What is glaze? A thorough explanation of its meaning and appeal

Definition and role of glaze

Glaze is a glassy coating material applied to the surface of ceramics.

Firing melts the glaze, giving the ceramic a beautiful luster and color, as well as providing protection and waterproofing. Glaze is an important element in combining aesthetic beauty with practicality. Glaze has three main roles:

1. Decorative effect: Glazes give ceramics beautiful luster and color, expanding the range of design possibilities. There are various types of glazes, such as transparent glazes and colored glazes, which give an attractive finish to the work.

2. Protective effect: Glaze protects the surface of ceramics and increases their durability, which makes the ceramics more resistant to scratches and stains and can be used for a long time.

3. Waterproof effect: The glaze makes the ceramics waterproof and less likely to absorb moisture. It is hygienic and can be used safely as a container for food and beverages.

Types of Glaze

There are many different types of glazes, but we will introduce four of the most common ones.

Transparent Glaze

As the name suggests, transparent glaze is a transparent glaze. It has a glossy texture and adds luster while preserving the color and pattern of the base material. It is used on many tableware and decorative items and is the most standard glaze. In Japan, Nippon Toryosha's No. 3 glaze is often used. It is also called lime glaze or white glaze.

Matte Glaze

Matte glaze is a glaze with no sheen. It has a subdued texture and gives a chic, modern impression. Matte glaze is often used for tableware and interior items with a contemporary design.

Milky Glaze

Milky glaze is a glaze that has a milky appearance. It completely covers the base material, creating a soft white or pale color. Milky glaze has a clean, soft impression.

Crystalline Glaze

Crystalline glaze is a special glaze in which crystals form within the glaze during firing. The unique patterns created by the crystals are beautiful and can be seen in works of art and high-end ceramics.

Glaze ingredients and manufacturing method

Glaze ingredients

Glaze has three basic components: silica, alumina, and a flux to dissolve these two.

-Silica: The raw material for glass, obtained from silica and feldspar.

-Alumina: It is obtained from a clay called kaolin and from alumina hydroxide.

-Fusing agents: Obtained from wood ash, limestone, barium carbonate, strontium carbonate, and lithium carbonate.

These three elements are used to adjust the texture and create glossy transparent glazes, matte glazes, opaque glazes, and more.
Metal oxides and other additives are added to give it more color.

Glaze manufacturing method

The mixed glaze ingredients are placed in a machine called a pot mill and ground together with water and alumina balls. The grinding time is adjusted depending on the particle size of the ingredients and how easy they are to grind.

If you are only making a small amount, such as creating a test piece, you can add water to a mortar and pestle and crush it by hand.

How to apply glaze

There are three main methods for applying glaze to ceramics.

1. Immersion: This is the most common method of immersing the pottery in the glaze. It is widely used because it allows for an even application of the glaze.

2. Spraying: This method involves spraying the glaze with a spray gun. This allows for fine control and is suitable for delicate pieces. It can create gradations and complex patterns.

3. Brush painting: This is a method of applying glaze using a brush. Since it is done by hand, each piece has a unique texture. It is often used in traditional crafts and art works.

The development of glazes in Japan

New pottery-making techniques introduced from the Korean Peninsula gave rise to sueki ware, which was fired using high-temperature reduction flames, in the 5th century, and early glazes also appeared.
During the Asuka and Nara periods (538-794), influenced by low-fired lead-glazed pottery introduced from China and the Korean peninsula, vibrant green-glazed pottery and Nara sansai began to be produced.

Furthermore, in the 9th century during the Heian period (794-1185), the Sanage kiln in Aichi Prefecture began producing ash-glazed pottery fired at high temperatures using artificial glazes.

During the Kamakura period (1185-1333), major kilns throughout Japan, known as the Six Ancient Kilns, developed and each refined its own unique glazing techniques. The techniques of the Seto kilns in particular were innovative, developing a wide variety of glazes and laying the foundations for Japan's ceramics industry.

From the Muromachi period (1336-1573) to the Azuchi-Momoyama period (1573-1603), tea pottery developed along with the spread of the tea ceremony, and pottery with unique glazing techniques such as Raku ware and Oribe ware were born. The black glaze of Raku ware and the green glaze of Oribe ware are highly regarded as tea utensils, and this tradition is still carried on today.

Up until this point, glazed ceramics were limited to luxury items.
However, when production of Arita ware began in the 1610s, glazed ceramics became common in Japan due to the popularity of Arita ware.

The cultural significance of glazes

Glazes are not merely decorative techniques, but are important elements that reflect the culture and values ​​of each era and region. Glazes allow us to feel the transitions of history and culture, such as ancient Egyptian faience, the three-colored glazes of the Tang Dynasty, and the green glazes of the Heian Period. The use of glazes in the tea ceremony and in artworks symbolizes their aesthetic value and philosophy, and glazes continue to have a profound impact on people's minds.

On the other hand, there are many glazes from the past, such as the National Treasure "Yohen Tenmoku (Inaba Tenmoku)", whose details have yet to be fully elucidated. These unexplained glazes are also fascinating research subjects for modern potters.

As you can see, the history and culture of glazes is extremely deep, and they have been loved and passed down by many people. Even today, their appeal has not diminished, and they continue to develop in new ways.

Points to note about glazes

There are a few things to keep in mind when using glazes. First, glazes may contain harmful substances such as lead. It is important to use glazes that have been confirmed as safe, especially when used on tableware. Also, firing glazes requires high temperatures and requires specialized kilns. If you are a beginner, we recommend that you work under the guidance of an expert.

Please rest assured that all glazes sold by Shinkai Shoten do not contain lead unless otherwise specified.

summary

Glazes are glassy coating materials that give luster and color to ceramics. There are many different types and application methods, and they have been used in many cultures since ancient times. Even today, they are used in a wide range of fields due to their beauty and functionality. By experiencing the world of glazes, you will be able to rediscover the depth and charm of ceramics.

Shinkai Shoten has published a book called " Introduction to Glaze Making: Mixing Examples Taught by a Long-Established Arita-Yaki Materials Store ." This book features approximately 1,600 test pieces in full color. In addition, it publishes 250 examples of glaze mixing combining 10 types of basic glazes and 6 types of colorants, and also introduces examples of firing using three types of clay (porcelain clay, white clay, and red clay) in oxidation firing and reduction firing. If you are interested, why not give it a try and make your own original piece?