Ninnie, I do the same thing. When I get fabric in hand, I get so inspired by it and always end up doing something totally different with it than what I started out to do.
We added on to our house and I have this sewing/guest room. We put in a 4x8 ft windows on the west side, and and there is a huge window in each of the other ouside walls as well. The daylight makes it so much easier to see the colors. I take off my glasses too if I happen to be wearing them. I know that glasses aren't suppose to change the color of what you see, but I swear mine do. Fortunately, I only need to wear my glasses when I'm tired or have a headache.
Ninnie