China Traditional Porcelain Teawares
Overview of Ru Yao Procelain
Ru Kiln, one called "Head of All Kilns on the Earth" in Chinese porcelain history as one of the five famous kilns ("Ru, Guan, Jun, Ge & Ding Kilns") in Song Dynasty, gets the name of "Ru" Since it is located in Ruzhou.
This kiln was specially picked out to produce porcelain for the court in Song Dynasty, so its products were called "RU Palace Porcelain" i.e. "Ru Porcelain" put simply. Whose soft quantity, delicate workmanship, unique color and colorful penetrations give you delightful enjoyment and pleasure, Quite often resulting in such characteristic effects of "Blue like the sky, gentle like the gem, fine like cicada' s wings, shining like the stars and smooth like the glaze". Ru Kiln technique survived various wars and anarchical periods in history with much treasured pieces of porcelain spread all over the world in museums of Peking, Taipei, Britain, Japan, etc; since it is the world' s rare treasure of mankind.Ru porcelain was exclusively for imperial use. It was produced on a small scale within a twenty-year period, and artisans conversant in its production techniques were few. There are believed to be just 60 pieces of Ru porcelain extant. Of all ancient Chinese ceramics, those made in the Ru kilns are the most precious, mainly because they are so rare. A mere fragment of Ru kiln porcelain sells for RMB 1,000 (about US $122).The Imperial Ru Kilns of the Northern Song Dynasty were in Ruzhou (present-day Linru County, Henan Province) -- for centuries a main producer of celadon. Archaeological findings indicate that porcelain production in Ruzhou was technologically advanced during the Tang Dynasty, but it was actually from 1086 to 1106, when Ru kilns were confined to imperial use, that Ru ceramics reached their zenith. Emperor Huizong personally oversaw the selection of craftsmen and materials involved in porcelain production. As his stress was on aesthetics rather than practicality. Ru kiln ceramics were small and exquisitely fashioned, seldom exceeding 20 centimeters in height. They were stationery or purely decorative items, such as brush washers, incense burners and vases. Emperor Huizong also had a passion for bronze ware, and was the first to produce porcelain whose shape imitated bronze.
The texture of Ru porcelain bases is fine and in an ash gray shade with a glaze that covers the entire body. When fired, each piece was placed on a rack whose nails left distinctive spur marks the size of sesame seeds on each base. The bodies of Ru porcelains are slender and symmetrical with an extremely hard, finely crackled sky blue, aquamarine or turquoise glaze.
Ru Kilns stopped production after the Jin invasion. Some artisans fled to the south, but owing to a lack of raw materials and different climatic conditions, were unable to produce porcelains of the same quality as those of Ruzhou.
Overview of Ding Yao (Ding kiln) Procelain
Ding Kiln is a famous kiln in Song Dynasty.
Product Characteristics: burning white china mainly, fine porcelain, quality thin with bright, glaze color moist like jade.
Ding Kiln (dìng yáo 定窑)Ding kiln is located in the Quyang county (qǔ yáng xiàn 曲阳县),Hebei Province (hé běi shěng 河北省), which is called Dingzhou (dìngzhōu 定州) in the Song Dynasty (sòng cháo
宋朝)(960—1276). It wasbuilt in the Tang Dynasty (táng cháo 唐朝)(618—907).
The Ding Kiln was known for its white porcelains. It used durablewhite clay (gāo lǐng tǔ 高岭土) as the roughcast (pī 坯), covered bywhite glaze (bái yòu 白釉). In the early Song Dynasty, thedecoration patterns were relatively simple, by the end of theNorthern Song Dynasty the paintings were much more complicated. Some of the Ding porcelains were imperial contributions to the court.On the other hand, the Ding aesthetic relied more on its elegantshape than ostentatious decoration; designs were understated, eitherincised or stamped into the clay prior to glazing. Due to the waythe dishes were stacked in the kiln, the edged remained unglazed,and had to be rimmed in metal such as gold or silver when used astableware.
Overview of Ceramic glaze
Glaze is a layer or coating of a vitreous substance which has been fused to a ceramic object through firing. Glaze can serve to colour, decorate, strengthen or waterproof an item.
Glazing is functionally important for earthenware vessels, which would otherwise be unsuitable for holding liquids due to porosity. Glaze is also used on stoneware and porcelain. In addition to the functional aspect of glazes, aesthetic concerns include a variety of surface finishes, including degrees of gloss and matte, variegation and finished colour. Glazes may also enhance an underlying design or texture which may be either the "natural" texture of the clay or an inscribed, carved or painted design.
Ceramic glazes generally contain silica to form glass, in combination with a mixture of metal oxides such as sodium, potassium and calcium which act as a flux and allow the glaze to melt at a particular temperature, alumina (usually from added clay) to stiffen the glaze and prevent it from running off the piece, colorants such as iron oxide, copper carbonate or cobalt carbonate, and sometimes opacifiers such as tin oxide or zirconium oxide.
Glaze may be applied by dry dusting a dry mixture over the surface of the clay body or by inserting salt or soda into the kiln at high temperatures to create a sea of sodium vapor that interacts with the aluminium and silica oxides in the body to form and deposit glass (see Salt glaze pottery). Liquid glazes—suspensions of various powdered minerals, and metal oxides—can be applied by dipping pieces directly into the glaze, pouring the glaze over the piece, spraying it onto the piece with an airbrush or similar tool, with a brush, or with any tool that will achieve the desired effect.
To prevent the glazed article sticking to the kiln during firing either a small part of the item is left unglazed or special refractory supports, kiln spurs, are used as supports which are removed and discarded after the firing. Small marks left by these spurs can sometimes be visible on finished ware.
Decoration applied under the glaze on pottery is generally referred to as underglaze. Underglazes are applied to the surface of the pottery, which can be either raw, "greenware", or "bisque" fired (an initial firing of some articles before the glazing and re-firing). A wet glaze—usually transparent—is applied over the decoration. The pigment fuses with the glaze, and appears to be underneath a layer of clear glaze. An example of underglaze decoration is the well-known "blue and white" porcelain famously produced in England, The Netherlands, China and Japan. The striking blue colour is achieved by using the powerful colorant cobalt in the form of either cobalt oxide or cobalt carbonate, both of which are still commonly used in glaze decoration today.
Mug with blue underglaze decoration on porcelain.Decoration applied on top of a layer of glaze is referred to as overglaze. Overglaze methods include applying one or more layers or coats of glaze on a piece of pottery or by applying a non-glaze substance such as enamel or metals (i.e., gold leaf) over the glaze.
Overglaze colors are low-temperature glazes that give ceramics a more decorative, glassy look. A piece is fired first, overglaze is applied, and it is fired again. Once the piece is fired and comes out of the kiln, its texture becomes smoother because of the glaze.