What does "ambrotype" mean?

An early type of photograph in which a glass negative appears positive when displayed on a black background.

Ambrotype

noun

noun ·Rare ·Advanced level

Noun

1
An early type of photograph in which a glass negative appears positive when displayed on a black background. historical

From Ancient Greek ἄμβροτος (ámbrotos, “immortal”) and τύπος (túpos, “impression”).