Emaciation

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Early Neolithic sherd with imprints of organic depletion

In ceramics production ( pottery ), leaning is a technique with which clays that are too fat are mixed with mineral or organic additives , for example sand or ground cullet ( fireclay ). This is especially important for handmade ceramics. Appropriate leaning reduces the plasticity of the clay, making it less tough and sticky and more stable for the vessel structure. During the drying process, the leaning supports the clay mass, which is shrinking due to the release of water, and during firing it ensures a better temperature distribution within the firing material. In the case of the completely fired body, various physical and mechanical properties such as temperature insensitivity, water absorption capacity, density and hardness can be influenced depending on the type and amount of the previously used lean.

analysis

The parameters of the ceramic analysis that can be evaluated are lean proportions, lean amount, lean shape, lean distribution, lean type and lean color. Some of these parameters can be identified in the fraction with the naked eye or via thin sections . Others require more extensive examinations.

The lean shape describes the external appearance of the materials used for leaning, such as rounded, sharp-edged, leafy or the like, as well as their grain or particle sizes. The lean amount describes the quantitative amount in comparison to the actual clay material, as well as its distribution in the clay matrix.

Lean types

Inorganic weight loss agents

Organic lean foods

These substances are intended to reduce the binding portion of the clay. They also counteract the shrinkage of the clay and prevent uneven drying. In addition, lean grains prevent the spread of cracks and thus increase the resistance to thermal shock. However, cultural reasons often lead to choosing a particular supplement. It is often difficult to distinguish between deliberate thinning and natural admixtures of clay. Today we mostly used fireclay as a temper.

Greece

Amphora , jug or pitho are often lean, as this is the only way to achieve the static strength required for the firing process in this format. Many of these statuesque sculptures were hollow figures which, because of the firing process in the kiln , did not have a support frame. Many votive statues with the motif of a kore have also been made from lean clay. In the case of the large-format head, the face and the rest of the head were molded in two separate but related shapes.

literature

  • Ingolf Bauer, Irmgard Endres-Mayser: Guide to the description of ceramics: (Middle Ages - Modern Times); Terminology - Typology - Technology . Archaeological State Collection, Munich 2005, ISBN 3-927806-32-3 , p. 95-98 .
  • Ruth Löffler: Leaning techniques in the Neolithic with special consideration of western and southern Germany . University of Cologne, Cologne 1987 ( uni-heidelberg.de [accessed on February 27, 2019] Master's thesis, supervised by Wolfgang Taute ).

Web links

Individual evidence

  1. ↑ Ruth Löffler: Leaning techniques in the Neolithic with special consideration of western and southern Germany . University of Cologne, Cologne 1987 ( uni-heidelberg.de [accessed on February 27, 2019] Master's thesis, supervised by Wolfgang Taute ).
  2. ↑ a b c d e f Ingolf Bauer, Irmgard Endres-Mayser: Guide to the description of ceramics: (Middle Ages - Modern Times); Terminology - Typology - Technology . Archaeological State Collection, Munich 2005, ISBN 3-927806-32-3 , p. 95-98 .
  3. ↑ on technology see a. Michela Spataro: A comparison of chemical and petrographic analyzes of Neolithic pottery from South-eastern Europe. In: Journal of Archaeological Science 38 2011, pp. 255-269; general Patrick S. Quinn (ed.): Interpreting silent artefacts: petrographic approaches to archaeological ceramics . Archaeopress, Oxford 2009.
  4. ^ Robert A. Cook, Lane F. Fargher: The Incorporation of Mississippian Traditions into Fort Ancient Societies: A Preliminary View of the Shift to Shell-Tempered Pottery Use in the Middle Ohio Valley. Southeastern Archeology 27/2, 2008 (Shell-Tempered Ceramics in the Eastern Woodlands), pp. 222-237.
  5. ↑ Brigitta Hulthén, Temper Variations in Ancient Ceramics, Technological or Cultural Origin? In: Third Nordic Conference on the Application of Scientific Methods in Archeology . ISKOS No. 5, Helsinki 1985, pp. 329-337.
  6. ↑ Ole style Borg, Analyzes of bone- and chaff-tempered Ceramics from Iron Age Scandinavia. In: European Journal of Archeology No. 4/3, 2001, pp. 398-404.
  7. ^ Rosemary M. Cleary, Bone Tempered Beaker Potsherd. Journal of Irish Archeology 2, 1984, 73-75. JSTOR 30001586 Accessed: 21-10-2016
  8. ↑ Ole style Borg, Analyzes of bone- and chaff-tempered Ceramics from Iron Age Scandinavia . In: European Journal of Archeology No. 4/3, 2001, pp. 398-404.
  9. ^ Roberta Tomber, Caroline Cartwright, Sunil Gupta, Rice temper: technological solutions and source identification in the Indian Ocean. In: Journal of Archaeological Science 38, 2011, pp. 360–366 doi : 10.1016 / j.jas.2010.09.014 .
  10. ↑ Michael B. Schiffer , James M. Skibo , Theory and experiment in the study of technological change. In: Current Anthropology 28, 1987, pp. 595-618.
  11. ↑ James M. Skibo, Michael B. Schiffer, Kenneth C. Reid: Organic-Tempered Pottery: An experimental Study. In: American Antiquity 54, 1989, pp. 122-146.
  12. ↑ Gordon Bronitsky, Robert Hamer: Experiments in Ceramic Technology: The Effects of Various tempering material on Impact and Thermal Shock Resistance. In: American Antiquity 51/1, 1986, pp. 89-101.
  13. ↑ Ole style Borg, Analyzes of bone- and chaff-tempered Ceramics from Iron Age Scandinavia. European Journal of Archeology No. 4/3, 2001, p. 399