Why use an underpainting?
Underpainting is the foundation, Take a blank canvas or a piece of paper define the light and shadows to establish your center of interest. You’re creating mass in the blank picture area.
Establishing the colors in the shadow areas support the three-dimensional illusion by bringing out the colors and highlights all while setting the tone for a finished piece of art. First thing is to set the key. Is your piece light and bright or dark and dramatic the underpainting is the place to start.
If you are working in warm tones start with a burnt sienna or burnt umber. When you are using color tones that are in a cool range use an ultra-marine or a hookers green. The color choice is yours just remember that whichever colors you use they will reflect the colors you see in the shadows.
The underpainting is only the first step
Now that you have picked a key to work in, start building the darkest areas first. Adding any paint colors that support these areas which will establish and support the perspective and define the shape you are representing. Once you have these areas determined work up to the lightest areas. By having a great foundation your painting will be unmistakably filled with richer color because the lightest areas will play off the color you have in the shadows.
A great underpainting can stand alone as a piece of art only you can decide how far you want to build on the image you create. Letting hints of the underpainting show throughout is adding to the richness of the illusion. Pick a color that is foreign to the reality of the subject like a turquoise or magenta that pop out in areas adding more interest. Working glazes on top of the existing paint will bring out a luminous quality to the picture area.
The underpainting process frees you up and give you the confidence to move forward with your painting. Experiment because now is the time to move things around or strengthen the composition before you go through with the final execution of the painting.
