Photoshop Tutorial - Web Safe Colors

Screen colours are created by mixing various values of red, green and blue. In older monitors which use an 8 bit colour system - where the hardware only supports 256 colours or a gif image is restricted to 256 colours, the range of colour options available to us is limited. A blend or gradient is created by 'dithering'. Pixels close to each other are given colour values which mean that the image as a whole displays the required appearance. The problem with this is that dithering is performed differently on different machines and the resulting image appearance can be unreliable.

One solution is to use a colour set which is 'agreed' between all computers. This is referred to as the 'web safe' color palette. While the name implies it is only applicable to the web, it is important wherever a cathode ray tube is used to display images, eg also on multimedia and in-store displays. In Photoshop and on web pages, colors are represented by values for Red, Green and Blue (RGB) channels. Web safe colors are particular combinations of RGB values. The acceptable values for each channel are given below:

The only time where web safe colours should not be used in Photoshop is where there is continual change in tone or in photographs.

Hexadecimal numbers.

Web safe colors, like other color values in Photoshop, are based on a hexadecimal numbering system. Our normal numbering system is a decimal system, ie there are 10 digits from 0 to 9. In a hexadecimal numbering system there are 16 digits. As we haven't got a single numerical character for any value over 9, letters 'a' to 'f' are used. Hexadecimal numbers may be represented as below: