Instant cameras greatly simplify the photograph taking process by making use of a technology that allows them to develop the photos as soon as they have been captured. However, before explaining the basics behind an instant camera, one must first understand how traditional photographic film works. Photographic film is practically a sheet of clear plastic coated with a series of light sensitive chemical compounds.
Some of the first black and white photographic films used layers of silver compounds. Further advancements in the field of photography eventually gave rise to color photographic films, which are coated with three light sensitive chemical compounds, each reacting to the three basic wavelengths of the visible spectrum, blue, green and red. As photographic film is being exposed, the silver compounds start to react according to the light intensity, forming metallic silver.
The film is then developed during a reaction with a chemical that turns exposed compound particles into silver. To complete the developing stage the film must be treated with three dye developers, each reacting with the individual color layers in the film. A developed film retains the negative image of the original, meaning that the colors are the opposite of the real ones.
Instant cameras function much in the same way, although the basic processes take place at once inside the plastic sheet of the film. A typical instant film sheet is formed of several layers of chemical, stacked on top of each other. First comes a clear plastic layer followed by an acid layer, a timing layer and an image layer. The dye developers come next, as they are placed on top of a base layer colored in black.
A reagent layer is placed between the dye developers and the image layer, and has the role of initiating the developing process. When a picture is taken, the reagent material is pushed to a side of the picture away from the light sensitive material. After the film has been exposed, a pair of rollers circulate the picture to evenly distribute the reagent chemical to develop the picture. Each light sensitive layer is then reacted to form an image.