Amphitype is a mid-19th century photographic process, introduced in 1851–1852 by Frederick Scott Archer and Peter Fry. It involved creating a weak collodion or underexposed albumen negative on a glass plate, which was then bleached and backed with a dark surface. When viewed by reflected light, the black backing produced the visual effect of a positive image, similar to an ambrotype. Amphitypes were used primarily for portraiture and artistic photography, offering a distinctive, high-contrast aesthetic. This historical process is significant in the development of early photographic techniques and is still studied by collectors and practitioners interested in 19th-century alternative photographic methods.