Hard pasteHard-paste porcelain was invented in China, and it was also used in , and most of the finest quality porcelain wares are in this material. The earliest European porcelains were produced at the in the early 18th century; they were formed from a paste composed of and and fired at temperatures up to in a wood-fired kiln, producing a porcelain of great hardness, translucency, and strength. Later, the composition of the was changed and the alabaster was replaced by and , allowing the pieces to be fired at lower temperatures. Kaolinite, feldspar and quartz (or other forms of ) continue to constitute the basic ingredients for most continental European hard-paste porcelains.
Soft pasteSoft-paste porcelains date back from early attempts by European potters to replicate Chinese porcelain by using mixtures of clay and . Soapstone and lime are known to have been included in these compositions. These wares were not yet actual porcelain wares as they were neither hard nor vitrified by firing clay at high temperatures. As these early formulations suffered from high pyroplastic deformation, or slumping in the kiln at high temperatures, they were uneconomic to produce and of low quality. Formulations were later developed based on kaolin with , s, or other feldspathic rocks. These are technically superior, and continue to be produced. Soft-paste porcelains are fired at lower temperatures than hard-paste porcelain, therefore these wares are generally less hard than hard-paste porcelains.
Bone chinaAlthough originally developed in England in 1748 to compete with imported porcelain, is now made worldwide, including China. The English had read the letters of missionary , which described Chinese porcelain manufacturing secrets in detail. One writer has speculated that a misunderstanding of the text could possibly have been responsible for the first attempts to use bone-ash as an ingredient of English porcelain, although this is not supported by modern researchers and historians. Traditionally, English bone china was made from two parts of , one part of and one part , although the latter has largely been replaced by feldspars from non-UK sources. But for example still uses 50% bone ash in the 21st century.
Materialsis the primary material from which porcelain is made, even though clay minerals might account for only a small proportion of the whole. The word ''paste'' is an old term for both unfired and fired materials. A more common terminology for the unfired material is "body"; for example, when buying materials a potter might order an amount of porcelain body from a vendor. The composition of porcelain is highly variable, but the clay mineral is often a raw material. Other raw materials can include , , glass, , , , and . The clays used are often described as being long or short, depending on their . Long clays are (sticky) and have high plasticity; short clays are less cohesive and have lower plasticity. In , plasticity is determined by measuring the increase in content of water required to change a clay from a solid state bordering on the plastic, to a plastic state bordering on the liquid, though the term is also used less formally to describe the ease with which a clay may be worked. Clays used for porcelain are generally of lower plasticity and are shorter than many other pottery clays. They wet very quickly, meaning that small changes in the content of water can produce large changes in . Thus, the range of water content within which these clays can be worked is very narrow and consequently must be carefully controlled.
FormingPorcelain can be made using all the shaping techniques for pottery. It was originally typically made on the , though were also used from early on. has been the most common commercial method in recent times.
Glazingis unglazed porcelain treated as a finished product, mostly for figures and sculpture. Unlike their lower-fired counterparts, porcelain wares do not need to render them impermeable to liquids and for the most part are glazed for decorative purposes and to make them resistant to dirt and staining. Many types of glaze, such as the iron-containing glaze used on the celadon wares of , were designed specifically for their striking effects on porcelain.
DecorationPorcelain often receives decoration using pigments that include and copper, or s, allowing a wider range of colours. Like many earlier wares, modern porcelains are often -fired at around , coated with glaze and then sent for a second -firing at a temperature of about or greater. Another early method is "once-fired", where the glaze is applied to the unfired body and the two fired together in a single operation.
FiringIn this process, "green" (unfired) ceramic wares are heated to high temperatures in a to permanently set their shapes, vitrify the body and the glaze. Porcelain is fired at a higher temperature than earthenware so that the body can vitrify and become non-porous. Many types of porcelain in the past have been fired twice or even three times, to allow decoration using less robust pigments in .
