Initially, Hill specified that the stamps should be 3/4 inch square, but altered the dimensions to 3/4 inch wide by 7/8 inch tall (approx 19 x 22 mm) to accommodate the writing at the bottom. The word "POSTAGE" at the top of the design distinguishes it from a revenue stamp, which had long been used in the UK; "ONE PENNY." at the bottom shows the amount pre-paid for postage of the stamped letter. The background to the portrait consists of finely engraved engine turnings.