Lot 1. A large Longquan celadon 'trigrams' tripod cache-pot, 15th century; 11 1/8 in. (28.3 cm.) diam. Estimate GBP 1,000 - GBP 1,500. Price realised GBP 1,912. © Christie's Images Ltd 2004

Of tapering cylindrical shape raised on three cabriole legs, the exterior moulded with the eight trigrams and freely carved with scrolling foliage between raised bands, the base pierced, covered in a celadon glaze of greyish-green tone, rim cracks and chips.

Provenance: E. T. Hall Collection, no. 559.

Monochrome Porcelains from the Collection of Professor E.T. Hall(1)
Rosemary E. Scott
Senior Academic Consultant to the Asian Art Departments

Professor Edward 'Teddy' Hall was a man who obviously enjoyed combining art and science, as evidenced by his directorship of the Research Laboratory for Archaeology and the History of Art at Oxford, and by his important collection of clocks (sold at Christie's London on 11 July 2003). This was a combination of interests that he was also able to pursue in his remarkable collection of Chinese ceramics. His passion was primarily for monochrome porcelains of the Ming and Qing dynasties, and, as can be seen in the pages of this catalogue, he built up one of the finest private collections of these beautiful wares. The pieces were shown to stunning effect in his home near Oxford, where visitors were dazzled by the brilliant spectrum of colours displayed in cases located in the hall, drawing room and sitting room. The collection encompassed a huge range of forms and colours, including groups of particularly rare and prized types, such as the ethereal clair de lune (lot *1*), as well as classic colours like the vibrant imperial yellow (lot *2*). 

While many collectors of Chinese ceramics undertake art historical research into the pieces in their collections, very few are personally able to undertake scientific research. Professor Hall, as both a chemist and physicist, as well as Director of the Oxford Research Laboratory, was able to apply his scientific knowledge to his own collection. The fact that he was able to contribute ground-breaking research to the body information on later Chinese monochromes is one of the things that set him apart from most other collectors. He had been interested in X-ray fluorescence analysis since the years of research for his D. Phil., awarded in 1953. Some thirty years later in November 1982 Hall and his co-author, A.M. Pollard, were able to present a paper entitled 'Analysis of Chinese Monochrome Glazes by X-ray Fluorescence Spectrometry' to an international conference in Shanghai. Using non-destructive methods, developed at the Research Laboratory over a number of years, Hall and Pollard were able to provide qualitative, if not quantitative, information on the materials used to produce the range of vivid colours seen on Ming and Qing dynasty monochrome porcelains. Their work remains one of the major sources of information on this subject. 

Although when most Westerners think of Chinese ceramics their thoughts turn to blue and white or porcelains decorated in the famille rose or famille verte enamel palettes, it has traditionally been single-coloured ceramics that have been among the most admired in China itself. It is worth bearing in mind that while extensive decoration can, to some extent, disguise poor potting or inelegant form, monochrome glazes will emphasise every flaw. Perhaps it is not surprising, therefore, that the popularity of monochrome ceramics was first established during a period in which the technology and status of ceramics reached an all-time high. It was in the Tang dynasty (AD 618-907) that ceramics were first truly appreciated by Chinese connoisseurs for their own qualities as beautiful objects, and at that time it was not the multi-coloured wares that were the subject of imperial approbation and literary praise, but the monochrome ceramics with plain white glazes or soft, grey-green celadon glazes. The latter ware, from the Yue kilns of Zhejiang province, was the recipient of particular praise from the Tang dynasty writer Lu Yu (AD 733-804). In Cha Jing (Tea Classic) Lu Yu paid these Yue celadon wares the ultimate compliment of declaring that they were the best vessels from which to drink fine teas. 

