Sunday, 2 August 2009
Porcelain or fine china is one of the earliest artworks introduced to the western world through the Silk Road. It is one of three types of pottery - the other two being earthenware and stoneware.
Porcelain is made by firing a type of clay known as kaolin, as well as other materials, in a kiln. Temperatures between 1,200°C and 1,400°C are required for this process. The toughness, strength, and translucence of porcelain arise mainly from the formation of glass and mullite within the fired porcelain.
Kaolinite is a type of clay which includes silicate, oxygen and alumina. Rocks that are rich in kaolinite are known as china clay or kaolin.
Porcelain, as we know it today, is believed to have originated in China, over 2000 years ago, in the late Eastern Han period. However, the earliest crude Chinese ceramic, made of kaolin, was found dating back to the Shang Dynasty (16th - 11th century BC). To read more on Chinese ceramic, check out this article on Wikipedia.
But most fascinatingly, porcelain, in its primitive clay form, is said to have been made by man some 27,000 to 31,000 years ago, dated with the discovery of the oldest piece of ceramic art sculpture in the world - The Venus of Dolní Vestonice, in the Czech Republic. She dates back to the Stone Age (see figure below).
Porcelain derives its present name from the Italian word ‘porcellana’ or cowrie shell, because of its resemblance to the translucent surface of the shell. Porcelain can informally be referred to as "china" in some English-speaking countries, as China (the country) was the birth place of porcelain making.
Porcelain is used to make table, kitchen, sanitary, and decorative wares such as objects of fine art and tiles. Its high resistance to the passage of electricity makes porcelain an excellent insulator. Dental porcelain is used to make false teeth, caps and crowns.
Porcelain can be divided into the three main categories: hard-paste, soft-paste and bone, depending on the composition of the paste (i.e. the material used to form the body of a porcelain object).
Hard-paste porcelain or ‘real’ porcelain (as this is the technique used by the Chinese porcelain makers) is made from a very pure mixture of kaolin and petuntse (also known as feldspar or China stone). Sometimes flint is added to the mixture.
The oldest Chinese dictionary, the Erya, defines porcelain as ‘fine, compact pottery’. The Chinese tradition recognizes two primary categories for its ceramics – high-fired and low-fired. Chinese ceramic are also classified as being either ‘northern’ or ‘southern’, depending on the source of the raw materials. If it is sourced from the Yellow River region (geographically placed in the north of China), it is ‘northern’; and it is categorized as ‘southern’ if the materials are from the surrounding Yangtze River area in southern China.
The downfall of hard porcelain is, despite its strength, it chips fairly easily and is tinged naturally with blue or grey (maybe this is the reason why most Chinese porcelain is painted blue?). It is fired at a much higher temperature than soft-paste porcelain and therefore is more difficult and expensive to produce.
The first English porcelain or china was the soft-paste china and was developed by Thomas Briand at a Chelsea factory in 1742. This was the first attempt by the English to emulate the hard-paste process perfected by the Chinese.
Soft paste porcelain contains kaolin, petuntse and 'frit' - a glassy substance that is a mixture of white sand, nitre, alum, salt and gypsum. Unfortunately, soft-paste porcelain is unable to hold liquids unless it is glazed. This however does not make the medium inferior but actually works very well for decorative art. When painted, the colours merge with the glaze to produce a wonderful silk-like effect that is very appealing to the eye and collectors.
In 1749, Thomas Frye, a painter, took out a patent on porcelain containing cattle bone ash (and yes, all fine bone china contains bone! Bet you did not know that…..hmmm…maybe this was one of the reasons why fine bone china did not take off in India!!!!). This was the first recorded reference to bone in porcelain making history, hence the term ‘bone china’. For whatever reason, when it was first tried, it was found that adding bone-ash to clay produced a white, strong, translucent porcelain. Bone china was developed as a substitute for hard-paste china.
In the late 18th century (around 1799), Josiah Spode II undertook further developments and subsequently popularized it, by mixing it with kaolin and china stone to compete with the fragile, imported Oriental porcelain. Bone china is extremely hard, intensely white and will allow light to pass through it. Josiah Spode II is unquestionably the most pre-eminent figure in bone china history.
Ironically, English bone china was intended to be a cheaper substitute for the hard-paste porcelain but by 1800, its quality had surpassed that of hard-paste and soft-paste china, due to its resistance to damage and its fine translucence. Ever since then, bone china has been synonymous with fine dining and artistic excellence.
For a list of English past and present china manufacturers, visit the La Galerie Celine Serrano, Paris website. The list is not exhaustive, but it provides a good source to start your ‘china’ research.