Usual color scanners represent a color original in a color range of the 3 basic colors red,
green and blue.
The DpuScan filters work based on this color model (sum of all colors = white).
You can imagine a color camera as 3 gray cameras each with a different color filter
mounted before it. Such a color filter can have a different density and thus allow different
amounts of light to go through or to be filtered out. The different density of these color
filters can be simulated by grading factors after scanning. Color can be brightened or darkened.
At a grading factor of 0% the color disappears completely, and in the gray image the color object
is thus darker. The grading factor modifies the color and the total brightness. Although a red
object may seem lighter by a grading factor above 100% in the red channel, the parts simultaneously
reported in the green and blue channels of the camera remain unchanged and will therefore influence
the brightness of the object in the gray image. By modifying the individual color amounts, however,
a better base can be gained for a good threshold.