I just finished a wedding quilt and used a small amount of Batik for the inner border and the binding. I had just put the border on and read on here - QB that the Batiks bleed. Paniced I though what will I do I have already quilted this. I was going to bind the quilt in the Batik also --soooooooo off to the kitchen sink to test -- WOW did it bleed. I bled it out 4 times in hot water and hung it on the clothes line to dry. Then applied the binding to the quilt and with a (4) color catchers washed the quilt. It didn't run on the white or sky blue. Whew--- but made a believer out of me for pre-washing everything. Also using some LQS fabric for a baby quilt -red 30"s print and decided I need to wash that too so off to the kitchen sink and sure enough it bled also. Washed it 6 times ! So in my opinion all fabric needs to be prewashed !