I went through a period of time that I pre-washed everything. Then, I decided, after reading many articles and opinions, I decided not to pre-wash any more fabric. Therefore, I have wound up mixing fabrics that are washed and not washed. And, I have encountered absolutely no problems. I quilt my projects moderately and I wash them when I finish them. I always use Shout sheets and they do indeed pick up color many times but no dye transfer on the fabrics of the quilt. There is shrinkage-mostly because of the batting- and I like that crinkly look. I might add that I use high quality fabric with a high thread count and tightly twisted yarns.