Chinese porcelain

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Chinese porcelain is porcelain, a type of ceramic, from China and has been created for well over a millennium. The term covers a wide range of Chinese high-fired ceramics, some of which would probably not be recognized as porcelain under some Western definitions of that term. It is usually green-fired or once-fired, which means that the body and the glaze are fired together. After the body of a piece is formed and finished it is dried, coated with a glaze, dried again and fired. In the high temperature of the kiln the body and the glaze are fused together to become a unit. Chinese enamelled wares are also produced in this way, but the enamels are added after the first, high-temperature, firing and the pieces are sent for a second firing in a smaller, lower-temperature kiln. Suitably modified with a flux, the material used to form the body of a piece of Chinese porcelain was often used as a glaze. The similarity in composition of the body and the glaze helped to produce a good fit between the two that reduced cracking in the glaze.

Contents 1 Materials 2 Classification 3 History 4 Increasing use of china clay in the South 5 Jingdezhen 6 Some notable Chinese porcelain wares 6.1 Tang sancai burial wares 6.2 Jian tea wares 6.3 Qingbai wares 6.4 Blue and white wares 7 Fakes and reproductions 7.1 Authentication 8 See also 9 Notes 10 References

[edit] Materials

Chinese porcelain is mainly made using porcelain stone, china clay or a combination of the two materials. Both rocks derive from the weathering and decomposition of granitic rocks. China clay (Gaoling) largely comprises the clay mineral kaolinite. Chinese porcelain stone, petunse (baidunzi), is a micaceous rock containing sericite and other minerals including quartz (Kerr and Wood 2004). Porcelain stone often occurs kaolinised to a greater or lesser extent.

Porcelain stone and china clay are both composed of platy minerals, which is to say that they are composed to varying degrees of small platelets of high surface area (external and internal) and are capable of holding relatively large amounts of water. This is of importance because some of the methods used for forming the body parts of ceramic pieces (throwing on a wheel, for example) depend upon the application of compression to align the platelets and increase the plasticity and workability of the clay body. In the case of throwing, compression is applied by the hand of the potter.

[edit] Classification

In the West whiteware ceramics includes the categories of earthenware, stoneware or porcelain, depending largely upon the composition of the body and the kiln temperature required for its firing. However, the Chinese tradition recognises only two primary categories of ceramics, high-fired [cí 瓷] and low-fired [táo 匋] (Pierson 1996). The oldest Chinese dictionaries define porcelain [cí 瓷] as "fine, compact pottery" [táo 匋] (Bushell 1977). In the West the property of translucence is often regarded as a defining feature of porcelain, but this is not the case in China, where any thick or opaque piece that rings with a reasonably clear note on being struck would be regarded as porcelain [cí 瓷] (Bushell 1977).

Chinese ceramic wares are also often classified as being either northern or southern, so called because present day China comprises two separate, and from the geological point of view distinctly different land masses, the northern and the southern. The two land masses were brought together by the action of continental drift, forming a junction that lies between the Yellow river and the Yangtze river. Geological differences between the northern and the southern land masses have influenced the nature of the ceramic wares made in the two areas and, for example, in the north ceramic wares tend to have bodies made with clays, in the south ceramic wares tend to have bodies made predominantly of porcelain stone^{[citation needed]}. In turn, this led to the development of coal-fuelled kilns suitable for the slow, high-temperature firing of clay-rich wares in the north and wood-fuelled kilns more suitable for the faster, lower-temperature firing of the stone-rich southern wares.

[edit] History

In the context of Chinese ceramics the term porcelain lacks a universally accepted definition. This in turn has led to confusion about when the first Chinese porcelain was made. Claims have been made for the late Eastern Han period (100 to 200 AD), the Three Kingdoms period (220 to 280 AD), the Six Dynasties period (220 to 589 AD), and the Tang Dynasty (618 to 906 AD). Some experts are currently of the view that the first true porcelain was made in the Chinese province of Zhejiang during the Eastern Han period. Chinese experts emphasise the presence of a significant proportion of porcelain-building minerals (china clay, porcelain stone or a combination of both) as an important factor in defining porcelain and shards recovered from Eastern Han kiln sites in Zhejiang, estimated to have been fired at a temperature of between 1260 to 1300 degrees Celsius, were found that met this condition (He Li 1996). However, so-called porcelaneous wares or proto-porcelain wares made using at least some kaolin and fired at high temperatures are known that date to well before the year 1000 BC. Unfortunately, the line that divides porcelaneous wares and proto-porcelain wares from true porcelain wares is not a clear one.

