It may seem
magic, but it really is a simple process. What is happening inside an instant
camera while you are waiting for your image to appear?
In order to
understand how instant cameras work, it has to be explained how a traditional
film works. Photographic film is a sheet of clear plastic coated with a series
of light sensitive chemical compounds. Color photographic films are coated with
three chemical compounds, each of them reacting to the three basic wavelengths
of the visible spectrum, blue, green and red. When you expose the film, the
sensitive grains at each layer react to light of that color, creating a
chemical record of the light and color pattern. To get a picture out of that,
you have to develop the film using more chemicals.
Instant photographs
work almost the same way, although the basic processes take place all at once
inside the plastic sheet of the film. The major difference between a common
photographic film and an instant film is that the instant film includes the
chemicals needed.
The instant
photograph consists of several layers of chemical, stacked on top of each
other. A clear plastic layer followed by an acid layer, a timing layer and an
image layer. The dye developers are placed on top of a base layer colored in
black. In order to initiate the developing process, a reagent layer is placed
between the dye developers and the image layer. When a picture is taken, the
reagent material is pushed to the side of the picture, away from the light
sensitive material. A pair of rollers circulates the picture to distribute the
reagent chemical evenly, to develop the picture. The light sensitive layer is
then reacted to form an image, which is already fully developed underneath, but
the chemical agents’ clearing up creates the illusion that it is created right
in front of your eyes.