In the Song dynasty (AD 960-1279) the appreciation of monochrome wares grew at court and in literary circles. Both the Northern (AD 960-1127) and the Southern Song (AD 1127-1279) periods saw the development of new kinds of high-fired monochromes which were esteemed by succeeding generations and influenced ceramics produced in later dynasties. Green celadons, white ceramics such as Ding wares (lot *3*), Jun, Ru, black-glazed ceramics, and the crackled glazed wares of the southern kilns were to prove the most enduringly appreciated and influential. The Ding wares owed their colour to the purity of the material from which they were made. The celadons, including Ru wares, and also the black wares owed their glaze colours to differing amounts of iron in the glaze constituents, while Jun wares obtained their opalescent blue colour partly from small amounts of iron and partly from the optical effects of the glaze structure.(2) 

With the beginning of the Ming dynasty and the enthronement of the Hongwu Emperor (AD1368-98) monochrome ceramics made for the court took on some of the roles previously reserved for bronzes - they were used for state ritual. As early as the second year of his reign in 1369 Hongwu Emperor re-established imperial production at the Jingdezhen kilns in Jiangxi province, and in the same year he issued an edict declaring that the vessels used on the imperial altars should henceforth be made of porcelain. While this move was undoubtedly driven by the need to conserve the copper, which would otherwise have been used in the manufacture of bronze vessels, its effect on the porcelains made for and preserved by the Ming and Qing courts was, of course, significant. The imperial altars at which the emperor personally made sacrifices were the Altar of the Sun, which was to be served with red porcelain vessels (lot *4*); the Altar of Heaven, which would have blue vessels (lot *5*); the Altar of Earth, which would have yellow (lot *6*); and the Altars of the Moon and to the imperial Ancestors, which would have white porcelain vessels (lot *7*). 

Red, blue, yellow and white porcelains were thenceforth made for use in rituals as well as for other purposes, and additional colours such as copper green and copper turquoise were added to the repertory of the Imperial kilns. Sometimes the personal tastes of the reigning emperor can clearly be seen in the porcelains made for his court. The Yongle emperor (AD 1403-24) seems to have demonstrated a distinct preference for white objects. The finds from excavations of the Yongle strata at the Imperial kiln site comprised well over 90 white porcelains. This reign was, of course, also the one in which the famous tianbai or 'sweet white' glaze (lot *8*) was established, as well as the one in which reign marks began to appear on imperial porcelain. This tianbai glaze was made almost entirely of 'glaze stone' with little or no 'glaze ash', and it therefore contains less calcium carbonate than the other Jingdezhen 'white' glazes, which makes it appear whiter. The emperor's desire for white porcelains was undoubtedly linked to his enthusiasm for Tibetan Buddhism, and other more personal reasons, but he appears to have had a genuine aesthetic appreciation for undecorated white objects and it seems that on one occasion he returned all the elaborate and costly gifts offered to him, and kept only those made of plain white jade. (3) This may further explain his fondness for the tianbai glaze, which has a soft unctuous feel, reminiscent of jade. The interest in white porcelains for more than ritual use was intermittent in the Ming dynasty, but resurfaced to a significant degree in the Qing dynasty for items such as those intended for the scholar's table (lot *9*). The Jingdezhen white wares joined those from the Dehua kilns (lot *10*) as highly desirable accoutrements for the literatus. 

