I'm not 100% sure on that one. Its only going to be a problem if its in the sun day in day out. Some colors don't care about UV...and some paints have UV inhibiters. Like I have some Golden paints that say, "formulated with 100% acrylic polymer dispersion"..bla..bla...UVLS. UVLS stands for Ultra Violet Filters and Stabilizers. I'm sure I'm getting some of this wrong...but for me...I try not to worry about it a whole lot...unless its the color yellow. If you ever see these old four color prints on the wall were the grass and trees look blue...it because the yellow has faded out of it.