Encyclopedia
tintype
positive photograph produced by applying a collodion-nitrocellulose solution to a thin, black-enameled metal plate immediately before exposure. The tintype, introduced in the mid-19th century, was essentially a variation on the ambrotype, which was a unique image made on glass, instead of metal. Just as the ambrotype was a negative whose silver images appeared grayish white and whose dark backing made the clear areas of shadows appear dark, so the tintype, actually negative in its chemical formation, was made to appear positive by the black plate
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