Preferred Sites for Latent-1 mage Formation

Abstract

AbstractThe relationship between grain disorder and sites of formation of surface latent-image specks on tabular silver-bromide emulsion grains has been investigated for small latent-image exposures. The technique was to expose the grains, partially develop them to reveal the sites at which developable latent-image specks had been formed, and then to form photolytic silver in the grains to decorate the disorder. It is shown by an electron-micrographic technique that many of the surface latent-image specks are formed where lines of platelets of photolytic silver meet the grain edges. It is concluded that in grains of the above type there may exist at least one specific type of disorder which provides surface sites where nucleation and aggregation of silver occur preferentially at small exposures. A direct demonstration is presented of the competition between surface and internal sites on and within a grain for the electrons produced by exposure.