Damage to museum objects due to light exposure

Damage to museum objects due to light exposure occurs by two processes: photochemical action and radiant heating effect. The basic physical processes are defined, and the effects of ultraviolet (uv), luminous flux and infrared (IR) exposure on object degradation are examined. Recent research is reviewed, and new data on wavelength dependency of fading lead to some reassessment of attitudes based on earlier data. The aim for lighting and conservation of museum objects is defined as satisfying viewers with the least possible amount of energy being absorbed by the displayed object. Current standards and recommended practices are reviewed, and it is concluded that museum lighting policies should be directed towards control of non-visible irradiance, both IR and uv, and that future research should move beyond examining fading effects of exposure to studying ways to satisfy viewers with minimum absorbed energy.