The Plate Characteristic: A Theory of the Linear Transform

Abstract

Two variants of the Baker transform, [Formula: see text] introduced by Kaiser and Arrak, apply to a deep emulsion, not to a coating, since their curvature is positive at high densities. In a deep emulsion, only two physical processes afreet the shape of the characteristics, absorption and polyphotonic fertilization. Since the (1-T) of the Kaiser transform is a measure of the number of silver grains formed, it should be replaced by the density. Thus the exposure equation demanded by theory is [Formula: see text] where P is the photon number, and K the ratio of the absorption cross sections of a crystal before and after development ‘A’ does not affect the shape of the characteristic, but only the speed. This equation for a deep emulsion is generalized to cover a coating, and shown to fit two characteristics recorded in the Kodak laboratories. Further it is found to be valid in all the emulsions used in spectrochemical analysis down to 214 mμ, and in some sensitized plates up to 809 mμ. It is not valid in a few fast emulsions, and three of these are named