different sensitization procedures has been followed. The data obtained allows an e timation of the urface potential which for pure ilver bromide, in accordance with earlier observations, is found to repel electrons from the surface. It has been now shown that the sign of the surface potential relative to the bulk is not changed by the ensitization proce s, remaining always negative independently whether the layer builds up on exposure negative, positive or no urface image at all. The variations in the value o...