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Our chief photographer shares his insights.

Color Correction

By Earl Nottingham

Unlike the human eye, cameras need a little help to get the color right in any light.

I’ve always been intrigued by the mechanics of the human eye, working in concert with the brain, which enable us to make visual sense of the world around us. It seems miraculous that a few tissue cells and electrical impulses, when configured just right, let us marvel at a magnificent sunset or the delicate colors of a flower. In humans, this eye-brain duet has the uncanny ability to discriminate minute variations of color throughout the visible spectrum; in other words, we can see a whole lot of colors. So many colors, in fact, that the gamut of human color perception exceeds any color combination that can be reproduced on paper or on television and computer screens.

While the eye allows us to see many colors, it is the brain that dictates how we perceive those colors. Sometimes the brain must compensate for the colors in a scene to be perceived as “natural” in our mind’s eye. For example, let’s consider a white shaggy dog on a sunny day. Illuminated under sunlight, the dog looks white. Even with the light of a cloudy day, or in the shade of a tree, he would still appear white to the human eye. However, a photograph of the same dog, under the same lighting conditions, would look completely different. In a photo taken on a cloudy day or under open shade, the dog appears blue. An image taken under household tungsten lights is yellowish and fluorescent lighting gives us a sickly green dog. This is because film can only see the subject based on the color inherent to each source of illumination. The brain compensates for those different lighting situations to give us what we expect to see — a white dog.

Luckily, there are methods to compensate for different lighting situations so that a subject will be rendered as its true color in a photograph. For film, the answer has traditionally been the use of the color-compensating filter. With normal daylight-balanced films under cloudy skies or open shade, complementary warm-colored filters help neutralize the bluish cast. Under household tungsten lighting, blue filters balance the yellow-red light. Even the sickly greenish cast from fluorescent lights can be eliminated with the magenta color of a fluorescent-to-daylight filter.

With the advent of the digital camera comes the benefit of in-camera color correction. Most digital cameras will have icons representing the various light sources; daylight, cloudy, open shade, tungsten and fluorescent. Some even have a custom white-balance feature that comes in handy for mixed light sources. And if there is still some residual color cast in the digital image, it can usually be taken out with photo-editing software.

But what if corrected light isn’t what you’re after? What if you want to enhance certain colors? This is where those same filters become fun and creative. For instance, if you want to accentuate the bluish cast of a cloudy day, use the tungsten filter (light bulb icon), which adds more blue. Conversely, if you want to add warmth to a sunset, use the cloudy or open-shade setting, which adds yellow. Even the magenta color from the fluorescent filter can produce some neat effects, especially late in the evening. Sometimes I inadvertently use the wrong color setting, and get serendipitous results that reveal a better photo than I had intended. Ah, life’s pleasant surprises

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