AMBROTYPE
Etymology
Noun
ambrotype (plural ambrotypes)
(photography, historical) An early type of photograph in which a glass negative appears positive when displayed on a black background.
Synonym: amphitype
Source: Wiktionary
Am"bro*type, n. Etym: [Gr. -type.] (Photog.)
Definition: A picture taken on a place of prepared glass, in which the
lights are represented in silver, and the shades are produced by a
dark background visible through the unsilvered portions of the glass.
Source: Webster’s Unabridged Dictionary 1913 Edition