One of the first mentions of porcelain by a foreigner was made by an Arabian traveller in the eighth or ninth century (during the Tang Dynasty) who recorded that "They have in China a very fine clay with which they make vases which are as transparent as glass; water is seen through them. The vases are made of clay" (Bushell 1906). The Arabs were well acquainted with glass and there can be little doubt that the author of these words knew that the vases were not made of that material.

During the Sui and Tang periods (581 to 906) a wide range of ceramics, low-fired and high-fired, were produced. These included the well-known Tang lead-glazed sancai (three-colour) wares, the high-firing, lime-glazed Yue celadon wares and low-fired wares from Changsha. In northern China, high-fired, translucent porcelains were made at kilns in the provinces of Henan and Hebei.

[edit] Increasing use of china clay in the South

During the Song and Yuan dynasties porcelain was made at Jingdezhen and other kiln sites in southern China using crushed and refined porcelain stone alone, but by the early eighteenth century china clay and porcelain stone were mixed in about equal proportions. China clay when added to the body material produced a porcelain of great strength and whiteness (whiteness, in particular, was a much sought after property of porcelain, especially that used for blue and white wares).

Porcelain bodies made from porcelain stone fire at a lower temperature, in the region of 1250 degrees Celsius, than those made with a mixture of china clay and porcelain stone, which require firing in the region of 1350 degrees Celsius.

The temperatures within a typical large, southern, egg-shaped kiln varied greatly, from hot, near the firebox, to cooler, near to the chimney at the opposite end of the kiln. One advantage gained by the addition in varying amounts of china clay was that the composition of the paste could be altered to suit the position that the wares made from it would occupy in the kiln, with a clay-rich mix being used for wares to be fired at the hot end of the kiln and a stone-rich mix being used for wares to be fired at the cooler end of the kiln.

[edit] Jingdezhen

The city of Jingdezhen has been an important centre for the production of ceramics in southern China since at least the early Han Dynasty. The early wares were low-fired but by the time of the Southern and Northern Dynasties (420 to 589) locally available raw materials were being used to produce a form of porcelain. In the year 1004, under the Song emperor Jingde, the newly re-named city of Jingdezhen was established as a centre for the production of Imperial porcelain. Detailed descriptions of the manufacture of porcelain at Jingdezhen during the Qing dynasty exist, including a memoir written by Tang Ying and the letters of Père d'Entrecolles.

Two letters written by Père Francois Xavier d'Entrecolles ^[1], a Jesuit missionary (and industrial spy) who lived and worked in Jingdezhen, described in detail the methods and materials used in the manufacturing process of porcelain wares in the later years of the reign of the Kangxi emperor; an important period in the history of Chinese ceramics. In his first letter, dated 1712, d'Entrecolles described the way in which porcelain stone was crushed, refined and formed into little white bricks known in Chinese as petuntse or baidunzi. He then went on to describe the refining of china clay, kaolin or Gaoling, the preparation of glazes, the stages of forming porcelain wares, glazing and firing. Père d'Entrecolles, explaining his motives for describing what he had seen at Jingdezhen, states that "Nothing but my curiosity could ever have prompted me to such researches, but it appears to me that a minute description of all that concerns this kind of work might, somehow, be useful in Europe" but his first letter came too late to be of much help in the European search for the secret of making porcelain. In 1743, during the reign of the Qianlong emperor, Tang Ying, the imperial supervisor at Jingdezhen produced a memoir entitled "Twenty illustrations of the manufacture of porcelain." Unfortunately, the original illustrations have been lost but the text of the memoir is still accessible, together with photographs replacing the missing illustrations and an additional commentary. ^[2]

Jingdezhen was the main production centre for porcelain exported to Europe. The large-scale trade started in the reign of the Wanli emperor (1572 to 1620), see the Wikipedia article on Chinese export porcelain for further information on this topic.

[edit] Some notable Chinese porcelain wares

[edit] Tang sancai burial wares

Sancai means three-colours. However, the colours of the glazes used to decorate the sancai wares of the Tang dynasty were not limited to three in number. In the West, Tang sancai wares were sometimes referred to as egg-and-spinach by dealers, not without reason, for three of the colours commonly used in its decoration were green, yellow and white (though the latter two colours might more properly be described as amber and off-white or cream).

