Reduction of the Photographic Grain

Development of the photographic material represents a more complicated process than any of those considered up to this point, but many of the results already discussed are directly applicable to the formulation of its mechanism. The direct studies of development have followed, in 

It is important to keep in mind that, in the development of the sensitive layer as a whole, we are dealing with an ensemble of reaction units where reaction may or may not proceed in a parallel fashion among the many units. Under certain conditions the kinetics of development of a typical single grain can be inferred directly from a measurement of the overall rate of formation of silver, but this is not true as a general proposition. Studies of development of the individual grains are of fundamental importance, since the grain is the real unit of development. 

Evaluation of the data obtained for regular development showed that the results of experiments involving several different emulsions and developer compositions could be expressed by the relation 

Equation (11) does not give an accurate relation between the rate of formation of silver and the extent of the silver/silver halide interface. 

Apart from the work of Rabinovich and some earlier observations of Meidinger (56) no quantitative studies of the reduction of individual grains have been reported. Some studies of the development of the photographic emulsion as a whole, however, have been carried out under conditions such that the kinetics of development of the individual grain can be inferred from those of the ensemble. 

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