By Oksana Love, Ph.D.
Polaroid, the first instant picture-making camera, became incredibly popular in the 1950s. However, as technology progressed — including smartphones with built-in cameras, the Polaroid company stopped making cameras.
Even so, there was always something magical about taking a Polaroid picture and watching it develop in your hands. This is likely why instant pictures have become popular once again! Today, you can find people taking Polaroid-style images at casual events and parties. The attraction to this type of camera is how quickly and easily images can be created.
After the company stopped making its instant cameras and film, a new team of scientists emerged. Calling themselves “The Impossible Project,” they decided to take on the adventure of learning the science of making Polaroids. As it turns out, instant films are all about chemistry!
So, how are these pictures made? The special film used for Polaroids looks thin and shiny, but it’s actually quite complicated. Each film contains different chemicals that help capture the image, develop the film, and produce a colorful picture. The film is made of stacked layers of silver bromide (AgBr) crystals that are sensitive to a certain color, as well as a mix of colorful dyes.
When you click on the button to take a picture, the film is exposed to light, and an image is produced (using Silver and light). This is what gives the picture a darker contrast, the same as with black-and-white photos. The areas of the film that are not exposed to light only allow certain dyes to come to the surface. These dyes are the opposite of the original color to which the first layer is exposed. For example, if a green area is exposed, then magenta dye cannot pass through. But turquoise and yellow dyes can pass, and they will mix to produce a green color. The film is then covered in the developing chemical, potassium hydroxide, which reacts with each of the dyes within the film. These dyes fill in the areas where the layer was not exposed to light. After this and additional chemical processes, the picture is ready!
Amazingly, all these reactions happen within a few minutes. Polaroids are indeed examples of picture-perfect chemistry!
References
- Jarvis, Lisa M. “What’s That Stuff? Instant Film.” CEN RSS, Chemical and Engineering News, 23 Mar. 2009, cen.acs.org/articles/87/i12/Instant-Film.html.
Oksana Love, Ph.D. is an Associate Professor at the University of North Carolina Asheville.
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