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Phosphor Band
Phosphor bands were introduced on British stamps from 1959 as a replacement for the previous graphite lined stamps as an aid in the mechanical sorting of mail. The phosphor is applied in vertical bands, or more recently, all over the stamp, and fluoresces under ultra-violet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the ... light. This enables the mail sorting machine to ''face'' the mail and sort it into types. Phosphor is now widely used on stamps around the world. It is necessary to use either a short- or long-wave ultraviolet lamp to view the phosphor, according to the type of phosphor used on the stamp. References Postage stamps of the United Kingdom Postal system of the United Kingdom Philatelic terminology {{philately-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graphite Lined Stamp
A graphite lined stamp is a postage stamp on which vertical lines of electro-conductive graphite are printed on the reverse. Graphite lined stamps were used in the United Kingdom from 1957 to 1960 as an experiment in the automation of mail sorting."Great Britain" in ''Commonwealth & British Empire Stamps 1840-1970'', Stanley Gibbons, 2008, page GB17. Usage and appearance In the United Kingdom, graphite lines were used exclusively on five stamps of the Wilding series from December 1957. They appear as one or two black lines printed vertically under the gum. The two lined stamps were to identify ''fully paid'' mail, which eventually became ''first class'' mail, while stamps with only one line paid the ''printed matter'' rate, or ''second class'' mail as it eventually became. On the two lined stamps, the bands are usually found widely spaced so that one appears at either side of the stamp, but they may also be found close together due to printing errors on the one and a half pence s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescence
Fluorescence is one of two kinds of photoluminescence, the emission of light by a substance that has absorbed light or other electromagnetic radiation. When exposed to ultraviolet radiation, many substances will glow (fluoresce) with colored visible light. The color of the light emitted depends on the chemical composition of the substance. Fluorescent materials generally cease to glow nearly immediately when the radiation source stops. This distinguishes them from the other type of light emission, phosphorescence. Phosphorescent materials continue to emit light for some time after the radiation stops. This difference in duration is a result of quantum spin effects. Fluorescence occurs when a photon from incoming radiation is absorbed by a molecule, exciting it to a higher energy level, followed by the emission of light as the molecule returns to a lower energy state. The emitted light may have a longer wavelength and, therefore, a lower photon energy than the absorbed radi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultra-violet
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. The photons of ultraviolet have greater energy than those of visible light, from about 3.1 to 12 electron volts, around the minimum energy required to ionize atoms. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack sufficient energy, it can induce chemical reactions and cause many substances to glow or fluoresce. Many practical applications, including chemical and biological effects, are derived from the way that UV radiation can interact with organic molecules. These interacti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postage Stamps Of The United Kingdom
Postage stamps and postal history of the United Kingdom surveys postal history and the postage stamps issued by that country (known in philatelic circles as "Great Britain"), and its various historical territories until the present day. The postal history of the United Kingdom is notable in at least two respects: first, for the introduction of postage stamps in 1840, and secondly for the establishment of an efficient postal system throughout the British Empire, laying the foundation of many national systems still in existence today. As the originator of postage stamps, the UK is the only country that does not need to specify the country on its stamps, but only the denomination. As they are protected by copyright, images of current UK stamps are not included in this article. Early history In the 12th century Henry I appointed messengers to carry letters for the government. It is estimated that between 1100 and 1135, 4,500 letters were carried by these messengers. During thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postal System Of The United Kingdom
Postal services in the United Kingdom are provided predominantly by the Royal Mail (and Post Office Limited which oversees post offices). Since 2006, the market has been fully opened to competition which has had greater success in business-to-business delivery than in ordinary letter delivery. The industry is regulated by Ofcom and consumer interests are represented by Consumer Focus. Since 1 October 2011, the main piece of legislation is the Postal Services Act 2011, although some parts of the Postal Services Act 2000 are still in force. The 2011 Act enables the government to privatise Royal Mail and to possibly mutualise Post Office Limited. History The quality of postal services in the 17th and 18th centuries improved with development of better roads and means of transport. Anthony Trollope is credited with major contributions to the development of postal services in the years 1851-1867, described, ''e.g.'' in Chapters 8 and 13 of his autobiography.Trollope, Anthony (1883). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
