Microtek 1000xl 参照マニュアル

The W&B Points dialog box in Native color mode

In Native color mode, the White & Black Points dialog box allows you to modify
the histogram in your RGB, CMYK, or Lab channel. Channels can be modified
individually or collectively (when you select "All") in the Channel box.

Following the selection of your channel, you can move the black and white
sliders below the histogram to set the shadow and highlight values,
respectively. The edit boxes below the sliders will reflect those values.

Channel box

Sliders

Edit boxes for shadow &
highlight values