Canon MultiPASS L6000 Software Manual page 139

Using the Black-point, Mid-point, and White-point buttons, you can
sample the respective tone in the preview image and base the image tone
settings on the sampling. You can also type a value in the Black-point,
Mid-point, and White-point boxes.
Under the histogram graph, you can slide the black, gray, and white
buttons to adjust the tones. However, you cannot edit the histogram
directly.
When you adjust the black-point, all tones in the image darker than the
selected black-point are adjusted to black.
When you adjust the midpoint, all tones in the image between the black-
point and the white-point are adjusted to the selected mid-point.
When you adjust the white-point, all tones in the image lighter than the
selected white-point are adjusted to white.
Chapter 6 Scanning 6-21