Both seasoned potters and those just beginning to explore clay as an artistic medium enjoy its fluidity and malleability. After shaping a form, ceramic artists often add color and designs to enhance the item’s look and feel. The type of decoration and colorant contributes to the finished look. How and when decorative elements are applied also affect the look. Decorative finishes can be applied on unfired clay, called greenware, on clay that has been fired once, called bisqueware, or on pieces that have been fired and glazed. There are many pottery decorating techniques that are easy for beginners to use to create unique pieces of ceramic art, including slips, stains, glazes, textures and paint.
Glazes are commonly used in pottery and serve several functions. They add to the aesthetics of a piece, create a waterproof barrier and enhance the surface strength. In essence, a glaze forms a glassy coating that seals the clay and protects it from stains and damage from corrosive substances. Applying paint, colorants and other decorative elements under the glaze seals them in, ensuring that they hold up to repeated washing and use. Applying paint over the glaze works well on decorative pieces. However, the paint will not hold up for items that are frequently washed or otherwise used. In addition, paint applied over a glaze may not stick. For this reason, most ceramics are decorated before glazing.
Underglazes are applied onto the clay surface before glazing. Potters use underglazes to create designs and patterns as well as to add color and texture. Slips, stains and commercially manufactured underglazes are popular types of underglazing. Specialty items, including underglaze pencils, crayons and pens, add exciting graphic possibilities. Experienced potters often make their own underglazes, creating unique colors, patterns and designs that become known as a ceramic artist’s signature style.
So why Is underglazing one of the best ceramic painting techniques for beginners?
Underglazing offers an almost infinite number of ways to decorate ceramics. Layering several types of underglazing creates depth and interest. Ceramic artists can choose simple motifs, complex patterns, single colors or a rainbow of colors to create one-of-a-kind pieces. A great advantage is that, when applied to bisque-fired surfaces, underglazing can be wiped or scraped off if a mistake is made. This is ideal for beginners as they explore different ceramic painting techniques. As beginners become more adept at using decorative media, firing between multiple coatings of underglazing sets each layer of design, building an interesting canvas that shines through the final glaze.
Types of Underglazes
The term underglaze applies to a broad spectrum of ceramic decorating media, including slips and stains as well as pencils, crayons and liquid coloring designed for use on unglazed clays. They are made from minerals and materials that bond with clay. Glazes are then applied over these decorative elements.
Slips, also called engobes, have been used for ceramic decoration since people began working with clay. Basically a thick slurry of clay and water, slips are applied to the surface of wet or leather-hard clay. Because they are made of clay and water, they easily bond to the surface and become part of the clay body. Slips can be made from the same clay as the ceramic piece, a different clay for a contrast in color or mixed with colorants. Slips add texture, sheen and color, depending on how they are applied. They are also used to join two pieces of pottery together.
Stains are made from colored pigments that are usually combined with metallic oxides and salts suspended in water. They can be added to clays, slips and glazes or applied as paint directly onto clay. The range of colors made commercially and the ability to mix pigments to create unique colors results in an expanded palette that covers the full color spectrum. Commercial pigments are stable and easy to use. They can be brushed or painted on, used as a wash or applied in thin layers. Adding oxides and frits allows the pigment to bond with the clay while keeping its color during firing.
Other types of underglazes, such as watercolors, pencils, crayons and colored chalks, are available commercially. They are made to bond to the clay surface and retain their color after firing. Most can be applied to greenware and bisqueware, providing an almost limitless array of decorative options.
Painting With Underglazes
Underglazes can be applied using a variety of techniques and tools, such as brushes, sponges, droppers, stencils and styluses. Some potters apply underglaze colorants straight from the bottle using the tip as an applicator. Others spray, pour or dip the medium onto the clay’s surface. Underglazes can be spread over clay in several ways to create an effect that enhances the artist’s design, such as marbling, feathering, splattering, texturing and painting. If you do not like the result, simply wipe it off when it is still in a liquid state and try something different.
Colored slips can be applied using several simple techniques. Marbling creates a flowing, abstract look. Drop small amounts of colored slip onto the clay with a pipette, and spread the mixture with a sponge, paintbrush, cloth or other applicator. Thicker slips add texture, creating images that rise up out of the clay background. Beginners can experiment with different types of applicators to see the effect that each makes on clay. To create a traditional painting on pottery, apply different colors of slip with a brush, just as an artist applies paint on a canvas.
The terra sigillata technique uses slips to create a classic, highly glossy surface. Potters in the Southwest pueblos commonly use this technique. A fine slip is applied over the entire surface of the piece and then polished or burnished before firing. Polishing aligns the platelets in the clay to make a smooth, reflective surface. After firing, many potters polish or burnish the surface again to heighten the effect.
Underglaze stains and pigments can be applied over unfired glazes, a technique used in making majolica ware that originated in the 15th century. With this technique, the glaze creates a glassy surface during firing, and the underglaze melts into the glaze below it. However, the type of glaze, chemical composition of the underglaze, type of clay and temperature of firing affect the outcome of the final product.
Underglaze chalks and crayons can be used just as they are or dissolved in water to create a liquid solution that can be sprayed, brushed or sponged onto the clay. Underglaze pencils come in a variety of colors and can be used for outlining, fine drawing and shading.
Liquid colorants work just like watercolors on a canvas. However, since clay is porous, liquids absorb easily into clay. Ceramic artists experiment with ways to apply washes to create lively, colorful designs. Techniques include wetting the clay before applying colorants to achieve a more even application. Other artists like the effect of blobs and smears that happen naturally with the medium. Exploring how colors absorb and spread lets potters experiment with ways to create unique designs.
Wax resist is another decorative technique that is fun for beginners. In this method, wax applied to the clay creates a barrier that cannot be penetrated by underglazes or glazes. After firing, the matte finish and natural color of the clay show through. Wax resist is ideal for stenciled designs and line drawings. It can also be applied over slips and other underglazes to add depth and texture.
Beginner potters learn through experimentation and trial and error how clays and topical applications work together to create unique, attractive ceramic art. Many materials designed for ceramic painting and decoration are available commercially, allowing beginners to explore different ways to create and apply color, texture and design. As potters gain experience, they find ceramic painting techniques that complement and enhance their designs. Applying underglazes on bisqueware presents the wonderful advantage of forgiveness inherent in the medium. If mistakes are made, most underglazes can be removed. In essence, the ceramic’s surface reverts to a blank slate that can be decorated again.