Photochromy

Photochromy is the art or process of reproducing colors by photography. [Note] Not to be confused with Photochromism (a reversible color change induced by light energy ). See Photochromism. Furthermore, a Photochrom is not the result of the photochromy process.

History
Colored images by direct exposure from nature using a Lippmann plate

Color printing method by the bleach-out process.