SIGMA DP3 Quattro - Manual (Page 62)

62
SETTING THE WHITE BALANCE (WB)
The color of light reflected by an object can vary depending on the color of
the light source illuminating it.
For example, a neutral colored object will reflect reddish light under
incandescent lighting, and greenish light under fluorescent lighting. The
human brain is able to compensate for differences in the color of a light
source, allowing us to see white objects as white, independent of the
lighting condition. Film cameras rely on special color-correcting filters and
film types to adjust for these differences in lighting. Digital cameras,
however, are able to use software to mimic the adjustments made by the
brain, so that colors that appear white to the human eye also appear white
in your photographs.