Chinese porcelainPorcelain was invented in China over a centuries-long development period beginning with "proto-porcelain" wares dating from the (1600–1046 B.C.E). By the time of the Eastern (CE 25–220) these early glazed ceramic wares had developed into porcelain, which Chinese defined as high-fired ware. By the late (581–618 CE) and early (618–907 CE), the now-standard requirements of whiteness and translucency had been achieved, in types such as . The wares were already exported to the , where they were highly prized. Eventually, porcelain and the expertise required to create it began to spread into other areas of East Asia. During the (960–1279 AD), artistry and production had reached new heights. The manufacture of porcelain became highly organised, and the s excavated from this period could fire as many as 25,000 pieces at a time,Temple, Robert K.G. (2007). ''The Genius of China: 3,000 Years of Science, Discovery, and Invention'' (3rd edition). London: André Deutsch, pp. 104-5. and over 100,000 by the end of the period. While is regarded as among the greatest of the Tang dynasty porcelain, Ding ware became the premier porcelain of the Song dynasty. By the , production of the finest wares for the court was concentrated in a single city, and , originally owned by the imperial government, remains the centre of Chinese porcelain production. By the time of the (1368–1644 AD), porcelain wares were being to Asia and Europe. Some of the most well-known arrived in Europe during this era, such as the coveted "" wares. The Ming dynasty controlled much of the porcelain trade, which was expanded to Asia, Africa and Europe via the . In 1517, Portuguese merchants began direct trade by sea with the Ming dynasty, and in 1598, Dutch merchants followed. Some porcelains were more highly valued than others in imperial China. The most valued types can be identified by their association with the court, either as tribute offerings, or as products of kilns under imperial supervision.Rawson, Jessica "Chinese Art", 2007, publisher:the British Museum Press, London, Since the , the largest and best centre of production has made . During the Ming dynasty, Jingdezhen porcelain become a source of imperial pride. The erected a at , and an exceptionally smoothly glazed type of white porcelain is peculiar to his reign. Jingdezhen porcelain's fame came to a peak during the Qing dynasty.
Japanese porcelainAlthough the Japanese elite were keen importers of Chinese porcelain from early on, they were not able to make their own until the arrival of Korean potters that were taken captive during the . They brought an improved type of kiln, and one of them spotted a source of porcelain clay near , and before long several kilns had started in the region. At first their wares were similar to the cheaper and cruder Chinese porcelains with underglaze blue decoration that were already widely sold in Japan; this style was to continue for cheaper everyday wares until the 20th century. began around 1660, through the Chinese and the , the only Europeans allowed a trading presence. Chinese exports had been seriously disrupted by civil wars as the Ming dynasty fell apart, and the Japanese exports increased rapidly to fill the gap. At first the wares used European shapes and mostly Chinese decoration, as the Chinese had done, but gradually original Japanese styles developed. was produced in kilns owned by the families of feudal lords, and were decorated in the Japanese tradition, much of it related to textile design. This was not initially exported, but used for gifts to other aristocratic families. and are broad terms for styles of export porcelain with overglaze "enamelled" decoration begun in the early period, both with many sub-types. A great range of styles and manufacturing centres were in use by the start of the 19th century, and as Japan opened to trade in the second half, exports expanded hugely and quality generally declined. Much traditional porcelain continues to replicate older methods of production and styles, and there are several modern industrial manufacturers. By the early 1900s, Filipino porcelain artisans working in Japanese porcelain centres for much of their lives, later on introduced the craft into the native population in the , although oral literature from Cebu in the central Philippines have noted that porcelain were already being produced by the natives locally during the time of Cebu's early rulers, prior to the arrival of colonizers in the 16th century.
European porcelainThese exported Chinese porcelains were held in such great esteem in Europe that in English ' became a commonly–used synonym for the Italian-derived ''porcelain''. The first mention of porcelain in Europe is in ' by in the 13th century. Apart from copying Chinese porcelain in ' ( ), the soft-paste in 16th-century was the first real European attempt to reproduce it, with little success. Early in the 16th century, Portuguese traders returned home with samples of kaolin, which they discovered in China to be essential in the production of porcelain wares. However, the Chinese techniques and composition used to manufacture porcelain were not yet fully understood. Countless experiments to produce porcelain had unpredictable results and met with failure. In the German state of , the search concluded in 1708 when produced a hard, white, translucent type of porcelain specimen with a combination of ingredients, including kaolin and , mined from a Saxon mine in . It was a closely guarded trade secret of the Saxon enterprise. In 1712, many of the elaborate Chinese porcelain manufacturing secrets were revealed throughout Europe by the French father and soon published in the ''Lettres édifiantes et curieuses de Chine par des missionnaires jésuites''. The secrets, which d'Entrecolles read about and witnessed in China, were now known and began seeing use in Europe.Baghdiantz McAbe, Ina (2008). ''Orientalism in Early Modern France''. Oxford: Berg Publishing, p. 220.
