Photographic Materials

The engineering of new types of photographic emulsions for specific applications requires a detailed understanding of the elementary processes leading to formation of the latent image. The two effects under scrutiny are charge transfer from sensitising dye molecules adsorbed on the microcrystals in the emulsion, and trapping of charge carriers on impurities inside these microcrystals. EPR is the central technique which can measure the optically created organic radicals and the paramagnetic impurity ions.