4/21 Update

In case you're a loser like me and care about shit like how Polaroids work:

Instant film may seem like a simple product in the package, but it is actually carefully composed of layers of dyes, emulsions, and developers—everything needed to capture the image, develop the film, stop the developing process, and neutralize any unused chemicals.

It uses the same general principles as the roll of color negatives you put in a regular point-and-shoot camera. A standard color negative has three layers of silver bromide crystals, each sensitive to a particular color (blue, green, or red). When film is exposed, a latent image is formed in each silver bromide layer as light reduces Ag⁺ ions to Ag.

Instant film contains those same three light-sensitized layers, but below each layer is an oppositely colored hydroquinone-decorated dye. For example, below the blue-sensitive silver bromide layer sits yellow dye, where yellow is the opposite or the "negative" color to blue on the color wheel. Analogously, below the green-sensitive crystals lies magenta dye, and below the red crystals lies cyan dye.

The image is formed through a complex, inverse filtering process: The dyes from unexposed layers are allowed to pass up through to the image layer and combine at the surface. For example, if a blue area is exposed, then no yellow dye can pass through but magenta and cyan can, and the mixing of these two colors forms blue.

After exposure, the film is ejected from the camera, passing through a set of rollers that spread developing chemicals across its surface. One of these developing chemicals is potassium hydroxide, which diffuses downward and reacts with all the hydroquinone-decorated dyes. The resulting dye molecules can then diffuse up through the light-sensitive layers wherever their corresponding silver bromide molecules have not been exposed.

The process ends when the potassium hydroxide reaches the timing layer, in which any leftover base is neutralized. Unexposed silver bromide is then dissolved by other components in the developing solution, including potassium thiosulfate and uracil.

The whole ordeal is finished in a minute or so and—voilà—a photograph is born.

Source: http://pubs.acs.org/cen/science/87/8712sci2.html

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