The following is an alphabetical list of terms, phrases and descriptions used in the graphics industry. These may be of use when creating files or for general reference.

8-bit colour/grayscale
In 8-bit colour, each pixel is has eight bits assigned to it, providing 256 colours or shades of gray, as in a grayscale image.

24-bit colour
In 24-bit colour, each pixel has 24 bits assigned to it, representing 16.7 million colours. 8 bits – or one byte – is assigned to each of the red, green, and blue components of a pixel.

32-bit colour
A display resolution setting that is often referred to as true colour and offers a colour palette of over 4 billion colours or 2³².

Additive Colours
Red, Green, and Blue are referred to as additive colours. Red+Green+Blue=White.

In bit mapped graphics, the jagged boundary along the edges of different coloured shapes within an image.

A technique for reducing the jagged appearance of aliased bit mapped images.

Background Processing
A feature that enables the computer operator to continue working while the computer executes another action, such as spooling data to a printer.

An artefact of colour gradation in computer imaging, when graduated colours break into largerblocks of a single colour, reducing the "smooth" look of a proper gradation.

Bit depth
The number of bits used to represent the colour of each pixel in a digital image, e.g. bit depth of 8 = 256 colours; bit depth of 16 = 65,536 colours; bit depth of 24 = 16 million colours.
The more bits of information per pixel means more available colours and more accurate colour representation.

Bitmap (BMP)
An image made up of dots, or pixels. Refers to a raster image, in which the image consists of rows or pixels rather than vector co-ordinates.

Image area (usually 3mm) beyond the trim area of a sheet or page. The "bleed" gets cut off during trimming.

The value of a pixel in an electronic image, representing its lightness value from black to white. Usually defined as brightness levels ranging in value from 0 (black) to 255 (white).

The act of adjusting the colour of one device relative to another, such as a monitor to a printer, or a scanner to a film recorder. Or, it may be the process of adjusting the colour of one device to some established standard.

Compact Disk – Read Only Memory – storage media capable of holding 650 Megabytes.

CMY (Cyan, Magenta, Yellow)
The three subtractive colour primaries.

CMYK (Cyan, Magenta, Yellow, Black)
One of several colour encoding system used by printers for combining primary colours to produce a full-colour image. In CMYK, colours are expressed by the "subtractive primaries"

(cyan, magenta, yellow) and black. Black is called "K" or keyline since black, keylined text appears on this layer.

Colour correction
The process of correcting or enhancing the colour of an image.

Colour Proof
A test print made on the output device to be used for a particular job. Proofs are commonly made at a fraction of the final size.

Colour Wheel
This is an aid to be used when selecting colours for a harmonious colour scheme. You can easily identify and split complementary colours.

Continuous Tone
An image where brightness appears consistent and uninterrupted. Each pixel in a continuous tone image file uses at least one byte each for its red, green, and blue values.
This permits 256 density levels per colour or more than 16 million mixture colours.

A visual effect in an image as a result of low brightness resolution which appears as bands of sharp, distinct, brightness change. Very similar to banding

A measure of rate of change of brightness in an image.
– High contrast implies dark black and bright white content;
– Medium contrast implies a good spread from black to white;
– Low contrast implies a small spread of values from black to white.

Crop Marks
Register marks used for accurate positioning of images in printing.

A tool used to measure the amount of light that is reflected or transmitted by an object.

Diffusion Dithering
A method of dithering that randomly distributes pixels instead of using a set pattern.

A system or device in which information is stored or manipulated by on/off impulses, so that each piece of information has an exact or repeatable value (code).

Digital Image
An image composed of pixels.

A method for simulating many colours or shades of gray with only a few. A limited number of same-coloured pixels located close together is seen as a new colour.

DPI (Dots Per Inch)
The measurement of resolution of a printer or video monitor based on dot density. For example, most laser printers have a resolution of 300 dpi, most monitors 72 dpi, most PostScript imagesetters 1200 to 2450 dpi. The measurement can also relate to pixels in an input file, or line screen dots (halftone screen) in a prepress output film.

A software utility designed to tell a computer how to operate an external device. For instance, to operate a printer or a scanner, a computer will need a specific driver.

EPS (Encapsulated PostScript)
A graphic file format developed by Aldus, Adobe, and Altsys to allow exchange of PostScript graphic files (image information) between application programs.

A program that accepts data as input, transforms it in some manner, and then outputs the transformed data. For example, a software program such as PhotoShop can take blurry pictures and filter them to produce a clearer picture.

Final Image Resolution
Generally speaking, the higher the resolution, the larger print you can make. Although print quality is affected by other factors as well, like exposure, colour quality, output quality, etc.
It's not just how many pixels, but what you do with them!

