瓷器的基本常识（英文）
市场英语
Ceramics is a field with two major categories: Pottery and Porcelain. Pottery was the first entirely man made objects produced by primitive societies. The basic materials and the techniques ud remained unchanged for thousands of years. A major development occurred during the 7th century AD in China, where with the discovery of kaolin and the method of creating hard paste porcelain, the field of ceramics started a new age.
regulationThe following information should provide the basics for the evaluation of modern European porcelain.
Esntial factors in the asssment of value:
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The body is the materials in which a piece is made of.
brsThe distinctions between the types of ceramics stem from the u of different material, th
e temperature at which the piece is fired in the kiln, and the proportion of vitreous (glassy) ingredients in the body. Important test is to hold the article up to a strong light. If light shows through the body of the piece, it is either porcelain or thinly potted stoneware. If the body does not transmit light, it is earthenware. This is a reliable rule of thumb. Stoneware is generally unglazed, or glazed with vaporized salt which creates a characteristically rippled surface.
Important consideration in valuing a piece, is the amount and quality of hand work involved in the creation of the body. Was it casted by machine, casted as a single unit, formed by a pattern or was it hand made? Hand piercing, intricate decorations such as flowers adds to the value of the piece.
Pottery
Pottery is of much coarr texture than porcelain. The two main types of pottery are porous earthenware and non-porous stoneware.
Earthenware:
Below 2200 F (1200 C) is the “low” temperature range, wares fired within this range are categorized as earthenware. Most common clays are suitable for earthenware, and the resultant body may be white, buff, brown, red or gray depending not only on the natural color of the clay but also on its iron content.
Stoneware:
Made from clays that allow shapes to retain their form at temperatures up to 2250 F (1400 C). In this “high” temperature range the clay “melts” and fus into a non-porous vitrified body of great strength. The vitrified bodies can be slightly translucent, are impervious to liquids and are extremely hard and durable. As with earthenware, the resultant bodies can vary in color.
Stoneware bodies were made in Europe, predominantly in Germany, from at least as early as the 15th century.
Porcelain
Porcelain is a fine variety of ceramics that was first made in China in the 9th century AD and widely imitated in the West till the 18th century.
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Overglaze decoration on hard-paste stands out distinctly, on soft-paste the decoration tends to sink into the glaze. The distinction between the two pastes is especially obvious on figures. The clo-fitting glaze on hard-paste enables crisper, more detailed modeling, whereas soft-paste figures have blunter outlines, often with glaze pooling in the crevices.
Hard-paste porcelain:
Hard-paste porcelain contains two esntial elements - kaolin (china clay) and petunt (china stone). Both are forms of decompod granite. They are fud together by firing in a kiln. First the object is fired to about 1650 F (900 C), then dipped in glaze, then refired at about 2400 F (1300 C). The china stone bonds the clay particles together and gives translucency: the high temperature gives object the consistency of glass (vitrifies it). Chips on hard-paste porcelain appear smooth and glassy.
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In Europe a source of kaolin was find and porcelain manufacture was attempted at Meisn, near Dresden. By 1718 petunt had been located, and so began the production of the hard paste white porcelain for which Meisn became famed.
样本容量Soft-paste porcelain:
Soft-paste porcelain was first made in Florence, Italy, in ca. 1575. As its name suggests, soft-paste is more easily scratched than hard-paste. The glaze sits on the surface of the ware, feels warmer and softer to the touch, and is less glittering in appearance. Chips in soft-paste have a floury appearance like fine-grained chalk.
Kinds of soft-paste:
Several soft-paste formulas were discovered, each using fine clay but adding different ingredients to provide the all-important translucency.
Frit porcelain:
Using powdered glass made from a combination of substances including white sand and gypsum.
Soapstone porcelain:
Using powdered soapstone. This yielded a white, more plastic body.
Bone-ash porcelain:
Using powdered calcined ox-bones. This body was denr, generally more thickly potted, and heavier.
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Bone china:
This characteristically English porcelain, invented c. 1794, is nearer to hard- paste than soft-paste. It made u of a large proportion of bone-ash added to hard-paste ingredients.
Feldspar china:
This was a type of English porcelain in which feldspar replaced china stone in the bone-china formula.
Biscuit:pollos
Biscuit is a term applied to a stage in the production of pottery or porcelain after it has been fired once and not glazed. It is specifically applied to porcelain figures sold in an unglazed state, Characterized by their matte, porous surface. They were made from the mid -18th century by Continental factories and in England by Derby from 1773.
