I agree with Jingle. I wash with tide pod and cold water and throw in a color catcher. I have never had a problem. That said, black is over dyed and it tends to need a couple of washings. I have noticed in antique quilts black is the first to disintegrate.
I have a front load washer so I can't do a lot of soaking. I would NEVER purchase a front load washer again by the way!