Porcelain

Porcelain, invented during the Han dynasty (206 BC – 220 BC) at Ch’ang-nan, China, has been used throughout humankind’s history to create a variety of durable objects kown for their traslusent and lasting finish.

Porcelain vessels by Jeong Won Lee – 2013

image source : https://artaurea.com/profiles/lee-jeong-won-2/

Main categories:

hard paste

Made of quartz, kaolin and feldspar (a mineral comprising mostly alluminium silicate) in order to produce a porcelain of great hardness, translucency and strength;

SOFT paste

Made of kaolin, quartz, nepheline syenite or other feldespathic rocks. It’s generally fired at lower temperatures therfore these wares are less hard than hard-paste porcelains.

BONE CHINA

Made of bone ash, feldespar and kaolin. It’s the strongest amongst all types of ceramics and it’s known for its whiteness.

 

Translucency and whiteness in porcelain

image source : https://artaurea.com/profiles/lee-jeong-won-2/

Production process:

Crushing and mixing

At the beginning of the production process, a combination of minerals is grinded using jaw crushers or mills. To create different types of porcelain, craftspeople combine raw materials in varying proportions in order to obtain the desired colours, thermal qualities and finish specifications.

After a cleaning process to remove improperly sized materials, the powdered minerals are mixed with water to make a wet paste called slip, which also pressed through a series of screens to further filter the paste.

Forming the body

Porcelain objects can be made using all the shaping techniques used for pottery. Slipcasting has been the most common commercial method in recent times: plaster moulds are filled with fresh slip to make sure the pores of the mould can absorb as much water as possible, leaving a thin layer of harden slip when the moulds are emptied.

Once the slip has completely air dried, the moulds can be peeled off the porcelain piece, which is hard enough to be handled without losing its shape, but its also soft enough to be modified.

Slipcasting process

image source : https://www.zanichelli.it/ricerca/prodotti/materiali-per-il-design-introduzione-ai-materiali-e-alle-loro-propriet

Firing and Glazing

After being formed, porcelain often receives underglaze decoration using pigments tor overglaze enamels, allowing a wider range of colours.Like many earlier wares, modern porcelains are then biscuit-

Ceramist firing porcelain dishes

fired at around 1,000 °C (1,830 °F) to vaporize volatile contaminants and minimize shrinkage during the next step of firing.

 

After being coated with glaze, the porcelain pieces are sent back for a second firing at a temperature of about 1,300 °C (2,370 °F) or more in a kiln, to permanently set their shapes and vitrify the the glaze.

image source : https://www.stocksy.com/2064698/ceramist-firing-porcelain-dishes

When was porcelain discovered?

Hard-paste porcelain originated in China during the T’ang dynasty (618-907 A.D.). By the time of the Ming dynasty (1368–1644 AD), porcelain wares such as the coveted “blue-and-white” ware, were being exported to other areas of Asia, Africa and Europe via the Silk Road. The European  imitation of Chinese artistic traditions led chinoiserie to enter European homes and expositions in the 17th century: its popularity peaked around the middle of the 18th century when it was associated with the rococo style.

What are the characteristics that make porcelain popular to this day?

– Even if the vitreous and translucent exterior makes it look delicate, porcelain is in fact the hardest ceramic clay ever used;

– Porcelain combines glass’s low porosity with clay’s ability to retain its shape when heated, making it both easy to form and ideal for domestic use;

– It’s used in electrical isolators and other industrial or medical applications thanks to its isolating properties;

– Porcelain polish has higher scratch resistance than paint, which is why it’s used from architectural applications (subway walls, school marker boards and signage) to home appliances and fixtures (barbecues, ovens, fireplaces, etc…);

– Porcelain coatings are used in applications where a bonded surface is required because of its higher temperature resistance and better tolerance to corrosion and staining.

Contemporary porcelain works

Vertebra – Stackable candleholder of enameled porcelain by Celia Nkala (2011)

image source : http://www.flodeau.com/2011/10/perception-park-bougeoirs-vertebre/#.UtKUimTuL2A

Porcelain boxes designed to look like they’re melting by Koji Shiraya (2010)

image source : http://kojishiraya.com/boxes+.html  

Foreigners (Mum beads) by Claudia Fontes (2016)

Flaxseed paper and porcelain sculpture

image source : https://www.artsy.net/artwork/claudia-fontes-foreigners-mum-beads


info source : http://www.madehow.com/Volume-1/Porcelain.html

https://www.britannica.com/art/porcelain

https://en.wikipedia.org/wiki/Porcelain