Pottery is a craft involving shaping wet clays and firing them under heat to trigger a chemical transformation, hardening the clay. Both functional and decorative objects can be made this way and they are often decorated with colorful glazes, as well as ornamental designs stamped, pierced, or carved into the clay. This is one of the oldest art forms in human history, and people have been making and using clay objects for thousands of years, as evidenced by finds at archaeological sites.
The first step in pottery production requires obtaining clay. Early humans probably worked with readily available clays, learning about which were most useful through trial and error. Today, people can work with clays specifically blended and formulated for pottery, as well as harvesting their own. Clays are often heavily processed to remove impurities and given them a uniform, even texture, allowing people to make delicate crafts like porcelain.
The clay is worked to remove air bubbles to reduce the risk of explosions during firing, and then it can be shaped. Pottery shaping may be done by hand, with crafts like the pinch pot and coil pot being some of the earliest known examples. Potters also work on wheels to shape plates, vases, bowls, and other objects. Clay can be carved to make sculpture, pressed into molds, or run through a press to flatten it into sheets before cutting with dies to achieve desired shapes.
When pottery objects are first made, they are too wet for firing. This wetness can be an advantage, as people can allow the clay to partially dry before working it some more, smoothing out the edges, creating ornamental designs, and so forth. Once the clay has dried sufficiently, it can be fired at low heat to harden it, a process known as bisquing. Bisqued pottery can be treated with glazes to add color or waterproof the pieces before putting them through a second firing to melt the glaze and finish transforming the clay.
The earliest potters produced their pieces in wood fires, and some people continue to use this tradition, usually burying clay ware in pits and baking it slowly over the course of hours or days. These naturally finished potteries may not be glazed, instead allowing the clay to take on its own colors from the firing process. Modern kilns may be fired with electricity or gas and can reach very high temperatures, providing an opportunity to work with glazes that do not perform well at low heat. The diversity of pottery is considerable, ranging from delicate fine porcelains with a translucent appearance to chunky handformed stoneware with a heavy, clunky feel.