actinic radiation

Actinism is the property of solar radiation that leads to the production of photochemical and photobiological effects. Actinism is derived from the Greek ακτίς, ακτῖνος (a ray or beam). The word actinism is found, for example, in the terminology of imaging technology (esp. photography), medicine (concerning sunburn), and chemistry (concerning containers that protect from photo-degradation), and the concept of actinism is applied, for example, in chemical photography and X-ray imaging.