tanning


tanning
/tan"ing/, n.
1. the process or art of converting hides or skins into leather.
2. a browning or darkening of the skin, as by exposure to the sun.
3. Informal. a thrashing; whipping.
[1475-85; TAN1, + -ING1]

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Chemical treatment of raw animal hides or skins to convert them into leather.

Vegetable tanning (using bark, wood, roots, or berries) has been practiced since prehistoric times. After removal of hair, flesh, or fat, a tanning agent displaces water from the interstices between the protein (mostly collagen) fibres in the skin and cements the fibres together. The agents most widely used are vegetable tannin, salts such as chromium sulfate, and fish or animal oil. The tanning of fair skin in humans by sunlight is completely different: ultraviolet light causes production and redistribution of the pigment melanin in epidermal cells.

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▪ leather manufacturing
      chemical treatment of raw animal hide or skin to convert it into leather. A tanning agent displaces water from the interstices between the protein fibres and cements these fibres together. The three most widely used tanning agents are vegetable tannin, mineral salts such as chromium sulfate, and fish or animal oil. See also leather.

      The oldest system of tanning (tannin) relies on the chemical action of vegetable material containing tannin, or tannic acid, on the protein constituents of skin. Vegetable tanning seems to have been practiced in prehistoric times. In historic times, the Hebrews tanned with oak bark, and the Egyptians, with babul pods. The Romans used bark, certain woods, and berries. The Arabs tanned with bark and roots, and in the Middle Ages they reintroduced the art into Europe via Spain. By the 18th century the value of materials such as oak bark, sumac, valonia, and hemlock was well established. The procedure, essentially unchanged in modern times, involves soaking hides in vats of increasingly strong liquors, or liquid extracts of vegetable tannin.

      Tanning with chromium salts, introduced at the end of the 19th century, was probably the first change in the chemistry of leather production in at least 2,000 years. Two methods are used. In the double-bath method the hides are first bathed in a mild chromic acid solution. In the second bath, sodium thiosulfate and another acid react with the chromic acid to produce basic chromium salts, which are deposited on the fibres of the skins. In the more common single-bath method the hides are soaked in revolving drums filled with increasingly strong chromium sulfate solutions. Aluminum and zirconium salts are also used in tanning.

      Oil tanning is an ancient method that is used for such soft, porous leathers as chamois and deerskin, which can be repeatedly wetted and dried without detrimental effects. Fish oil is sprinkled onto the hides and pounded in with mechanical hammers. The hides are then hung in ovens, and the oxidized oil adheres to the skin fibres.

      The two main raw materials of tanning—animal hide and vegetable tannin—are available almost everywhere. As a result, tanning has spread throughout the world. It remains one of the first industries to be established in areas or nations undergoing industrialization.

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Universalium. 2010.

Look at other dictionaries:

  • Tanning — Tan ning, n. The art or process of converting skins into leather. See {Tan}, v. t., 1. [1913 Webster] …   The Collaborative International Dictionary of English

  • Tanning — Tanning, Dorothea …   Enciclopedia Universal

  • Tanning —   [ tænɪȖ], Dorothea, amerikanische Malerin, * Galesburg (Illinois) 25. 8. 1910; Autodidaktin, ab 1946 Ȋ mit M. Ernst. Ihre Werke (Gemälde und Objekte) sind vom Surrealismus geprägt …   Universal-Lexikon

  • tanning — [tan′iŋ] n. 1. the art or process of making leather from hides 2. the act of making fair skin brown, as by exposure to the sun 3. Informal a severe whipping; flogging …   English World dictionary

  • Tanning — For other uses, see Tanning (disambiguation). For human tanning, see Sun tanning. Tannery redirects here. For other uses, see Tannery (disambiguation). Tanned leather in Marrakech …   Wikipedia

  • Tanning — Dorothea Tanning (* 25. August 1912 in Galesburg, Illinois, USA) ist eine US amerikanische Künstlerin und lebt in New York. Inhaltsverzeichnis 1 Leben 2 Weblinks 3 Werke 4 Literatur …   Deutsch Wikipedia

  • Tanning — Tan Tan, v. t. [imp. & p. p. {Tanned}; p. pr. & vb. n. {Tanning}.] [F. tanner, LL. tannare. See {Tan}, n.] 1. To convert (the skin of an animal) into leather, as by usual process of steeping it in an infusion of oak or some other bark, whereby it …   The Collaborative International Dictionary of English

  • tanning — UK [ˈtænɪŋ] / US noun Word forms tanning : singular tanning plural tannings 1) [uncountable] making animal skins into leather 2) [uncountable] the act of turning skin darker using light a tanning salon 3) [countable] an act of hitting someone… …   English dictionary

  • tanning — noun Tanning is used before these nouns: ↑bed, ↑booth, ↑lotion, ↑salon …   Collocations dictionary

  • tanning — tan|ning [ tænıŋ ] noun 1. ) uncount making animal skins into leather 2. ) uncount the act of turning skin darker using light: a tanning salon 3. ) count an act of hitting someone many times, especially with a stick …   Usage of the words and phrases in modern English


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