Flat Bed Scanner
An optical scanner in which the original image remains stationary while the sensors (usually a CCD linear array) passes over or under it.
The scanned material is held flat rather than being wrapped around a drum.

GIF File Format
Stands for Graphic Interchange Format, a raster oriented graphic file format developed by CompuServe to allow exchange of image files across multiple platforms.

Halftone Image
An image reproduced through a special screen made up of dots of various sizes to simulate shades of gray in a photograph. Typically used for newspaper or magazine reproduction of images.

A term used to describe the entire range of colours of the spectrum; hue is the component that determines just what colour you are using. In gradients, when you use a colour model in which hue is a component, you can create rainbow effects.

ICC (International Colour Consortium)
Established in 1993 by eight industry vendors for the purpose of creating, promoting and encouraging the standardisation and evolution of an open, vendor-neutral, cross-platform colour management system architecture and components.

Image Processing
Capturing and manipulating images in order to enhance or extract information.

Image Resolution
The number of pixels per unit length of image. For example, pixels per inch, pixels per millimetre, or pixels wide.

Ink-Jet Printer
An ink-jet printer forms text and images out of dots created by jets of ink. Colour ink-jets support many different media sizes and output resolutions.

JFIF (JPEG File Interchange Format
A minimal file format which enables JPEG bitstreams to be exchanged between a wide variety of platforms and applications.

JPEG (Joint Photographic Experts Group)
A technique for compressing full-colour bit-mapped graphics JPEG Compression. A file compression standard established by the Joint Photographic Experts Group that uses a combination of DCT and Huffman encoding to compress images.
JPEG is a "lossy" compression algorithm, meaning that it slightly degrades image quality.

Mid Tones
The range of tones between the highlights and shadows of a photograph or halftone - between 30% and 75% value.

Undesirable screen patterns that occur when screened reproductions are made from halftone proofs.

Adobe Acrobat PDF format is based on the PostScript level 3 language and PDF files can represent both vector and bitmap graphics.

A graphics file format used primarily on Macintosh computers. PICT files can contain both object-oriented and bit-mapped graphics. There are two types: PICT I and PICT II. PICT II is the current standard and supports colour up to 24-bit.

Pixel (Picture ELement)
The smallest element of a digitised image. Also, one of the tiny points of light that make up a picture on a computer screen.

Pixels Per Inch (PPI)
A measure of how much detail you see in your images.

A page description language developed by Adobe Systems, Inc. to control precisely how and where shapes and type will appear on a page. Software and hardware may be described as being PostScript compatible

Raster images are made up of individual dots; each of which have a defined value that precisely identifies its specific colour, size and place within the image. (Also known as bit mapped images.)

The final step of an image transformation or three-dimensional scene through which a new image is refreshed on the screen.

The number of pixels per unit length of image. For example, pixels per inch, pixels per millimetre, or pixels wide.

Short for Red, Green, and Blue; the primary colours used to simulate natural colour on computer monitors and television sets. Also the primary colours used in photographic film/paper layers and photographic digital imaging equipment.

RIP (Raster Image Processing)
A piece of hardware or software that converts object-oriented graphics and fonts into the bit maps required for output on a printer.

The degree to which a colour is undiluted by white light. If a colour is 100 percent saturated, it contains no white light. If a colour has no saturation, it is a shade of gray.

Averaging pixels with their neighbours. It reduces contrast and simulates an out-of-focus image

Subtractive colours
Transparent colours that can be combined to produce a full range of colour. Subtractive colours subtract or absorb elements of light to produce other colours.

TIFF (Tagged Image File Format)
The standard file format for high-resolution bit-mapped graphics. TIFF files have cross-platform compatibility.

Protocol for exchanging information between applications and devices such as scanners and digital cameras. TWAIN makes it possible for digital cameras and software to "talk" with one another on PCs.

USB (Universal Serial Bus)
The USB offers a simplified way to attach peripherals and have them be recognised by the computer. USB ports are about 10 times faster than a typical serial connection. These USB ports are usually located in easy to access locations on the computer.

Vector Graphics
Images that are stored as lines and curves, instead of pixels. Unlike bitmap graphics, vector graphics can be scaled to any size without losing information. (Note DPI if enlargement is 800% & upwards the Output DPI must be Set to Max

You can add copyright information to Photoshop images by including a digital code added as noise to the image file. This digital watermark isn't visible and does not affect image integrity.

What You See Is What You Get. Refers to the ability to output data from the computer exactly as it appears on the screen.



Printers Maidstone | Printers Aylesford | Printers Medway | Printers Kent | Printers London | Printers National | Labels | Signage | Vehicle Wrapping | Vehicle Graphics | Installs | Exhibition Graphics