Lightfastness of printing inks

Light fastness refers to the colour or material. Due to its high UV component, sunlight can have a strongly disintegrating effect. Colour changes, especially in the red and yellow range are visible first. The degree of light fastness is determined on the Blue Wool Scale. In Europe, the Wool Scale to DIN 53952 corresponds to an exposure time of between 700 days (Wool Scale 8 - excellent light fastness) and 5 days (Wool Scale 1 - very low light fastness).