Canon BJC-3000 Series User Manual page 422

Using the White Calibration Sheet
The white calibration sheet provided with the scanner cartridge is used for maintaining the
correct color balance of scanned images. White level calibration is required when the
scanner cartridge is used for the first time and when the white level calibration data needs
to be updated.
When white level calibration is needed, you will see this screen when you click the Prescan
or Scan button.
Windows
Macintosh
Using the Scanner 422