An extremely bright light, like a setting sun or a streetlight, is often surrounded by region of intense color, which I like to call the color corona.
In photography this effect is generally known as a lens flare. A halo of light often appears around a very bright source, caused by the internal scattering of light within the lens elements. That halo or corona takes on the native color of the source, even if the source has burned out (or “clipped”) the film or the sensor to pure white.
Photographic lens flares often include starbursts, rings, or hexagons.
These photographic lens artifacts can be added with Photoshop to give a fantasy painting—either digital or traditional—a realistic effect, but beware: if they’re overstated they can quickly become a gimmick.
A similar effect happens when a bright light travels into the human eye. Light scatters in the eyelashes, cornea, lens, and aqueous humor—the jellylike liquid inside the eye. The light then hyperactivates a region of the cones around the central spot of light.
The color corona also forms around the reflections of the light source on a specular surface like water. This close-up is from a painting from Dinotopia: First Flight. The color corona floods out from the bright water reflections and melts all adjacent silhouettes. A color corona can help to make a source seem brighter than the white of the paper, and actually make a viewer squint involuntarily.
This painting by Peder Mønsted capitalizes on this idea of an intense color corona adjacent to the setting sun. The mountains seem to be taking on fire from the sun, rather than retiring to a cool distant hue.
Related GJ post: reverse atmospheric perspective.
Wikipedia entries on aqueous humor, lens flare.
ARC entry on Peder Mønsted