I'm fascinated by early color photography...it takes a time we think of being in black & white and makes it accessible and modern. In the hands of Auguste and Louis Lumière, the "lowly, lumpy potato" made color photography possible in the early 1900s. The photos were called autochromes.
The Lumière brothers gathered up their potatoes and ground them into thousands of microscopic particles; they separated this powder into three batches, dying one batch red-orange, one violet and one green; the colored particles were thoroughly mixed and sifted onto a freshly varnished, clear glass plate while the lacquer remained tacky; excess potato bits were swept from the plate, which was pressed through steel rollers to flatten the colored grains, transforming each into a minuscule color filter measuring from .0006 to .0025 millimeters across. Gaps between the colored particles were filled in with carbon black, the plate was varnished again and a thin, light-sensitive emulsion of silver bromide was brushed over that. Now the plate was ready for the camera. When the shutter was opened, light filtered through the translucent potato grains, and a multicolored image was imprinted on the emulsion. After the negative plate was developed in the lab, it was washed and dried, covered with another piece of glass to protect the emulsion and bound with gummed tape. Et voilà! A color photograph unlike any seen before.
Here's a slideshow of some photos taken by this process. Here's some autochromes of Mark Twain from 1908.
More early color photography (not necessarily autochromes): Sergei Mikhailovich Prokudin-Gorskii's stunning photographs of Russia circa 1909-1915, photos of WWI, photos of WWII, and photos of America in the late 30s/early 40s (color corrected). (thx, david)
