I prewash everything including Batiks. Haven't had any bleed yet but I sure don't like the wierd smell they put off when ironing them. I use just a little of my favorite scented detergent to cover the scent.
Just checked out there site. They have absolutely beautiful fabrics but some of them are way pricey, as much as $9.99/half yard. Ouch!! And Yes, I said half yard.