Back coat

Optional layer applied to backside of tape substrate layer, useful in reducing tape friction and distortion, as well as dissipating static charge in playback. See image. [BAVC]


Backing film layer that supports the magnetic layer in a magnetic tape. Polyester Terephthalate (PET) has been the most commonly used tape substrate for analog videotape. Polyeythelene Napthalate (PEN) is commonly used for digital videotapes. Also called base or substrate. [AMIA]


Tapes [with Sticky-shed] will not playback easily, if at all. If properly identified, these tapes can benefit from exposure to elevated temperatures for several hours, which bakes the binder back onto the base material. This consolidation of binder and base stabilizes the tape system so that it can be played once while the information is copied on to a more stable format. Baking tapes is an extreme measure that irreversibly physically modifies the tape [and should only] be performed by professionals who have experience in dealing with problem tapes.[Vidipax]


The frequency range of a particular transmission method. In video systems, this value is expressed in MHz, and the better the signal, the greater the bandwidth required. [Projector People]


A type of video distortion that appears as black lines extending to the right of bright objects. [BAVC]


Pertaining to a number system that has just two unique digits... Computers are based on the binary numbering system, which consists of just two unique numbers, 0 and 1. All operations that are possible in the decimal system (addition, subtraction, multiplication, division) are equally possible in the binary system. We use the decimal system in everyday life because it seems more natural (we have ten fingers and ten toes). For the computer, the binary system is more natural because of its electrical nature (charged versus uncharged). [UPF]

Binary number

A number that can be represented using only two numeric symbols, 0 and 1. Binary numbers are used by computers because they can easily be represented and stored by hardware that utilizes switches, magnetic fields, or charge polarities that are normally in one of two states. The on/off, north/south, or positive/negative states can easily represent the 1s and 0s of a binary number, respectively. [AMIA]


The polymer used to bind magnetic particles together and adhere them to the tape substrate. [BAVC]


Shorthand for binary digit, which has two optional values "0" or "1." Eight bits means 8 binary digits. There are 256 possible combinations for 8 binary digits and therefore color depth of 8 bits represents 256 (2x2x2x2x2x2x2x2) possible colors. Because each pixel of a video picture contains 3 samples Y', R-Y', B-Y', the possible colors of an 8-bit system would be 16.7 million (256 x 256 x 256). Nowadays archives will be receiving digital material into their collections or will be generating it as part of their preservation program. It is therefore necessary that we understand digital and analog technology. [BAVC]

Bit error rate (BER)

The percentage of bits that have errors in playback. One possible indicator for the deterioration of digital videotape is an increase in the bit error rate prior to error correction. Playback is never perfect and there are many possible causes of error such as noise, dirt and dust, and dropout. In the binary world of digital data a bit is either correct or incorrect. Since it only has two states, the challenge is to correctly identify whether a bit is correct or not. To enable this the data is therefore coded by adding redundant bits. All systems build in redundancy and error correction mechanisms. Information about bit error rates can refer to the bit error rate prior to error correction or the residual errors after error correction. [BAVC]

Bit mapped graphics

The type of graphic that is defined and addressed on a bit-by-bit basis which makes all points on the screen display directly accessible.[Projector People]

Bit rate

The amount of data transported in a given amount of time, usually defined in Mega (Million) bits per second (Mbps). Bit rate is one way to define the amount of compression used on a video signal. [BAVC]


An image made up of a given number of pixels, each with a specific color value, laid out in a grid. Ideal for reproducing photographic representations, because a sufficient quality and quantity of pixels can give the appearance of a continuous tone image. [Getty]


The sequence of 1s and 0s passed among computers and input/output devices, typically containing a text message or audiovisual content. [Variable Media]


A composite color video signal comprised of composite sync, reference burst and a black video signal which is usually at a level of 7.5 IRE (0.05V) above the blanking level. Also refers to fade-to-black between scenes. Also known as Color black and Blackburst. [BAVC]

Blanking level

Also known as pedestal, the level of a video signal, which separates the range that contains the picture information from the range that contains the synchronizing information. [BAVC]


The sticking together or adhesion of successive windings in a tape pack. Blocking can result from deterioration of the binder, storage of tape reels at high temperatures, and/or excessive tape pack stresses. See also: Sticky shed.[BAVC]


The defocusing of regions of a picture where brightness is excessive. Also refers to adjusting the white levels, on video monitors, to the point of leaving gray and becoming white. [BAVC]

BNC (Bayonet Neill Concelman)

Named after inventors Paul Neill & Carl Concelman. Used with coaxial cables, this connector receives all R, G, B, H-Sync and V-Sync information, and composite video. [Projector People]

Born digital

Creations originally generated in digital form rather than copies or surrogates of analog originals, and which exist entirely in a digital environment. Examples include software, Web pages, hypertext fiction, and digital art. [Getty]


Disturbance in the picture or sound signal caused by loss of sync or by videotape damage. [BAVC]


High-speed data transmission or a transmission medium in which a wide range or band of frequencies is available to transmit data, allowing more information to be transmitted in a given time frame. As of this writing, broadband is sometimes defined as services that offer bit rates of 1.544 megabits per second (Mbps) and above. May also be referred to as wideband. Digital Subscriber Lines (DSLs) and cable modems allow broadband transmission. See bandwidth [Getty]


A program that recognizes, interprets, and views Web documents (usually coded in HTML) on the World Wide Web. Netscape and Microsoft Internet Explorer are the most common Web browsers that display graphics as well as texts; others include Mozilla, Opera, and Safari. The same Web page may appear different on different browsers since browsers generally access and interpret codes differently. [Variable Media]

Bumping up

Transferring a program recorded on a lower quality videotape to a higher quality videotape (e.g., from Hi8 to Betacam). Bumping up to a higher format allows footage to be preserved on a more stable tape format and makes it possible to edit in a higher-end editing environment. [BAVC]

Burst (or Color Burst)

The reference for establishing the picture color, burst is seven to nine cycles (NTSC) or ten cycles (PAL) of subcarrier placed near the end of horizontal blanking to serve as the phase (color) reference for the modulated color subcarrier. [BAVC]

Burst vector

In composite video signals, the amplitude and angle of the color reference signal. [BAVC]


A multi-digit binary number is called a word. A word of 8 binary digits or bits is called a byte. The amount of data that can be moved over time is expressed as MBps (Megabytes per second) or KBps (Kilobytes per second). A kilobyte of memory contains 1024 bytes, one megabyte contains 1024 kilobytes and a gigabyte contains 1024 megabytes. These concepts are essential to understanding issues relating to the storage and format choices of digital materials as well as the terminology surrounding the measurement of errors. [BAVC]