When taking
a photograph with an instant camera, the actual picture can be hold in hands a
few minutes later. What may seem like magic is in fact the result of a chemical
reaction. The process begins with the plastic film base that is coated with silver
particles. These particles are light-sensitive. Black and white films have one
layer of silver, whereas color films have three layers which are sensitive to
different colors. The top layer is sensitive to blue light, the layer in the
middle is sensitive to green and the third layer is sensitive to red light.
When a film is exposed, the light-sensitive particles react to the different
colors and form metallic silver. In order to get a picture, the film needs to
be developed. Instant cameras are similar to a photo laboratory because they contain
all chemicals which are necessary for the developing process. There is a
developer layer attached to each color layer. The reagent, a mix of light
blockers, neutralizers and other elements starts the chemical chain reaction and
activates the developer on each layer. The reagent is collected in a blob at the
white bottom of the film sheet. After having taken the picture, the camera
rollers push the chemicals from the blob in the middle of the film sheet and
roll it up to the end of the frame. The reagent chemicals then move through the
layers and, after a chemical reaction, appear as colors. When watching an
instant image develop, this chemical reaction can be seen.
[255]
