Gain is a system's mean ratio of signal output to signal input. [EAI]

Gamma correction

A process used with video and computer graphics images to correct brightness and internal micro-contrast within the image, allowing a change of ratio between the brightest red component of an image and the weakest red.[BAVC]


The range of voltages allowed from a video signal, or a component of a video signal. Signal voltages outside of the range (i.e., exceediing the gamut) may lead to clipping, crosstalk or other distortions. [BAVC]


A gigabyte (GB or GiB) is a unit of measurement in computers of one thousand million bytes. Because computers work on the binary system, rather than a gigabyte being 103 megabytes (1000 MBs), the term gigabyte can also mean 210 megabytes (1024 MiBs). [EAI]


Copy of original video program material. The original videotaped material (source footage) is the first generation. A copy of the original is a second generation tape and so on. Generally the edited master tape is a second generation tape. In analog systems, extensive efforts are made to keep generations to a minimum, since each copy or process adds noise and other artifacts resulting in diminished quality with each generation. [BAVC]

Generational loss

Degradation caused by tape duplication. [BAVC]


Synchronizing signals between two video sources, which is necessary when overlaying computer graphics on an image from VCR, camera, or videodisc player. [Projector People]


A shadowy or weak image in the received picture, offset either to the right or to the left of the primary image, and the result of transmission conditions where secondary signals are created and received earlier or later than the primary signal casued by a reflected RF signal. [BAVC]


A shadow or weak secondary image as seen on a monitor or display which is created by multiple path broadcast transmission errors. [Projector People]


A form of low frequency interference, appearing as a narrow horizontal bar moving vertically across the picture. [BAVC]

Global conditionals

Variables in a software program that represent the overall state of the system and can be used to modify it. [Variable Media]


Programming instructions that tell a computer to skip from one line of code to another. Go-tos are a typical hallmark of procedural, as opposed to object-oriented, programming. [Variable Media]

H Sync

AKA Horizontal synchronization. A marker, which indicates to a computer or video signal that it is the beginning of a line. [Projector People]


Computer programmer of outstanding skills. Hackers are generally granted the term if they are able to create or modify programs, crack codes, defy security system and / or possess a well established computer expertise.

Hard Drive (HD)

A magnetic disk drive used as the main memory of most personal computers. [AMIA]


Hardware comprises all of the tangible elements in a computer, as distinguished from the data it contains or operates on and the software that provides instructions for the hardware to accomplish tasks. [EAI]


A type of emulation consisting of refabrication or substitution of an artwork's equipment or material. For example, to imitate the physical appearance of the obsolete video monitors in an original video installation by Nam June Paik, reconstructions might custom build cathode-ray tubes or embed flat sreens in old television casings. [Variable Media]

HDTV (High Definition Television)

High definition, wide-screen television broadcasting with digital audio. [Projector People]


Magnetic pickup device in a VTR used to record, erase or reproduce video and audio signals. [BAVC]

Head clogging

The accumulation of debris on one or more heads, usually causing poor picture clarity during playback. Clogging of the playback head with debris causes dropout. [BAVC]

Head switching

ANSI (American National Standards Institute), ASTM (American Society for Testing and Materials), ISO (International Standards Organisation), NISO (National Information Standards Organisation), RLG (Research Libraries Group). [BAVC]

Helical scan

A method of recording video information on a tape resulting in recorded parallel tracks that run diagonally across the tape from one edge to the other. [BAVC]

Hertz (Hz)

A unit used to measure frequency. One hertz equals one cycle per second. [BAVC]


Hi8 is a much improved, highband version of Video8 (8mm video). The peak-white frequency moved from 5.4 to 7.7 MHz. The deviation moved from 1.2 to 2 MHz (making it incompatible with Video8) It produced a horizontal resolution of over 400 lines and had an optional second AFM track for stereo sound. [Vidipax]


Short for High Fidelity.

High definition

Television with definition approximately doubled with reference to the conventional TV both vertically and horizontally and with increased picture aspect ratio. A format with a new screen aspect ratio of 16:9 (the current is 4:3) and capable of reproducing twice the resolution in horizontal and vertical dimensions than existing standard definition broadcast systems. [Also referred to as HDTV]. [ScreenSound Australia]

High fidelity

High fidelity refers to a quality standard by which the reproduction of sound or images is very faithful to the original and there exists little or no distortion. [EAI]

High gain screen

A screen that uses one of more methods to collect light and reflect it back to the viewing audience, which will increase the brightness of the image over a white-wall or semi-matte screen. [Projector People]

High resolution

Where resolution is the amount of detail an image holds, higher resolution means more image detail in any media. Image resolution can be measured in pixels, lines, pixels per inch (ppi), and many other ways. [EAI]

Horizontal frequency (kHz)

The total number of horizontal lines scanned per second in a displayed image. [Projector People]

HTML (HyperText Markup Language)

The code used to generate hypertext documents on the World Wide Web through the use of tags and attributes. The "hyper" of the title means that users can jump quickly to other files on the Internet by clicking on linked text or images. [Variable Media]


(Tint, Phase, Chroma Phase) One of the characteristics that distinguishes one color from another. Hue defines color on the basis of its position on the spectrum, i.e., whether red, blue, green or yellow, etc. Hue is one of the 3 characteristics of television color, along with saturation and luminance. In NTSC and PAL video signals, the hue information at any particular point in the picture is conveyed by the corresponding instantaneous phase of the active video subcarrier.[BAVC]