I was reading a blog entry about cow facts and one thing that was mentioned was that cow’s gelatin is used in making photographic films. I got curious of course and I did a little searching and reading and here’s what I found out: Photographic film is a sheet of plastic (polyester, nitrocellulose or cellulose acetate) coated with an emulsion containing light-sensitive silver halide salts (bonded by gelatin) with variable crystal sizes that determine the sensitivity, contrast and resolution of the film. Most of the gelatin in photographic film, which I assume is the one used to bond the silver halide salts, is from cattle bones. And here’s another interesting fact, some layers in color films use gel made from pig skins.

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