The Digital Light Fastness Tester is used for determining the color fastness of textile to light using an artificial Light source - Mercury Ballast Tungsten Filament Lamp (MBTL) mounted centrally so that the light distribution is constant. The equipment is suitable for all types of textiles except photocrometic coloured textiles. A test specimen together with blue wool standards is exposed to the light from a MBTL fading lamp. The colour fastness of specimen is assessed by comparing its fastness with that of 1-8 Blue Wool standards.