Prediction and preventing of fading caused by the light on art materials

Guaranteeing the ideal environment condition to the safeguard of collections is the main care of the museum curators. Also the light has to be controlled as it causes irreversible damage on the objects by photochemical action or radiant heating effect. Exhaustive studies of photo-damage processes by accelerated aging test, to simulate materials (old and recent art materials) behaviours, and well definite and detailed limiting requirements by norms for the lighting (sunlight or lamplight ) are important for this aim. These values can be used to project correctly cultural heritages by choosing the most appropriate lighting source, that permits the best light for the object and that assures longest life at him. A critical review about the actual norms is described in this paper together with a possible way to approach the open problems.