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Cool Blues,
Hot Pinks, and White BalanceArthur H. BleichContributing Editor
Light actually has a measurable "color temperature" expressed in degrees Kelvin and named after its inventor. Candles and firelight measure around 1,000 degrees Kelvin. Ordinary household ("tungsten") bulbs about 2,000. Noon sunlight measures close to 6,000. An overcast day can hit 9,000. And sunless blue skies have been measured at 12,000. Fluorescent tubes usually emit cool light but they also come in a warmer version. So you can have "Daylight" tubes and "Warm White" tubes with, perhaps, a difference between them of several thousand degrees Kelvin. In the early days of color film every box carried this suggestion: "For best results take pictures with this film in sunlight between the hours of 10 a.m. and 3 p.m." That's because between those hours the sunlight was neither too warm nor too cool and people's faces would record more or less naturally on film without taking on a red or blue tone.
With film, you also had to know the conditions under which you were going to shoot and then pick a film balanced for "Daylight" or "Tungsten" or your pictures would look pretty bad. Fluorescent lighting was always a nightmare, usually requiring a dark color correction filter which would cut the light so severely, you sometimes couldn't shoot the picture at all. With digital cameras, though, it's a whole new ball game. These little marvels can automatically balance the color of light electronically so that nothing comes out looking too hot or too cold. It's called "White Balance" (WB, for short), which simply means the camera tries to keep white objects fairly white, so they don't take on extreme color casts.
Of course, it did that perfectly, the color balance of all your pictures would be the same and the result would be quite boring. So it balances the white only to a point. And on most digital cameras, there are also white balance settings that can be set manually to further correct color temperature to suit your taste. Sometimes, you can even use the "wrong" settings to get interesting creative effects. Setting the white balance for "Tungsten" will cool a picture down by adding blue to it. That makes sense because tungsten light is on the yellow-orange side and adding blue will bring it back to what we're used to seeing. When you set the white balance to "Cloudy" it does just the opposite. Since cloudy days are usually blue-gray, it'll add some warm color to the image to bring it back to "normal." Try this. Set your digicam to "Auto" white balance, find a white wall and shoot some pictures of it at various times during a sunlit day. You'll then see how that wall actually changes color. But it will look white to you when you take the pictures because your brain will automatically white balance it. You must learn to switch off the white balance control in your brain so you can begin to appreciate how different color qualities of light can help you make better photographs. Some photographers love to shoot subjects bathed in the warm orange-pink light that occurs just before sunset. Others use cool, blue pre-dawn light for special effects. Once you learn to recognize different color temperatures and how to use your white balance controls, you can begin to turn ordinary shots into an extraordinary ones. © Arthur H. Bleich 1999, All rights reserved.You Are Invited to Click Over to Arthur's |
