What Color is Your Underpainting? The Monochromatic and Two-Color Methods

As any of my students will tell you, I am a great advocate of starting a painting with an underpainting. Also called a block-in or wipe-out, the underpainting develops the drawing, composition, value, and even basic color direction from the outset. It’s the ultimate foundational approach.

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For those interested in exploring underpainting technique more deeply, I have a 90-minute “Technique Takeaway” video called Smart Starts — The Power of Underpainting.

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I present the monochromatic underpainting technique step-by-step in my book, Landscape Painting: Essential Concepts and Techniques for Plein Air and Studio Practice. In this article, I’d like to address a specific aspect of underpainting in greater detail: What color should the underpainting be?

A traditional, classic underpainting is monochromatic — it’s made with only a single pigment color. The pigment is applied thinly in an additive and subtractive manner to achieve a full range of values. This is why the pigment color used must be dark enough to hit the darker values in your painting. Colors with darker mass tones like ultramarine blue, burnt sienna, or burnt umber can do this very well, while lighter- or medium-valued colors like yellow cannot. White paint is not used in monochromatic underpainting. Lighter values are achieved by wiping away excess tones to reveal the underlying white of the gessoed surface.

The most important thing to understand about choosing a color for the underpainting is this: whatever pigment is chosen is a color, so it will influence the color direction of the painting. The color you choose should push you in the color direction you want to go, and allow the successive layers of color to integrate. With monochromatic underpainting, there are two approaches to choosing a color: using a color that is similar to the dominant color of the scene or using a single color that contrasts with it.

Monochromatic underpainting with harmonizing color

In this approach, I ask myself, What is the average overall color of the scene? In University Bridge the subject was predominantly blue, so I chose ultramarine blue for the underpainting color. Because it corresponds to many of the blues found in the subject, the underpainting immediately aligns itself with the overall color direction of the subject.

• Advantages: Easier than two-color underpainting (below). Recommended for those just learning the underpainting method, but also a solid choice for seasoned painters. Makes tonal studies that are beautiful in their own right.
• Disadvantages: Initial strokes of full color may look out of place against the monochromatic underpainting, until more coverage is achieved.

In University Bridge I chose ultramarine blue for the underpainting color because it corresponded to the many blues found in the subject — in the sky, the water, and the shadows of the bridge. (The underpainting shown here is the start of a similar painting.) Color contrast was achieved as warmer colors —  the warm base of the bridge and the green girders — were laid over the cooler undertones. In some spots the original ultramarine blue shows through the final layers of paint.

What I Don’t Pre-tone My Surfaces

Some painters use the same underpainting color for every painting, even pre-toning the surfaces before they begin (a practice I don’t recommend). If each subject has its own unique color harmony, which calls for a particular color response, I can’t expect the same underpainting color to work for every painting. I’ve always preferred to choose the underpainting color in the moment, as an immediate response to the impression of color and light I see in the subject.

Monochromatic Underpainting with Contrasting Hue

This is a popular approach among landscape painters. Rather than selecting an underpainting color that corresponds to the dominant color of the scene, the painter intentionally chooses one that contrasts. In a scene with lots of green, for example, the painter might choose a complementary color like alizarin or burnt sienna. The idea is that the underlying red can react with subsequent layers of green, adding vibration and interest to the color tapestry. The red might even peek through the final layers of color in many areas.

• Advantage: It can provide exciting color reactions as the subsequent layers of colors react with the underlying color.
• Disadvantages: Like the monochromatic underpainting, initial strokes of full color may seem out of place until enough coverage is achieved.

Two-color underpainting

Two-color underpainting is my favorite approach to underpainting. It establishes basic shapes, values, and composition, just as the monochromatic approach does; however, it does more to establish the overall color direction of the painting. It works like this: rather than using a single pigment color, it uses two colors. The entire surface is toned with the first color, which corresponds to the light, warm aspect of the scene. Then, a second darker and cooler color is developed over that. This is the layer that articulates the shapes and values. If the two colors are chosen well, the underpainting can establish a light and dark structure, temperature differences, and the overall color direction of the painting.

Two-color underpainting is more difficult than monochromatic underpainting because It requires a greater ability to interpret the average colors in the subject. Additionally, the two colors used are not necessarily colors squeezed straight from the tube; they often have to be mixed. But whether we use a single color straight from the tube or we have to mix it, we always start with two base colors. A light, warmer color and a darker cooler color.

• Advantages: It can immediately establish the overall color direction of the painting, in both light (warm) and cool (dark) areas. Initial strokes of full color do not look as out of place as they might in a monochromatic underpainting.
• Disadvantage: Technically more difficult than the monochromatic underpainting. Requires a keen ability to interpret the color of the subject. I advise painters to achieve proficiency with the monochromatic method before trying the two-color. 

Demonstration 1

In Step 1 (left) the initial layer was a solid undertone of Naples yellow. This corresponded to the average color of the warm light I saw in the scene. In Step 2 (right) I built up my second layer with a slightly grayed out version of Ultramarine Blue, which corresponded to the cooler shadow areas of the subject. With this dark color, I define the values and structure of the composition.

The color in the final painting has a lot in common with the two-color underpainting — which is the idea. The beauty of the two-color method is that, if I choose my colors well, the underpainting can establish the overall color direction of the painting very quickly.

Technique. One of the reasons two-color underpainting in oils is more difficult than monochromatic underpainting is because of the potential for the second color (in this example, the darker blue) to mix with the underlying layer. Be sure that the first layer adheres to the gessoed surface very well. (Use as little solvent as possible.) The second color can easily dissolve and blend with this underlying layer, so the more firmly the initial layer adheres, the better. As with all underpainting, you should avoid rubbing too much or using too much solvent, or you will wind up removing the pigment from the canvas entirely.

If you are working in the studio, you have the option of laying in the initial tone on the first day, and then coming back the next day when it’s dry and ready for layer two. There will be much less commingling of the two colors.

Demonstration 2

STEP 1

As in Cottonwood, Union Bay, this painting also begins with a light warm undertone. I make sure this first layer is thin — not thin and “washy,” but using using almost no solvent. This allows the pigment to adhere well to the gessoed surface. This will help minimize any mixing between this first layer and the second color in Step 2. I rub back all the excess pigment with a rag.

STEP 2

Step 2 is where I do most of my structural development: values, drawing, and composition. My second color is violet (Dioxazine Purple), which is complementary of the yellow undertone. So in this early stage, I am setting up several color relationships that establish my color strategy: light (yellow) and dark (violet); warm and cool; and complementary, which gives me an extra boost of color contrast. Because this is a plein air painting, done wet-into-wet, the first layer hasn’t yet dried. So the purple begins to mix and blend with the yellow, creating some neutral tones. Such commingling with the two-color underpainting is to be expected. This completes the underpainting — which suggests quite a lot for such an early stage.

STEP 3

As additional color development begins, colors are thinly applied, allowing much of the two underpainting colors to show through. Could I have taken the color development further? Certainly. The key takeaway is that the color in the later stages is directed by the value, temperature, and complementary color pairings I established at the outset.

Above, one subject as a two-color underpainting and as a monochromatic underpainting. Each strikes in a beautiful harmony, but does so in different ways.

Additional Resources

from Landscape Painting: Essential Concepts and Techniques for Plein Air and Studio Practice
Underpainting, page 132
Underpainting demonstration, page 136