Ceramics have been used from prehistoric times to modern times, and glazing has greatly improved their durability, hygiene, electrical conductivity, and aesthetic value. Glazing is an important technique for smoothing the surface of ceramics, making them impermeable to water and electricity, and giving them a variety of colors to increase their practical and aesthetic value.
One of the most common objects we use in our daily lives is ceramics. It comes in many different forms, from the dishes we use in the kitchen to the toilets, sinks, and tiles we use in the bathroom. It’s also widely used for crafts and decorations, and has become an important material for interiors and art. This gives you an idea of how widespread ceramics are. But it’s not just a modern invention, it’s an important tool that’s been evolving since the time humans started using tools. Pottery has grown alongside the development of human culture and has undergone many changes along the way.
The history of ceramics dates back to prehistoric times. Neolithic ceramics, represented by comb-patterned earthenware, show that humans at that time began to make their own tools for living in dwellings. Pottery was often used for storing water, food, and ceremonial purposes. Later, in the Bronze and Iron Ages, the technological development of ceramics accelerated dramatically, and by the time we reach the modern era, it has become as important for its practical as it is for its artistic qualities. This long history of ceramics hasn’t just remained in the past; it has expanded its role and continues to be used in our lives today.
So what is it about ceramics that has allowed it to be so widely used for so long? For starters, it’s the ease of availability of the material. Soils like clay were a natural resource that was readily available to humans as they settled down. But a bigger reason is the many benefits of glazing pottery. Glazing was an important technique that increased the durability, functionality, and aesthetic value of ceramics, allowing them to remain with humans for thousands of years.
The first advantage of glazing ceramics is that it provides a smooth surface. The smooth surface of ceramics made it easier to clean, which played a big role in its positioning as a hygienic vessel and sanitary ware. If you look at prehistoric combed earthenware, you can easily see that it has a rough surface. This is because the earliest pottery was made using a simple process of ‘molding clay – drying – firing’. However, when the glaze is applied and then heated once more at a high temperature of over 1200 degrees Celsius, the silica (SiO₂) and alumina (Al₂O₃) in the glaze undergo a chemical reaction to form a glassy substance. This glassy substance sticks to the surface of the porcelain, giving it a smooth texture. This smooth surface is not only easy to clean, but also hygienic as it holds less dirt, which is one of the main reasons why porcelain has become such an important part of modern life, especially as bowls and tiles.
The second advantage is that porcelain doesn’t let water through. If it absorbed water or leaked, it wouldn’t be able to be used as a sanitary ware or bowl. Unglazed ceramics are prone to leakage because the clay particles are not dense enough to hold water. However, glazing covers the surface of the pottery with a glassy substance that eliminates the gaps that allow water to pass through, making it perfect for holding and using water. This characteristic allowed it to be used not only for sanitary ware, such as toilets and basins, but also for various vessels for holding water.
The third characteristic of pottery is that it is glazed, which makes it very electrically conductive. If the electrical conductivity of porcelain is high, it can be fatal in the event of an electrical leakage in a space surrounded by tiles or sanitary ware, such as a bathroom. However, thanks to the glassy substance created during the glazing process, porcelain is virtually impervious to electricity and does not absorb moisture, making it a safe material to use. This is one of the reasons why porcelain is not just used for bowls and tiles, but has become an important material for many different industries.
Another advantage is that glazes play an important role in determining the color of ceramics. In general, the color of ceramics depends on the metallic components in the glaze. For example, celadon from the Goryeo Dynasty uses a glaze that contains iron oxide (Fe₂O₃), which gives it its jade color through a special step called “reduction firing” during the firing process. This process removes the oxygen from the kiln, which removes the oxygen from the iron oxide, leaving only Fe in the pottery, giving it a beautiful blue-purple color. White porcelain from the Joseon Dynasty is white because it uses white clay and a glaze that does not contain metal ions, while jinsa from the late Joseon Dynasty is red because it contains copper (CuO) in the glaze. In modern times, cobalt oxide (Co₂O₃) can be added to the glaze to create blue, chromium oxide (Cr₂O₃) to create green, and a mixture of chromium and lead to create yellow. These different colors play an important role in the artistic and decorative uses of ceramics.
In this way, glazing not only strengthens the physical properties of ceramics, but also enhances their aesthetic value. This has made ceramics more than just a utilitarian tool, but also a work of art, and its importance has grown. However, the development of ceramics will not stop here. Today, with the advances in science and technology, glazing techniques are constantly evolving. Lighter glazes, more durable glazes, and self-cleaning glazes will make ceramics more versatile in the future. In particular, increasing ease of use through lightweighting could be an important technological advancement to keep up with modern society.
In conclusion, ceramics have been an important part of human life for a long time, and glazing has enhanced its functional and aesthetic value. These developments will continue, and ceramics will continue to be used for a variety of purposes well into the future.
