A tintype photograph, also called a ferrotype and a melainotype, is a type of photograph that was developed in the 1850s. The image is an underexposed negative image that was produced by exposing light on a collodion emulsion on a piece of iron. A collodion emulsion is a mixture of cellulose nitrate, ether and alcohol. The image on a tintype is fragile and must be treated with care to avoid permanent damage. Tintypes were usually presented in a leather...