Four celluloid fantasy postcards. These are quite common, as objects made from celluloid were fashionable for a while. They seem to have been quite versatile. Here we see gold printing, collage, glitter, scalloped edges and the card in the bottom righthand corner looks to be very skillfully hand painted.
Celluloid is considered as the first plastic and was widely used as an ivory replacement. It was used in the film industry until replaced by acetate films in the 1950s. Table Tennis balls are made of celluloid!