Ionic defects and the photographic process

Abstract

The photographic process involves the interaction of photoelectrons and holes with ionic defects present near the surface and in the interior of silver halide microcrystals. The physical changes which take place in pure silver halide crystals upon exposure to light have been examined and discussed. In practical photographic systems, microcrystals of mixed halides, such as Ag(Cl, Br) and Ag(Br, I), are often employed. Since these mixed crystals range in size from ca. 0.5–5 µm, they have a high surface-to-volume ratio. Thus a detailed description of defects at silver halide surfaces, as well as in the interior, is important to the understanding of photography. By combining the insights provided from theoretical work with experimental findings, a picture has evolved of the role of ionic defects.