In Situ Measurement of Coupling Reactivity by Dye Density Yield Competition

Abstract

A quantitative and in situ method for measuring relative coupling reactivities of coupler dispersions in colour negative films is presented. Relative reactivities of different dispersion formulations of the same coupler and of different couplers can be obtained without knowledge of relative extinction coefficients of the resulting dyes. Kinetic competition medhods. are used to generate a series of dye density yields (slope of image dye density versus developed silver) by processing in a series of developer solutions where the concentration of an added competitor (sulphite or water soluble Coupler) is varied. The method is based on the Weaver-Bertucci Equation, which gives an algebraic relation between reactivity and dye yield.