A/D Converter : Analog to Digital Converter. Generic term for any device that changes continuous wave (analog) activity to binary (digital) codes, or vice versa.
Abend: Abnormal End. Also called system crash. Usually caused by input or data presented to a computer which is beyond its ability to cope. If an abend happens in a single-task program (like DOS), the machine will cease to take input ("lock up") and must be restarted ("re-booted"). Multitasking operating systems (like UNIX) allows other programs to continue running while only stopping the one causing trouble.
Aberration: In lenses, it is a failure to form a perfect image. Two important types of aberration in photography to avoid are spherical and chromatic.
Ablate: To remove. Used in reference to the formation of laser-readable "pits" in the recording layer of optical disks.
Abort: The unintentional premature termination of a process or program in an electronic environment caused by operator, software, or system error or miscommunication.
Absorption: In optics, it is the property which causes the partial suppression of light through a transparent or translucent material. In paper, the ability to take up liquids (ink and water) in contact with it. In filters, the ability to absorb part of the spectrum of white light and transmit or absorb other parts of the spectrum.
Abstract: A brief restatement of the contents of a file or document.
Accelerator board: A printed circuit board added to a PC to increase its performance speeds. For example, if you have a Macintosh containing a Motorola 68000 CPU, you can purchase an accelerator board containing the faster 68030 CPU.
Access: The process of obtaining data from, or transfereing data to a storage device, register or RAM.
Access Method: The technique or the program code in the operating system that provides input/output services. It defines where a group of data will be stored on a medium. By including the access method in the basic operating system, computer makers have made the programmer's job much easier.
Access Time: The amount of time it takes a computer to locate an area of memory for data storage or retrieval.
Acetate: A transparent sheet placed over originals or artwork, allowing the designer to write instructions and/or indicate a second colour for placement.
Achromatic: Without color. A lens which refracts light of all colors equally is said to be achromatic.
Acid Paper: Non-permanent papers (PH below 7.0).
Actinic: The chemical change violet or ultraviolet light produces in certain photosensitive film.
Active Display Area: The portion of an image that falls inside the viewing area of a computer monitor.
Actuator: Mechanism that moves an object; for example, the read/write head on a disk drive.
ADB: Apple Desktop Bus. The Macintosh plug-in port where the keyboard, mouse, trackball, graphics tablet, etc. are connected.
Additive Color Theory: White light contains equal parts of red, blue and green. If three lights were to project through the colored filters of red, blue and green to the same intensities on a white screen, where they overlap all 3 colors would be white. Where only 2 colors overlap the subtractive colors of cyan, magenta or yellow would be formed. (See Subtractive Color Theory.)
Additive Litho Plate: A substance is added to a plate surface in order to develop the image.
Additive Primaries: Are red, blue and green. In color reproduction, equal parts of red, blue, and green light give us the sensation of white light. These colors are used in the form of filters in order to create the complementary colors, cyan, yellow and magenta.
Address: (1) Disks and other storage devices have numbers that identify locations by sector and by byte. Retrieval software searches for the address assigned to the desired information in order to locate it. (2) Used as a verb, it means what a computer can access: "This Mac can address 5 megs of RAM."
Address Mark: Two byte address at the beginning of both the ID field and the data field of the track format on a disk drive. The first byte is the "A1" data pattern, the second byte is used to specify either an ID field or a data field.
Addressable Capacity: The number of locations on an image that are addressable. To calculate, multiply the addressable vertical positions (row) by the addressable horizontal positions (column). Think of a matrix of dots, 8 across by 16 down. The addressable capacity of this matrix is 128.
Adhesives: In paper, glues that bind coated paper ingredients together.
Adobe Type Manager: Software from Adobe Systems for Macintosh and IBM PC's that eliminates jagged edges on screen fonts and allows inexpensive laser printers to reproduce postscript fonts accurately and clearly. 1-800-64-ADOBE
ADSTAR: Automated Document Storage And Retrieval. Generic term for systems that identify, select and display images that have been previously electronically stored.
Advanced Research Project Agency (ARPA): The agency resposible for the formation of the forerunner of the Internet. See also Defense Advanced Research Project Agency.
Affinity: Natural attraction for, as salt for moisture.
AFP: AppleTalk Filing Protocol. The protocol that non-Apple networks need to use in order to access data in an AppleTalk server.
AFS: Andrew File System. Named after Andrew Carnagie by its inventors at Carnegie-Mellon University, AFS is a distributed file system available for UNIX and other operating systems.
AI: Artificial Intelligence, the field of computer science dedicated to developing computers that mimic the complex relational functions of the human brain.
AIIM: Association for Information and Image Management. Trade association and professional society for the micrographics, optical disk and electronic image management markets. 1100 Wayne Ave., Suite 1100, Silver Spring, MD 20910. (301)587-8202.
Air Knife Coating: In paper, coating method wherein a thin blade of air is used to apply coating to the sheet uniformily.
Algorithm: Set of mathematical steps used to solve a problem or conduct an operation.
