I've done a printed black backing fabric with a white-on-white (plus some applique) on the front when using W&N batting. Nothing showed through or was shadowed other than when the quilt was soaking wet (and then it dried back to it's state where nothing showed). Even black printed fabric is not dark black on the back side. You could always take some with you to the store, but I think mainly this is a problem with other types of batting.