Tuesday, January 16, 2007
The Color Of Light
Master white balance for greater quality and control
When the white balance is accurate, neutral tones can be rendered correctly. When white balance is incorrect, these neutral tones (black, white and gray) will be tainted by colorcasts. An incorrect white balance will introduce a green, blue or red colorcast that will immediately strike us as unnatural. Though you may be able to "fix" this in Photoshop, you're introducing an additional step into your workflow, which still may not lead to the best image possible by you or your camera.
Auto And Manual White Balance
It seems easy enough to use the camera's auto setting so we don't have to worry about white balance. The camera's sensor, when combined with the advanced internal-processing algorithms, more often than not delivers good results. However, a good result doesn't automatically equate to the best result possible.
The reason is that when the camera is determining white balance, it's looking at the color content of the scene. This isn't much of a problem when you have a mix of colors and tones. However, if you're shooting a subject or scene where a strong color, such as yellow or red, is dominating the frame, it can throw off the white balance, resulting in less-than-accurate neutral tones. In addition, if you shoot two photos of the same subject consecutively, but the angle changes, causing red to dominate one photo and yellow, the other, the subject will have inconsistent color because of the auto white-balance changes.
Since I want the best color possible, I don't depend on the auto white-balance setting but instead set it manually using one of the multiple presets. Identified by symbols on a camera dial or electronic menu, these presets (sun=daylight, bulb=tungsten, tube=fluorescent) determine the white balance for a particular temperature setting on the Kelvin scale. If I shoot an image in which a powder blue wall is filling the frame, a manual white-balance setting won't be fooled into thinking that I'm shooting early in the morning when cooler light might make a white wall that blue.
This is a dramatic example, but you may be surprised to find how different color can look when shot with an auto white-balance setting versus a preset.
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