RADIOCHEMICAL STUDIES ON THE INFLUENCE OF PHOTOGRAPHICALLY ACTIVE SUBSTANCES ON THE KINETICS OF THE TRANSFER OF SUBSTANCES TO SILVER-HALIDECRYSTALS .4. THE INFLUENCE OF ORGANIC ANTIFOGGANTS

A report is given about the influence of organic antifoggants and stab ilizers respectively on the kinetics of the mass transfer in the syste ms AgBr(s)-antifoggants-Br-82((1))(-) and AgI(s)-antifoggants-I-131((1 ))(-) in the course of the Ostwald ripening from AgBr and AgI crystals respectively. For the investigations the antifoggants 5-Mercapto-6-su lfobenzimidazole (MBI), 1-Phenyl-5-mercaptotetrazole (PMT), 2-Mercapto benzthiazole and 5-Methyl-7-hydroxy-1,3,4-triazaindolizine (MHT) were used. It was found, that the velocity of the Br-82(-)- and I-131(-)-ma ss transfer is decreasing, when the concentration of the used antifogg ants is increasing and come to a characteristic borderline limit. Whil e the antifoggant 5-Mercapto-6-sulfobenzimidazole (MBI) is relatively effective in stunting the velocity of the mass transfer by AgBr alread y in little quantities, it shows a negligible significant influence by AgI. These results are interpreted through the adsorption of the anti foggant molecules on active centres of the crystal growth and the inte raction with interstitial silver ions in the range near the surface of the silver halid crystals. The characteristic concentrations are obta ined for the case, where used the antifoggants, they should also have significance of photographic importance. The kinetics of the Br-82(-) and I-131(-) mass transfer processes on AgBr and AgI crystals respecti vely can therefore serve as an indicator for the efficiency of photogr aphic active substances and give reverence to application of the sort and quantity of the respective antifoggant by photographic application s. The interaction of the antifoggants with the gelatin is of importan ce in this case. The activation energies for the mass transfer of the Br-82(-) on the AgBr and the I-131(-) on the AgI crystals depends on t he antifoggants and its concentration, the presence of gelatin and the nature of the AgBr and AgI crystals respectively.