Transparent Watercolor

Modern moist watercolor paints are sold in paste form in tubes and also in a stiffer, more solid form in pans. They are of equal value, tubes being more popular than pans because of convenience in handling. Originally, watercolors were put up in hard, dry cake form, but for the past hundred years or so the popularity of these has steadily declined in favor of the moist colors. [p. 148]

The Mechanics of Watercolor - Watercolor paints are made by grinding pigments very fine in a gum-arabic binding medium, together with certain necessary modifying ingredients. These ingredients usually are: (1) glycerin and honey [or sugar syrup], which are plasticizers added in order to keep the colors moist and [p. 150] to improve their working properties; (2) a preservative to keep them from becoming moldy; and (3) a wetting agent such as oxgall or a synthetic one to make them take well and spread uniformly on the paper. The proportion of binder and pigment is very carefully balanced in order to give the paints exactly the correct properties. The tiny grains of pigment become enmeshed in the relatively coarse fibers of the paper, and this action is of much importance in holding the color to the paper, as is the adhesive action of the gum binder. Watercolor painting consists therefore of a very thin layer of pigment particles held just sufficiently to be a permanent coating; it is not a real paint film like the layer of gouache and therefore is not subject to some of oil paint's defects, such as cracking, peeling, or blistering.

A careful balance of the modifying ingredients in watercolor paints is necessary to give the correct working properties and to insure the proper balance of solubility; that is, the dried layer of a good watercolor paint is sufficiently resistant so that it is possible to apply subsequent brushstrokes without picking it up entirely. On the other hand, the paint will not be so insoluble that it cannot be softened or run into when the painter so desires.

Transparent watercolors are quite difficult to make successfully. Hand painters seldom attempt to make their own except in unusual circumstances. The best watercolors of the shops leave little to be desired; their universal popularity has led to widespread availability and the development of a high degree of quality. [p. 151]

Status of Watercolor Paintings - It may be noted that watercolor and gouache are sometimes considered minor techniques when compared with oil painting. This is principally because they are used to instruct beginners and children, or because they are popular for use in making sketches and rough notes from which to paint complete pictures in oil. Actually, watercolor painting is [p. 158] as difficult to master as any other technique. Although its effects are more limited than those of oil, it has a distinct appeal of its own, and the process is sufficiently flexible and adaptable to a wide enough range of effects so that it qualifies as a true fine-arts medium. It occupies a serious and important place in present-day easel painting. [pp. 158-159]

[Mayer, Ralph. The Painter's Craft. An Introduction to Artist's Methods and Materials. Revised and updated by Steven Sheehan, Director of the Ralph Mayer Center, Yale University School of Art. New York: Penquin Group. 1948. 1991.]