I had bought colored pens when I made a stencil for my neices "Grateful Dead" quilt and didnt have any trouble with them running on white but the baby quilt I made had red fabric and it ran like crazy when I used the pens. Im thinking somewhere that I read you could wash the fabric in vinegar? But I might be thinking of something else! Thanks for the tips, Ill look for the sharpies next time I go to Wal mart. I also would love to see a picture of your quilt as I havent picked out a pattern yet, its just an idea starting to form!