The Shadow/Highlights tool provides control over the brightness in the shadows/highlight regions of your image.

Shadows: The Shadows slider controls the brightness of the shadows region of the image. The value range is -1 to 1. The default value of 0 does not affect the shadows or dark regions of your image. Moving the slider to a positive value brightens up the shadows of your image without altering the perceptual contrast level of the shot. Moving the slider to a negative value will remove brightness from the shadows of the image. .

Highlights: The Highlights slider controls the brightness of the highlights region of the image. The value range is -1 to 1. The default value of 0 does not affect the highlights of your image. Moving the slider to a positive value brightens up the highlights of your image without altering the perceptual contrast level of the shot. Moving the slider to a negative value will remove brightness from the highlights of the image.