Instant Film
Edwin Land demonstrates Polaroid camera to an Optical Society meeting, 1947, after his daughter asks why she had to wait so long to see her picture.
Credit: iStock
Perhaps the allure lies in the instant gratification and tangibility of being able to snap a photo and hold a print immediately in your hand, or maybe it’s just the pleasure and nostalgia of watching a fuzzy image in a white plastic frame come into focus. Regardless of the source of its appeal, instant film has had a dedicated following since the Polaroid camera hit the market in 1948.
According to Polaroid, the idea of a photo lab in a box came to inventor and physicist Edwin Land in 1944, when his daughter asked why she had to wait so long to see a picture taken while vacationing. Over the course of three years, Land figured out how to achieve a one-step photography process.
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.
Visit “What’s That Stuff” to read more about instant film.
Excerpted with permission, Chemical & Engineering News
Copyright © 2009 American Chemical Society