Monday, December 21, 2009
Perfect White Balance—12/21/09
Ensure accurate color with your camera’s histogram
Many cameras, though, also offer the ability to examine color values via an RGB histogram. Some photographers utilize this information to get a general sense of brightness as it relates to colors in the image—say, to insure green leaves aren’t lacking in detail.
In some camera histograms these three colors are overlaid on the same chart; other times, a separate graph is used for each RGB value. In each case this simple, graphic color information can be invaluable for setting and verifying the perfect white balance. Here’s how: If the spikes on the graph occur in the same place for each value (red, green and blue) then equal amounts of each color are present in the scene—meaning that it’s neutrally balanced.
To put it into practice, simply fill the frame with a neutral gray card or a white piece of paper and make an exposure. With the white balance accurately matched to the lighting, the spikes on the RGB histogram will line up. If the white balance is improperly set, the RGB histogram will show it via misaligned peaks.