Heliochromy

Part of speech: noun

Definitions

1. A photographic or printing process that uses the action of sunlight to create colored images on a sensitized surface
2. A method of producing color pictures or prints by exposing light-sensitive materials to solar radiation
3. The technique of capturing or reproducing colors through the chemical action of sunlight on specially prepared photographic media

Etymology: Heliochromy is a compound built from three parts: "helio-" from Greek "hēlios", the sun; "chromo-" from Greek "chrōma", colour; and the English suffix "-y", which turns the pair into a noun naming a process. Together they describe colour produced by sunlight. The word belongs to the vocabulary of early photography, when inventors were still working out how light could fix images onto surfaces. Its meaning is therefore literal: making pictures in colour with the sun's action, rather than by painting or dyeing. The parts are classical, but the combination is a modern technical coinage, not a term that existed in antiquity.