Glossary of Digital Imaging Terms A-L

A B C D E F G H I J K L M N O Q R S T U V W X Y Z

Accelerator - A specialized hardware or software device to augment the performance of a platform's CPU bus or I/O.

Addressable resolution - The maximum number of pixels an imaging device is capable of manipulating, and not necessarily the same amount the monitor is capable of displaying.

Additive primaries - Red, green, and blue light when combined produce white light.

Adobe Systems, Inc. - A software applications company located in Mountain View, CA, known for PhotoshopTM, TypeManagerTM and IllustratorTM.

Airbrush - A digital tool which gives the effect of spraying a paint/air mixture over an image. Most graphic packages incorporate an assortment of brushes that are user definable.

Algorithm - A set of mathematical rules for solving a problem in a step-by-step process with a specific beginning and end.

Aliasing - In graphic imaging, the undesirable components resulting from the combination of signals or inadequate preparation of signals prior to digitization.

Alphanumeric - A combination of letters and numbers.

Analog - A continuously variable electric voltage or signal.

Anti-aliasing - The smoothing and removing of aliasing effects by electronic filtering and other techniques, such as blending of hard edges. Also blending objects-oriented art with bit mapped art. Some current systems and hardware generators have automatic anti-alias research circuitry. Application - The highest level of software that the user sees. It is above the operating system's software level, which may be running within an environment. Also a generic term for software programs and/or developers.

Archive - Long-term offline storage. Current popular media are 8mm magnetic tape and optical discs.

Architecture - The basic design of a computer system, its circuitry, microprocessor, memory, etc., and its connectivity of components.

Arcus tm - A flatbed CCD scanner produced by Agfa.

Artifact - A visible defect in an image, such as aliasing and more.

ASCII - An acronym for the American Standard Code for information Interchange, which converts keyboard input into digital information. It covers all the printable and control characters.

Aspect ratio - In computer graphics, the images' relationship of width to height must be kept the same when it is displayed on several screens.

AutoCAD tm - A CAD software program for PC, VAX, Macintosh and UNIX platforms.

Background processing - Concurrent processing work performed by the computer to carry out the investigative instructions of the operator while other activities are being performed.

Barco Graphics - A Belgium company (U.S. headquarters, Dayton, OH) is a supplier of monitors and high end computer-driven electronic color systems for prepress, photo, design, advertising, and packaging. The Creator workstations offer vector-based and pixel imagine capabilities. Barco is UNIX environment on Silicon Graphics platform.

Blanding - Stair-stepping of shades in a gradient or on the blend.

Batch processing - The performing of a group of computer tasks at the same time.

Baud rate - The speed at which computer data can be transmitted via modem. Example: Modem rates may be 1200, 2400 and 9600 baud. To determine the number of bytes transferred per second - divide the baud rate by 8.

Bernoulli box - A removable magnetic storage system.

Bezier curve - A mathematically defined curve made up of four points, two ends and two in between, that affect its shape.

Bi-cubic interpolation - A Matrix for comparison of central pixels to surrounding pixels.

Binary - A numbering system based on 2s which use 0 and 1 when written. Binary files are about half the size of similar ASCII files.

BIOS - Basic input/output system. The computer part that manages communications between the computer and peripherals.

Bit-Derived from Binary digit. The smallest unit of information in a computer. 8bits = 1byte. Bit map - An image formed by a rectangular grid of pixels. Bit mapped graphics are constructed with individual pixels or dots, rather than object-based or vector-based graphics. High-definition color consists of 32 bits.

Bit-mapped graphics - Raster graphics which are made up of pixels or dots.

Bleeding edge - Technology that is slightly ahead of its time.

Blend - The joining of two or more colors without a noticeable line.

Blur - The art of softening the detail of a digital image. The process can be applied selectively to portions of an image.

Bubble-Jet - Printers - made by Canon for reflective and transparent prints. The desktop model is the CJ-10 and the BJ - A1 makes 23"-wide copies.

Buffer - A temporary storage space in computer memory before it is transferred.

Bundling - Combining two or more different functions into one expansion board or peripheral device. Also combining software "bundled" with hardware.

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 standard unit of measure - 8bits = 1 byte. Each 8-bit byte represents a character.

