Years ago my son and I were opening packs of 1991 NBA Hoops and came across cards that went through the printers while red ink, yellow ink or both were missing from the backs of the cards. I tried to link to one example, card #281 here but I'm not sure it worked. With the red ink missing I now have two cards, one that's normal and one that's missing the card number, the Detroit Pistons in the basketball in the lower left corner and the red stripe behind the large "Detroit Pistons" at the top.
Along with this card I have cards 242 (Rick Adelman) and 242 (Cotton Fitzsimmons with the same issue. Card #284 (Indiana Pacers) I have missing the yellow ink on the back. Card 248 (Charles Barkley All Star) I have three ways... normal, missing yellow, missing yellow AND red. I have kept them in screw down holders over the years as something unique to look at. Would they have any value and should they be handled here as variations or just detailed card entries noting the missing ink?.