GROUNDS From the beginning of the earliest history of the creative arts, grounds were used in the preparation of the creative process. A ground is a first coat of paint or other preparation applied to the surface to be painted. It is designed to protect that support from dampness and atmospheric pollution as well as make a suitable surface which holds the paint. The ground gives the desired qualities of color, smoothness, rough texture, absorbency, or repellent base. The four types of commonly used grounds are oil, gesso, emulsion, and acrylic. Oil -- made by grinding pigment, then mixing with oil. Usually linseed oil or walnut oil. Gesso -- made of ground gypsum or chalk mixed with water, glue, or gelatin (which hardens as it cools) to provide a dense, brilliantly white absorbent surface for an assortment of paints. It is applied to the support's surface in several coats. The first coarse undercoat is called "gesso grasso": the final fine surface coat is known as "gesso sotile." Allowed to harden thoroughly, it is then lightly sanded. The result is surface as smooth as an egg shell. It accepts paint readily, but has enough texture to act as a slight brake, which helps the artist control the brush stroke. Emulsion -- a painting medium containing materials which will not mix (such as oil and water or water and resin), unless combined by an emulsion agent. Agents can be natural (egg yolk or milk of figs), artificial (gums or varnishes), or soponified (fatty oils or wax). Tempera is an example of an emulsion. The egg tempera is equal parts powdered pigment, egg yolk and water. Egg is the perfect binder when used in the proper amounts. Tempera secures the adhesion of the paint to the surface. Tempera has the longest use in the ancient arts. Many of the early arts could not be chemically tested successfully, so the grounds remain unknown. Acrylic -- a synthetic paint based on acrylic polymer resin. When dry it is water resistant, flexible, stable, non-fading, and non-yellowing. It can be mixed with linseed oil, water, and other media. It can be used for all techniques and for washes used in watercolors. It has great adhesion and remarkable durability. Despite these qualities, it is disliked by many artists because it dries too fast. To learn more about the vast use of ground in various art forms, I recommend the following resources available in the library of the Mint Museum: LOOKING AT ART Adelhird M. Gualt 1983 ILLUSTRATED DICTIONARY OF ART TERMS Kimberly Reynolds/Richard Seddon 1981 SURFACES IN CREATIVE DRAWING Ernest Rottger/Dieter Klante, Friedrich Salzmann 1970 VASARI ON TECHNIQUES Giorgio Vasari 1511-1575 METROPOLITAN SEMINARS IN ART John Canady Portfolio #9 Elaine D. Gmerek February, 2003 .