Selective Latent Image Distribution in Silver Halides

A photographic system of two evaporated layers of silver halides is investigated. It consists of a thicker silver bromide or silver bromoiodide polycrystalline basic layer on top of which a very thin film of silver chloride is deposited. The dependence of the sensitivity on the thickness of the two layers is followed. The thermal annealing of the basic silver bromide increases considerably the photoresponse of the system.It is suggested that the electrons generated randomly in the basic silver bromide or silve bromoiodide layer are injected into the thin silver chloride. The latent image distribution revealed by differential development supports this assumption.