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B
- B (bulb)
- Is the letter on the shutter dial that the shutter will stay open while the real is depressed. This is used for time exposure that are longer than your camera's preset shutter speed.
- B&W
- Abbreviation that stands for " black and white. "
- Back focus
- Distance between the back surface of the lens and the image plane, when the lens is focused at infinity.
- Back-lighting
- Light coming from behind the subject.
- Background
- Areas shown behind the main subject in a picture.
- Background colour
- This is the colour that appears when part of an image is erased, cut or deleted.
- Background Processing
- Allows assignment of specific operations to the background while the computer continues to perform previously assigned instructions.
- Backing
- The dark coating, normally on the back of a film, but sometimes between emulsion and the base, to reduce halation. The backing dye disappears during the processing.
- Backlight control
- An exposure compensation introduced when the subject of a picture is lit from behind (which can fool a camera's metering system, creating a silhouette effect).
- Baffle
- A type of shield that prohibits light from entering an optical system.
- Balanced fill-flash
- Balanced fill-flash is required. In balanced fill-flash operation, flash output is controlled to keep it in balance with the ambient light on the scene. Nikon offers Automatic balanced Fill-Flash where flash output is automatically compensated to be in balance with the ambient light.
- Banding
- A visible stepping of shades in a gradient. A artifact of colour gradation in computer imaging, when graduated colours break into larger blocks of a single colour, reducing the smooth look of a proper gradation.
- Bandwidth
- General term for the amount of data that can pass through a given channel at one time. When using a dialup connection, the Internet for example, your bandwidth is limited by your telephone connection and modem, and will typically be 2-4 kilobytes per second. Information requiring more than this flow of data will be impractical for this connection.
- Barn door
- Are an accessory used on spotlights and flood lamps to control the direction of light and width of the beam.
- Barrel
- The chassis of a lens. It usually is cylindrical and contains the lens element and iris diaphragm.
- Barrel distortion
- A lens aberration or defect that causes straight lines to bow outward away from the center of the image.
- Bas-relief
- In digital photography, this refers to an effect produced with a Photoshop filter, which makes an image appear to be slightly raised off the surface.
- Base
- The material on which the emulsion is coated on film, photographic paper or videotape. Available in a choice of materials, including paper, cellulose, triacetate, glass and estar.
- Base exposure time
- Is the initial exposure time used for making a "straight" print.
- Base plus fog
- The optical density of an unexposed area of processed film. This takes into consideration the density of both the base and the emulsion.
- Base resolution
- The PhotoCD image resolution (512 x 1024) that is established for display on current televisions.
- Batch numbers
- Set of numbers printed on packages of sensitive materials to indicate common production coating.
- Batch processing
- The performing of a group of computer tasks at the same time.
- Batch scanning
- Sequential scanning of multiple originals using previously-defined, unique settings for each.
- Batteries
- Batteries for digital cameras can range from AA size to NiCad (nickel-cadmium), to NiMH (nickel-metal hydride) to lithium ion. nickel cadmium (NiCad): Rechargeable batteries that use an alkaline electrolyte. They have a longer life than non-rechargeable batteries. NiCad batteries have a memory, so they need to be run all the way down before recharging. Otherwise, they will begin to run out of power sooner. nickel metal hydride (NiMH): A rechargeable battery that lasts longer than a NiCad and has no memory, so it is easier to manage. lithium ion: More expensive than either the NiCad or NiMH, but holds a charge much longer.
- Baud
- Named after the French telecommunications technician Baudot. It is the unit used to measure data transfer (1 Baud = 1 bit/sec.). Therefore, for example, the specification - "28,800 Bauds" means that data can be transferred at a rate of 28,800 bits per second.
- Bayer pattern
- A pattern of red, green, and blue filters on the image sensor's photosites. There are twice as many green filters as the other colours because the human eye is more sensitive to green and therefore green colour accuracy is more important.
- Bayonet lens mount
- A method of mounting a lens onto a camera body. The lens is inserted into the camera and given a short turn to lock it into place. Except for a few instances, a bayonet mount camera will not accept bayonet mount lenses made by a different manufacturer. The most common method of lens mounting.
- Bellows
- An accordion-like, light tight device. On a camera, it goes between the lens and the camera body. When used as an accessory to a 35mm camera, it enables it to focus on a close subject and achieve a greater-than life-size magnification on film. On an enlarger, it goes between the lens and the enlarger head and the lens is focused by adjusting the length of the bellows.
