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.
References
Photochromy Wikipedia(Text) CC BY-SA