Lightfastness definition

Lightfastness refers to the degree that pigments, dyes and paints alter their color or fade due to exposure to UV or daylight heat, alkalis, or acids.  The estimate lifespan of a print may be found by certain tests, like the Wilhelm Laboratory reports or the Blue Wool Scale.  A print’s lightfastness may be impacted by various factors including the paper and ink used.  Some inks fade much faster than others.