Originally Posted by feline fanatic
Just be aware, a color catcher will ONLY keep bleeds or excess dye from settling on other fabrics in the wash. They will not set dyes. So if you have a bleeder fabric it will still continue to bleed even after washing with a Shout Color Catcher. To set dyes you need to prewash in a product called Retayne. You may be able to find it at your LQS but best bet is to buy it on line.
I agree with Feline Fanatic. Retayne has worked well for me, on reds and greens. Only takes 1-2 teasp per yard of fabric. Instructions are to use prior to washing.
Also, you could test the fabric by placing a 2 or 3 inch
piece in hot water to see if it bleeds. The water will turn red or place the wet fabric on a white paper towel. Maybe it would only be necessary to prewash the fabric to release loose dye.