Setting A shutter-speed setting on an adjustable camera that allows for time exposures. When set on B, the shutter will stay open as long as the shutter release button remains depressed. The part of the scene the appears behind the principal subject of the picture.
Background is the area shown behind the main subject in a picture.
Background density is the density of any selection of a negative or print on which there is no image. Also referred to as Fog level . Backing is a dark coating, normally on the back of a film, but sometimes between emulsion and base, to reduce halation . The backing dye disappears during processing. Backlighting Light coming from behind the subject, toward the camera lens, so that the subject stands out vividly against the background.