Professor Hall's collection is especially rich in monochrome porcelains from the Qing dynasty (AD 1644-1911). This is not surprising, since the re-establishment of fine imperial porcelain in the high Qing period meant that well potted, elegant, shapes with monochromes glazes once again came to the fore. The late 17th and 18th century also saw the reigns of emperors who were great patrons of Imperial porcelains and who took a personal interest in their production. The desire of these emperors for new colours also encouraged the expansion of the glaze and enamel palettes at the Jingdezhen kilns. The Imperial kilns of this period came under the supervision of extremely able men, some of whom have been particularly associated with the monochrome glazes produced during their time of tenure. One of these was Lang Tingji, who was Governor of Jiangxi province and concurrently supervisor of the Imperial kilns from AD 1705 to 1712. The name Langyao (Lang wares) has been applied to several monochromes made under his supervision. It is most often applied to pieces with a brilliant copper red glaze (lot *11*), but is sometimes also applied to porcelains with copper green glazes (or, more properly, enamels), and to very thinly potted white wares. There is inevitably debate over which of the fine copper red porcelains made during the reign of the Kangxi Emperor (AD 1662-1722) may be designated 'Langyao', and thus ascribed to the seven years of Lang Tingji's supervision. It is recorded that Lang Tingji was famous in his lifetime for producing copies of the fine glazes of the early 15th century. However, in the case of copper red, changes to the glaze recipe resulted in reds that were sometimes of an even greater brilliance. The Qing red glazes generally contained greater quantities of calcia and alumina, and smaller amounts of silica and alkalis than their 15th century predecessors. This had relatively little effect on their appearance, but the Qing red glazes also contained somewhat less copper, and this contributed to the production of a brighter red. The Kangxi copper red glazes also had a longer firing time, and this resulted in their appearing glassier than their 15th century counterparts. While most Qing dynasty copper reds had slightly thinner glazes than those of the 15th century, the Langyao copper red wares generally have thicker glazes, with a richer red colour, and are glassier, probably due to being fired at a somewhat higher temperature. The shaded white band around the mouth of Langyao reds is also frequently more pronounced than on other Qing dynasty copper red porcelains. This white band, seen to come extent on most Ming and Qing copper red wares, is due to the fact that the development of the colloidal copper which provides the red colour is inhibited both by contact with the atmosphere in the kiln and also with the clay body. The colour only develops in the centre of the glaze, and where the glaze is not thick enough to sustain this central layer, for example where it has run thin at the rim, the glaze appears almost colourless. The E.T. Hall Collection contains a wonderful range of Qing dynasty copper red glazes, allowing, for example, comparison of the glaze on the early 18th century &ILangyao bottle vase (lot *12*) with a later 18th century Qianlong saucer (lot*13*), with its finely ground glaze components, even colour, and narrow white band around the rim.

Another type of Kangxi copper red glaze that is well represented in the Hall Collection is the so-called 'peachbloom' glaze (lot *14*). In Chinese this glaze is usually called 'apple red', but is sometimes given more fanciful names, such as 'drunken beauty', 'beauty's blush', or 'baby's face'. It seems most likely that this glaze was developed towards the end of the Kangxi reign, and very few of these wares appear to have been made after 1722. While essentially a copper red glaze, peachbloom is less homogeneous and more complex, having areas of soft raspberry colour and some of clear copper green, where greater quantities of pigment have reoxidized. Normally copper will give red if fired in reduction and green when fired in oxidation. This glaze has, therefore, been the subject of considerable research in the last twenty years, and the results seem to suggest that the effect may have been achieved by spraying on a copper-lime pigment between two layers of clear glaze. Made in a limited number of relatively small shapes, Kangxi peachbloom glazes have been greatly admired since they were first made. John Ayers, who has extensively researched these peachbloom porcelains, believes that they were probably originally made as presents for members of the court (4). The extent to which they have subsequently been prized can be seen in a beautiful jar in the Hall Collection (lot *15*), which began as a vase. At some stage the neck was broken, but rather than abandon such a lovely piece, its then owners reduced the neck, had an ivory lid made, and converted the vase into a jar. 

Both the copper red and the peachbloom were high-firing glazes, but a low-firing copper glaze had been regularly used in China since the Han dynasty (206 BC-AD 220). This was a lead-fluxed green glaze using copper as its colorant. On porcelain the green glaze had to be applied to a pre-fired biscuit body or on top of a pre-fired porcelain glaze. This means that it should more properly be called an enamel, but it is often referred to as a glaze for convenience. Like other lead-fluxed glazes, this bright green glaze could only be fired to a relatively low temperature, well below that required for the firing of porcelain, hence the need for a second firing. This copper green 'glaze' was used in two main ways in the Qing dynasty. One version used the green over a biscuit-fired body, often in combination with incised decoration (lot *16*). The effect of this was to produce a brilliant, richly coloured, shiny green, which enhanced the incised decoration beneath it. In the other copper green effect the green colour appears to have been applied over a crackled, Guan-like, glaze (lot *17*). The translucent green enamel takes on a warmer and softer appearance when applied over the crackled glaze, and somewhat resembles green jade, which may have been the original intention. The green enamel could also be applied over a normal porcelain glaze, but this was less common in the Qing dynasty than it had been in the early Ming. 

