The practice of easel painting in oil paint on canvas has been universal since the seventeenth century; it did not arise as a sudden invention but was the result of a long development. Scholars have traced this development in considerable detail through the various schools of art, and the subject can be studied by reference to the books listed in the bibliography. There are several milestones or turning points in the history of European easel painting which can be noted briefly as follows:

The early tempera paintings, notably those of Italy were done on gessoed grounds on wood panels. Working under the patronage of the Church or the reigning families, the artists reflected the artistic tastes of their times. The results achieved were exactly what the painter desired; the rather limited effects and the rather intractable materials were manipulated by developing superior skill and craftsmanship rather than by adopting more fluent or easily handled materials. Giotto is an outstanding example of the early Italian painters in this tradition; the works of Boticelli and Fra Angelico exemplify the high point of technical achievement in pure egg tempera.

A subtle change then followed; as small amounts of waxy, oily, or resinous materials began to be introduced into the tempera in various ways, paintings showed a definite degree of technical change. These were characterized by a somewhat more fluent command of brushwork and a trace of softening or blending of colors, but for the most part they retained the same dry, linear quality of the earlier type. The culmination of this later type of tempera painting may be seen in the work of the Venetian painters of the fifteenth century--such as Antonello, Domenico Veneziano, and Andrea del Castagno--who refined their tempera paintings throughout with oily or resinous transparent glazes. Also , in the Northern countries, following the innovations of the Van Eycks and others at Bruges, the works of van de Weyden, van der Goes, and Memling show the use of oil glazes over tempera and sometimes [p. 133] oil underpaintings carried on to the highest degree of jewel-like perfection.

The artists have two instruments which they use to express their intentions in paint; they are line and color or tonal masses. In their importance to painting techniques neither one can be rated above the other, and when discussing them the same general terms are applied to each. Two completely different technical approaches may thus be distinguished.

In the first, line predominates and the painters cited above always retained completely and meticulously their original draftsmanship. Underpainting was never entirely obscured by the final painting; its effect had a strong and direct influence on the finished work. The pictures are by no means colored drawings; they are veritable paintings, but the color or tonal element is subordinate to the linear quality.

Excerpted from: Oil Painting; Visual Arts References and Resources: Notebook