actinic

1. (by extension) Harsh and bright, especially blindingly so.Examples: "He bounded over cresting waves that shone in the actinic glare."; "And what actinic, mind-wrenching form could the countermeme take? How could human hands assemble something so devastatingly powerful and hold it steady; what human mind could wield it without exploding from the inside out?"

2. (medicine) Caused by extensive exposure to ultraviolet light.Examples: "In medicine, actinic keratoses usually occur in sundamaged skin and exhibit hyperkeratosis."

3. (chemistry, photography) Of or relating to actinism, the range of photochemical effects produced by exposure to electromagnetic radiation, particularly sunlight.Examples: "It should be borne in mind that the actinic power of the sun is subject to considerable variations, due to its elevation above the horizon."; "I got my picture, and it turned out quite a good one, despite the rather poor light which at that time of day, 7 p.m., was lacking in actinic value."