While I’m waiting for my canvas to arrive from the canvas-stretching company, I’ve been thinking about how I’ll proceed with the painting. Normally after I transfer my drawing to the canvas, I do an underpainting over it. This is a preliminary layer- a very simple, thinly painted, monochromatic and undetailed version of the finished work. I usually use burnt sienna, an orange earth tone, and lead white. I keep the values lighter than they will be in the finished work, because I prefer to over-paint onto a lighter base. I do this for two reasons. First, because if I want to glaze (add a transparent layer of color), it must be over a lighter ground to show properly. Second, even more opaque layers look more bright and true when painted over a light ground.
I also omit details at this stage. I would only have to repaint them in the over-painting! I paint very thinly, so the brushstrokes won’t show through later, in case I want to make changes.
This monochromatic underpainting serves several purposes. It provides a unifying color scheme for the whole finished painting. Bits of this color (in this case, burnt sienna) show through here and there, making it seem like the whole composition exists in the same light and place. It is also easier to begin putting down color in my overpainting if I don’t have to do it onto a bright white canvas. It is easier to judge value relationships if the underpainting already suggests what the different values should be. Most importantly, it is an easy way to begin! Details aren’t important, color isn’t an issue, brushwork isn’t seen, even the exact values aren’t important (as I said, I paint all the values in this underpainting lighter anyway). Painting is hard enough without feeling like you must do too much at once. My method of painting allows me to work in stages, tackling different problems in order. First I do a drawing, then I think about values in a value study, then I do a monochromatic underpainting. Finally, I will think about color, and then details.
I was considering tackling the underpainting in a slightly different way in this painting. Since the green cloth is so important to the final effect, I want to make sure the color is very bright. In the Sir Thomas Moore portrait, the green cloth is very bright and was probably painted using a transparent glaze over a yellow layer beneath. Maybe I should try underpainting the cloth area as usual, in burnt sienna and lead white, but make the values very light. Over this, I could glaze a layer in yellow and then when dry, glaze over it in viridian green. For the shadow areas, I could glaze additional layers of ultramarine blue and raw umber, and for the highlights, I could scumble some lead white over the dry glaze.