Watercolor Painting: Technique and Materials
The term watercolor may be defined in three ways. It can refer to any type of painting that uses water-bound pigments; or to the pigments themselves; or it may be used to designate an art form, that is, watercolor painting as distinguished from oil painting.
The earliest method of painting in a water-bound medium is a fresco. Applied directly to damp, fresh (fresco) plaster, the color is totally absorbed, becoming an integral part of the plaster itself. This dries to a rock-hard amalgam, the result of a chemical action between the lime (calcium hydroxide) in the plaster and the carbon dioxide in the atmosphere. In a later method, pigmented color was bound with egg, and the resulting emulsion, known as tempera, could then be diluted with water. Gouache, an opaque form of watercolor used with great effect by Chinese artists, is achieved by mixing white with pigmented color.
As an art form, "true" or "pure" watercolor painting consists of glazing transparent colors, applied in delicate washes, one upon the other, allowing the paper to act as an illuminating agent. Considerable luminosity and brilliance is created by the contrast between the reflective luster of the raised surfaces of a granular paper and the depth and richness of the heavily loaded color in the hollows. But although watercolor is transparent, successive washes cause the interaction of absorption and reflection to become more complex, resulting in a loss of luminosity and freshness and giving rise to a "muddy" quality. The maxim "Never lose your paper" thus remains as true today as when it was first coined.
A careful selection of paper has always been considered of paramount importance, and watercolorists each have their favorite one. Some prefer a heavy, thick paper; others, a light, thin variety. These range in weight from 72 pounds (32.4 kg) per ream, to 400 pounds (180 kg) for pasteless boards. Watercolor paper is available with three types of surface: smooth, or "hot-pressed"; with a medium grain, or "not" surface; and a "rough" surface, which, as its name implies, carries a heavy grain. The best quality watercolor papers are handmade from white linen rags. Although expensive, they withstand rough treatment, and color on them retains a fresh and lively character. Many of today's good quality mold-made papers are much cheaper, and although made by machine, offer an acceptable substitute for handmade papers. Not all watercolor papers are white. The 19th-century English watercolorists David Cox and Peter de Wint favored tinted, coarse-grained wrapping papers with a mottled surface, modern versions of which are still manufactured.
Brushes also play a major role in watercolor painting, and great attention is given to their preparation. The best and most costly brushes are made from pure red sable, taken from the tail hairs of the Siberian kolinsky, a type of mink. Although expensive, these soft yet springy brushes will last for many years if treated with care. Other brushes are made from the hair of camel, ox, badger, and squirrel and from nylon and other man-made fibers. The ideal brush should be of reasonable length—never short and stubby. It should be thick at the ferrule and should taper to a fine point. Yet some great watercolorists have seen fit to break this rule. Although both the broadest wash and the finest detail can be achieved with a single large sable, most watercolor artists use three or more different-sized brushes.
In the manufacture of watercolor paint, the finely ground pigment—fine enough to pass through a screen of 325 meshes to the square inch—is not simply mixed with water. A binding agent must be added to ensure that the paint adheres to the paper and remains stable, not flaking off when dry. In the past, when artists ground their own colors and prepared their own paints, all manner of binding agents were mixed with the pigments to provide a vehicle: flour, animal size, rice paste, casein of cheese, and other ingredients secret to a particular artist.
The most successful, however, were found to be a variety of gums: gum arabic, tragacanth, and fish glue, among others. Today, artists' colormen bind their pigments with gum arabic, counteracting brittleness by adding honey and sugar and keeping the paint moist with glycerin. Adding glycerin is doubly important in preparing the moist color packaged in tubes, the most efficient and economical way for the artist to use watercolor. Gum arabic is preferred as a binder, for although it readily dissolves in water, enough remains in the paint to act as a thin varnish, which gives the color additional luminosity. A quaint conceit of English watercolorists was to add alcohol, usually brandy or whiskey, to their paint water to accelerate drying.
The four or five simple colors at the disposal of the ancients has grown steadily over the centuries into a rich range of colors, and today the watercolor artist can choose from over 100 different ones, obtained from vegetable, mineral, and synthetic sources. This in itself can be a snare, for although only an approximate hue can be obtained by mixing pigmented primary colors (red, yellow, and blue), it is nevertheless advisable to restrict a palette to less rather than more colors.