! Autochromes !

In 1903, French brothers, August and Louis Lumière, patented a color photographic process.

Fine grains of transparent potato starch were dyed and applied to a glass plate. The plate was pressed to create a minuscule color filter. A light sensitive emulsion of silver bromide was applied and the color plate was ready for the camera. Once processed, the result was a color transparency.
The autochrome was the first viable color photographic process based on this technology.
To learn more about autochromes, seeThe Autochrome: 100 Years of Color Photography
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