"There are two different ways to think about the pixels on a camera's CCD. "Actual" pixels is a simple count of every pixel present on the CCD. "Effective" pixels, however, is a count of all the pixels used to record an image (some pixels on a CCD aren't used to record picture information) and it's almost always a tiny bit lower than the "actual" count. Effective pixel count is widely used, because it's a much more accurate way to assess a camera's maximum picture capture capability."

An ICC profile stored inside a TIFF, EPS, PDF, PSD, image, defining the colour space in which the image data are interpreted.

Applying a special effect to an image that gives it a 3-D, embossed-looking surface.

The light-sensitive layer of film or paper. In black and white films the emulsion usually consists of very fine grain of silver halide suspended in gelatin, Which blacken when exposed to light. The emulsion of colour films contains molecules of dye in addition to the silver halide.

The side of the film coated with emulsion. In contact printing and enlarging, the emulsion side of the film-dull side-should face the emulsion side of the photo paper-shiny side.

A technique used in preventing unauthorized third parties from viewing information that you are uploading or downloading. Encryption is most commonly used when credit card information is being transmitted. When encryption is used, the data being sent is split into sections and each section is sent through different connections. The two most common encryption patterns are 56-bit and 128-bit (the higher the number, the more secure the connection is).

The improvement of an image either through colour and/or density change.

Application of an algorithm to correct images for the fact that machines and people perceive tonal gradations differently.

An image processing technique where the range of tones or colours in an image file are expanded in order to produce a more pleasing image.

Exchangeable Image File: the file format used by most digital cameras. For example, when a typical camera is set to record a JPEG, it's actually recording an EXIF file that uses JPEG compression to compress the photo data within the file.

An Exif Print-capable camera is great if you're going to be printing out photos on an Exif Print-compatible photo printer. The camera records information like exposure settings and light metering at the time when a photo was taken, and attaches that information to the picture file. A compatible printer takes note of this info and adjusts its settings accordingly, to permit the most accurate, lifelike photo print possible.

"An instrument for measuring the intensity of light so as to determine the shutter and aperture setting necessary to obtain correct exposure. Exposure meters may be built into the camera or be completely separate units. Separate meters can sometimes measure the light falling on the subject (incident reading) as well as the light reflected by it (reflected reading)

A supplementary flash unit that connects to the camera with a cable, or is triggered by the light from the camera's internal flash. Many fun and creative effects can be created with external flash.