Are you color blind, or have the red backed cards faded to yellow? There shouldn't be any with yellow backgrounds.
Sorry, that wasn't as clear as I'd imagined... I didn't mean the backgrounds are yellow... The logo on the back of the cards are either yellow+red or blue. I don't know why I focused on the yellow But no, the cards are not at all faded.
@Yelgrun: I'm in central California