Mixing two colors to get gray

At this point, I would like you to explore the use of two colors and white to mix your grey tones. Select burnt Sienna, ultramarine and titanium white. Burnt sienna and ultramarine blue, mixed in proper proportions, make a good dark color—a black. Mixed with varying amounts of white, this mixture makes all the intermediate grays. I’d like you to use this mixture for the remaining exercises in value and, subsequently, form, because it gets you used to mixing color and away from the use of black paint.

Please understand, that I have nothing against black. It is useful, when the object you are painting is in fact black. But too often, the beginning student uses black to darken color. In this workbook, I want you to discover other ways to darken color while not dulling it.

Exercise
In this exercise, you begin mixing color to produce grey. You should have white, ultramarine blue, and burnt sienna on your palette. If you mix the blue and the sienna in the right proportions, you get a good black. Combining with white will produce all your intermediate gray tones. Set up a simple still life with good directional lighting. Concentrate on translating it as a drawing using only 3 values, a dark, a medium and a light tone. Mix the three tones on the palette, using the palette knife in order to restrict yourself.

To get a good distribution of values throughout the painting from very light to very dark values, it is useful to start with a medium-toned ground. If working with oils, I recommend mixing a medium grey and covering the canvas evenly and letting it fry a sufficient amount of time. (Hint: if you want to do this, raw umber mixed with flake white or underpainting white gives you the fastest drying time and a nice warm gray. I know, I know, I didn’t include these colors on the supply list. Get over it.) An alternative is to use gray gesso or black gesso mixed with white gesso. Most canvases are prepared these days using white gesso. Try to get a gray that is midway between black and white.

The reason it is useful to work on a toned ground is that, if you start to apply values to a white canvas, the white of the canvas acts as part of the tonal composition and you are liable to find yourself working too dark or too light overall.

Alternate exercise:
If you want to practice working on a medium toned ground, You can start with a medium grey paper and use black and white chalks.