I prewash all the fabrics I'm using for a quilt altogether in a RETAYNE hot water wash and then put in the dryer, as per instructions on the bottle. I've always had good results with no problems of fabric bleeding later on. I measure before and after washing & drying and note shrinkage differences in each piece. Even the same complete line of fabric will shrink differently and I don't want the 'pucker' look after laundering. It's just a routine for me.