Adsorption of Gelatin to Silver Bron1ide

Paper presented at a symposium on “Photographic Gelatin” organized by the Science Committee of the Royal Photographic Society on 19 22 September 1967 in Cambridge

Abstract

Adsorption and desorption isotherms for gelatin on silver bromide at both pH 6 5 and 3 5 were obtained. At pH 6 5 the adsorption was higher than at pH 3 5 but a proportion of the gelatin was desorbable. There was no detectable desorption at pH 3-5. In addition the effect of adsorbed gelatin on the fixation time of silver bromide sols was examined. The decrease in fixation time observed with added gelatin was most marked at pH values below the isoelectric point, and at the lower temperatures examined. It is concluded that the net charge on the gelatin molecule in relation to the charge on the surface plays an important part in the configuration of the adsorbed layer although it has a comparatively small effect on the total amount of gelatin adsorbed. When the charge is the same as that on the surface, the proportion of adsorbed segments is small and the rate of desorption becomes significant

Notes

Paper presented at a symposium on “Photographic Gelatin” organized by the Science Committee of the Royal Photographic Society on 19 22 September 1967 in Cambridge