Tang sancai wares were northern wares made using white and buff-firing secondary kaolins and fireclays (Wood 1999) at kiln sites that include Tongchuan in Shaanxi, Neiqui county in Hebei and Gongxian in Henan (Wood 1999). The clays used for burial wares were similar to those used by Tang potters for the bodies of high-fired whitewares, but the burial wares were fired at a lower temperature than contemporaneous whitewares. Burial wares, such as the well-known representations of camels and horses, were cast in sections, in moulds, the parts being luted together with a clay slip. In some cases, a degree of individuality was imparted to the assembled figurines by hand-carving.

[edit] Jian tea wares

Jian blackwares, mainly comprising tea wares, were made at kilns in the county of Jianyang in the province of Fujian and reached the height of their popularity during the Song dynasty. The wares were made using locally-won, iron-rich clays and fired in an oxidising atmosphere at temperatures in the region of 1300 degrees Celsius. The glaze was made using clay similar to that used for forming the body, but fluxed with wood-ash. At high temperatures in the kiln phases within the molten glaze separated to produce the patterning called hare's fur. Some pooling of the glaze is usually evident in Jian wares and where the bowls were set tilted for firing the glaze often ran into drips on one side of the bowl.

The hare's fur Jian tea bowl illustrated is in the Metropolitan Museum of Art in New York. It was made during the Song dynasty (960 to 1279 AD) and exhibits the typical pooling, or thickening, of the glaze near to its foot. The hare's fur patterning in the glaze of this bowl resulted from the random effect of phase separation during early cooling in the kiln and is unique to this bowl, no two bowls have identical patterning. The bowl also has a dark brown iron-foot which is typical of these wares. It would have been fired, probably with several thousand other other pieces, each in its own stackable saggar, in a single-firing in a large dragon kiln. One such kiln, built on the side of a steep hill, was almost 150 metres in length, though most Jian dragon kilns were fewer than 100 metres in length.

An eleventh century resident of Fujian wrote: "Tea is of light colour and looks best in black cups. The cups made at Jianyang are bluish-black in colour, marked like the fur of a hare. Being of rather thick fabric they retain the heat, so that when once warmed through they cool very slowly, and they are additionally valued on this account. None of the cups produced at other places can rival these. Blue and white cups are not used by those who give tea-tasting parties" (Bushell 1977).

Jian tea wares of the Song dynasty were greatly appreciated and copied in Japan, where they were known as temmoku or tenmoku wares. Phase separation in the iron-rich glazes of Chinese blackwares was also used to produce the well-known oil-spot, teadust and partridge-feather glaze effects.

[edit] Qingbai wares

Qingbai wares were made at Jingdezhen and at many other southern kilns from the time of the Northern Song Dynasty until their almost complete eclipse, starting early in the fourteenth century, by underglaze-decorated blue and white wares. Qingbai in chinese literally means "clear white". The qingbai glaze is a porcelain glaze, so-called because it was made using porcelain stone. The qingbai glaze is clear, but contains iron in small amounts. When applied over a white porcelain body the glaze produces a greenish-blue colour that gives the glaze its name (qingbai in Chinese means greenish-blue). Bowls, some with incised or moulded decoration and varying from the everyday to more finely made pieces represent the overwhelming bulk of surviving qingbai wares.

The Song dynasty qingbai bowl illustrated was possibly made at the Jingdezhen village of Hutian, which was also the site of the Imperial kilns established in the year 1004. The bowl has incised decoration, possibly representing clouds or the reflection of clouds in the water. The body is white, translucent and has the texture of very fine sugar, indicating that it was made using crushed and refined porcelain stone, rather than a mixture of porcelain stone and china clay. The glaze and the body of the bowl would have been fired together, in a saggar, possibly in a large wood-burning dragon-kiln or climbing-kiln typical of southern kilns of the period.

Though not the case with the bowl illustrated, many Song and Yuan qingbai bowls were fired upside down in special segmented saggars, a technique first developed at the Ding kilns in Hebei province. The rims of such wares were left unglazed but were often bound with bands of silver, copper or lead.

