The Penny Black was the world's first official adhesive postage stamp, issued by Great Britain on May 1, 1840, for use from May 6.
The idea of an adhesive stamp to indicate prepayment of postage was part of Rowland Hill's 1837 proposal to reform the British postal system. In 1839, the British Treasury announced a competition to design the new stamps, but the submissions were not liked, and the Treasury chose instead to use a profile of Queen Victoria by William Wyon, that had been done for a medal previously. The word "POSTAGE" appeared at the top of the stamp, and "ONE PENNY" at the bottom, with a background of finely engraved engine turnings[?]. In addition, the two lower corners contained letters designating the position of each stamp in the sheet, "A A", "A B", and so forth. As the name suggests, the stamp was printed all in black.
The stamps were printed by Perkins Bacon.
Although May 6 was the official first date, there are three covers postmarked May 2, presumably due to postmasters selling the stamps prematurely.
The Penny Black was in use for only a little over a year; in a manner familiar to technologists of the 20th century, usage experience showed that even a red cancellation on a black stamp was rather hard to see, and so the Treasury switched to the Penny Red and cancelled it with black ink.
The Penny Black is readily available, but because of its significance is in great demand by collectors and therefore not cheap; in 2000 a used copy cost about US$200, and an unused copy about US$3,000. (By contrast, a used Penny Red was $3.)