photonegative

[ foh-tuh-neg-uh-tiv ]
/ ˌfoʊ təˈnɛg ə tɪv /

adjective Physics.

pertaining to a substance, as selenium, having a conductivity that decreases upon absorption of electromagnetic radiation.

Origin of photonegative

First recorded in 1910–15; photo- + negative

British Dictionary definitions for photonegative

photonegative
/ (ˌfəʊtəʊˈnɛɡətɪv) /

adjective

physics (of a material) having an electrical conductivity that decreases with increasing illumination