One remarkable example of qingbai porcelain is the so-called Fonthill Vase, described in a guide to Fonthill Abbey published in 1823 as "...an oriental china bottle, superbly mounted, said to be the earliest known specimen of porcelain introduced into Europe". The vase was made at Jingdezhen, probably around the year 1300 and was sent as a present to Pope Benedict XII from the court of the last Yuan emperor of China, in 1338. The mounts referred to in the 1823 description were of enamelled silver-gilt and were added to the vase in Europe in 1381. An eighteenth century watercolour of the vase complete with its mounts exists, but the mounts themselves were removed from the vase in the nineteenth century and lost. The vase is now in the National Museum of Ireland. It is often held that qingbai wares, which were not subject to restrictions and regulations applied to the production of some other porcelain wares, were made for everyday use and that, even though they are highly regarded today, they were not valued as significant at their time of production. The Fonthill Vase, given by a Chinese emperor to a pope, might appear to cast at least some doubt on this view. It is, however, also the case that qingbai wares were mainly mass-produced and that they received little attention from scholars and antiquarians.

[edit] Blue and white wares

Following in the tradition of earlier qingbai porcelains, blue and white wares are glazed using a transparent porcelain glaze. The blue decoration is painted onto the body of the porcelain before glazing, using very finely ground cobalt oxide mixed with water. After the decoration has been applied the pieces are glazed and fired.

It is believed that underglaze blue and white porcelain was first made in the Tang Dynasty. Only three complete pieces of Tang blue and white porcelain are known to exist, but shards dating to the eighth or ninth century have been unearthed at Yangzhou in the Jiangsu province. It has been suggested that the shards originated from a kiln in the province of Henan. In 1957 excavations at the site of a pagoda in the province Zhejiang uncovered a Northern Song bowl decorated with underglaze blue and further fragments have since been discovered at the same site. In 1970 a small fragment of a blue and white bowl, again dated to the eleventh century, was also excavated in the province of Zhejiang. In 1975 shards decorated with underglaze blue were excavated at a kiln site in Jiangxi and, in the same year, an underglaze blue and white urn was excavated from a tomb dated to the year 1319, in the province of Jiangsu. It is of interest to note that a Yuan funerary urn decorated with underglaze blue and underglaze red and dated 1338 is still in the Chinese taste, even though by this time the large-scale production of blue and white porcelain in the Yuan, Mongol taste had started at Jingdezhen.

Starting early in the fourteenth century, blue and white porcelain rapidly became the main product of Jingdezhen, reaching the height of its technical excellence during the later years of the reign of the Kangxi emperor (du Boulay 1973) and continuing in present times to be an important product of the city.

The tea caddy illustrated shows many of the characteristics of blue and white porcelain produced during the Kangxi period. The translucent body showing through the clear glaze is of great whiteness and the cobalt decoration, applied in many layers, has a fine blue hue. The decoration, a sage in a landscape of lakes and mountains with blazed rocks is typical of the period. The potting is well executed and the porcelain body is finely textured, indicating the presence of a significant proportion of china clay in the paste. The piece would have been fired in a saggar (a lidded ceramic box intended to protect the piece from kiln debris, smoke and cinders during firing) in a reducing atmosphere in a wood-burning egg-shaped kiln, at a temperature approaching 1350 degrees Celsius.

[edit] Fakes and reproductions

Chinese potters have a long tradition of borrowing design and decorative features from earlier wares. Whilst ceramics with features thus borrowed might sometimes pose problems of provenance, they would not generally be regarded as either reproductions or fakes. However, fakes and reproductions have also been made at many times during the long history of Chinese ceramics and continue to be made today in ever-increasing numbers.

• Reproductions of Song dynasty Longquan celadon wares were made at Jingdezhen in the early eighteenth century, but outright fakes were also made there, using special clay and artificially aged by boiling in meat broth, refiring and storage in sewers^{[citation needed]}. Père d'Entrecolles records that by this means the wares could be passed off as being hundreds of years old.

• At Jingdezhen the two remaining wood fired, egg-shaped kilns produce convincing reproductions of earlier wares and at Zhejiang province good reproductions of Song Longquan celedon wares continue to be made in large, side-stoked dragon kilns.