‘C' - High-level computer language which is used for many of today's graphics programs.

Cache - A temporary storage area for information which locates itself between the hard disk and the RAM by employing intuitive logic. It also speeds up the access time of the data.

CAD - An acronym for computer-aided design - CAD programs for engineering, architecture, integrated circuits and graphics design save considerable time over conventional methods.

Calibration - The setting of computer system components to a standard which will produce the same readable results on each unit, i.e., color calibration is necessary in the workstation to achieve the same results on the output.

Canvas - The entire image displayed on the monitor, but not necessarily at full resolution.

Capture - To pick up information, i.e., capture an image on a scanner or digital camera.

CCD - Charge Coupled Device light detector, converts light into proportional (analog) electrical current. CCD elements are used in desktop scanners, camcorders, video cameras, and some graphic arts scanners.

CCD array - A device that mounts many CCDs together to allow for capture of many pixels at the same time.

CCD color scanner - An input scanner using a lens and a linear CCD array to produce the scan raster.

CD-I - Compact Disc Interactive - A compact disc player that connects to a TV and also reads Photo CD images.

CD-R - Compact Disc Recordable writes data to discs, which can then be read by standard CD-ROM drives.

CD-ROM - Compact Disc Read Only Memory - a data storage system which holds up to 680 MB of information. Playback is through a CD-ROM drive unit.

CD-ROM XA - Or eXtended Architecture, is a type of drive for compact disc- read only memory that is compatible with Photo CD and other CDs.

Centronix - A common PC (parallel) network interface.

CEPS - An acronym for Color Electronic Prepress System.

CGM - Computer Graphic Metafile, (vector based), is a standard format which allows graphics images to be transferred from one application to another.

CIE - An alternative set of color standards adopted by Adobe, and named after the Commission International de l'Eclairage. Or, CIE-based color spaces are called objective or device independent color spaces for communication of color.

Clock Speed - The speed of the computer is measured by electronic circuits in an internal timing device.

Cloning - To make an exact duplicate of digital image data. In digital systems it is possible to copy part of an image onto another.

CLUT - Color Lookup Tables - A color referencing system.

CMYK - Printers' primary colors, Cyan Magenta, Yellow and Black.

Color curves - A mechanism for controlling color changes, and matching colors. Color curves are set by user-adjustable lookup tables that define a color transform, which may be applied to each primary additive or subtractive color in the image.

Color Gamuts - Any color medium representing its own range of color, including film, a monitor, printed images or the human eye.

ColorGetterTM - Optronics' moderately priced drum color scanners.

Color Laser ImagerTM - 3M's digital printer which outputs 8x10 to 12x18" photographic quality prints or transparencies. Interfaces are possible through Sun, SGI or VMS host, and a video pickup to grab signals off the computer.

Color mixing - The artistic process of mixing color electronically.

Color proof - Proofs may be in-house for checking composition, or a representation of the final print for client OK. Common types are CromalinTM, MatchPrintTM, inkjet, dye sublimation and laser copies.

Color separations - The process of separating a color image into four subtractive colors, CMYK, in either positive or negative form.

ColorSetterTM - Optronics internal-drum PostScript image setters.

Color transform - A color management system - the transformation of one color to another. Color transparency -A photographic or lineart image on transparent film.

Composite (Comp) - A term for combining images, artwork, lineart and type.

Compression ratio - The sampling of digital data to increase storage capacity in a computer, or for faster transmission of data via modem.

Connectivity - The ability to connect electronic imaging components together so they function in harmony.

Contrast - The relationship between the lightest and darkest areas of an image (D-Min/D-Max).

Conversion - In computer imaging, to change a CMYK file to RGB or vice versa, or to convert one file format to another.

Copy - The text element of a page. Also to electronically copy any data to another position or page.

Copy brush - A means of coping one area of the screen image to another position. Also known as clone, shift and texture.

CorelDrawTM - A PC graphics software package with abundant drawing and editing tools. Its features include autotracing bitmaps, blending, calligraphic pen strokes, fills, import/export filters, masking and Pantone® color and perspective, and comprehensive connectivity. By Corel Systems Corp., Ottawa, ON.

