Der Wirkungsmechanismus von Antischleiermitteln und Emulsionsstabilisatoren

Abstract

The effect of fog inhibitors as stabilizers of photographic emulsions is based on the prevention of the catalytic action of the active centres during digestion, storage and development by the adsorbed antifogging agents. The effect of the emulsion stabilizers in the emulsion depends on the accelerated formation of the ripening products in a photographically inactive state away from the surface of the silver halide grain, by contrast with normal digestion. This type of formation of the deposit is conditioned by increased concentration of the emulsion stabilizers in the gelatin adsorbed on the silver halide grain and by the high reaction velocity of their silver salts. The silver ions of the emulsion stabilizer salts are not bound to gelatin and therefore are not hindered in their ability to react with the digestion agents compared with the other silver salts present in the gelatin phase. The inefficiency of emulsion stabilizers in the developer is due to their desorption from the active centres of the grain by potassium bromide, developing agents and sulphite. The speed increasing effect of emulsion stabilizers added to the emulsion depends on the displacement of some of the gelatin adsorbed on the grain.