• Before World War II, the English potter Bernard Leach found what he took to be genuine Song dynasty cizhou rice-bowls being sold for very little money on the dock of a Chinese port and was surprised to learn that they were in fact newly made.^{[citation needed]}

• In modern times the market for Song dynasty Jian tea-bowls has been severely depressed by the appearance in large numbers of modern fakes good enough to deceive even expert collectors. It is reported that some of these fakes show evidence of having had genuine Song dynasty iron-foot bases grafted onto newly made bodies.

• In the late nineteenth century fakes of Kangxi period famille noire wares were made that were convincing enough to deceive the experts of the day. Many such pieces may still be seen in museums today, as may pieces of genuine Kangxi porcelain decorated in the late nineteenth century with famille noire enamels. A body of modern expert opinion holds that porcelain decorated with famille noire enamels was not made at all during the Kangxi period, though this view is disputed (de Boulay 1973).

• A fashion for Kangxi period (1662 to 1722) blue and white wares grew to large proportions in Europe during the later years of the nineteenth century and triggered the production at Jingdezhen of large quantities of porcelain wares that looked back to the ceramics of the earlier period. Such blue and white wares were not fakes or even convincing reproductions, even though some pieces carried four-character Kangxi reign-marks that continue to cause confusion to this day. Kangxi reign-marks in the form shown in the illustration occur only on wares made towards the end of the nineteenth century or later, without exception.

[edit] Authentication

The value of testing in the authentication of Chinese porcelain is disputed. The most widely-known test, the thermoluminescence test (TL-test) can be used to provide an estimate, within very wide limits, of the date of last firing. The test is carried out on small samples of porcelain drilled or cut from the body of a piece, which can be risky and disfiguring. For this reason the test is rarely used for dating finely-potted, high-fired ceramics. Additionally, many porcelain items, particularly high-fired vitreous porcelain, are not suited to TL testing. Other tests can be used to determine the composition of glazes and body materials, for comparison with the results of analyses carried out on reference specimens of known provenance. It is however widely held that at best, testing can only be of use when combined with other, more traditional, methods for helping to establish provenance. Such methods might including comparative techniques, expert opinion and the evaluation of written and verbal records, where these are available.

[edit] See also

• Blanc-de-Chine (the white wares of Dehua).
• Canton porcelain (Jingdezhen porcelain decorated at Canton for export to the West).
• Chinese export porcelain (Chinese porcelain made for export to the West).
• Dehua porcelain factories (the factories at Dehua).
• Famille jaune, noire, rose, verte (enamelled wares of the eighteenth and nineteenth centuries).
• Kraak porcelain (blue and white export wares in the Dutch taste).
• Longquan Celadon (the celadon wares of Longquan county).
• Swatow ware (wares exported through the port of Swatow).
• Yixing clay (the red stonewares of Yixing).

[edit] Notes

1. ↑ Two letters written by Père Francois Xavier d'Entrecolles at Ceramics Today.com
2. ↑  Tang Ying's "Twenty illustrations of the manufacture of porcelain." at the Seattle Art Museum.

[edit] References

• de Boulay, Anthony (1973). Chinese Porcelain. Octopus Books, London. ISBN 0-7064-0045-3.
• Bushell, S. W. (1906). Chinese Art. Victoria and Albert Museum Art Handbook, His Majesty's Stationery Office, London.
• Bushell, S. W. (1977). Chinese Pottery and Porcelain. Oxford University Press, Kuala Lumpur. ISBN 0-19-580372-8.
• Fuchs II, Ron W. (2005). Made in China: Export Porcelain from the Leo and Doris Hodroff Collection at Winterthur. Winterthur, DE: Winterthur.  ISBN 0-912724-26-9
• He Li, (1996). Chinese Ceramics. The New Standard Guide. Thames and Hudson, London. ISBN 0-500-23727-1.
• Kerr, Rose and Wood, Nigel (2004). Science and Civilisation in China, Volume 5, Part XII: Ceramic Technology. Cambridge University Press. ISBN 0-521-83833-9.
• Kotz, Suzanne (ed.) (1989) Imperial Taste. Chinese Ceramics from the Percival David Foundation. Chronicle Books, San Francisco. ISBN 0-87701-612-7.
• Pierson, Stacey, (1996). Earth, Fire and Water: Chinese Ceramic Technology. Percival David Foundation of Chinese Art, University of London. ISBN 0-7286-0265-2.
• Wood, Nigel (1999). Chinese Glazes. A.C. Black, London. ISBN 0-7136-3837-0.