US #1926 18¢ Edna St. Vincent Millay - Black Color Shift

1981 Black Color Shift Error
Stamps produced on the multicolor Giori Press required two passes through the press - one for the engraved inscriptions, the second for the multicolored offset-printed image. Somehow only the engraved black inscription was shifted on this eye-catching error, moving the denomination from the right corner to the left on this 1981 mint single. (#1926 color shift single)