Colour Negative Granularity: A Simple Theoretical Approach^*

* Present address: Riverside View, Riverside, Clapham, via Lancaster LA2 8DR.

Abstract

Attention is drawn to the similar departures from standard theory in the granularity- density relations for under-developed black-and- white materials and for colour negative layers of limited coupler content when developed normally. In the former case the decrease in size of developed grains zvith increasing density offsets the effect of increasing number of such entities per unit area, so that granularity may show little or no increase with density. In a colour negative layer the density contribution of a dye cloud may decrease with increasing density owing to the same effect, and be further reduced by coupler starvation which progressively reduces the ratio of dye to mass of developed silver.

The area distribution of fluctuations in dye density must relate to the fluctuations in developed silver per unit area. Thus the granularity-density relation for a colour negative layer should be deducible from the fluctuation in weight of developed silver (related to the silver granularity) and the relation between dye density and weight of developed silver per unit area. Experimental confirmation of this concept is provided. The use of the approach for exploring the influence of coupler properties and degree of development on speed- granularity relations for colour negative layers is indicated.

Notes

* Present address: Riverside View, Riverside, Clapham, via Lancaster LA2 8DR.