The second method of controlling the tonal range or brightness of a picture is lighting. In this case the gray scale is controlled by the amount of light falling on objects in the picture.
A white wall can be shadowed and appear dark. The wall’s brightness is now being controlled by the amount of light falling on the wall, rather than by the actual tone of the wall itself. Bright objects can be made to look dark, and dark objects can be made to look bright, depending on the lighting.