Microtek ArtixScan M1 Pro User Manual page 38

The Gradation tool lets you adjust the midtones
(the mid-level grays) of the lightness channel
"L" of an image without altering the color itself.
This is because even with changes to the
luminance or lightness value, the chroma and
hue values are kept constant.
To prevent color images from losing saturation
when adjusting the lightness, ScanWizard Pro
provides a Saturation Range option. With this
option, colors outside of a given chroma range
are not affected by the manipulation of the
gradation curve.
In the example here, the original image is
underexposed, with the middle tones of the
image being too dark. The solution: Lighten the
tones to brighten up the image.
1. Place the image to be corrected on your
scanner.
2. Click the Overview button, and you will see
the image appear in your Preview window.
3. Select the area to be prescanned with the
Scan Frame tool, then click the Prescan
button to obtain a prescan image, and switch
to the Prescan view in the View menu.
4. Click the Gradation tool in the Settings
window. The Gradation screen will appear.
5. Move the pointer over the curve, and drag
the center of the curve to the left. This
brighten up the midtones of the image.
6. Check the Preview box so that the image in
the Preview window is updated with the
latest image correction. The update is done in
the background and so may take a few
moments to show.
7. Click OK to confirm the correction.