The theory of photographic processes, part II: On the chemical dynamics of development, including the microscopy of the image

Abstract

The investigation of development described in a previous communication was extended by the application of microscopic methods. The fact that both the silver haloid and the resulting silver are distributed through the film in the form of particles of minute but measurable size, allows us in this way to detect finer qualitative differences in, and to draw independent deductions on the processes of exposure and development. The size of the grain is important, both from the practical point of view and from the theoretical: in the one case as bearing on spectroscopical and astronomical photography, in the other on account of the great importance of the degree of surface-extension for heterogeneous systems. The method has been used previously by Abney, Abegg, Kaiserling, Ebert, and others, but by far the most systematic and important inquiry is that of K. Schaum and V. Bellach.