Page 27 - Decorative Arts, Part II: Far Eastern Ceramics and Paintings, Persian and Indian Rugs and Carpets

For centuries, the decoration of ceramics exclusively by means of single-color glazes, occasionally mod-
ulated through the introduction of crackle in the glaze, has been a major feature of Chinese ceramic history. The
inherent qualities of glazes—thickness, luster, translucency, and color—have been exploited to create various
visual and tactile effects. Occasionally, discreet surface manipulation of the clay body, such as simple low relief,
incised designs, or applied slip decoration under the glaze, contributes to the design.
Many of the shapes crafted in monochrome porcelains arise naturally from the potter's wheel, the
inevitable results of the process of throwing, but there were many built and molded forms as well. Shapes copy-
ing Song ceramics or directly copying ancient bronzes are not uncommon (see, for example, the small beaker vase
in the shape of an archaic bronze gu, 1972.43.16). In general, however, monochrome porcelains are uncomplicat-
ed in overall design, however technically complex their glazes.
The Qing-dynasty high-fired glazes are seen at their glorious best in the Widener collection, which focuses
on a few of the most highly prized single-color wares from the late seventeenth through the nineteenth century. Its
extensive representation of green, peachbloom, and blue glazed wares allows the viewer to appreciate the interplay of
varying forms and color tones. There are fewer representations of other colors, including yellow, white, and turquoise.
Chinese glazes owe their many colors to a very few minerals and their oxides—copper, cobalt, iron, and
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manganese. Some monochrome glazes employed combinations of oxides, which served to modify the standard
repertoire of colors.

COPPER
Copper, both pure and in its oxides, produces a surprising number of chromatic effects, from blues, greens, and
turquoises to dark reds and soft, pale reds. It is a difficult colorant to control, with few perfect results and many
variations. It seems as if no two copper glazes are exactly alike, as the array of effects exhibited by peachbloom
seal paste boxes or oxblood vases attests. Flawless examples of any glaze derived from copper are a tribute to the
extraordinary accomplishment of the potters.
Copper oxide in an alkaline glaze produces various shades of red when fired in a carefully controlled
reducing atmosphere. (The same copper-oxide glaze will fire to a green color in an oxidizing atmosphere.)
Copper readily reduces from cupric oxide to cuprous oxide and eventually converts to metallic copper. The
famous deep red monochrome glaze, commonly known in China as langyao and in the West as oxblood or sang-
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de-boeuf, contains a concentration of only 0.1-0.5 percent by weight of finely divided colloidal copper. Oxblood
glaze is colored by copper, despite fanciful tales crediting precious gems or human blood as ingredients. The dif-
ferent names used for this glaze illustrate the complex derivation of both Western and Chinese color terms, which
has produced many seemingly arbitrary designations.
The oxblood glaze was not actually an innovation of the Qing potters but rather a revival of a glaze first
devised in the early Ming dynasty. Its perfection occurred sometime between 1705 and 1712 when Lang Tingji, a
governor of Jiangxi Province (where Jingdezhen is located), was appointed by imperial decree to supervise the
imperial kilns. He was responsible, again by court decree, for reviving the copper-red glaze. Thus, these red
monochromes are officially and conveniently known in China as langyao (Lang ware).
Prize oxblood pieces (such as 1942.9.528), incorporate a variety of jewel-like reds, giving the vessel a strik-
ing sense of life, as if the glaze were still flowing over the surface. Streaks slide in the depths as the glaze moves over
a contour. Color thins and then thickens. Oxidized pale green areas may appear, as well as areas of clear glaze where
pigment is absent. A faint crackle increases the sparkling quality of the surface. At the foot, the glaze rolls to a con-
trolled stop, forming a thick welt. This ability to neatly regulate the glaze was no longer evident in later examples of
this type; on these, the glaze flow continued at the base and had to be ground off (see the small vase, 1972.43.32).
Later red glazes tend to be opaque and duller in hue, with consistently uniform coloration over the sur-

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