MeissenVon Tschirnhaus along with were employed by , and , who sponsored their work in and in the town of . Tschirnhaus had a wide knowledge of science and had been involved in the European quest to perfect porcelain manufacture when, in 1705, Böttger was appointed to assist him in this task. Böttger had originally been trained as a pharmacist; after he turned to alchemical research, he claimed to have known the secret of transmuting dross into gold, which attracted the attention of Augustus. Imprisoned by Augustus as an incentive to hasten his research, Böttger was obliged to work with other alchemists in the futile search for transmutation and was eventually assigned to assist Tschirnhaus. One of the first results of the collaboration between the two was the development of a red stoneware that resembled that of . A workshop note records that the first specimen of hard, white and vitrified European porcelain was produced in 1708. At the time, the research was still being supervised by Tschirnhaus; however, he died in October of that year. It was left to Böttger to report to Augustus in March 1709 that he could make porcelain. For this reason, credit for the European discovery of porcelain is traditionally ascribed to him rather than Tschirnhaus. The was established in 1710 after the development of a kiln and a glaze suitable for use with Böttger's porcelain, which required firing at temperatures of up to to achieve translucence. Meissen porcelain was ''once-fired'', or ''green-fired''. It was noted for its great resistance to ; a visitor to the factory in Böttger's time reported having seen a white-hot teapot being removed from the kiln and dropped into cold water without damage. Although widely disbelieved this has been replicated in modern times.
Soft paste porcelainThe pastes produced by combining clay and powdered glass () were called ''Frittenporzellan'' in Germany and ''frita'' in Spain. In France they were known as ''pâte tendre'' and in England as "soft-paste". They appear to have been given this name because they do not easily retain their shape in the wet state, or because they tend to slump in the kiln under high temperature, or because the body and the glaze can be easily scratched. ;France Experiments at produced the earliest soft-paste in France, but the first important French soft-paste porcelain was made at the before 1702. Soft-paste factories were established with the in 1730 and at in 1750. The was established in 1740, moving to larger premises at in 1756. Vincennes soft-paste was whiter and freer of imperfections than any of its French rivals, which put Vincennes/Sèvres porcelain in the leading position in France and throughout the whole of Europe in the second half of the 18th century. ;Italy of was founded in 1735 and remains in production, unlike which was moved from to by , after producing from 1743 to 1759. After a gap of 15 years was produced from 1771 to 1806, specializing in styles. All these were very successful, with large outputs of high-quality wares. In and around , Francesco Vezzi was producing hard-paste from around 1720 to 1735; survivals of are very rare, but less so than from the Hewelke factory, which only lasted from 1758 to 1763. The soft-paste fared better, lasting from 1764 to 1812. The produced from about 1752 to 1773, then was revived from 1781 to 1802. ; England The first soft-paste in England was demonstrated by Thomas Briand to the in 1742 and is believed to have been based on the Saint-Cloud formula. In 1749, Thomas Frye took out a on a porcelain containing bone ash. This was the first , subsequently perfected by . discovered deposits of kaolin in , and his , established in 1768, used kaolin and to make hard-paste porcelain with a body composition similar to that of the Chinese porcelains of the early 18th century. But the great success of English ceramics in the 18th century was based on soft-paste porcelain, and refined earthenwares such as , which could compete with porcelain, and had devastated the industries of France and other continental countries by the end of the century. Most English porcelain from the late 18th century to the present is bone china. In the twenty-five years after Briand's demonstration, a number of factories were founded in England to make soft-paste tableware and figures: * (1743) * (1745) * St James's (1748) * (1748) * (1750) * (1750 or 1757) * (1751) * (1757) * (1759) * (1767)
Russian porcelainIn 1744, the signed an agreement to establish the first porcelain manufactory; previously it had to be imported. The technology of making "white gold" was carefully hidden by its creators. had tried to reveal the "big porcelain secret", and sent an agent to the Meissen factory, and finally hired a porcelain master from abroad. This relied on the research of the Russian scientist . His development of porcelain manufacturing technology was not based on secrets learned through third parties, but was the result of painstaking work and careful analysis. Thanks to this, by 1760, became a major European factories producing tableware, and later porcelain figurines. Eventually other factories opened: Gardner porcelain, (1832), Kuznetsovsky porcelain, Popovsky porcelain, and .
