Black & White Error Cards?

Hey everyone, I recently started collecting again and went to a card shop with a couple friends. I started searching through a box of bulk and came across these 2 error cards I have never seen before. I was curious to know if anyone might know anything about this kind of error. Please see the attached photos below and let me know if you would like more pictures.


Quality control wasn’t great especially then. IMO I don’t think it hurts the value much unless you grade them. Then they’d get slammed.
Some people may like those mistakes though. I don’t know why;)

Cards are printed via offset printing. The colours cyan, magenta, yellow and black get added on in separate layers. The layers sum together to form all the colours on the card. In this case the CMY layers seem to have not been applied to the cardstock properly. Only black was applied appropriately hence the black and white (the base colour of the cardstock is white) effect.