Specifies methods for exposing to a xenon-arc light source under controlled environmental conditions. The procedure may include measurements of the irradiance and radiant exposure at the surface of the specimen. It is recommended that a similar material of known behaviour be exposed simultaneously with the experimental material as a reference. A xenon arc, when fitted with suitable filters, produces radiation with a spectral energy distribution similar to that of terrestrial sunlight in the UV and visible regions of the spectrum. General guidance is given in ISO 4892-1.