015 - May 14, 2010 -- Get the Red Out
A common problem that all photographers contend with is getting the colors right in the photograph. Sometimes we like to photograph without a flash to better catch the mood, or maybe to not disturb others by having the flash go off in front of their eyes. Can you imagine the start a new-born baby gets if we snap a picture – with flash – from 5 feet away? If you’ve taken photos indoors, without a flash, under incandescent lights, it’s likely that you have noticed a distinct red color cast on the photo. For instance, if using available light, the photo was of a child making a wish before blowing out the birthday candles, the reddish color cast can make an attractive, warm photo; if, however, the photo was a dance recital picture, the reddish color cast may have caused some unattractive results. So, where does that color cast come from? You probably didn’t notice it before taking the photo.
The color cast comes from the type of light that was available for the photo. All light sources have distinct spectrums (mix of colors) that “color” the subject. We may not notice the color shift prior to the photo because our mind knows the colors to expect under normal daylight, so we adjust our perception of what the eye sees to what the mind expects to see: we expect to see healthy skin tones; we expect to see red stop signs. The camera simply records the light reflected from the subject that comes through the lens – whatever color cast it happens to have.
If we were using film camera technology, color correction could be done by using a colored filter either before the picture was taken or later when the print was made to compensate for the color cast. With digital technology, we have the same two basic choices: adjust the camera settings before the picture or adjust the pict file when we process the photo.
Before we take the pict, if we think of it, if we have time, and if the camera will allow it, we can sometimes adjust the camera settings to compensate for the lighting. If the camera allows light setting changes, you may find a series of icons that symbolize different lighting conditions: automatic white balance (AWB), flash, bright sun, cloudy day, incandescent light, fluorescent light, shadow, shade. (Check your camera’s documentation to find out what settings may be available.) Each setting tells the camera’s computer how to record the numbers that represent the colors. Depending on the camera, some settings will work well and some not so well; each setting will make the same mathematical adjustment to the pict file regardless of variations in the lighting. I generally leave my cameras set for automatic white balance and do the adjustments in the processing phase.
If the photos are to be color balanced during the processing phase, some type of computer program is needed; these programs can range from very simple to very complex. The simplest will tell the print process to automatically “adjust for skin tones”. This usually works if there are skin tones that the processing scanner can recognize. The more complex programs allow you to adjust the color balance, intensity and saturation of each color; this can be a little tricky at first, but becomes quite easy as you get accustomed to the process - and it’s well worth it for accurate colors. To correct a photo for the extra red from incandescent light, lower the red value and increase the green value (and sometimes blue) slightly. In extreme cases, lowering the saturation level of the red sometimes works as well. In more complex programs, you may have the option to change the light temperature as well.
The color balancing process is made much easier by photographing a “gray card” (or “color card”) using the available lighting, then using a computer program to batch process all of the files to match the color adjustments needed for the gray card photo. The gray card is a card showing white, medium gray and black; when photographed under different light, the photo shows the color shift and provides an easy reference to color correct – the process is similar to setting the white balance on a video camera.
Usually color casts can be corrected to make photos look better either by changing settings on the camera or during processing, but not always. Keep in mind: sometimes the uncorrectable photos make excellent black and white photos: it’s easy to do by either converting to gray scale or de-saturating all colors.
Tip #1: Consider leaving your camera set for Automatic White Balance, photograph a reference gray card and process the color balance later.
Tip #2: If you use camera settings to adjust for lighting, remember to reset back to AWB.
Tip #3: If the photo can’t be color adjusted successfully, try converting it to black and white.
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