Deal with variable light on your painting

Judy P asks:
"James, I've can't remember if you ever discussed the topic about painting in daylight, and the value problems it causes. Umbrellas are a pain, so often I paint in the sun, with my canvas and palette aimed away, not getting hit by the light. But even if I am in shade, often my painting ends up way too dark, with little contrast, when I get it inside. 

That just happened yesterday. My painting looked successful while I was working, good value contrast, strong color and temperature variation. Then I bring it inside, and all of that is lost. I'm been doing plein air about 6 years now- how long does it take to make that automatic eye adjustment, to paint lighter and brighter than you perceive? Do you have any tips to keep on top of this problem during painting? So far my only aid is to use the middle grey paper palette to keep track- lighter or darker than middle. But 'paint what you see' is problematic!"

Painting under an umbrella held on a C-stand at right

Judy, You've got two important questions here. The first is how to set up your artwork so that the light on it isn't jarringly different from the scene you're looking at. The second is how to accommodate your eye and brain to the inevitable differences in illumination.

The answer to the first question is that you ideally want the illumination on the artwork—both the painting and the palette—to be identical to the light in the scene—identical both in terms of brightness and color. 

A close match of illumination levels makes color choices easier

If you're painting a front-lit subject, the full sun shining on your painting may be OK, but it may be too harsh and bright. This can be a problem for gouache and other water media because it makes the paint dry too fast.

One of the worst problems is dancing shadows and dappled light from a tree or the line of a cast shadow going across half your picture or your palette. This makes accurate color judgments almost impossible.

To solve all these problems, a diffuser can smooth out variations in illumination and reduce the brightness of the sun. It also makes a softer light that's nicer to work under. A diffuser is a layer of thin, translucent white nylon cloth suspended above your painting and easel. It might be a white umbrella or a smaller frame that's held closer to your work and that's less susceptible to wind.


Here's a video trailer that introduces some of the options of diffusers. (Link to YouTube)

Painting toward the light (or contre-jour) gets rid of the problem of uneven, dappled, or overly bright light, but it can sometimes be hard to get enough light on your work.

Using a diffuser while painting contre-jour

In some instances, like pubs or concerts, there's nothing I can do about the light being way too dim or differently colored on my work relative to the subject. In that case, I often work in black and white.

In the video below, I share some tips for increasing the light on your painting when you're facing toward the light. If you're working in deep shadow, there are ways to bounce light or use portable illumination to get the light levels higher and more even. I show how to build several basic diffusers in my video tutorial How to Make a Sketch Easel .


Most of these things can be made from inexpensive materials. (Link to YouTube)

The second problem has to do with accommodating your eyes to different light levels and getting the right contrast within your painting. A gray palette can reduce glare, but you need a white palette for transparent mixtures. Also, even if you use the gray palette, I find it's helpful to always have at least a patch of pure white and pure black in view somewhere as a reference to calibrate the rest of your values.

When I'm painting in bright sun, the problem for me is that my pupils get fatigued from alternately opening and closing. That can cause headaches as well as making it hard to judge relative values. The ability of your pupils to rapidly dilate and constrict diminishes with age.

In direct sun I tend to misjudge the variations in the colors, and either make the lights too dark or the darks too light. Regardless of the relative illumination levels, you have to always be conscious of comparing values within the little universe of your composition. To avoid "middle value mumbling," it helps to group the light values together and the dark values together, and keep the lights and darks separate.
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How to Make a Sketch Easel (video tutorial) on Gumroad
Previously on GurneyJourney 
White Umbrellas
Contre-jour Lighting
Middle Value Mumbling