A postage stamp is adhesive paper evidence of a fee paid for postal services. Usually a small rectangle attached to an envelope, the stamp signifies the person sending it has fully or partly paid for delivery. Postage stamps are the most popular way of paying for retail mail; alternatives include prepaid-postage envelopes and postage meters. The study of postage stamps is philately. Stamp collecting is the hobby of collecting stamps.

History

Although James Chalmers and Lovrenc Košir lay claim to the concept of the postage stamp, postage stamps were first introduced in the United Kingdom of Great Britain and Ireland on May 1, 1840 as part of postal reforms promoted by Rowland Hill. With its introduction the postage fee was to be paid by the sender and not the recipient, though sending mail prepaid was not a requirement. The first stamp, the Penny Black, put on sale on 1 May, was valid from 6 May, 1840; two days later came the Two pence blue. Both show an engraving of the young Queen Victoria and were a success though refinements like perforations were instituted later. At the time, there was no reason to include the United Kingdom's name on the stamp, and the UK remains the only country not to identify itself by name on the stamps (the monarch's head is used as identification).

Stamps were not officially perforated until January 1854, except in the parliamentary session of 1851, when stamps perforated by Mr. Archer were issued at the House of Commons. In 1853, the Government paid Mr. Archer £4,000 for the patent.

Other countries followed with their own stamps: the Canton of Zürich in Switzerland issued the Zurich 4 and 6 rappen on 1 March, 1843. Although the Penny Black could send a letter less than half an ounce anywhere within the UK, the Swiss continued to calculate mail rates on distance. Brazil issued the Bull's Eye stamps on 1 August, 1843. Using the same printer as for the Penny Black, Brazil opted for an abstract design instead of a portrait of Emperor Pedro II so that his image would be not be disfigured by the postmark. In 1845 some postmasters in the U.S. issued their own stamps, but the first official stamps came in 1847, with 5 and 10 cent stamps depicting Benjamin Franklin and George Washington. A few other countries issued stamps in the late 1840s. Many more, such as India, started in the 1850s and by the 1860s most countries had stamps.

Following the introduction of the stamp in the UK the number of letters increased from 82 million in 1839 to 170 million in 1841. Today 21 billion items are delivered by post every year in the UK.

Postage stamp design
Main article: Postage stamp design

Stamps have been issued in shapes besides rectangle, including circular, triangular and pentagonal. Sierra Leone and Tonga issued stamps in the shapes of fruit; Bhutan issued one with its national anthem on a playable record. Stamps have been made of embossed foil (sometimes of gold); Switzerland made a stamp partly of lace and one of wood; the United States produced one of plastic, and the German Democratic Republic issued a stamp of synthetic chemicals. In the Netherlands a stamp was made of silver foil. On paper, stamps have been produced by a variety of printing techniques such as lithography, line engraving, photogravure, intaglio and web offset printing.