What Are Ceramic Pigments?

Colors

• According to "Ceramic Arts Daily," ceramic artists can make use of 44 different pigments, mixing them in a variety of ways to create a vast range of colors. Many of these colors gain in impact when you apply a transparent gloss over them. Some color combinations that might seem intuitive, however, pose challenges with ceramic pigments due to the way the various metallic oxides and other ingredients tend to react with one another. You cannot use black mix with white to obtain gray, for example, because oxides of several colors go into the creation of the black pigment and the dominant color in the mix will stand out instead of leaving you with a neutral gray.

Materials

• Ceramic pigments generally consist of some combination of salts, metallic oxides, alumina, silica and natural clays. These different materials each convey different colors to the final pigment. A combination of zinc, chromite, cobalt and alumina, for instance, produces a blue-green pigment, with the ratio of chrome to cobalt allowing for a bluer or greener result. These mixtures exhibit more stability than oxides, natural coloring agents that can react with one another or with the heat of the kiln to spoil the intended result. An alcohol base serves as a solvent to keep the pigments from oxidizing.

Application

• Netzsch Grinding & Dispersing refers to the three primary methods of applying ceramic pigment as underglaze, in-glaze and on-glaze. You can apply pigments to a ceramic object by mixing them into the clay itself, by adding them to the glaze or by painting them onto the surface. To mix the pigment into the clay, add it to the clay and water mixture at a concentration of 10 to 15 percent. Mixing the pigment with a ground-glass substance called frit before painting it onto the object's surface will help keep the colors from shifting during glazing and firing.

Considerations

• Before you try to use ceramic pigments, you should read the labels on the packaging to make sure you understand any temperature restrictions or other potential concerns involved in such use. Some pigments contain toxic substances, making them unsafe for use in eating or drinking vessels unless covered with a non-toxic glaze. Testing the pigments out with the glaze, clay and frit you intend to use will help ensure that you get the results you want.