CPU/ Central Processing Unit - A large chip which holds the "brains" of the computer.

CRT/cathode ray tube - The computer's monitor. Also used in some film recorders. Crunch - A computer term for processing of compressing data.

CT/Continuous Tone - A picture file. Also called contone. A CT file uses one byte each for its RGB values, allowing up to 256 density levels per color and more than 16 million different combinations of colors.

Cursor - A location marker on the monitor.

Cut/paste - To cut out an image or line element, usually by masking it, and repositioning the elements(s) elsewhere.

DAT - Digital Audio Tape format is a mini tape format for image storage and backup. Decompression - To open up compressed file(s).

Default - A present option which is assumed to be normal when no other parameters are set. Density - The degree of opacity of an image.

De-skewing - Straightening an image that has been scanned crookedly, or straightening type that is slanted.

Device - Independent Color - Coloring management systems, or portable color dictates that digital color data be processed and rendered accurately on any device.

DI - Acronym for Digital Imaging.

Diamond Scan - Mitsubishis' flatbed scanner. Also Diamond PostScript printers.

DIC - An acronym for Device Independent Color.

Dice-Net - Digital Ideas Color Equipment Network from Page Prep, Suffern, NY. A file server for Canon copiers and Bubble Jet printers, also Scitex workstations, electrostatic plotters and Solitaire film recorders.

DIF - Data Interchange Format, a standard for access between programs.

DG - Image and line data that has been translated into numerical values for manipulation and reproduction without loss of quality.

Digitize - The process of converting analog data to digital information.

Digitizing tablet - A device which accepts position signals from a mouse or stylus and presents them to the computer.

DIP switch - Dual Inline Package - a set of switches used to adjust computer peripherals.

Directory - A catalog of computer contents/files.

Disc - Magnetic or optical storage medium - discs may be flexible "floppy" or rigid.

Disk cache - Improves performance of disk controller via high-speed memory.

Diskette - or disk - a magnetic storage medium for reading and writing information.

Distortion - Changing the size of an image in a non-proportional manner. Also known as "anamorphic scaling." Dither - The process of adding dots to a small area in order to smooth out the appearance of an image, or specifying colors to adjacent pixels in order to simulate intermediate colors in a bit mapped image.

D-MAX - The highest level of density.

D-Min - The lowest level of density.

DOS-Disk Operating System from Microsoft Corp. - Computer program instructions controlling storage and utilization of information.

DOT - A hafttone dot used in color separations. Haftone dots have fixed density of CMYK, but variable size. By varying the size and shape of a halftone dot, continuous tone colors can be created. Also the minimum addressable point in a dot-matrix printer.

Dot matrix - The process of printing with dots to create images, lines and text.

DPI-Dots per inch - the number of distinct pixels that can be produced horizontally or vertically in a linear inch.

Drag - To depress the mouse button to complete an action.

D-RAM - Dynamic Random Access Memory - a computer memory device offering high data packing density and data rates. Also Dram chips for PCs.

Driver - A form of buffer - a circuit designed to isolate a load from the driving force.

Drop Shadow - A graphic art effect designed to simulate the shadow cast by three dimensional shapes.

Drum scanner - An optical scanner with the image mounted to a cylindrical drum. A narrow beam of light passes through the drum and enters a lens behind which beam-splitters and photo multipliers detect the varying light reflected from the original and produce digital electrical signals.

DTP - Acronym for desktop publishing, including typesetting, image handling and page composition.

Dye sublimation - Also diffusion transfer printing - has a variable dot intensity which can create more colors than possible with thermal printers. Most CT printers use dye-sublimation thermal-transfer technology.

Dynamic range - The color or shade of gray assigned to each pixel. Also the difference between the smallest amount and the largest amount of gray that a system can represent. Also the difference between the lightest highlight and the D-Max that the system can scan, manipulate and write.

EISA -32-bit Bus for PCs.

Electrostatic output - Reflection print or backlit transparency produced form various size plotters using CMYK toners to form C-T images.

Element - A image, or line art, in whole or part of the page, composite or file.

Elliptical Dot - A halftone screen dot that can produce better tonal gradations than a circular dot.

