This flag sets the threshold mode of your scanner:
Automatic threshold: The threshold level is automatically decided while the scanner is reading.
Dynamic threshold: The threshold level is dynamically decided while the scanner is reading.
Please refer to your scanner manual for more information about your scanner’s threshold functions.
0 (disabled – default)
Values from 1-5 enable the Dynamic threshold mode. 1 is lightest, 5 is darkest.
Values from 6-8 enable the Automatic threshold mode:
6 = Dark, 7 = Normal, 8 = Light