PORCELAIN

Porcelain is one of the most valued types of ceramics since ancient times.

We tell you about its exciting history, why it was so appreciated, the myths about its arrival in the West.

We review their types and differences. We will see the existing artistic porcelain possibilities.

CERAMICS AND PORCELAIN

Sometimes there is confusion as to what is one and what is the other, and the terms are used interchangeably, sometimes erroneously.

To define it in an initial and simple way, porcelain is a ceramic material obtained by firing certain clays rich in kaolinite at higher temperatures than those used in most types of ceramics, i.e. all porcelain is ceramic, but not the other way around.

What is porcelain and what is not:

The difference between ceramic and porcelain is that the latter requires certain characteristics to be considered as such:

Composition:

The average basic composition of porcelain is usually 50% kaolin and the other half quartz and feldspar (approx. 25% each). It will contain other materials in different proportions, which vary from one type to another.

Sometimes they can be part of the decoration, such as metal oxides in small quantities. En otros, forman una parte importante de su composición, como las cenizas de hueso, que pueden alcanzar más del 30% del total en el caso del tipo “Bone China”.

Let’s say that while the raw material for any ceramic will suffice to be clay, sand and other materials: in the case of porcelain it requires a more refined and pure clay in kaolinite, the key mineral of its composition, which must be present in large proportion.

Cooking:

Its firing temperature is higher than that of most ceramics, such as earthenware.

It is fired at more than 2700º F, sometimes reaching 3200º F or more, in porcelain that will be used in industrial applications and will have greater resistance to severe temperature and pressure conditions.

Firing is carried out in two or more phases: the first at a high temperature to obtain a moldable paste, which once cooled gives rise to a porous result. The second is a vitrification or glazing process where it acquires, in addition to its hardness, a low porosity, which gives it that impermeability and smooth texture. This is finally a porcelain that does not absorb water. After the whole baking process, depending on the thickness, we can obtain pieces of certain transparency.

ORIGIN

Porcelain was born in China, where it was called tzu. This name, in Mandarin (simplified) Chinese is currently spelled 瓷 (Cí).

However, the difference with the majority of many other languages is that this term in Chinese is common to refer to porcelain and earthenware.For this reason, confusion is generated both in the research on its origin and in the present time to discriminate between one and the other.

In ancient times there were different types and styles of very varied compositions, so it is difficult to know exactly when and where it was born.

There is some consensus that porcelain began to be produced with some regularity during the dynasty. Tang (which lasted from 618 to 907), a period of great splendor in the manufacture and export of ceramics (see Tang ceramics) however, there are studies that place it further back in time, from the 6th to the 7th century, during the dynasty Sui. Other historians still backdate his birth to a time from the 3rd century BC to the 3rd century AD.

ITS HISTORY IN EUROPE

When did you come for the first time:

It is known from the inventories of the Duke of Normandy that in 1363 the existence of porcelain pieces forming part of collections is already recorded. Another slightly later inventory that also included porcelain was that of Lorenzo de Medici in 1487.

Porcelain arrived in Europe through the silk route; it was a highly appreciated product and a very important emerging business for the time, so there was an enormous interest in it, not so much in its importation as in being able to find it. the coveted secret of its composition.

In the 17th century, the “Dutch East India Company” had the monopoly of its importation in Europe, as we were saying, it was an increasingly important business.

The best known in Europe is the one produced during the Ming dynasty from the 14th to the 17th century. This material, already known since ancient times by the Chinese people, once it arrived in Europe tried to be replicated with great effort.

Marco Polo and porcelain:

Well, the first thing is: Marco Polo did NOT import porcelain into Europe. It did not even directly divulge its secrets, nor its manufacture, nor its composition.

The story is as follows:

Marco Polo falls prisoner of the Genoese, in 1298 his cellmatea Pisan writer named Rustichello de Pisa transcribes what he said about a material used as an exchange or currency that consisted of pearly shells, the “pearly” porcelain material could have been confused with this currency. These writings are the ones that have come down to us.

The secret of its production: German porcelain.

The achievement of being able to replicate the pieces that arrived from China occurred at the beginning of the 18th century with the conjunction of two interesting characters of the time:

On the one hand, we have Johann Friedrich Böttger (Dresden, Germany, 1682-1719) whose fame at the time, curiously enough, was not for creating porcelain, but for having been able to create gold, fame, on the other hand, fostered by himself, since he claimed to have succeeded, by means of what was supposed to be the philosopher’s stone or the Magnum Opus of alchemy, in transmuting metals into the precious golden material.