Alias: a computer system name that points to another name, instead of an underlying object. Most Web URLs are either whholly or partly aliases (to protect the underlying file system on the Web server they point at).
Aliasing: Condition when graphics, either constructed with lines (vectored) or dots (bitmapped), show jagged edges under magnification.
Alkaline Paper: Permanent papers (PH of 7.5 - 8.2).
Allocate: To reserve the required amounts of a resource, such as memory.
Alpha Testing: Testing conducted internally by the manufacturer, alpha testing takes a new product through a protocol of testing procedures to verify product functionality and capability.
Alum: Aluminum sulfate (an acid salt) used in the paper making process.
America Online: An online information provider, usually known by its initials (AOL), which got its start as a dial up service off the Internet and which has become the largest Internet Service Provider in the world.
Angstrom Unit: A unit of measurement of the length of light waves. It is equal to 1/10 of a millimicron, or one ten-millionth of a millimeter. There are approximately 254,000,000 Angstrom units in an inch.
Animated Graphics: Moving diagrams or cartoons. Often found in the computer-based courseware, animated graphics take up far less disk space than video images.
Annotation: The ability to attach notes to graphics or images by typing them in, using a light pen or digitizing tablet. Useful for clarifying documents or editing images.
Anodized: In paper, refers to grained.
ANSI: American National Standards Institute. A standards-setting, non-government organization which develops standards for "voluntary" use in the United States. Standards set are accepted by vendors in that country. ANSI is located at 1430 Broadway, New York NY 10018, (212)642-4900
Antihalation: The property of a film or plate, usually with an opaque backing, which prevents halation.
Antioffset Powder: Powder which creates a gap between sheets of paper to aid in the ink drying process.
Antique Finish: In paper, a toothy, open texture, usually giving a hand-crafted look.
Aperture: A small opening in a plate or sheet. In cameras, the aperture is usually variable in the form of an iris diaphragm and regulates the amount of light which passes through the lens to the film.
API: Application Program Interface. Generic term for any language and format used by one program to help it communicate with another program.
APR: Automatic Picture Replacement. A Scitex term describing a feature in their systems which allows a low resolution F.P.O. image to be automatically replaced by its high resolution scan when being output.
Apple: Apple Computer, Inc., Cupertino, CA. Manufacturer of personal computers. Heavy penetration in the graphics/desktop publishing business.
AppleScript: Apple's scripting launguage for the Macintosh OS, which is commonly used to program CGIs for Macintosh-based Web servers.
AppleTalk: The Apple networking protocol used to connect Macintosh computers with each other, or with shared devices. AppleTalk, with the appropriate interface card, can also be used to connect to DOS-based platform computers.
Application: Generic term for any software program that carries out a useful task. Word processors and graphics programs are applications.
Applicator Roll Streaks: In paper, streaks on a coated sheet caused by an interruption in coating flow.
Architecture: Refers to the way a system is designed and how the components are connected with each other. There are computer architectures, network architectures and software architectures.
Archival: In paper, the stock contains no groundwood or optical brighteners.
Archive: A copy of data on disks, CD-ROM, mag tape, etc., for the long-term storage and later possible access.
Areal Density: Bit density multiplied by track density, or bits per square inch of the disk surface. Bit density is measured around a track, and track density is radially measured.
Array: A table of numbers or text which the computer holds in its memory.
Ascender: A typographic term for the portion of lowercase characters that rises above the main body of the letter. The lowercase letters b, d, f, h, k, l and t have ascenders.
ASCII: American Standard Code for Information Interchange. Pronounced AS-key. It's the most popular method used by small computers for converting letters, numbers, punctuation and control codes into digital form. Once defined, ASCII characters can be recognized and understood by other computers and by communication devices. ASCII represents characters, numbers, punctuation marks or signals in seven binary bits. A capital "C", for example, is 1000011, while a "3" is 0110011.
ASCII sort: A means of alphabetizing that accounts for capital letters and numbers. To arrange something in an ASCII sort, numbers (digits) come first in numerical order, followed by capital letters in alphabetical order, followed by lower case characters in alphabetical order. This glossary is NOT in an ASCII sort.
Aspect ratio: The relationship of width to height. When an image is displayed on different screens or on paper or microform, the aspect ratio must be kept the same. Otherwise the image will be "stretched" either vertically or horizontally.
Asynchronous Communications: A way for one computer to send data to another, without requiring precisely sychronized data pulses. All data transmitted via a modem, or sent out of a computer's serial port, is asynchronous. Special codes are embedded in the stream of pulses so that the receiving computer can locate each byte of data.
AT Interface: Disk drive interface on the IBM PC-AT computer and compatibles, sometimes called the IDE interface.
Audio Video Interleaved (AVI): The format of the full-motion video files used by Windows 9x.
Authentication: A method for identifing a user prior to granting permission to access, change, or delete a system or network resource.
Autoflow: In a word processor package, a mode of text placement in which text flows continuously onto successive pages or columns. Additional pages are usually created as needed, depending upon the application.