Canon D646U - Manual (Page 21)

21
S T E P 1
Setting the Scan Mode
When an image is scanned, it is read as a collection of “dots.” The scan mode that
is selected determines how each of these dots is represented in the output. The
following four scan modes are available.
Black and White
Expresses images in two colors only: black or white. A dot is expressed as either
black or white according to its brightness level and the value set as the threshold
value, which can be freely set. Select this mode to output to a monochrome
printer.
Grayscale
Expresses images in 256 shades of gray. Select this mode to scan black and white
photographs or create monochrome images from color images.
Color
Expresses each color channel (RGB) in 256 shades (8 bit). Select this mode to scan
standard color photographs.
Hint
Scanning the same image in the four different scan modes produces
different file sizes. By size, black and white mode requires the least disk
space, followed in order by the grayscale and the color modes. Before
scanning, check the data volume indicated on the control panel.
The numerator indicates the amount of
disk space required for the scanned image
while the denominator indicates the
amount of disk space available. When the
required space exceeds the available
space, the scan button is unavailable.