my hubby asked for one of my quilts to hang at his office- i gave him a black & white one i had finished- about 4 months later i stopped in and found a few of the strips of black background fabrics were very noticably faded- a couple gray- a couple a brown---i was quite upset- it was from the florescent lights- not the sun- i reclaimed the quilt-
and replaced it with one the fading would not be so---damaging
i think any light can cause problems - in my sewing room i have a roll up shade over my fabric shelves- i roll it up when i'm working- and drop it down when i leave the room