A tintype, also known as a ferrotype or melainotype, is a direct positive photograph made onto a thin sheet of coated metal prepared with a photographic emulsion. A successor to Daguerreotypes and Ambrotypes, the technique was developed in the 1850s and was in wide-spread use by the 1860s and into the early 1870s when the Carte de visite became increasingly popular. (Wikipedia: Tintype)
