The Gradation Curves tool is very powerful and allows the user to
adjust the Gradation (midtones), Contrast, Shadow and Highlight points,
and overall Brightness. It is also possible to manually reshape the
curve to reflect specific image requirements (e.g. S-curves).
The user can define the shape of the curve using either
the slider or via numerical input. We can also decide whether midtone gradation
adjustment is based upon a Normal (N) or Logarithmic (L) scale. Typically
images that show darker than average 3/4 tones will benefit from the use
of the L midtone gradation adjustment.
