CONTRIBUTOR: Shahjahan Alhassan - 13th Oct 2001

The purpose of colour in screen displays is more than just making things look pretty. Used properly, colour can communicate. Used carelessly, it can confuse. Horton (1994) suggests the following guidelines regarding the use of colour.

Design in black and white and then add colour to make it work better, not the other way around. Black and white overcomes the following problems:

• Colour blindness - If you can see then you can at least see in black and white.
• Low quality display - Poor quality monitors make viewing and recognising colour difficult.
• Small images - The part of the human eye that perceives detail is most sensitive to differences in lightness, thus small icons or those read at a distance require high contrast.
• Imperfect viewing conditions - If users need to share one screen, icons become harder to recognise. Screen glare reduces contrast and decreases legibility.
• But there are several good reasons to use colour.

Colour adds excitement and fun to what would otherwise be a boring display. Given the choice, would you rather use a database on a PC using Windows 95 or on a VAX terminal using UNIX?


Colour can be used to draw the user's eyes to important information, otherwise the user will skip from one place to another never quite seeing the detail you want them to see. A typical example is where coloured bullet points are used to mark items in a list. Emphasising or de-emphasising an area or group of items, can be achieved by using colours of high contrast or colours close to the items background. Small items on the screen can be made to stand out using distinct colours.


Using a unique colour to identify an item being searched can greatly reduce the time for a user to find an item on screen.. In addition to this fewer colours help the item stand out.


Items displayed in familiar colours are recognised more quickly than those without colour, and much better than those in unusual ones. Showing an item in colours that are stereotypical to it increases familiarity.


Colour can be effectively used to categorise and group items that are related or of a similar nature. We naturally see items of the same colour as a group or type.


Colour can suggest ranking or sequential order among items and can represent numerical value within a range. Using a colour with varying degrees of lightness can show order, or by using a varying colour range i.e. from red (warm) to blue (cool) to represent temperature.


Some colours are liked more than others are. This should be a consideration when selecting the colours used by the system. But reactions to colours are so personal and subjective that there is no way of knowing which combination will work best.

Staring at a large area of one colour for long periods of time reduces the user's ability to perceive that colour. Most people find that a balanced colour combination is more comfortable. Each pixel has a red, green and blue (RGB) value from 0 to 255. A balanced combination being if the RGB values of all the pixels on the screen average out to a neutral grey (127 for each). Different characteristics of colours (warm or cool and dark or light) can also be balanced.

Avoid using garish colours. By following trends and studying those past, present and predicted, a fair idea of what is acceptable and not can be had. Proven colour combinations and colours found in nature seldom offend.

Allow the user to adjust the colour scheme of the software where possible. By letting users choose their own colours for items on screen, tailoring it to suit there personality and needs. It enables many of the above problems to be overcome.