The Development of a Silver Halide Grain

Abstract

The present knowledge of the mechanism of development is critically reviewed in a form intended to promote discussion. The distinction between image and fog development is discussed with special reference to the formation of filamentary silver which is seen as being associated with the catalytic mechanism. Several of the classical theories of development catalysis are compared. The increasing tendency to treat temperature coefficients in terms of activation energies is examined and a general pattern is suggested for the energy levels for the main phenomena. An attempt is made to give a meaning to redox potentials in development kinetics by considering the developer to act as a solvent for the grain by virtue of its ability to maintain a low silver ion concentration in solution.