Originally Posted by tedzan

My speculation regarding this card is simply this scenario. The pressman at American Lithographic was printing a run of PIEDMONT
backs on pre-printed sheets (of fronts). Subsequently, a job order called for OLD MILL backs. But, the pressman forgot to replace
the blue ink in his press with Black ink. And, continued printing the OLD MILL backs with the Blue ink remaining from the prior PIED-
MONT press run.

TED Z