collodion process

A dry - or more commonly - a wet process using collodion as a medium to support a light sensitive emulsion. The wet-collodion process was described by Frederick Scott Archer in 1851 and, after refinement, was used by numerous 19th-century photographers from c.1854 onwards. It remained dominant until the mid 1870s. Collodion was also used to produce direct positives on glass (ambrotypes) and tin (tintypes).