I painted this scene from observation on a cloudy day at the Mamaroneck Harbor in New York State. The rays seem to radiate from the area of the sun, but actually they’re essentially parallel, and we’re looking at them in perspective.
The effect should be used sparingly in fantasy paintings, because it can easily become a tired cliché. Maybe that’s because it is so often overused to suggest the glory of heaven, or because it shows up in paintings when the conditions aren’t completely suitable.
Beams of light occur when the following three conditions are met:
- A high screen of clouds, foliage, or architecture is punctured by a few openings. The canopy must block most of the light to allow a darker backdrop against which the sunbeams can be seen.
- The air is filled with dust or vapor. The smaller the particles, the more there will be chromatic scattering, making the light source seem more yellow or red (see link). Watery mist won’t affect the color of the light as much as fine dust.
- The view is toward the sun. Large droplets scatter most of the light forward at small angles to the direction of the light. When you’re looking away from the light source, the beams become invisible.
The conditions might exist in a circus tent, a ruined building, or a dark forest interior. As with dappled light, the farther away the aperture, the more the edges of the beam become diffused by the time they reach the ground. You won’t see a sunbeam from a far cloud making a small spot of light on someone’s lawn.
Keep in mind, too, that sunbeams from a cloudy source, like the Bierstadt above, are shining through an uneven aperture, making three dimensional columns of light with an amoeba-like cross-section. This has the effect of making the edges and amounts of light extremely variable.
I used the sunbeam effect in Dinotopia: The World Beneath because I really wanted the scene to look magical, and I wanted the humans at left to be at a disadvantage, looking into a bright illumination.
Note that the sunbeam affects the shadow values of the forms even more than the values of the light side. You could accomplish this in acrylic by airbrushing a light tone where the beams appear, but white pigment overlaid will tend to make the colors look chalky.
In this oil painting, I premixed one string of colors for the areas inside the light beam, and a whole separate string for the colors of the darker unlit forest.
Related GJ posts on dappled light, link and chromatic effects of dust, link.
Albert Bierstadt from the San Antonio Museum of Art, link.
Tomorrow: Art By Committee