Physical Retardance by Modified Gelatin

Abstract

The effect of the isoionic point of gelatin on physical ripening properties was studied by the physical retardance test using modified gelatins. Carboxylic groups were blocked by the amidation reaction and amino groups were blocked by the acylation reaction.

Physical ripening speed decreased in relation to the ratio of blocked carboxylic groups and increased when the ratio of carboxylic groups increased due to acyl substitution. However we found that the final particle size of silver halide did not depend on the isoionic point of the gelatin. It was assumed that the charge shift in the gelatin molecules affected the physical ripening speed and did not affect the final particle size.