Silver bromide shape control

This understanding of the observation later led to the design of relatively defect free crystals with carefully controlled internal and surface sensitivity through chemical sensitisation. Crystals of silver bromide were precipitated and treated with sensitisers. Further deposits of silver bromide then buried the sensitivity centres. Figure 11.6b shows the resulting monodispersed crystals. These direct positive emulsions designed by F. Evans [37-39] were probably the first commercially exploited examples of crystals which were so perfectly formed and uniform. Previous emulsions contained a mixture of shapes and sizes due to relatively uncontrolled precipitation processes. 

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