Emboss - Usually done photo-mechanically, but some EIM & CEPS systems can accomplish the process in seconds.

Emulsion - Coating on the light-sensitive material. The opposite side of the base.

Encapsulated Postscript - EPS translates graphics and text into a code which the printer can read & print.

Environment - Every computer works within a netware or software surrounding. The condition in which a computer operates. Also, an operating system used to support another operating system is an "environment."

EPS - See Encapsulated PostScript.

Erase - The process of removing information form memory or storage. Part of a file or image may be erased.

Ethernet - A networking system providing transfer of data between computer systems and peripherals over a coaxial link.

Exabyte - A type of 8mm tape drive and storage cartridge.

Feathering - The process of merging borders, or softening the edge around a mask.

Fiber optics - Very thin cables used in transmitting data.

Film recorder drum - The highest quality film recorder. They may be sheet- or roll-fed with exposure via white light or laser. It is possible to image on negative or positive film plus photographic print material.

Fire 1000TM - A digital drum film recorder from Cymbolic Sciences Intl., (CSI) Vancouver, B.C. (formerly McDonald Dettwiler).

FieryTM - EFI's file server to transfer and queue data to color output devices. File server - A computer which controls another device.

Flat bed scanner - A CCD linear array scanner with a non-moving surface handling film and artwork from 35mm up, with varying resolutions.

Floppy disk - A removable magnetic storage medium.

Floptical - A21 MB data PC floppy drive.

Flying spot scanner - A scanner in which the original is held inside a dark chamber while a beam of light flies across it in a raster pattern.

Format - A computer operating arrangement of data words, letters, characters, files, etc. In transferring files, the sender should use a file format which the receiving program can read. Frame grabber - A computer expansion board (card) which actually grabs a signal from a TV or digital image and converts it into another file format or digital computer graphics language.

Freedom Of The PressTM - A PostScript language interpreter that converts PostScript language files into bit-mapped images that a printer can understand.

FreeHandTM - A PostScript language drawing tools for Macintosh marketed by Aldus. The PC MS Windows version incorporates text and graphics.

GB - Gigabyte, or 1,073,741,824 bytes of memory.

Gamma - The measuring curves which shows the degree of darkness or lightness of an image.

Gateway - A server which connects nodes and networks of different architectures by way of protocol conversions. Postscript is a gateway to digital transferal of data.

Gaussian brush - A brush with variable density.

GCR - Gray Component Replacement - The process of reducing the amount of CMY and replacing them with black.

Generation loss- Photographic duplicates suffer from generation loss; digital data do not suffer loss when copied without processing.

GITO - Garbage In, Garbage Out.

Global work - Editing that affects the entire picture or page.

GPIB Interface - Graphic Port Interface Bus - A standard interface in the graphic arts for graphic computers and peripherals.

Grab - To select a portion of the screen's image for editing or insertion into another file.

Gradient - A smooth spread between colors.

Graduated - The process of moving smoothly from one color to another as in vignette.

Graduation - A smooth transition between black and white and from one color to another, or color deficiency.

Grain - A texture or mottling effect.

Gravure - A quality printing process used in long-run work, especially publications.

Gray scale monitor - The display of distinct gray, black and white pixels.

Greeking - An old typography term for simulating text to fill a given area.

Grid - Regularly spaced horizontal and vertical lines across the picture for accurate positioning when moving elements for compositing.

GUI - Graphical User Interface - a computer control system whereby the operator commands the computer with a mouse or stylus.

Hacker - Slang for a non-professional dedicated computer operator.

Haftone -HT - A printing process controlled by the size and shape of dots.

Hard copy - Refers to a print or proof, as opposed to viewing on a monitor.

Hard dot - A dot with smooth ,crisp edges.

Hard drive - A built-in or off-line fixed storage medium which holds large amounts of data that can be accessed rapidly depending on the power of the computer.

Hardware - The physical/mechanical parts of an electronic imaging system.

HDTV - High-Definition Television - The coming system - at least double the resolution we have today.

High fidelity color - or expanded gamut color printing for spectacular color.

Highlight - The lightest areas of the image or page.

Howtek - A Hudson, NH developing company of flatbed and drum scanners and output devices.

