Fading artwork?
Fading is when a color becomes paler, this is normally due to the action of light. The strength of a pigment and it's ability to not fade is called lightfastness.
Fading can occur in a surprisingly short period of time and some art mediums, especially watercolors and prints are especially prone to it due to the pigment being largely diluted to begin with. Most colors will also fade faster when mixed with white rather than in mass tone.
When a paint fades it is generally because the strength of the pigment source is weak, to avoid an artists paint fading, refer to the paint's ASTM rating which will give an indication of the pigment source and it's lightfastness. A poster paint for children for example will use poor pigments that will fade easily and rapidly rated at ASTM 5. A professional artists quality paint will use a more expensive pigment course that doesn't fade easily and is likely to be rated ASTM 1 or ASTM 2.
If you desire to paint professional and what your paintings to have good longevity always choose colors of ASTM 1 or ASTM 2 and if the manufacturer includes Woolscale test results (usually 3 numbers separated by colons) then check the last number, as it represents the test at 5% in white; this is very revealing and a good indicator as to the color’s resistance to fading.
Regardless of the pigment source all artworks are prone to fading if they are not cared for properly, be sure to read the article; Storing artwork properly.
