Polaroid film contains chemicals needed for developing and fixing the photograph. A negative sheet is exposed inside the camera, then lined up with a positive sheet and squeezed through a set of rollers between which a coating of reagent is spread. This activates the developing process in which unexposed silver halide grains are solubilised by the reagent and transferred by diffusion from negative to positive. This process takes roughly a minute, after which time the negative is peeled away to reveal the image, which has been transferred to the positive receiving sheet.
The first Polaroid cameras, invented by Edwin H. Land, were marketed in 1947 and produced black and white images. Polaroid instant colour prints and slides were launched in 1963. Due to the digital photography revolution, Polaroid stopped making Polaroid film in 2008.