The story of oil painting generally and from its technical side can be simply and briefly told.
Up until the modern or technically scientific period the apprentice had to master a comparatively simple formula. This formula stipulated but two essentials: an underpainting in monochrome, and an overpainting or glaze. The underpainting was at first in tempera and the glaze in oil until the Renaissance, when generally the change was made to include the underpainting in oil (and usually in lead). This underpainting was a monochrome sometimes in brown, sometimes black or green or blue depending upon the school or period. Such a separation between underpainting and glaze was made in order to enable the painter to concentrate first exclusively upon the composition of the form and values, thus enabling him to devote his final efforts upon the composition of the color. This convention was adequate until the scientific era when man required or thought he required a more relative universe, and began a historical retreat from absolutes.
Now many of these absolutes which were abandoned were well abandoned, including the absolute monochrome as an expression of form and values in the underpainting. It was found, and I think rightly, that the underpainting must be in three colors (hues). In other words, it was discovered that colors (hues) actually could and should be instrumental in making forms and values. Thus it is now generally known and accepted that yellow as well as white makes form and light, that blue makes shadow and space, and that red makes void. It is seen that with the introduction of the polychromatic underpainting new problems have been posed for the painter. He either faces these problems and tries to solve them or he abandons himself to subjective abstractions which are generally autobiographical introspections, and this helps along the chaos. One of the first problems to face the serious modern artist is this: if great masterpieces were painted in Renaissance and mediaeval times why not use the old techniques? The answer may be couched in the axiom that all manís communications must be in contemporary language or they perish.
I believe that all metaphysics of space (as well as local color) are recorded in the glaze rather than in the underpainting. For the underpainting is properly confined to the metaphysics of form and void only; and I think that the old tradition of the thick impastothe bravura, if you willbelongs to the underpainting. The only development beyond tradition is the use of cadmium yellow, cadmium red, and alizarin instead of browns or warm colors: red and yellow come first (in the underpainting), then in the glaze, the blues come first. The painting is finished in yellow and white.