Yellow, including the so-called 'imperial yellow' flourished during both the Ming and Qing dynasties and is well represented in the Hall Collection. The warm-toned imperial yellow (lot *18*), sometimes called 'chicken fat yellow' in China, was another lead-silicate glaze, which, in this case, owed its colour to small amounts (about 3.5 of iron oxide. It seems probable that the 'imperial yellow' was fired at a slightly higher temperature than other, similar, yellows in order to obtain a better colour and clarity. In both dynasties it was either applied directly to the pre-fired body or on top of a high-fired glaze. The former method typically gave a richer, warmer, colour, while the latter gave a more even, slightly fluid appearance. This yellow is of particular interest, not least, because according to Qing regulations only the emperor, empress or dowager empress could use vessels which were yellow both inside and out. Those of lesser status had to use combinations of colours appropriate to their rank. 

In the early 18th century a new yellow monochrome appeared, which was quite different from the translucent, warm, yellows produced using iron as a colorant. This new yellow which was also low-firing and had to be applied to the surface of a pre-fired porcelain body or glaze, was lemon in tone, and was opaque (lot *19*). The colorant for the lemon yellow was one of those identified by Hall and Pollard in their 1982 research paper. They found that this citrus yellow was coloured using lead antimonate (lead and antimony), thus settling once and for all the scholarly debate about the use of antimony in Chinese ceramics. Their results are also interesting because they showed that the monochrome colour was different from the opaque lemon yellow enamel used in the famille rose palette, which was made using lead stannate (lead and tin). Related to the monochrome lemon yellow was another new colour, which was also examined by Professor Hall and his co-author - opaque lime green (lot *20*). The lime green was similarly coloured using lead antimonate, but with the addition of copper.

It is probable that these new colours were developed in the Yongzheng reign (AD 1723-35) under the auspices of the most famous of all the supervisors of the Imperial kilns - Tang Ying (AD 1682-1756). In the first year of Yongzheng Tang Ying was appointed Vice-Director of the Imperial Household Department at court before being sent to Jingdezhen in 1726, initially working as assistant to Nian Xiyao, but soon assuming complete responsibility for production at the Imperial kilns. Tang Ying became a knowledgeable ceramicist in his own right, and also had literary talent. His surviving writings provide much useful information about production at Jingdezhen. In 1735 Tang wrote Taocheng jishi bei (Memorial on ceramics inscribed on a stele). This lists some fifty-seven different types of glaze. While some of these were inherited from the Ming dynasty and others were initiated during Kangxi's reign, it is clear that a number were developed as a response to the Yongzheng Emperor's desire for new colours.

Although the pink enamel that gave the famille rose palette its name appears to have been developed in the last years of the Kangxi reign, the colour seems first to have been used successfully as a monochrome under Yongzheng (lot *21*). Like its famille rose counterpart, the monochrome pink was coloured using colloidal gold, and could be used as a bright, translucent, colour or could be mixed with lead arsenate to provide a pastel pink. As Hall and Pollard noted in their analysis, this lead arsenate was also used to create the opaque pastel turquoise (lot *22*) monochrome that gained popularity in the Yongzheng reign. They also found that arsenic, with copper as the main colorant, was among the glaze constituents which produced the speckled Robin's egg glaze (lot *23*). This latter glaze appears to be lead-based, with copper as the main colorant and arsenic as the opacifier. It has been suggested that the speckles may have been produced by spraying a contrasting enamel colour onto the fired glaze and re-firing.

Translucent turquoise glazes had occasionally been used in China as part of the sancai (three colour) palette as early as the Tang dynasty, and were used on architectural ceramics and related figures and vessels from Song times. However, current evidence suggests that turquoise monochrome porcelains were not produced in any number at Jingdezhen until the Yuan dynasty (AD 1279-1368). Even in the Ming dynasty relatively few seem to have been produced, but in the Qing dynasty there appears to have been a new appreciation of turquoise monochromes at court, and this is reflected in the Hall Collection (lot *24*). These turquoise glazes owed their colour to copper, but unlike the copper green glazes, the turquoise glazes were of high potassia, alkaline type, rather than lead-fluxed, since this gave a more brilliant colour and a harder, more stable glaze.

