Light fastness testing involves subjecting samples to intense artificial light to assess the impact on the
material.

Poor performance in light fastness testing indicates that a product is likely to fade when exposed to light. In the case of clothing this may result in product returns or complaints from customers so if garment manufacturers can undertake light fastness testing during R&D this can provide a warning sign when developing clothing and other consumer items that are likely to be exposed to sunlight.

This test method provides the general procedures which are currently in use for determining the colorfastness to light of textile materials. Samples are exposed to an artificial light which is similar to sunlight source, and Xenon or Carbon is used as artificial illuminant.