"One of the three subtractive primary colours. It is produced by mixing equal amounts of Red and Blue and is the "M" in CMYK."

Outline of dots created by image editing program to show area selected for manipulation, masking or cropping.

This tool is used to select a portion of an image. This selection can be altered without affecting the other parts of the image.

In most new digital cameras there is a matrix metering option which uses 256 areas of the frame to calculate the best overall exposure value.

Material that information is written to and stored on. Digital photography storage media includes CompactFlash cards and CDs.

"Normally, a camera taking roll film (typically 120/220 but also 70mm and a range of obsolete roll film sizes), though there are arguably "medium format" cut film sizes such as 21/4x31/4", 21/2x31/2", 6.5x9cm, and possibly even quarter plate (31/4x41/4"). The most usual formats on 120 films are 645 (15-on or 16-on, around 42x56mm), 6x6cm or 21/4 square (12-on, around 56x56mm), 6x7cm (10-on, around 56x70mm) and 6x9cm or 21/4x31/4" (8-on, around 56x84mm), though nominal 6x8cm, 6x12cm, 6x17cm, and even 6x24cm formats also exist."

A unit of memory equal to 1024 kilobytes.

An image or image sensor with equaling one million pixels.

Computer hardware that can store information for later retrieval. This term can mean either hard disk memory or RAM memory. See also RAM.

A memory card slightly smaller than a single stick of chewing gum. Like CompactFlash and SmartMedia, it is flash-based storage for your photos.

Data about data, or information known about the image in order to provide access to the image. Usually includes information about the intellectual content of the image, digital representation data, and security or rights management information.

Files that can be shared by more than one application program.

A phenomenon in a scanner in which two colours that appear the same to an observer are registered as different by the scanner, or two colours that look different to an observer are accepted as identical by the scanner. Instrument metamerism is a non-recoverable error, because the input cannot be determined from the output.

An area of medium brightness, neither a very dark shadow not a very bright highlight. A medium gray tone in a print.

The range of tones between the shadows and highlights of an image.

A light built into a flash unit that remains on while the flash is turned or on standby mode, permitting the photographer to assess highlight and shadow areas that will be created when subsequently exposing the film in the brighter light of the flash.

Undesirable banding when scanning a halftone image due to the halftone screen interacting with the scanning grid.

An undesirable screen pattern in colour printing that results from screen angles of overprinting halftone. Moiré usually results when you scan a halftone or when you scan images taken directly from magazines.

The process of correcting the colour rendition settings of a monitor to match selected colours of printed output.

"Same as RGB

A digital video format developed by the Motion Pictures Expert Group.

The frequency response of an optical system. Also a test that measures the optical frequency response of a scanner or other optical system. See also transfer function.

a method to reduce noise by averaging several pictures (introduced with early video cameras and later on with scanners)

An image made up of two or more images superimposed in the camera or on the computer (or average the single pictures software)