What shape is the sky? As landscape painters we must remember that the sky is not a flat plane in the distance, but a vault which arches up toward and over the viewer’s head.
The fact that we are depicting a vault rather than a flat plane affects the perspective we see in the clouds, the colors and values in various parts of the sky and the amount and quality of light.
But, it should also affect the way we depict it in paint. Specifically, the direction of our brushstrokes! When we want to depict other shapes or forms we often think in terms of the direction of brushstrokes. For example, we might use a horizontal stroke to help define the volume and girth of a tree trunk, or a short curved stroke to suggest the shape of leaves and foliage. So, when we paint the sky, we should use vertical strokes to help show that it is a vault, arching up and over the head of the viewer. Using vertical strokes will instantaneously add a sense of “bigness” to your skies. Even a cloud filled sky can benefit from some well placed vertical stokes. So, give those vertical strokes a try!