Baking Displacement

Is there any way to set the min and max gray scale with displacement baking, I want to make brushes for sculpting by using displacement baking to make a gray scale image. Or mus i take the image into gimp and adjust levels.

pretty sure you could clamp the min max with the compositor.
But I think usually you just let the map be standard and use the Depth or Strength to adjust how far to apply the displacement.
What would clamping the tonal range do other than that?