The light sources used to produce light also present related emissions of electromagnetic radiation not perceptible by the human eye, but can induce effects on people or things exposed to the same luminous flux.

Typical examples of newspapers radiation emitted along the light are the heat produced by an incandescent lamp and the tan and discoloration produced by sunlight.

Even the diodes LEDs are not exempt from the production of radiation-related, especially the diodes with high color temperature light and cold (>6500°K).

The intensity of this radiation, mainly UV, grows proportionally to the increase of the “light power” of the LED diode and the possible harm or risk is inversely proportional to the cone within which the light is emitted (beamwidth).

Any risks or photobiological damages are induced by radiation that are at the extremes of the visible range (380-780nm) that is:

– Infrared (IR-A, IR-B, IR-C) typically able to produce thermal effects;

– Ultraviolet (UV-A, UV-B, UV-C) in a position of producing ionizing effects instead.

These photo-biological effects or damage, created by UV or IR, are charged to the skin, to the underlying tissue (erythema, photo-aging, photo-toxic reactions, skin burns), to the eye and its component parts: crystalline and cornea (cataract, photokeratitis, photoretinitis, scotoma).

It was therefore necessary to adopt a set of procedures that provide for the identification of radiation that produce photobiological effects, to define exposure limits, to define a criterion for measuring radiation above and finally to define risk groups in which the light sources take part.