This mint block of 1993 Federal Duck stamps lacks its black engraving, including the plate block number. A collector discovered the error while trying to purchase a plate number single at a Hastings, Nebraska, post office. Examining the supply on hand, neither he nor the clerk could find a stamp with a plate block number. They discovered this error during the search. Collectors have identified between 120 and 150 stamps with the error.
The stamp features Minnesota artist Bruce Miller's painting of Canvasbacks, created using acrylic paint. Printed on the offset/intaglio D press, the plate number used was 191659. The 60th federal duck stamp issued, it was first sold on June 30, 1993, and was the fifth issue to feature Canvasbacks.