The fluorescent effect, the conversion of invisible UV light into visible light, is canceled out by the same UV light over time, causing the effect and therefore the intended expression of the painting to disappear. These are not real pigments but dyes and in addition to the fluorescent effect disappearing, the color itself will also fade considerably. This process takes place within 5 years under museum conditions, i.e. under relatively friendly conditions.
On tubes, labels and colour cards the lightfastness of Royal Talens products is indicated by the following symbols: +++ = at least 100 years lightfast under museum conditions ++ = at least 25 - 100 years lightfast under museum conditions + = at least 10 - 25 years lightfast under museum conditions º = at least 0 - 10 years lightfast under museum conditions These light fastnesses have been tested under museum conditions.