Photographs consist of three different parts:

• Support layer: glass, plastic film, paper, or resin-coated paper

• Binder layer: the emulsion or binder layer is what holds the final image material or image-forming substance to the support (most commonly gelatin, but also albumen or collodion)

• Final image material: made of silver, colour dyes, or pigment particles (usually suspended in the emulsion or binder layer)