[drcy]

Old photos, say cabinet cards and pre war news photos, are usually dried out and are less likely to stick to anything anymore. Photos sticking in album pages and to glass were usually either modern or put in the albums or glass when they were still new. If you stack them, stack them back to face. Even with modern photos, if you stack them back to front they will only rarely stick. It was the gelatin film on the fronts that was sticky and moist, and it usually dries out with time. Old cabinet cards are usually bone dry.