While making adjustments for overall image brightness, you can choose from [-1], [0], or [+1] for even richer expression of gradations, in either the black or the white areas.
Setting to [-1] creates subdued brightness while the gradations of the shadowy areas are intensified; setting to [+1] increases overall brightness while deepening the gradations of the highlighted areas. * Unless Active D-Lighting is set to OFF, the level of Brightness cannot be adjusted.