HPGL - Hewlett-Packard Graphics Language.

Hue - A component of color, or the wavelength of light pf pure color.

Hybrid - A term applied to El systems that meld electronics with silver-halide images.

HyphenTM - A PostScript interpreter (RIP).

Hz - An abbreviation for hertz - an international unit of frequency which equals one cycle per second.

Icon - A small graphic image on the screen used to represent a file or directory.

IllustratorTM - Adobe's drawing software for PC a Mac computers.

Image processing - Comparable to data processing whereby captured image data can be manipulated by color, size, shape and position.

Imagesetter - Output devise to image onto separation film. They are the preferred PostScript compatible and non-PostScript devices.

Imapro - An Ottawa, Canada manufacturer of hardware and software, including the QCS line of flatbed scanner QCR CRT film recorders, and photo and prepress imaging software.

Inkjet printer - The process of spraying tiny droplets of ink onto opaque or transparent material. One type is bubble jet whereby the ink is heated causing a bubble to form, and the pressure produced by the expanding bubble forces the ink out of the head. The second uses a piezoelectric diaphragm, which through vibration forces the ink out of the print head.

Input - Media such as cameras and scanners used to convert images to digital data for transferring to a workstation. Also storage media, tape, and discs, can be classified as input devices.

Interactive - Work done by an operator where the results of the work appear instantaneously, or in real time on the monitor as it performs other activities. Also combining complex applications, i.e., graphics, voice, music, video etc.

Interface - The process of making components or peripherals work together.

Interpolation - A technique for increasing the size of a graphic file by creating pixels. Also an extrapolation algorithm. There are two types, sequential and bi-cubic.

I/O - Acronym for input/output. Input may be camera, tape, disk, video, scanner, and output may be tape, disk, CD ROM, film recorder, printer, plotter, or imagesetter.

IRIS - Inkjet continuous-tone printer line owned by Scitex. It lays down variable-sized dots yielding high resolution and prints on any substrate.

ISA - A 16-bit bus for PCs.

Isomet - Manufacturer of high-resolution PMT drum scanners and acousto-optic modulators.

Jaggies - Another word for stair-stepping or staircased edges of a raster or vector image. This problem can appear when low-resolution files are blown up to large sizes.

JPEG - "Joint Photographic Expert Group" have proposed a standard for still image compression. It breaks down digitized pixels into blocks. Each 16 x 16 pixels is reduced to 8 x 8 pixels by subtracting every other pixel. Data is retrieved by decompression at some loss. This process speeds up the transfer of data.

Jukebox - A storage device for multiple optical disc, and one or more discs drives. It will automatically select or changeover as needed. Also Kodak's term for Photo CD's automated disc library.

Kerning - To kern is to tuck a letter under the overhang of another, such as the lower case "a" under the capital "T" to reduce the amount of white space or leading between characters.

Keyboard - Today's accepted term to replace the word typing because keyboard relates to a computer. In the U.S., QWERTY "the first six letter from the left," is the standard style.

Kilobyte - Kb, or 1.024 bytes of information.

Knockout - A masking technique used to separate an element from the background.

LAN - An acronym for Local Area Network.

Laser scanner - An acronym for Light Amplification by Stimulated Emission of Radiation. Lasers provide stable and coherent single color light.

Layering - The process of placing one image on top of another and eliminating the lines underneath.

Leaf Systems - A Scitex-owned manufacturer of CCD scanners (Leafscan), hardware and software.

Link - A catch-all word for connecting any computer device to another, i.e. input to output, modem to receiver. Also the connection of one internal function to another, and points on a display.

LinotronicTM - An imagesetter line made by Linotype/Hell, including capstan and internal drum devices.

Lossless - Image and data compression that reduces the file size without data loss.

Lossy - Image compression, such as JPEG, that reduces the size of the image through the loss of some information.

LPI - An abbreviation for lines per inch.

LUT - Look-up tables - A digital processing method by which an input color value can be matched in the output, or for color conversion. Also a table of colors a computer can display. Luminance - The brightness of a color.

LVT - Initials for Light Value Technology, a Kodak company, manufacturer of high-end drum film recorders.

A B C D E F G H I J K L M N O Q R S T U V W X Y Z


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