ABSTRACT
Sunlight is an important cause of damage to coatings. Short-wavelength ultraviolet (UV) light has long been recognized as being responsible for most of this damage.
Accelerated weathering testers use a wide variety of light sources to simulate sunlight and the damage that it causes. Comparative spectroradiometric measurements of sunlight and laboratory testers of various types show a wide variety of UV spectra. These measurements highlight the advantages and disadvantages of the commonly used accelerated light sources: enclosed carbon arc, sunshine carbon arc, xenon arc, and fluorescent UV. The measurements suggest recommendations for the use of different light sources for different applications.