In the same way that the E.T. Hall Collection demonstrates the versatility of copper as a colorant, it also provides excellent examples of the variety of glazes in which iron is the major colorant. The warm yellow glazes with their small percentages of iron have been mentioned above, but iron in slightly larger amounts was used to produce attractive coffee-coloured monochromes ranging from delicate cafe au lait (lot *25*) to the rich brown that the Chinese often refer to as 'soy sauce' coloured (lot *26*). Hall and his co-researcher noted that the Qing dynasty versions of these glazes contained manganese and rubidium, in addition to iron. Still larger amounts of iron (between 5 and 8 were used to produce the rich black glazes of the Qing dynasty. This could produce rich glossy brown-toned black glazes with an appearance reminiscent of molasses (lot *27*), but in the Kangxi reign a new black was added to the repertoire which had a surface that earned it the name 'mirror black'. This black glaze was demonstrated by Hall and Pollard to contain not only iron but also manganese and cobalt, adding to the intensity of its colour and sheen of its surface. Mirror black was often decorated with gilding, which was very fugitive and frequently remains only as a faint tracery on the glaze surface (lot *28*).

Another inventive monochrome glaze was produced using iron as its colorant, but with deliberate under-firing so that fine crystals of the pyroxene family developed during long cooling (lot *29*). This type of glaze goes by many evocative names in China such as 'teadust', 'snake-skin', 'eel-skin', and 'old monk's habit', but is characterised by colours ranging from dark golden brown to yellowish-khaki, all with micro-crystalline effects creating delicate variations on the surface. Surface variations are also seen on another iron coloured glaze popular in the Qing period and with fine representatives in the Hall Collection. This is the 'iron rust' glaze (lot *30*) - a lime-alkali glaze with an over-saturation of iron oxide (in the region of 16, which is fired in a reducing atmosphere up to about 1280 C, then the firing continued in a strongly oxidising atmosphere, and finally the glaze was cooled slowly with the result that the glaze itself has a rust tone and fine iron oxide crystals appear on the surface. 

The monochrome colour containing the highest percentage of iron is so-called 'iron red', which obtains its tomato-red hue and matt surface texture from about 20 of ferric oxide. Once again this was over-saturation, and most of the iron did not dissolve in the glaze and re-crystallised during cooling. The earlier iron-red monochromes, like those of the middle and late Ming dynasty, usually had somewhat uneven colouration, however in the early 18th century the potters found that if they ground the constituents even more finely, and substituted potassium nitrate for some of the lead oxide in the original recipe, they could achieve the even orangey-red tone that is usually referred to as 'coral' red (lot *31*). Once again, the Hall collection has fine examples of these iron red porcelains.

We should not leave the monochromes that owe their colour to iron without mentioning the pale celadons of the Qing dynasty, of which are so beautifully represented in the E.T. Hall Collection (lot *32*). Although celadon-type glazes, coloured with small quantities of iron, applied to a porcelain body were produced at Jingdezhen in the early Ming period, the Kangxi potters perfected a particularly delicate version applied to very white (low iron) body. The delicate celadon glaze was coloured using only about half the amount of iron found in typical Longquan celadons, and was further modified in the Yongzheng period to produce an even more finely textured and slightly bluer pale celadon glaze. These celadons and the others created with minute variations on tone and texture have been much admired by Chinese connoisseurs and have been given names such as douqing (bean green) and dongqing (eastern green) in the Kangxi reign, dongqing (winter green) and fenqing (soft green) in the Yongzheng reign. The very pale blue-toned celadon glaze continued to be favoured in the Qianlong reign, as evidenced by the exquisite chrysanthemum dish in the Hall Collection (lot *33*). The form of this dish was one particularly beloved by the Yongzheng and Qianlong emperors. Records show, for instance, that in 1733 chrysanthemum dishes of twelve different monochrome colours were made for the Yongzheng emperor, while a later order from the Qianlong emperor demanded four hundred and eighty chrysanthemum-shaped vessels of various forms and sizes. The application of celadon glazes to porcelain, which had started at the Imperial kilns at Jingdezhen in the early Ming dynasty, was one of several archaistic trends that continued into the Qing reigns. Other Song dynasty glazes that were particularly revered by the Ming and Qing emperors were Northern Song Ru ware (lot *34*) and Southern Song Guan ware (lot *35*) and Ge ware. Sometimes later wares made with these archaistic glazes were made in ancient forms; sometimes the glazes were applied to contemporary forms. The Yongzheng emperor is recorded to have specifically required that good copies of Song glazes be produced at Jingdezhen, and fortunately the successful copying of these Song dynasty stoneware glazes on Qing dynasty imperial porcelains was something for which Tang Ying was to become well known. 

