The Brightness Regions effect allows separate adjustness of the shadows, midtones and highlights.
It is available as a CC Layer, an Effect Layer or a User Effect.
From the Control Panel, the trackballs adjust black, mid and highlight Brightness Regions when the Color panel is set to Brightness Regions.
The thresholds for black, mid and white can be altered from the top menus by pressing B.M or W respectively. The RGB values for black, mid and white can also be adjusted from the top menus by pressing B.M or W a second time. These buttons are on the right of the top menu when Brightness Regions mode is selected.