Abstract: A reusable dosimeter for sun radiation comprising a matrix with at least one active chemical compound distributed therein, capable of reversibly changing its original color to a new color due to a chemical reaction induced by exposure to UV radiation, said matrix made of a material having transparency sufficient for visual detection the change of the original compound's color to the new color, said active chemical compound being capable of changing its color after exposure to UV radiation with an efficacy corresponding to at least 1 MED, and reverting back to its original color after being kept in the dark for about 6 hours.

Abstract: A disposable dosimeter for sun radiation comprising a matrix with at least one active chemical compound distributed therein, capable of changing its original color to a new color due to a chemical reaction induced by exposure to UV radiation, said matrix made of a material having transparency sufficient for visual detection the change of the original compound's color to the new color, said matrix containing at least one absorbing compound capable of absorbing the UV radiation, said active chemical compound being capable of changing its color after exposure to UV radiation with an efficacy corresponding to at least 1 MED, said UV radiation being accumulated during at least 15 minutes of exposure and said active chemical compound having a resistance to change the new color neither during exposure to temperatures up to 50.degree. C., nor during exposure to visible light.