Xerox WorkCentre Pro 385 User Manual page 239

Color Channel
The Color Channel radio buttons are used to specify the color channel in
which to change the Highlight, Shadow and Midtone values.
The only channel available to be selected when using the WorkCentre 385
to scan is the Gray channel. Red, Green and Blue are used for scanners
capable of scanning documents in color.
Highlight
The Highlight value represents the lightest value in an image. All pixels
above this point will be rendered as pure white. If you subsequently broaden
the highlight points on the Level Adjustment graph, the pixels will be re-
mapped within the new range, thus allowing you to see more detail in the
image.
6-20 Scanning