Puzzled
I had a job that I overprinted a 100% black barcode over a white box with a cmy color underneath, the barcode for some odd reason knocked out the white box to the color underneath. The white box was not overprinting. What would cause this to happen. It makes no sense to me. My fix was to not uverprint the black but that also didn't make any sense either. What would have cause the black to knockout the white box. White consisted of 0% C 0% M 0%y 0%K.
