I would wash it with color catchers. I think it is about 50/50 as to it will bleed or not, more for some red fabrics. I had one red marbled type fabric which started out maroon, and after six washes was still bleeding and now a rosy, red color. I put it in a rummage sale and a great price of $4 and a note on it that said "this fabric is still bleeding". One of the many reasons why I stopped using 108 wide backing is that if I have to prewash it, it is too hard to press so now I just use regular width fabric. Those two seams to stitch them together is a lot easier for me than dealing with the giant hunk of 108 wide fabric.