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Phosphor Banded Stamp
{{no footnotes, date=February 2012 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 (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiatio ... 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. External links Phosphor and British Machin stamps. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graphite Lined Stamp
A graphite lined stamp is a postage stamp on which vertical lines of Electrical conductor, 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 on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the electromagnetic spectrum (invisible to the human eye), while the emitted light is in the visible region; this gives the fluorescent substance a distinct color that can only be seen when the substance has been exposed to UV light. Fluorescent materials cease to glow nearly immediately when the radiation source stops, unlike phosphorescent materials, which continue to emit light for some time after. Fluorescence has many practical applications, including mineralogy, gemology, medicine, chemical sensors (fluorescence spectroscopy), fluorescent labelling, dyes, biological detectors, cosmic-ray detection, vacu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultra-violet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), 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 and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules. Short-wave ultraviolet light damages DNA and sterilizes surfaces with which it comes into contact. For huma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postage Stamps Of The United Kingdom
Postage stamps and postal history of Great Britain surveys postal history from the United Kingdom and the postage stamps issued by that country 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. Until 2022 any postage stamps since the 1971 Decimal Day, decimalisation of British currency could be used; old "definitive" design stamps without barcodes are no longer valid from 1 February 2023, with old ones exchangeable for barcoded ones indefinitely. Special Stamps with pictures and Christmas Stamps without a barcode remain valid ... [...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 transportation. 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 (18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
