Canon BJC-55 User Manual page 445

Scanner Problems
Check 3
D C
ID YOU SCAN A MONOCHROME IMAGE USING THE OLOR OR
G ?
RAYSCALE SETTING
If the Scanning Mode is set to Color or Grayscale, the scanner detects and
scans even the grades of the density, and white may not be recognized as
white.
When you scan a monochrome image, always set Black & White in the
Scanning Mode so the scanner can scan using only two values between
white and black.
For details on how to set Black & White in the Scanning Mode, use the
online Help.
Windows
Changing the Scanning Mode
Changing the Scanning Mode
Macintosh
Using the Optional IS-12 Color Image Scanner Cartridge 445