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Glossary

additive primary colors

The colors of red, green and blue (RGB) - which give the perception of white when combined equally. These are the colors of the color system used by monitors and scanners.

bi-level data

Image data that is composed of 1 bit per pixel. A pixel is represented by a single bit of digital data that can be expressed as only 1 (light) or 0 (dark).

bit

Short for binary digit. The smallest unit of data in computer processing. A bit can represent one of two values: on, represented by a 1, or off, represented by a 0.

bit/pixel

The unit that indicates the number of bits allocated for a pixel. The larger the bit value, the more detail of a pixel will be reproduced.

brightness

A scanner function to lighten or darken the output image data.

byte

A unit of information consisting of eight bits. A byte can represent a control code or character.

carriage

A component of the scanner that contains the optical sensor and light source for scanning.

color correction

A method of adjusting the color image data for a particular type of device so that the reproduction results are as close as possible to the original colors.

color separation

A process of converting full-color images into a limited number of primary colors. Additive primary colors (red, green, and blue) are used by the scanner, and the subtractive primary colors (cyan, magenta, and yellow) plus black are used for printing press separation.

daisy chain

A SCSI bus arrangement that allows several devices to be connected simultaneously in a line to a single computer. See SCSI.

default

A set of values used when no other selections have been made. These are sometimes called factory defaults if the original values have not been changed since the scanner left the factory.

Default Gateway (Address)

The IP address of a special device used to route data from one part of a network using TCP/IP to another. See also IP address, TCP/IP, and Internet.

DHCP

Dynamic Host Configuration Protocol, a TCP/IP network protocol that enables hosts to obtain temporary IP addresses from one or more centrally administered servers.

DHCP server

Dynamic Host Configuration Protocol server, a computer which has been configured to respond to DHCP requests from other computers on the network.

dithering

A process in which software or an output device simulates continuous tones with groups of dots.

DNS

Domain Name System, a naming service which allows the looking up of IP addresses based on host (domain) names.

document

The item, such as a sheet of paper or a book, that is placed on the document table for the scanner to read.

dpi

Short for dots per inch. A unit of measurement for resolution. The higher the value, the higher the resolution.

dropout color

A color the scanner does not recognize and ignores. You can select and deselect dropout colors in the scanner software.

ESC/I

Abbreviation for EPSON Standard Code for Image scanners. A system of commands that allows you to control image scanners from your software.

ESC/P

Abbreviation for EPSON Standard Code for Printers. A system of commands that allows you to control printers from your software.

gamma

Gamma is a value that expresses the relationship between the input and output of a device. By adjusting the gamma, the brightness of the mid-tones of an image can be changed without affecting the shadows and highlights.

grayscale

Images represented with various shades of gray in addition to black and white.

halftoning

A method of reproducing images with patterns of dots to improve the quality of the output.

home position

The position at the rear (nearest the cover hinge position) of the scanner where the carriage rests before a scanning operation.

interface

A piece of hardware, a method, or a standard used for connection between or among computer devices.

Internet

A worldwide network of computers and communication devices, the largest of its kind, originally conceived as a research project of the US government. The Internet is composed of many different types of connections, including electrical and fiber optic cabling as well as wireless communications.

IP address

Internet Protocol address, a numeric address which uniquely identifies a computer connected to a network using TCP/IP, such as the Internet. See also Internet and TCP/IP.

LAN

Short for Local Area Network, a computer network in which the attached devices are in close proximity (like in the same office or building).

line sequence

A type of color scanning that separates primary colors line by line. The carriage makes only one pass.

LMHOSTS

A file of IP addresses and their associated host (domain) names. An IP address and its associated host (domain) name can be found by referring to this file.

moiré

A moiré is a cross-hatch pattern that appears on scanned images when scanning printed material. It is a result of interference that occurs due to the difference between the pitches of the scanning and the halftone screens.

monochrome

Black and white images, or images represented only by the intensity of luminosity.

Network Interface Card

A name for the adapter (printed circuit board), installed in a PC, that enables it to communicate over a LAN.

OCR
Optical Character Recognition

The technology that allows computers to "read" text from physical objects. OCR requires a graphical representation of text to interpret, which usually comes from a scanned image.

page sequence

The type of color scanning in which the entire image is scanned once for each separate color.

pixel

Short for picture element. Each image is composed of a number of pixels. Pixels are also counted in units of dots.

plain bi-level

Bi-level image data without the halftoning process.

port

An interface channel through which data is transmitted between devices.

primary colors

Basic colors. See additive primary colors and subtractive primary colors.

resolution

Indication of how finely an image is resolved into pixels. Can be measured in dots per inch (dpi), pixels per inch (ppi), or samples per inch (spi).

scan

An operation performed by the sensor and the carriage. The image is divided into pixels by scanning.

scanning area

The physical size of the image that can be scanned by the scanner.

screen calibration

Adjustment of the monitor display to reproduce as closely as possible the original image data.

SCSI

Small Computer System Interface. This is one method used to connect your computer to peripherals such as scanners, hard disk drives, CD-ROM drives, and others.

SCSI ID

The numbers that all devices in a SCSI connection (see daisy chain) use to identify each other. If the same ID number is used by two devices in the same daisy chain, the devices cannot operate properly.

Subnet mask

A numeric designation, with the same format as an IP address, which determines how much of an IP address is used to partition a network using TCP/IP into smaller entities called subnets. See also IP address, TCP/IP, and Internet.

subtractive primary colors

The colors of cyan, magenta, and yellow (CMY) which produce black when mixed in certain amounts. In printing, black is often added to give more definition as mixing of actual inks cannot produce pure black.

TCP/IP

A widely used family of protocols for communicating data between computers in a network.

terminator

A device that stops electronic signals, and prevents them from proceeding or returning to other devices. This is necessary to stop a signal from continuously reflecting between devices.

threshold

A reference point that is used to determine whether data will be processed as "on" or "off". In the case of color image data, "on" means that a certain color will appear in a pixel or dot, and "off" means that color will not appear there.

tone correction

A method of adjusting the tone curve so that the reproduction results on different types of output devices have gradations similar to the original image.

tone curve

The graph that shows the contrast ratio between the input (original image) and output (image data) in image processing.

unsharp mask

Originally a photographic process in which a sharply focussed and a slightly out-of-focus image are combined to produce a sharper image. This process is simulated by software to produce the same effect.

WINS

Windows Internet Naming Service, a naming service which allows the looking up of IP addresses based on host (domain) names.

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