It is very important to duplicate or restore classical photographic prints considering their present status of deterioration. Our experiments show the stabilities of printing-out images under several storage conditions. Printing-out prints on salted paper, albumen paper, and printing-out-paper (POP) were prepared and incubated under the conditions of high temperatures and humidities. As a result, the degrees of discoloration and fading of the prints were remarkable on the albumen paper print, and smallest on the POP print under the conditions of 20°C and 86% RH. To investigate the effect of gold-protection, both albumen paper prints, toned by Kodak GP-1 solution, and untoned ones were incubated under the conditions of 70°C and 50% RH. This test confirmed that the period for decreasing the density range on the toned albumen paper prints were tested under the humidity conditions of 86%, 70% and 50% RH at 85°C, and the periods required for the density range to decrease by 10% and 22%, respectively, were compared. When such deterioration of a print is going on, it is necessary to duplicate it before the highlight details vanish. The processes and formulae shown in this article may be utilized to duplicate the printing-out images.