- Bellows factor
- The exposure compensation necessary when focusing on close subjects, which becomes necessary when the subject is closer than ten times the focal length of the lens. As a lens is placed closer to the subject, focusing the lens causes it to move farther from the film, and, therefore, less light falls on the film. Consequently the exposure must be increased.
- Between-The-Lens Shutter
- A shutter whose blades operate between two elements of the lens. Most medium format cameras like the Hasselblad have one family of lens with shuttle and another without. Most lenses in this family have a smaller maximum aperture than the other family.
- Bézier curve
- A mathematical curve that describes a vector path. In Photoshop Bézier curves are created by plotting anchor points with the pen tool.
- Bi-concave lens
- A simple lens or lens shape within a compound lens, whose surfaces curve toward the optical center. Such a lens causes light rays to diverge.
- Big data
- Any part of a layer that extends outside the physical dimensions of a Photoshop document.
- Bilevel
- A type of image containing only black and white pixels.
- Binary number system
- A numbering system used in computers consisting of only 1's and 0's.
- Bios
- Basic input / output system. The computer part that manages communications between the computer and peripherals.
- Bit
- The basic unit in a binary numbering system. Binary Digit. A single bit is expressed in the base 2, either on or off. Imagine using bits of data to express gray scale. Progressive levels display are expressed as increasing powers of 2. In a one bit system (21) there would only be white or black. A four bit system is 24 (16 gray scale levels) where a six bit system is 26 (64 levels of gray). The more gray, the better the picture.
- Bit depth
- This refers to the grey scale range of an individual pixel. A pixel with 8 bits per colour gives a 24 bit image (8 bits X 3 colours is 24 bits). CCD sensors are coloured in a pixel by pixel method. 30/32 bit colour is billions of colours. 24 bit colour resolution is 16.7 million colours. 16 bit colour is 65,536 colours. 8 bit colour is 256 colours. 8 bit grey scale is 256 shades of grey. 1 bit is black or white.
- Bit mapped image
- An image created from a series of bits and bytes that form pixels. Each pixel can vary in colour or gray-scale value. Also known as a raster image.
- Bitmap
- The method of storing information that maps an image pixel, bit by bit. There are many bitmapped file formats, .bmp, .pcx, .pict, .pict-2, tiff, .tiff, .gif (89a), and so on. Most image files are bit mapped. This type of file gives you the jaggies, when examined closely you can see the line of pixels that create edges. Bitmap images are used by all computers. The desktop or screen information for all Windows machines uses .bmp files, while the Macintosh uses pict files
- Bitonal
- An image or file comprised of pixel or dot values of either black or white.
- Black
- In four-colour printing (CMYK) black is the fourth colour, represented by the " K ".
- Black generation
- When converting an RGB image to CMYK colour mode, black generation refers to the values that are generated for the black plate used in commercial printing.
- Black limit
- A colour separation setting that establishes the maximum percentage of black ink in a CMYK image. The setting is made before an RGB image is converted to a CMYK image. The press and paper planned for the publication usually determine the proper black limit setting.
- Black point
- This is the colour that produces colour values of 0, 0, 0 for each of the RGB components when scanned or digitized. Normally, the black point is 0 percent neutral reflectance or transmittance.
- Black point compensation
- A setting in Photoshop that adjusts for differences in black points when converting colours. When selected, the full dynamic range of the source colour space is mapped to the full dynamic range of the destination colour space. When deselected, the dynamic range of the source colour space is simulated in the destination colour space.
- 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 colour processes.
- Bleed
- Printing term referring to an image or inked area which extends to the edge of a printed piece. The bleed is the portion of the artwork that is beyond the trim marks of the piece. The bleed is required to account for any slight misalignment during trimming which would otherwise result in an unprinted strip of paper appearing at the edge of the finished piece.
- Blemishes
- Pimples, scars, spots, and other defects which may be softened or removed by negative retouching, print spotting, and/or airbrushing (sometimes called "artifacts").
- Blend
- In computer graphics software, the intermediate steps between two objects that are created when the objects are merged together via a specified number of intermediate transformations.
- Blooming
- Each pixel (photosite) on a digital camera sensor (CCD/CMOS) has a limit as to how much charge it can store. Blooming (or Streaking) is the name given to an overflow of charge from an over saturated pixel (photosite) to the next on the sensor. This problem is addressed with the addition of "anti-blooming gates" which can be thought of as vertical drain ditches running beside each row of pixels, these gates allow the overflowing charge to run away without affecting surrounding pixels. Anti-blooming gates, while mostly successful (and certainly for more modern sensors) blooming can still be a problem in very extreme exposures (very bright edge against a virtually black edge) and is typically visible as either a vertical streak or white halo extending for several pixels. The effects of blooming often amplify the visibility of chromatic aberrations. Blooming is really good at destroying the detail of leaves shot against a bright sky.
