Sunday, March 30, 2008

Color Corona

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


Darren said...

The shape of a photographic lens flare is determined by the shape of the lens diaphragm (aperture) which is often a polygon.

More photographic based lens flare info here:

An interesting use of lens flare in a painting is in Jacob Collins header image here:

James Gurney said...

Thank you for the info and links. Fascinating stuff. I love that painting by Jacob Collins.

Pinflux said...

Awesome post - thanks for sharing :D


Tom said...

Beautiful paintings James

You feel the sun radiating throughout both paintings holding everything place like the center of a carrousel. Which at the same time creates a strong sense of distance between two faraway points especially in the second painting. And the color is great.
How long did it take to do these two paintings? And if you have the time in some post I would love to hear about Tom Lovell. I sent some of my drawing to him in Arizona when I was 15 and he sent me back a wonderful 4 page letter. He had no school recommendations as he felt art schools had deteriorated in there teaching methods, since he went to school. And boy was he right everything was abstract and conceptual. You where kinda laugh at when you said you like the work of illustrators.
Thanks for all the great posts.

Shawn Escott said...

This effect amazes me. I was actually studying this the other day while watching the sunset and our neighborhood lamp post. It is really hard to wrap my head around what is happening. I try so hard to understand it but my eyes just can't pick it all up. Especially if I was to try and paint it.

It does look as if the sun is shinning in your painting and my eye wants to squint down... amazing!

Unknown said...

I love the Pteranodon painting. You captured a real sense of freedom and majesty. I know what you mean about lens flares getting a little gimmicky. I love Drew Struzan, but he can go a bit overboard. Yours have added a lovely sense of warmth and atmosphere. Well done!

Sarah Stevenson said...

Very clever use of the color corona. I find it a lot less "obvious," I guess, than the lens flares, and a better approximation of in-person human vision.