This prompted both the Prussian King Frederick I and the Saxon King Augustus II to try to get their hands on his secret.

The latter manages to “hold” Böttger not very amicably, “persuading” him to make gold for his kingdom. Böttger all he could manage was a red earthenware. It must be said that as an alchemist, he was an expert for the time in the art of cooking, achieving high temperatures unattainable at that time. The king, however, put him to work with the second key figure of the time:

Ehrenfried Walther von Tschirnhausa German physicist, physician and mathematician, who had already achieved a “first porcelain” using mixtures of various silicates and earths. However, it was not up to the standards of the products imported from China. In reality, what he achieved was what today are called soft pastes, fired at a lower temperature than what is necessary for what is considered porcelain.

The following occurred, the previous knowledge in creating “soft pastes” of von Tschirnhaus, plus the addition of kaolin to the mixture (to the previous elements used as other feldspars, alabaster, etc.) and Böttger’s knowledge in the art of achieving high temperatures, namely reaching up to 2700º F, they materialize in the first European white porcelain in 1708.

This brings us to the first factory, which was located in Meissen (Saxony). The successive ones spread throughout Europe and with them what was initially a secret formula became popular. Today the term is mentioned as the first Meissen porcelain as the first in Europe.

You can see this amazing vídeo about the 300th anniversary of Meissen porcelain.

English porcelain:

In 1618 a factory was founded in Southwark, one of the first in England, known for its glazed pieces, polychromes, natural decorative motifs (including complex animal figures) and intended for various utilities.

Between 1743 and 1745 another of the most important factories was created in Chelsea, where at first German methods were used, taking Meissen porcelain as a guide, although later the model of Sèvres (France) was adopted. This factory was acquired by the owner of the one in Derby and for 15 years the two coexisted until the one in Chelsea ceased its activity and was closed and demolished.

Chelsea factory fountain (1749-1752). Nelson-Atkins Museum of Art.

Other well-known factories are the Nottingham Road factory, which was active until the middle of the 19th century, and the King Street factory, which was sold to the Derby factory in 1935.

Perhaps the best known is the Royal Crown Derby Porcelain Co. Ltd. (“royal” since this title was bestowed by Queen Victoria in 1890). With a long history as one of the best known, consolidated and long-lasting factories.

TYPES OF PORCELAIN

Depending on the types and stages of cooking, there will be one result or another, as well as the raw materials used.

Soft paste porcelain:

Also called bisque, biscuit porcelain, bisque porcelain or simply biscuit.

It does not have great hardness or resistance, it is easy to scratch, its cover is fragile and is more porous than the so-called hard porcelain.

A distinction is made between artificial soft clay porcelain, which includes French porcelains, and natural soft clay porcelain, which uses lime phosphate as a flux and has a color similar to ivory.

Firing at temperatures between 2000 °F and 2300 °F

Hard paste porcelain:

Its composition includes kaolin and other feldspathic materials, and it cooks at a higher temperature than the previous one, between 2300 °F and 2700 °F.

This hard porcelain is more resistant to shocks, more compact and less porous, which makes it more impermeable. When working with a relatively thin thickness, a nice translucent effect is achieved on the parts.

It is originally from China, probably appeared during the second century.

There is also talk of a material called hard earthenware, fired at about 2200º F. It is also called semi-porcelain, when in fact it is an imitation of earthenware.

Another possible classification, which we will not go into here, is according to their place of origin. Apart from the Chinese, those produced in Germany, such as Meissen (like its place of origin, which we have already mentioned), Nymphenburg and Berlin, are very famous.

Hand-painted porcelain bowl by Lucinda Clay

Bone china:

It is the so-called bone ash porcelain, being this material 30% of its composition. It is of British origin and began to be produced in the 18th century. Very white and more transparent, it is also very resistant and hard, which makes it highly valued.

What about “cold porcelain”?

Well, this is a term that is often heard a lot nowadays, although it is NOT porcelain as such, neither by the ingredients of which it is composed nor by the way in which it is worked, mainly because it is not baked, it is made to be able to dry in the air. It is a mass elaborated in a homemade way that usually includes vinyl glue, corn starch and other ingredients. It is a material that is very moldable and ductile, very used in handicrafts.

You may also be interested in these guides on materials other than porcelain:

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