- Blotters
- Sheets of absorbent paper made expressly for photographic use. Wet prints dry when placed between blotters.
- Blowup
- Slang for an enlargement, a print that is made larger than the negative or slide.
- Blur
- The art of softening the detail of a image. The process can be applied selectively to portions of an image.
- Bmp
- File format extension for bitmap images.
- Body
- The light-tight box that contains the camera mechanisms and protects the film from light until you are ready to make an exposure.
- Boom
- A adjustable metal arm, attached to a firm stand, on which lighting can be mounted. Some booms are also made to support camera.
- Boot
- To start or restart your computer; loading your operating system.
- Bordering
- Automatically locating the correct edge of an image on a scan so that marking from the edge, frame, etc is not capture.
- Bottom weighted
- Refers to the area of the picture that the camera will meter for exposure. When making an auto exposure the camera is programmed to look at a number of spots in the scene, and if the camera was designed to use bottom weighted metering, most of those spots will be in the lower half of the picture. (See center weighted and exposure.)
- Bounce flash
- Flash illuminating a subject by reflection off a surface as opposed to direct flash, which is flash light aimed straight at the subject. Sometimes also called " Bounce lighting."
- Bounce light
- Light that does not travel directly from its source (bounce flash) to the subject but is first reflected off another surface. This technique softens the light by directing it at a ceiling, wall, board, or similar 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.
- Bpi (Bits per Inch)
- Defines the density of data in a bitmap image.
- Bps ( bits per second )
- Refers to the number of bits transferred in one second. The bps not often found on modems and serial interfaces.
- Bracket flash
- Often called handle mount flash. It comprised of one arm of the L-shaped bracket extends under the camera body and uses the camera's tripod socket to mount the camera on the bracket. The vertical arm of the bracket serves as a handle and mounts a flash unit in an accessory shoe often on top of the handle portion, but there are other methods. Flash mounted in a bracket usually requires a separate electrical cord to make the electrical connection between camera body and flash unit.
- Bracketing
- To make several exposures, some greater and some less than the exposure that is calculated to be corrected. Bracketing allows for error and permits selection of the best exposure after development.
- Brightness
- The balance of light and dark shades in a image. Brightness is distinct from contrast, which measures the range between the darkness and lightest shades in a image. Brightness determines the intensity of shades; contrast determines the number of shades you get.
- Brightness range
- The difference in luminance between the darkest and lightest areas of the subject, in both negative and print.
- Brilliance
- The intensity of light reflected from a surface. It is sometimes an alternative term for luminosity.
- Broad Lighting
- Conventional portraiture often positions the model in a pose such that their bodies are not facing the camera directly, but are turned to one side or the other. If the main light is positioned such that the illuminated portion of the face is framed in the image rather than the shadowed portion as in Short Lighting.
- Browser
- A program used to display information, especially on the Internet.
- Buffer
- A special area set aside either in hardware or software for temporary storage. Usually, the bigger the buffer, the faster the computer can process other data.
- Buffer ram
- Fast memory chip in a digital camera. Buffer Ram is used to store images whilst they are recorded onto the much slower removable media card. This allows cameras to take a number of shots in rapid succession without waiting for the previous image(s) to be written to the card.
- Built-in light meter
- A reflective exposure meter that is a built-in component of a camera so that exposures can be easily made for the cameras position.
- Bulb setting
- A shutter setting marked B at which the shutter remains open as long as the shutter release is held down. This is used for time exposures that are longer than your camera's preset shutter speeds.
- 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 in
- Basically, a darkroom process that gives additional exposure to part of the image projected on an enlarger easel to make that area of the print darker. This is accomplished after the basic exposure by extending the exposure time to allow additional image-forming light to strike the areas in the print you want to darken while holding back the image-forming light from the rest of the image. Sometimes called printing-in.
- Burst images
- A series of images taken in rapid succession, captured at a preset speed. Burst images are usually used to capture a person or object in motion. The number of images captured will vary, depending on how long the shutter button is held down and how much memory is available.
- Bus
- A path in the computer to transfer information within the computer or to the device(s) to which the data are addressed.
- Byte
- A unit of measure equal to 8 bits of digital information. The standard measurement unit of a file size.
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