Posted By:
AnthonyI think it depends on both the card and the set. Any oddity in T206 is a hotly collected card, the same oddity in '35 Goudey would have no difference in value.
Blank back cards, to me, are just printing mistakes, the same as wrong backed cards. No extra value at all, and if offered one I'd probably pass if I already had the card.
Hernansk, Bakep, Herrer are all errors as well, but have the noteriety and the long history to have made them as sought after as true variations. It doesn't hurt that the grading companies note the version on the flips and pop reports, and included them in registries as variations.