Canon 0206b003 - EOS Digital Rebel XT Camera SLR Instruction Manual page 66

Editing Images
Click White Balance Function
Makes white the standard for the part you selected and automatically adjust the white balance.
1
Click the [Click] button.
When you move the cursor over
the image, the cursor [ ] changes
to [ ].
2
Click the part where is to be the standard.
The white balance is adjusted so that the point clicked appears white.
If you click on another point over the image, the white balance is adjusted again.
When you finish this operation, click the [Click] button or right-click.
The image is adjusted based on the value of 1
You can also adjust the white balance by clicking an achromatic color (neutral gray) part
of the image.
2-10
1 pixels from the clicked point.