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Geometric Lathe
A geometric lathe was used for making ornamental patterns on the plates used in printing bank notes and postage stamps. It is sometimes called a guilloché lathe. It was developed early in the nineteenth century when efforts were introduced to combat forgery, and is an adaptation of an ornamental turning lathe. The lathe was able to generate intersecting and interlacing patterns of fine lines in various shapes, which were almost impossible to forge by hand-engraving. They were used by many national mints. Further reading *Peter Bower, 'Economic warfare: Banknote Forgery as a deliberate weapon', and Maureen Greenland, 'Compound plate printing and nineteenth-century bank notes, in Virginia Hewitt, ed. ''The Banker's Art: Studies in paper money'', pp 46–63, and pp 84–87, The British Museum Press, 1995, () See also * Security printing * Spirograph * Tusi couple * Guilloché Guilloché (; or guilloche) is a decorative technique in which a very precise, intricate and rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bank Note
A banknote—also called a bill (North American English), paper money, or simply a note—is a type of negotiable promissory note, made by a bank or other licensed authority, payable to the bearer on demand. Banknotes were originally issued by commercial banks, which were legally required to redeem the notes for legal tender (usually gold or silver coin) when presented to the chief cashier of the originating bank. These commercial banknotes only traded at face value in the market served by the issuing bank. Commercial banknotes have primarily been replaced by national banknotes issued by central banks or monetary authorities. National banknotes are often – but not always – legal tender, meaning that courts of law are required to recognize them as satisfactory payment of money debts. Historically, banks sought to ensure that they could always pay customers in coins when they presented banknotes for payment. This practice of "backing" notes with something of substance is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postage Stamp
A postage stamp is a small piece of paper issued by a post office, postal administration, or other authorized vendors to customers who pay postage (the cost involved in moving, insuring, or registering mail), who then affix the stamp to the face or address-side of any item of mail—an envelope or other postal cover (e.g., packet, box, mailing cylinder)—that they wish to send. The item is then processed by the postal system, where a postmark or cancellation mark—in modern usage indicating date and point of origin of mailing—is applied to the stamp and its left and right sides to prevent its reuse. The item is then delivered to its addressee. Always featuring the name of the issuing nation (with the exception of the United Kingdom), a denomination of its value, and often an illustration of persons, events, institutions, or natural realities that symbolize the nation's traditions and values, every stamp is printed on a piece of usually rectangular, but sometimes triangular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guilloché
Guilloché (; or guilloche) is a decorative technique in which a very precise, intricate and repetitive pattern is mechanically engraved into an underlying material via engine turning, which uses a machine of the same name, also called a rose engine lathe. This mechanical technique improved on more time-consuming designs achieved by hand and allowed for greater delicacy, precision, and closeness of line, as well as greater speed. The term ''guilloche'' is also used more generally for repetitive architectural patterns of intersecting or overlapping spirals or other shapes, as used in the Ancient Near East, classical Greece and Rome and neo-classical architecture, and Early Medieval interlace decoration in Anglo-Saxon art and elsewhere. Medieval Cosmatesque stone inlay designs with two ribbons winding around a series of regular central points are very often called guilloche. These central points are often blank, but may contain a figure, such as a rose. These senses are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Century
A century is a period of 100 years. Centuries are numbered ordinally in English and many other languages. The word ''century'' comes from the Latin ''centum'', meaning ''one hundred''. ''Century'' is sometimes abbreviated as c. A centennial or centenary is a hundredth anniversary, or a celebration of this, typically the remembrance of an event which took place a hundred years earlier. Start and end of centuries Although a century can mean any arbitrary period of 100 years, there are two viewpoints on the nature of standard centuries. One is based on strict construction, while the other is based on popular perception. According to the strict construction, the 1st century AD began with AD 1 and ended with AD 100, the 2nd century spanning the years 101 to 200, with the same pattern continuing onward. In this model, the ''n''-th century starts with the year that ends with "01", and ends with the year that ends with "00"; for example, the 20th century comprises the years 1901 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornamental Turning
Ornamental turning is a type of turning, a craft that involves cutting of a work mounted in a lathe. The work can be made of any material that is suitable for being cut in this way, such as wood, bone, ivory or metal. Plain turning is work executed on a lathe where a transverse section through any part of the work comprises a plain circle. Ornamental turning, also called Complex turning, is executed on a lathe with attachments which convert that plain circular section to variants of outline; these range from a simple series of cuts taken at intervals around the work (so producing grooves or bumps on the surface) to non-circular movements whereby the whole of the circular shape is removed to give a completely different form. Such shapes are achieved by various means, the principal ones being: * Cutting with a fixed or revolving cutter while the work is rotated on a non-radial path, e.g.- eccentrically, elliptically, epicyclically or, following a path determined by a template or recipr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mint (coin)
