Great Britain 1840 1d grey-black Plate 1a, SG3Great Britain 1840 1d grey black Plate 1a, SG3. A very fine used four margin example from the first printing plate, lettered OE and showing moderate plate wear, neatly cancelled by a crisp upright red Maltese Cross. Plate 1 of the penny black was put to press on 11 April 1840 and registered on 15 April 1840. As the plate had not been hardened in a rush to meet the target issue date it soon showed signs of wear. GB Specialised Catalogue No: AS2.