Abstract: The development of emulsion layer is a gross process of the reduction of the emulsion grain population. Under the conventional development condition, the rate of density growth will give the information about the distribution of induction period among grains corresponding to the given exposure. The density difference among steps with different exposure depends on the relative rate of density growth of the steps, in turn depends on the different development behavior among grains. In the paper, the close relationship between the high contrast and the different development behavior among grains is discussed by taking two high contrast non-Lith systems as examples.

Key words: high contrast, infectious development, antifoggent