I prewash everything now. Have been quilting for two years and garment sewing for forty years. Took wonderful quilting classes at the local quilt shop and learned a lot. But they said not to prewash fabric and I have already, in just two years, had three disasters! PREWASH your fabrics!! I am just now doing a project with Batiks. Prewashed the Batik fabric and the water was BLACK. Oh yah, baby....I am a believer...PREWASH!!!!!!