The sky is the key to the landscape. It determines the quality and quantity of the light, the color unity and the value contrast of your painting. Most landscape painters begin with the sky for these reasons.
When painting the sky, remember that it’s the lightest value in the picture. Carefully analyze the value of the sky, perhaps using a red filter. It contains the sun -- the source of the light -- and clouds, which are light in value and color.
Desert Morning, 12 x 9"
Now analyze the color. Look at the quadrant of the sky containing the sun and compare the color there to the exact opposite quadrant. Notice that it's warmer in color and slightly lighter. Ask yourself what color the other two quadrants are, as well. The sky progresses from a warmer blue to a slightly cooler color, depending on the direction you're facing.
Depending on where you live, the value of the sky may be lighter or darker than you think. Our beautiful bright blue skies in
, or any high and dry climate area, can appear to be very dark, but you shouldn’t let your blue become a gloomy color. Keep it light and airy. Conversely, in more humid, lower climes the sky may appear to be quite light in color, but you shouldn’t over-lighten it too much. Make your skies colorful, controlling the value. New Mexico
Summer Heat, 9x12"
Even when we know this, we sometimes need to be reminded of it: The blue of the sky is deepest at the zenith and lightens at the horizon. This knowledge can help to create the effect of the giant blue bowl of the sky looming overhead, darkest at its highest point. The atmosphere around our planet when seen from space proves to be a fragile layer no thicker than an eggshell, speaking proportionally. The darkness of the zenith of the sky is essentially the black void of space seen through a thin blue shell of air. As we rise higher in altitude, even less of this blue atmospheric layer colors the sky, so that you see more of the darkness of space through less of the air. In arid areas the atmosphere contains less water vapor, making for clear, bright skies. In humid parts of the world the increased water vapor, which is less transparent, causes the sky to be a milky, paler blue. At lower altitudes the sky is paler in color because there’s actually more air to look through before reaching the black of space. At higher altitudes the thinner air makes for brighter, intensely blue skies. Think of the difference between the panorama you see standing on the top of a peak in the desert southwest, where the air is thin and dry, and the view from a bluff above the ocean looking out to sea. Both may be dramatic and beautiful, but high dry air gives a longer view than does thick humid air.
When painting skies around my home I like to use a mixture of blue-violet and blue-green to create the color of the sky. I’ve observed that summer skies seem to lean toward turquoise while winter skies are more violet. However, I urge you to observe for yourself and analyze whether this is true. Such a benchmark may be helpful in choosing whether to layer blues that lean a bit more toward green or violet.
Last Snow, 9x12"
As strange as it seems, the sky will appear to be not so light on a bright sunny day. The reason is that the sunlight flooding onto it raises the value of the land plane. The difference between the land and sky values is less than when clouds add highly contrasting shadows. A gray-day sky is lighter in value than a clear-day sky because the clouds catch and hold the light, much as does milk glass, making it brilliant, almost glaring, compared to the clear glass effect of a cloudless day.