Electric insulating materialPorcelain and other have many applications in engineering, especially . Porcelain is an excellent insulator for use with s, especially in outdoor applications (see ). Examples include: terminals for s, bushings of s, and insulation of high-frequency .
Building materialPorcelain can be used as a , usually in the form of s or large rectangular panels. Modern porcelain tiles are generally produced by a number of recognised international standards and definitions. Manufacturers are found across the world with Italy being the global leader, producing over 380 million square metres in 2006. Historic examples of rooms decorated entirely in porcelain tiles can be found in several European palaces including ones at in , Museo di Doccia in , in Naples, the and the nearby . and the . More recent noteworthy examples include the in , and the in Houston, Texas, which when constructed in 1929 had a porcelain logo on its exterior.“Porcelain Tile: The Revolution Is Only Beginning.” Tile Decorative Surf. 42, No.11, 1992. A more detailed description of the history, manufacture and properties of porcelain tiles is given in the article “Porcelain Tile: The Revolution Is Only Beginning.”
Bathroom fittingsBecause of its durability, inability to rust and impermeability, glazed porcelain has been in use for personal hygiene since at least the third quarter of the 17th century. During this period, porcelain chamber pots were commonly found in higher-class European households, and the term "bourdaloue" was used as the name for the pot. However bath tubs are not made of porcelain, but of on a metal base, usually of . Porcelain enamel is a term used in the US, and is not porcelain but .
Dental porcelainis used for crowns, bridges and veneers.
Manufacturers* The Americas ** *** *** ** *** *** , Inc. *** *** *** *** * Asia ** China *** *** ** *** , (1993–present) *** , (1881–present) ** *** *** *** *** *** ** *** ** *** *** ** *** Dankotuwa Porcelain *** Noritake Lanka Porcelain *** Royal Fernwood Porcelain ** *** ** *** (1890–1936, 1994–present) *** (1970–present) *** (1989–present) *** (1976–present) *** (1963 – early 1990s) *** (1957–1994) ** *** RAK Porcelain ** *** (1970–present) *** (1352–present) * ** *** , 1718–1864 *** , 1923–present ** *** (1953–present) ** *** , (1792–2011) *** , (1794–present) *** a.s., , Eichwelder Porzellan und Ofenfabriken Bloch & Co. Böhmen (1864–present) *** , (1907–present) ** *** *** *** *** *** *** *** *** (1775–present) *** ** *** ** *** (1693–1766) *** (1730–1800) *** (1740–1756) *** (1745–1765) *** (1756–present) *** (1789–present) *** *** ** *** ** *** (1777–present) *** (1826–present) *** Porcelain Manufacture (1853–present) ** *** (1735–present) *** (1743–1759) *** (1771–1806) *** (1922–1972) *** () ** *** Jiesia ** *** *** *** ** *** *** (1941–present) *** *** *** ** *** *** *** *** *** ** *** *** *** , located in the district of Aveiro ** *** (1744–present) *** (1766–present), near *** (1802–present), *** (1832–present), ** *** (1760–1812) *** (1808–present, intermittently) *** ** *** ** *** *** ** *** (1775–present) *** (1884–present) *** (1747–1776) *** *** (c. 1745; merged with Derby in 1770) *** *** *** *** *** *** *** (1793–1968; merged with Royal Doulton) *** *** *** *** *** (1750/57–present) *** (1815–2009; acquired by ) *** (1751–2008; acquired by ) *** (1767–2008; acquired by ) *** (or "Girl-in-a-Swing", 1750s) *** *** *** , (factory 1759–present, porcelain 1812–1829, and modern. Acquired by )
See also* * * *
References* , ed., ''Sotheby's Concise Encyclopedia of Porcelain'', 1990, Conran Octopus. * Le Corbellier, Clare
Further reading* Burton, William (1906)