In the E.T. Hall Collection there is an especially impressive group of porcelains which have blue glazes coloured with cobalt. These range from pieces with dark inky blue glaze (lot *36*) through brilliant sapphire (lot *37*), to soft lavender (lot *38*), and finally to the delicate pale blue known as clair de lune (lot *39*). The main colorant in all these glazes is cobalt, but it is worth noting that the cobalts used in the Yuan and early Ming dynasties were high in iron, which affected the colour of the glazes made using them, as did the manganese in the cobalts used from the early Ming dynasty. Hall and Pollard noted, for example, that manganese was present in the clair de lune glaze they anaylised, as was rubidium. The nickel and copper in some cobalt ores could also alter the tone of the glaze. In addition glazes where the pigments were high in alumina tended to develop cobalt aluminates in firing and produce cooler blues, while those containing more silica produced cobalt silicates which gave warmer, more purplish, blues. 

Cobalt was also a constituent of the glazes on the range of aubergines and purples in which the Hall Collection is so rich. The main colorants for the aubergine glazes (lot *40*) are manganese and a small amount of cobalt. The deeper aubergine purples appear to have a slightly larger amount of cobalt (lot *41*), while Hall and Pollard found that the deep violet purple glazes (lot *42*) are coloured with manganese with the addition of cobalt, but also contained copper and rubidium. Cobalt was also occasionally used by Qing potters in their attempts to imitate Song dynasty splashed Jun wares. The Qing glazes, which are usually called flambe/ae in the West (lot *43*) and either Jun hong (Jun red) or yao bian you (kiln transmutation glaze) in China, could not be made using a single glaze, but with three glazes of different compositions. The main colorant for both the blue and red glazes was copper, while the khaki brown glaze on the base contained iron. However Professor Hall and his co-researcher found that the Yongzheng glazes they examined had no cobalt, but that blue areas of a Qianlong flambe/ae glaze did contain cobalt. Hall and Pollard pointed out in their paper that small amounts of cobalt are hard to detect when there are significant quantities of iron present, but indicated how they had achieved this. 

For Professor Hall this collection must have been a constant source of intellectual stimulation, but it would also have been a source of visual delight, and this appreciation of these remarkable porcelains for their exceptional beauty can be shared by non-scientists, be they scholars, connoisseurs or collectors. 

Endnotes: 1. E. T. Hall and A. M. Pollard, 'Analysis of Chinese Monochrome Glazes by X-ray Fluorescence Spectrometry', Scientific and Technological Insights on Ancient Chinese Pottery and Porcelain, Shanghai Institute of Ceramics, Academia Sinica (eds), Science Press, Beijing, 1986, pp. 382-6.
2. The research on this topic is discussed by Nigel Wood in Chinese Glazes - their Origins, Chemistry and Recreation, A&C Black, London, 1999, pp. 118-24.
3. Liu Xinyuan, Imperial Porcelain of the Yongle and Xuande Periods Excavated from the Site of the Ming Imperial Factory at Jingdezhen, Urban Council, Hong Kong, 1989, p. 73.
4. John Ayers, 'The 'Peachbloom' Wares of the Kangxi priod (1662-1722)', Transactions of the Oriental Ceramic Society, Vol. 64, 1999-2000, pp. 31-50.

Christie's. Chinese Monochrome Porcelain from the Collection of the late E. T. Hall, London, 7 June 2004