oil painting » Painting techniques » Under painting
Underpainting gets its name because it is painting that is intended to be painted over (see overpainting) in a system of working in layers. There is a popular misconception that underpainting should be monochromatic, perhaps in gray-scales. In fact, a multi-color underpainting is much more useful and was used extensively by artists such as Giotto (whose technique is described in detail by Cennino Cennini), as well as by Jan van Eyck and Roger van der Weyden (whose technique has been studied with modern scientific analysis). This technique was pioneered by Titian in the High Renaissance. The colors of the underpainting can be optically mingled with the subsequent overpainting, without the danger of the colors physically blending and becoming muddy. If underpainting is done properly, it facilitates overpainting. If it seems that if one has to fight to obscure the underpainting, it is a sign that it was not done properly.
The underpainting is where you build the foundation of your painting. An underpainting really can be classified as any paint that has dried and is again painted upon. Although some people will use a full palette, most underpaintings are done with one or two colors. If you are not skilled in color mixing and getting the correct value without thinking too hard, a monochrome underpainting will help you work out some of the most important problems of your
I like to make an underpainting in one or two colors. Sometimes I use a full palette. I will first establish the main part of my painting and worry about adjusting or brightening the color later, when I can devote my full attention to it.
For a beginning or even intermediate painter, using a full palette to begin a painting can be very confusing. You are having to decide on color, value, form, contrast, placement, composition etc. It could seem very hard to concentrate on all of theses things at once. If you were to begin to try to learn to juggle, you would not start with four items, you might want to start with two or even one, learning to throw one ball in the air and catch it, before trying four. So, for now, forget color and concentrate on tones, values and contrast.
You should want your underpainting to dry quickly because you will paint over it. Therefore you should use mediums that will help your paint dry faster. The less medium in your underpainting the better, but if you add medium to your paint make sure it is quick drying.