METHOD FOR MEASURING THE STABILITY OF SILVER IMAGES TO AERIAL OXIDATION AND THE IMAGE STABILIZATION BY A THIOL

Despite the increasing concern about image degradation of stored or displayed photographs by aerial oxidants, no predictive method for measuring the image stability to such oxidants has been reported, mainly because of lack of proper acceleration means. In this study, a proposed method uses hydrogen peroxide and glycerol in liquid/vapor equilibrium. It maintains a constant testing atmosphere of 120 ppm H2O2 and 80% RH. The vapor concentration is considered to provide an order of 10(4) times acceleration of the urban environment and may give a prediction of long-range keeping. Silver-gelatin type photographs stabilized by AG-guard treatment and by gold toning, together with unstabilized controls, were measured by the proposed method to indicate the usefulness of the method. Good stability of the AG-guard-treated images, as well as the gold-toned images, were clearly shown by this predictive method.