Celluloid was phased out in the 1930's with the advent of safety film. Color photography was commercialized in 1935 with the introduction of Kodachrome. Polaroid instant prints were introduced in 1948. Today almost all photographic film consists of silver bromide on acetate film. Almost all photographic paper is silver bromide on various papers.
Most photography is based on silver as the light-sensitive agent.
But there are several non-silver processes. Platinotypes are based on platinum chloride. And the gum bichromate process is based on light-sensitive chromium compounds. The gum bichromate process was popular from about 1880 to 1920, particularly among artists. It has the advantage of relatively simple chemistry and color photography is as easy as black and white with this process.