Canon D20 - Manual (Page 105)

Color and Continuous Shooting
105
For image colors that look natural under the light in your shot, adjust white
balance to suit the light source where you are shooting. Set the white balance
under the same light source that will illuminate your shot.
Follow the steps in “Adjusting White Balance”
to choose
.
Aim the camera at a plain white subject, so
that the entire screen is white. Press the
n button.
X The tint of the screen changes once the white
balance data has been recorded.
Custom White Balance
• Colors may look unnatural if you change camera settings after
recording white balance data.