A mint is an industrial facility which manufactures coins that can be used as currency. The history of mints correlates closely with the history of coins. In the beginning, hammered coinage or cast coinage were the chief means of coin minting, with resulting production runs numbering as little as the hundreds or thousands. In modern mints, coin dies are manufactured in large numbers and planchets are made into milled coins by the billions. With the mass production of currency, the production cost is weighed when minting coins. For example, it costs the United States Mint much less than 25 cents to make a quarter (a 25 cent coin), and the difference in production cost and face value (called seigniorage) helps fund the minting body. Conversely, a U.S. penny ($0.01) cost $0.015 to make in 2016. History The first minted coins The earliest metallic money did not consist of coins, but of unminted metal in the form of rings and other ornaments or of weapons, which were used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Security Printing
Security printing is the field of the printing industry that deals with the printing of items such as banknotes, cheques, passports, tamper-evident labels, security tapes, product authentication, stock certificates, postage stamps and identity cards. The main goal of security printing is to prevent forgery, tampering, or counterfeiting. More recently many of the techniques used to protect these high-value documents have become more available to commercial printers, whether they are using the more traditional offset and flexographic presses or the newer digital platforms. Businesses are protecting their lesser-value documents such as transcripts, coupons and prescription pads by incorporating some of the features listed below to ensure that they cannot be forged or that alteration of the data cannot occur undetected. A number of technical methods are used in the security printing industry. Security printing is most often done on security paper, but it can also occur on plastic m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirograph
Spirograph is a geometric drawing device that produces mathematical roulette curves of the variety technically known as hypotrochoids and epitrochoids. The well-known toy version was developed by British engineer Denys Fisher and first sold in 1965. The name has been a registered trademark of Hasbro Inc. since 1998 following purchase of the company that had acquired the Denys Fisher company. The Spirograph brand was relaunched worldwide in 2013, with its original product configurations, by Kahootz Toys. History In 1827, Greek-born English architect and engineer Peter Hubert Desvignes developed and advertised a "Speiragraph", a device to create elaborate spiral drawings. A man named J. Jopling soon claimed to have previously invented similar methods. When working in Vienna between 1845 and 1848, Desvignes constructed a version of the machine that would help prevent banknote forgeries, as any of the nearly endless variations of roulette patterns that it could produce were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tusi Couple
The Tusi couple is a mathematical device in which a small circle rotates inside a larger circle twice the diameter of the smaller circle. Rotations of the circles cause a point on the circumference of the smaller circle to oscillate back and forth in linear motion along a diameter of the larger circle. The Tusi couple is a 2-cusped hypocycloid. The couple was first proposed by the 13th-century Persian astronomer and mathematician Nasir al-Din al-Tusi in his 1247 ''Tahrir al-Majisti (Commentary on the Almagest)'' as a solution for the latitudinal motion of the inferior planets, and later used extensively as a substitute for the equant introduced over a thousand years earlier in Ptolemy's ''Almagest''. Original description The translation of the copy of Tusi's original description of his geometrical model alludes to at least one inversion of the model to be seen in the diagrams: :If two coplanar circles, the diameter of one of which is equal to half the diameter of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guilloché
Guilloché (; or guilloche) is a decorative technique in which a very precise, intricate and repetitive pattern is mechanically engraved into an underlying material via engine turning, which uses a machine of the same name, also called a rose engine lathe. This mechanical technique improved on more time-consuming designs achieved by hand and allowed for greater delicacy, precision, and closeness of line, as well as greater speed. The term ''guilloche'' is also used more generally for repetitive architectural patterns of intersecting or overlapping spirals or other shapes, as used in the Ancient Near East, classical Greece and Rome and neo-classical architecture, and Early Medieval interlace decoration in Anglo-Saxon art and elsewhere. Medieval Cosmatesque stone inlay designs with two ribbons winding around a series of regular central points are very often called guilloche. These central points are often blank, but may contain a figure, such as a rose. These senses are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Money Forgery
Counterfeit money is currency produced without the legal sanction of a state or government, usually in a deliberate attempt to imitate that currency and so as to deceive its recipient. Producing or using counterfeit money is a form of fraud or forgery, and is illegal. The business of counterfeiting money is nearly as old as money itself: plated copies (known as Fourrées) have been found of Lydian coins, which are thought to be among the first Western coins. Before the introduction of paper money, the most prevalent method of counterfeiting involved mixing base metals with pure gold or silver. Another form of counterfeiting is the production of documents by legitimate printers in response to fraudulent instructions. During World War II, the Nazis forged British pounds and American dollars. Today some of the finest counterfeit banknotes are called ''Superdollars'' because of their high quality and imitation of the real US dollar. There has been significant counterfeiting of Eur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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