What I learned
While I have always underpainted I gained a better knowledge of some of the things you can do through the underpainting. It is here that you can establish tone, value and composition. So the Underpainting can be a very important part of the painting. Using it to serve your creative idea can make your painting. Rush through it, and the painting becomes much more difficult to execute.
First layers after support gesso (white). This is important. If you paint with oils directly on the fabric/surface, the oils will eventually damage the support.
The next layer of base color is applied simply to take the white off. There are a few options for this and they are mostly interchangeable. These options are:
· Colored gesso
· Mat acrylic
All of these are inert as far as oils are concerned, and you can use what suits you. I knew you could underpaint with acrylics, but did not realize there were differences between products. Many art acrylics are high gloss, and there can be some problem with adhesion with the really high gloss brands. This is especially true if you are using thin, medium rich glazing layers. Mat gloss acrylics work better for Underpainting, as they provide a better surface for future layers of oil paint. These can use used under both traditional oils and the newer water-sellable oils. New to me is the idea that you can use gouache successfully under oils. Gouache and watercolor has been used for centuries for underpainting it seems. It was at one time routine to sketch with watercolor as a preliminary step in painting. They may be why these mediums are still seen as lesser mediums to oils.
The first layer, or overall tone simply tones or tints the support, “taking the white off”. This is a matter of personal choice, but most artists find that tinting does help to hold the composition together tonally. Many feel that if small areas of the canvas should “peek” through, the undercolor is a better choice than flecks of the white canvas. Several of the paintings this week really showed how using a strong color underneath can help to unify a painting. A few flecks of a similar color/shade throughout a painting goes a long way in making all the color choices unit. And you do not need to worry about coverage, simply establish your painting and go.
New to me was the use of India ink to sketch out the painting, drawing with ink onto the established ground. Following the simple line drawing was working in a tonal value of the painting with ink washes. Here again, you can choose to allow some of this to show through to the final painting. This leaves this choice viable throughout the painting. Even if you choose to cover this layer completely, it does help to establish the lights and darks. When the tonal washes are done, you can stand back and see just how well your painting hangs together, or if major or minor changes need to be made, before a lot of work and effort with layers of paint have gone into the work. I have found this to be a real help in the early stages of a painting.
After you do the value study of the painting there is more you can do for your painting. A complementary study in either mat acrylic or gouache can add more interest and depth of color. Any of this layer that shows through makes the oil paint more vivid. Where subtle shading is necessary for any part of a painting, establishing an underpainting in a solid mid-tone helps to hold the object together through all the lights and darks.
In summary, why underpaint? Underpainting helps you establish tone, light or dark, warm or cool and provide harmony over the entire canvas. Also if small areas of the canvas get a lighter coverage in paint and some of it shows through, it is generally more pleasing to have a neutral color or even a more exciting color that can hold the painting together rather than some random white dots.