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Canton tea cup
Bone china Bone china is a kind of porcelain body originally developed in the UK in which calcined ox bone, bone ash, is a critical ingredient. It is distinguish by brilliant whiteness, translucency and strength. canton tea cup may be an example of this procedure. The first use of bone ash in ceramics is credited to Thomas Frye in in the late 1740s in which he used it to make a type of soft-paste porcelain. In Towards the end of the 18th century, Josiah Spode undertook further developments, and subsequently popularised it, by mixing it with kaolin, China stone and china clay to compete with the imported Oriental porcelain. The initial elementary recipe of three and a half parts china clay, four parts china stone, and six parts bone ash still remains the standard English body. Bone china production ordinarily involves a 2 stage firing where the initial "biscuit" is fired without a glaze at 1280°C (2336°F) giving a translucent product and then it is glaze, or glost, fired at a lower temperature less than 1080°C (1976°F). canton tea cup is probably produced using this method. Soft-paste porcelain Soft-paste porcelain is a kind of porcelain and consequently a ceramic material. Its origin dates from the first undertakings by European potters to clone Chinese porcelain by using mixtures of china clay and frit or ground-up glass; lime and soapstone were known to have also been used in some formulations. As these initial compounds suffered from high pyroplastic deformation, or slumping in the kiln at high temperature, it was uneconomical to manufacture them. Combinations were later produced based on feldspars, kaolin, nepheline syenite, quartz and other feldspathic rocks. These were technically superior and continue in production today. Hard-paste porcelain Hard-paste porcelain is a hard, dense ceramic that was initially manufactured from a mixture of the feldspathic rock petuntse and kaolin fired at very high temperature. It was first made in China in about the ninth century. The secret of its manufacture was unknown in Europe until 1709, when Böttger of Meissen, Germany discovered the formula. Regardless of attempts to keep it secret, the process spread to other German ceramic manufacturers and in time became well known throughout Europe. Hard-paste porcelain is known to be fired at a range of temperatures to create a myriad of different end results. Depending on the firing technique, hard-paste porcelain can be made to resemble stoneware or earthenware. But generally, it is not necessary to use hard-paste porcelain for these lower temperature ceramics. Hard-paste porcelain can be used to make porcelain bisque, a hard crystalline product fired at extremely high temperatures in a pressure controlled environment. This process makes a translucid bright white ceramic. Unlike other bisque ceramics, porcelain bisque is almost impermeable by water, making it unnecessary to glaze the body before painting. Manufacturers such as Precious Moments, Hummel and Lladro employ hard-paste porcelain simply for this reason, this could include canton tea cup.
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