J's Online Drawing Lessons

Pigment

• Oil Painting Lessons

A leading manufacturer of artist's paint currently lists at least 108 different colors of oil paint. The pigments selected for these colors are uniform in particle size, compatible with oil binders, are reasonably resistant to atmospheric gases and light, and are for the most part permanent. These modern pigments are also relatively uniform in consistency, workability, and drying time from color to color. Even though some of the 108 colors are mixes of two or more pigments (a flesh color might be a mix of reds, yellows, and titanium white), this represents an incredibly varied and comprehensive palette for the contemporary painter.

Modern high-quality artist's paints are manufactured to such exacting standards that the contemporary artist need not be terribly concerned about using impermanent or unstable colors. In fact, few painters take much notice of the pigments used in their paint and rarely have to consider the compatibility of the colors that they are mixing together on the palette. It is tempting to believe that whatever use is made of the paint, the results will be faultless.

By comparison, the options available to artists of the fourteenth through seventeenth centuries, for example, were very limited. The pigments commonly used during this period of Western painting numbered about fifteen. The most common were three blues, azurite (copper carbonate), ultramarine blue (lazurite), and smalt (cobalt glass); and possibly four reds, red lead (lead tetroxide), vermilion (mercury sulfide), iron oxide red, and carmine lake (made from the dried bodies of the cochineal, a South American insect). For many painters not all of these pigments were available at all times, and some (ultramarine blue, for example, made from the semiprecious stone lapis lazuli) were so prohibitively expensive that they could be used only on paintings for which the painter had received a substantial advanced sum for materials.

Fig. 2.4. A modern commercial three-roll mill producing, in this case, permanent green oil paint (Courtesy, Daniel Smith Artists' Materials.)

There were other colors available, notably simple earth pigments— yellows and browns. Dyes of various kinds and minerals were continually being developed for other industries. These materials were often tested for use by painters, and in some cases the palette was expanded significantly by this experimentation. The more common result was that these pigments turned out to be incompatible with other tried and true materials. They proved to be unstable in some way, either by changing color, fading, cracking, or by altering the materials placed in contact with them.

Artists tend to be experimental by nature and are willing to try untested materials or procedures that suggest an improvement in the capacity of materials to project their ideas. Along with this air of curiosity there also exists a concern for permanence and general high quality. Although periodic experimentation has been the norm throughout history, most painters have had a rather conservative attitude about their choice of pigments. Powers of invention are focused on how to maximize through mixing the limitations of a small number of trusted colors.

What follows are descriptions of several types of paint and the methods of applying them. There are nearly as many variations of these methods and formulations of materials as there have been painters, but nearly all painters have based their approach on historical models that still define the art and craft of painting.

Fig. 2.5A,B,C. Diagram showing layers of plaster applied to a masonry substrate in the construction of a fresco painting. Each layer is kept damp until after the succeeding layer is applied, and the colors are applied to the final layer before it dries, or within about eight hours. As the composite of layers dries, some water migrates from the surface back through the surface layer or intonacco (A), and arriccio (B) toward the masonry wall (C) while the rest evaporates into the air at the surface. Carbon dioxide is drawn into the plaster, transforming the calcium hydroxide into calcium carbonate. During this process, platelets of calcium carbonate lock the particles of pigment into the surface of the plaster. This process acts as the equivalent of an organic binder found in more conventional paints. See Appendix J for an analysis of a cross section of the Detroit Industry frescos by Diego Rivera.