The techniques and materials that are used for human self-expression are vast and diverse. While any number of different materials and manipulations have been classified as “art” at one time or another, there are certain techniques that are most commonly associated with art. Primary among these are painting and sculpture. Within these techniques, there is a large array of materials that are commonly used.
The discipline of painting usually utilizes two factors: the ground and the paint. The ground is the surface that supports the paint, and may be made of masonite, wood, paper or cardboard, but is most frequently made of canvas. Paints include oil, watercolor, guache (an egg-based pigment) and encaustic (wax mixed with color). In some paintings, these techniques are used together. For example, oil and encaustic can frequently be found mixed in the same work. Different types of paint tend to be preferred with different grounds. Watercolor is more frequently done on paper, due to its absorbent qualities, while oil painting is more frequently done on canvas, due to its strength and ability to support larger works without sagging or tearing.
Sculpture is any artwork that exists in three dimensions, and can be constructed of virtually any material. Common materials used in traditional sculpture include marble, plaster, clay, steel, bronze, soapstone and wood. Some sculptures are created by carving away to reveal a work, as is done with stone and wood. Others are poured into a mold and allowed to harden, as is the case with bronze. Still others are built up from independent parts, as with welded steel sculpture. Three-dimensional work often incorporates objects from outside of the discipline of art, and the line between “art” and “the real world” can be blurred in some works, as is the case with art furniture, which exists both as artistic expression and as practical furnishing.
Mixed media work really has few rules. While it can incorporate traditional materials such as oil paint, wood or marble, mixed media art can also be made of electrical components, grass, piles of old books, broken bricks or garbage. In addition, mixed media work can blur the line between painting and sculpture, either by building out a painting until it it unclear whether it is a painting or a sculpture, or by incorporating painting into a work that began as a three-dimensional work.