reversal film

photography

Also known as: positive film, slide film, transparency film

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July 13, 2026

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Reversal film, also known as slide film, is a type of photographic film that produces a positive image directly, rather than a negative. This process involves breaking down the image into its primary color components (blue, green, and red) using separate sensitized layers within the film. Each layer responds to a specific color of light and is then processed to create a positive dye image in a complementary color. For example, the blue-sensitive layer creates a yellow positive image of everything that is not blue.1

The structure of reversal color film typically includes multiple emulsion layers, each containing silver halide and a color coupler that forms a specific dye. A yellow filter layer prevents blue light from reaching the lower layers, and a film base provides support. This process allows for the direct creation of color transparencies.21

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history of photography
Color photography
With this reversal (slide) film, color transparencies could be obtained that were suitable both for projection and for reproduction. A year later the Agfa Company of Germany developed the Agfacolor negative-positive process, but owing to World War II the film did not become available until 1949. Meanwhile,…
Read More
With this reversal (slide) film, color transparencies could be obtained that were suitable both for projection and for reproduction. A year later the Agfa Company of Germany developed the Agfacolor negative-positive process, but owing to World War II the film did not become available until 1949. Meanwhile,…
Read More