Abstract: This paper deals with the mechanism of latent image formation on chemical sensitized emulsion based on the model proposed in the previous paper. From the current work, some results were obtained: (1). silver sulfide specks on the surface of a silver bromide grain can be photoelectron traps and photohole traps at same time. As photoelectron traps, they are in larger dimension than the single kink site, however they are not deep ones like the single kink site. It is these specks which help the emulsion to promote photographic sensitivity and improve LIRF> but they should also be responsible for despersion of photolyzed silver atoms and HIRE. As photohole traps, their only function is slowing down the photohole movement and delaying the bromine formation but can not remove photohole permanently. (2). Gold sensitization not only can decrease the size of minimum developable centers but also increase the anti-oxidization ability of the clusters, furthermore, there should be other sensitization mechanisms which we still do not know. Ag₂ can be partly thansformed into developable centers through gold-intensification. (3). The nature of the silver specks formed from reduction sensitization is same as that formed during exposure. This do not mean they must grow up, in fact, most of them would be destroyed during exposure. Two important functions of reduction specks are to increase the probability of latent image formation and remove photoholes or bromine therefore increase the number of net electrons in the grains which is especialy in favour of latent image formation.

Key words: computer simulation, latent Image formation, chemical sensitization, kinetics