A Study of the Effects of the Concentration of 2-Mercapto-4-Phenylthiazole on the Clearing Rate of a Chlorobromide Emulsion and Evidence of the Presence of Activity Sites

It has been hypothesized than materials which tightly adsorb on sliver halide lattices will attach themselves preferentially at certain points, usually referred to as activity sites, which have areas of only a few percent of I the total crystal surface. An experiment using the mechanism of Photosolubilization as revealed by R. K. Blake and others of the E. I. DuPont de nemours Research Laboratories measureing the clearing rate of a chlorobromide emulsion doped with 2-mercapto-4-phenylthiazole indicates that the fixing rate is substantially modified by very small concentrations of this compound, and that the rate remains essentially constant over quite a wide range of concentrations with sharp breaks at what are believed to be of the order of one or two percent coverage and complete coverage of the 2 crystal surface