Background light - The lighting that illuminates the background and does not affect the lighting of the subject

Backscatter - Suspended particles in water that are illuminated, and therefore captured on film as a cloud or scattering of light dots, when using a flash underwater near the lens.

Balance - Compositional harmony of a scene based on the placement of elements of different sizes, shapes and colours.

Barndoor -  These are small “gobos” (light-blocking devices) that fall under the general category of “grip equipment.” They are accessories that attach to studio lights and swivel on hinges (just like the doors on a barn) to allow the photographer to control the light’s direction and the width of the light beam.

Bare bulb - Electronic flash unit used without a reflector or diffuser.

Batch numbers - Series of numbers imprinted by the manufacturer on the packaging of film and light-sensitive products to indicate that the materials are all from the same production batch, and therefore share closely-similar qualities, such as film speed and contrast.

Bellows - A folding sleeve-like device that fits between the lens and the camera that allows for extended separation of lens and film plane. A bellows is used in close-up photography, and performs a function similar to that of extension tubes, except that the tubes are fixed and the bellows is minutely adjustable.

Between-the-lens shutter  - A shutter situated between two lens elements.

Black frames - Unexposed frames on a roll of film.

Bleach - A chemical bath to convert the black metallic silver that forms a photographic image into a compound such as a silver halide, which can then be dissolved or dyed. Bleach is used in toning and in many color processes.

Bleed - Describes a photographic print that extends to the edges of the paper and has no visible border or defined margin area.

Blix (bleach-fix) - A combined bleach and fixer bath used to shorten color processing.

Blow-up - As a noun, blow-up (or blowup) is another term for an enlargement of a photographic print. As a verb, it is the actual enlarging of the image, as in “Please blow up this negative to an 11" X 14" print.”

Blur - Denotes a photograph in which movement, either camera movement, zoom lens movement or movement within the scene (e.g. a subject in motion), is recorded at a slower shutter speed than is necessary to “freeze” the motion as a sharp image. Blur is often intentionally created by a photographer who wishes to convey a sense of motion.

Bounce flash - A technique of softening the light from a flash source by directing it onto a ceiling, wall, board or similar reflective surface before it reaches the subject.

Box camera - Simple camera with a fixed, single-element lens and a light-tight box to hold the film. The shutter and aperture are usually pre-determined and unalterable (typically 1/25 sec at ƒ11.) Early consumer cameras developed by George Eastman were box cameras (e.g. the “Brownie” camera) . They could not be focused, per se. The lens was set to a hyperfocal distance that gave acceptably-sharp pictures if the subject was a given distance from the camera and correct exposure depended upon bright sun illuminating the scene.

Bracket or Bracketing - Refers to taking a series of pictures, at least three, of the same subject with varying exposures - (1) the main exposure, which is presumed to be correct, but may not be; (2) an overexposure, generally of ½ or 1 stop’s difference from the main exposure, and (3) an underexposure of ½, 1 or 2 stop’s difference from the main exposure. The theory behind exposure bracketing is that the photographer may not be certain that the main exposure is best for the subject matter, and the subsequent exposures will provide “insurance” that at least one of the images will provide acceptable exposure. Sometimes, though, the photographer may simply want to see the effects of different exposures of a scene. The term “bracket” is analogous with grammatical brackets or parentheses, where they are located on either end of a phrase. “Bracketed” exposures fall on either side of the exposure that is presumed to be correct.

Brownie - Brand name of Kodak’s first consumer box cameras.

B.S. - B.S. refers to the British Standard for film speed measurement. BSI refers to the British Standards Institute which determined the B.S. system. It employed the same film speed numbering system as the American Standards Association- ASA. Both are now defunct, having been replaced by ISO for rating of the sensitivity of film and photographic materials.

Built-in light meter  - A reflective exposure meter that is a built-in component of a camera.

Bulk film - Film produced in very long, uncut strips - rolls that are too long to fit into cameras not equipped with a bulk camera back accessory. Many photographers buy their film in bulk, then load the bulk film into a “bulk film loader” which permits them to cut the bulk film into however many frames they wish, and to load the smaller strips into film cartridges that permit film reloading. It is an economical way to purchase film.

Burning or Burning-in (printing-in) - A technique used in printing photographs whereby selected areas of an image are given more exposure than the rest. Other areas are shaded from the light during this time.