look-up table

The GIF format was introduced in 1987 and contains one eight-bit channel of data giving it the ability to reproduce up to 256 colours at any one time from a palette of 16.8 million. This means that although a GIF is no good for saving continuous tone imagery such as photographs, it is extremely well suited to images that contain large blocks of  colour such as logos and line art. The advantage of saving so few colours is found in the sharpness of detail and the ability to keep file sizes low.

Outputting your graphics to look their best is an important part of any workflow. When saving for the web you're aim is usually to find a compromise between file size and quality. Here we'll look at how we can get the best out of the Graphic Interchange Format using Photoshop and Imageready.