B:  see bulb

Back lighting:  light that comes from behind the subject toward the camera

Bleed mount:  to mount a print so that there is no border between the edges of the print and the edges of the mounting surface

Blocked up describes highlight areas that lack formal texture and detail.  Due to excess contrast caused by overexposure or overdevelopment

Blotters:  sheets of absorbent paper made expressly for photographic use, wet prints dry when placed between blotters

Bounce light light that does not travel directly from its source to the subject but is first reflected off another surface

Bracket:  to make sever exposures, some greater and some less than the exposure that is calculated to be correct.  Bracketing allows for error and permits selection of the best exposure after development.

Brightness:  a subjective impression of the lightness of an object.  The correct term for the measurable quantity of light reflected or produced by an object is luminance

Broad lighting:  Portrait lighting in which the main source of light illuminates the side of the face turned most toward the camera.

Built-in meter a reflected-light exposure meter built into a camera so that light reading cam be made directly from camera position

Bulb:  a shutter setting marked B at which the shutter remains open as long as the shutter release is held down.

Burn-in:  to darken a specific area of a print by giving it additional printing exposure