This part of ISO 105 specifies a method for determining the colour fastness and ageing properties of all kinds and forms of dyed and printed textiles and/or other organic substrates under the action of an artificial light source representative natural daylight (D65), and under the simultaneous action of heat. Of the five different sets of exposure conditions specified (see 6.1), four use D65, and the other one uses a somewhat lower cut-off wavelength. The test method gives special consideration to the light and heat conditions that occur in the interior of a motor vehicle. The five different sets of conditions using the different optical filter systems specified may produce different test results. Results from tests performed using different apparatus (instrument types) for the same set of conditions and optical filter system shall not be compared, as comparable performance has not been validated.