Ceramics is one of the oldest forms of art that humans have engaged in, with records of pottery making that is was over twenty thousand years old. For the centuries, pottery artists have worked with different materials known as clay which is best suited for particular uses. It is important to note that the main categories of pottery clay are three and these include earthenware, stoneware and porcelain. Each of them has its specific characteristics for which potters have to choose the clay to use.
Earthenware
Earthenware is a non-glossy, porous kind of clay, which can be red or brown in color after firing. The clay contains iron and other mineral particles that can strengthen earthenware so that it can be fired at high temperatures, up to around 2,200°F (1,200°C). When used at lower temperatures, earthenware still allow the passage of liquids into the material thus making it easily absorbent. Because of its porous nature, it is not ideal to use in any vessels that are designed to hold fluids in the long-run.
Ceramic clays used in the preparation of earthenware are ideal since they are easy to work with and fairly pliable. This is because they can be easily pushed, pulled, and shaped to desired forms, particularly when working on earthenware. Pottery was one of the earliest art forms and a craft practiced by early societies and cultures in the ancient world. It is important to note that natural earthenware clay is not very plastic in nature, that is, it cannot be rolled easily into smooth, even shapes. In order to have a workable and strong clay to model on, potters mix the earthenware clay with other materials which are non-clay known as tempers. Some of the typical earthenware tempers are fine sand, pebbles or potsherds which are fragments of fired and ground ceramics.
Hence, due to the fact that it is cheap to manufacture, a larger portion of the pottery today is made from earthenware. Some of the things that are usually made from this material are flower pots, tiles, cooking pots and statues among others. Also, through the process of capillary action, earthenware materials are best suited in making candles and oil lamps due to its porous nature.
Stoneware
Compared with earthenware clay, stoneware clay is denser and less permeable, and it incorporates minerals that allow firing at between 2,200 and 2,600°F (1,200 and 1,400°C). The heat makes the clay partially vitrified and less porous, and thus gives better cover to prevent the liquids from penetrating the material.
Stoneware clay is excellent for the production of closed products because it is very fine and porous and when fired at a higher temperature, it becomes almost non-porous. I received several compliments on its durability against scratching and chipping and against wear and tear. Some these attributes make stoneware ideal for kitchenware items such as plates, bowls and mugs. Stoneware also has different colors, such as brown, grey and white. This way, artisans can create stoneware in natural color and, if the client wants it, they can paint it in bright colors using glazes.
This is a high-firing process which makes the stoneware very strong but brittle and capable of cracking or breaking at high variation in temperatures. To avoid development of cracks, potters use bisque stage to preheat the stoneware clay pieces in the kiln. The closer packing of molecules also results in fewer impurities being burned off during firing, which lowers the chances of explosion contained gases.
Porcelain
Porcelain can be considered as the finest group of pottery clays that offer thin-bodied ceramic ware after firing that is either white or light in colour. Kaolin clay is dominant in its composition and renders a plastic, fine-grained product one that is useful when crafting on the wheel. The workability of porcelain is such that it can take detailed and fine forms due to the presence of water.
Fired in a temperature range of 2,200°F and 2,500°F (1200°C to 1400°C), porcelain is most non-porous and most highly vitrified ceramic material. The tightly packed glass system results in a hard and rigid material compared to earthenware or stoneware ceramics. It also increases the ability of porcelain to allow light through thin wall thicknesses, making it the ideal material.
One of the key considerations when working with porcelain is technical proficiency in preparing the material and firing it. Excess moisture impacts the appearance and shape of the items; they become misshapen or develop cracks. Lack of heat means there is no possibility of vitrification which helps to close the pores. In this case, successful firing is the attainment of a delicate porcelain that can produce bell-like sound when rang.
Due to its low perviousness porcelain is used for sculpture and ornamental as well as tableware products. Refractory hard paste porcelain which is not thermal shocked made it possible to new porcelain articles such as vases and tea sets. More expensive than any other material, porcelain remains a luxury that keeps many people, especially those of low stature, away from it.
Conclusion
Now, let me explain to you that earthenware, stoneware and porcelain are all sorts of pottery but they are totally different from each other. Earthenware increases accessibility due to its poor firing, and therefore, it is an entry level clay that may not need high technical skill. The practicality of stoneware in terms of hardness and the range of colors found in the given stoneware pieces align well with the use of artisan techniques. It is therefore not hard to see how porcelain, with its exceptional light transmission and delicate, often brittle structure, becomes objects of luxury and rarity. Over the course of centuries, pottery is chosen by the specific clay to meet the further vision of pottery maker as creative, skillful and functional.