Canon varioPrint 115 Operation Manual page 269

Optimize the Scan Quality
8.
Select the desired value to change the settings for the [Light] and [Dark]areas on the scan.
[Light]: When the area must be darker, then select a value of -1 to -3. When an area on the output
is light gray but must be white, then select a value of 1 to 3.
[Dark]: When an area on the output is dark gray but must be black, then select a value of -1 to -3.
When the area must be lighter, then select a value of 1 to 3.
9. Press [OK].
268 Chapter 11 - Carry Out Scan Jobs
Canon varioPRINT DP line