The sky is the giver of light in the landscape and the earth the receiver. This simple observation has been at the core of understanding the landscape since artists started painting. John F. Carlson in his popular book, Carlson’s Guide to Landscape Painting, separates the basic landscape into four sections of light and dark value: the sky, being the source of light, is the lightest; the flat earth of fields and bodies of water is second; the angled earth of hills and mountains is third; and the upright nature of trees and vegetation makes them the darkest. Of course there are situations that dispute this theory, but in general it’s a good observation and has helped many to become more sensitive to the quality of light and its reflective abilities, which is what makes us better painters.
Having dark, upright trees against a light sky produces one of the most beautiful and difficult to handle situations in the landscape: sky holes. The amount of visible sky holes depends on the density of the foliage, but as an artist friend often said, “You have to give the birds a place to fly in and out.” It’s commonly believed that once a value and color are selected for the sky area, the sky holes should be painted with the same tone.
However, when this is done, the holes appear too light and bright, looking more like ornaments on the tree instead of light traveling through the tree. This is where keen observation—and a good understanding of the physics of painting—will prove invaluable. The appearance is due in great part to two conditions. First, the light behind the tree has to travel through the mass of the tree to your eyes—a tunnel of sorts. Along that path, it’s diffused and scattered, and thus becomes weaker. Second, the relationship it will have with the darkness of the tree can make it appear lighter than it really is (refer to my previous blog on simultaneous contrast). Since these sky holes have to penetrate the bulk of the tree, and are visually isolated by the darkness of the tree, the pigments chosen to portray them should be slightly darker than the rest of the sky. The larger the sky hole, the lighter its center can be.
Another problem is the definition with which these sky holes are painted. Overly sharp edges flatten out the tree, making it look like a piece of paper that has had holes cut out. This can be remedied by smearing one edge of the pastel mark with the flick of your finger. This better translates the illusion of light bouncing its way through the tree space.
By implementing these simple remedies, our painted trees will appear more lifelike, providing my friend’s birds a place to fly in and out.