Frederick Scott Archer (1813- May 2, 1857) invented the wet plate collodion process in 1851. Collodion, a thick and syrupy liquid, is made by dissolving nitrated cotton in a mixture of alcohol and ether. This revolutionized photography. Prior to that exposure took up to 20 minutes and the photos could not be duplicated.

 

Archer’s innovation was to coat a glass plate with a mixture of collodion and potassium iodide, and then dip the plate into a silver nitrate solution to make it light-sensitive. This negative could then be used to make prints on albumen (egg whites sensitized with silver nitrate), salt prints, and most recently silver gelatin paper.

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