Applying the Equalize dynamic plug-in
The Equalize dynamic plug-in creates a layer that lets you adjust the contrast in underlying images. It does this by adjusting black and white points and distributing the brightness levels throughout the entire range of available levels.
The Equalize dynamic layer is applied to a rectangular selection.
The Equalize dynamic plug-in creates a histogram showing the number of pixels for each brightness level value. Equalize allows gamma adjustment, which lightens or darkens an image without changing highlights or shadows.
To create an Equalize dynamic layer
• Choose the Rectangular Selection tool 
from the toolbox, and then drag in the document window to select an area.
from the toolbox, and then drag in the document window to select an area.
, and choose
3
In the Equalize dialog box, adjust the contrast by dragging the small black and white markers under the histogram.
Any values in the image located to the right of the white marker become black; any values to the left of the black marker become white.
4
Drag the Gamma slider to adjust only the midtones of an image and leave the white and black areas untouched.
If you don’t like the results, click Reset to restore the default settings.
You can also use the Opacity slider in the Layers panel to adjust the effect.