Why is the use of colour and good contrast important?

Considering colour and contrast isn't just about people being blind or having vision issues, it is important to everyone for many reasons:

• there are approximately 3 million colour blind people in Britain, approximately 4.5% of our population
• colours on a screen or a projector can seem less vibrant in the sunshine and may not be readable if there is too little contrast between foreground and background
• tired or older eyes have to work harder when colour contrast is poor, this can lead to eyestrain and headaches

How to do it - Use sufficient contrast for text and background colours

If your document or content has a high level of contrast between the text and background, more people can see and use the content in a variety of situations.

How to do it - ensure that colour is not the only means of conveying information

People who are blind, have low vision, or are colour-blind might miss out on the meaning conveyed by colours alone so use other distinguishing factors too, such as labels.

A quick tip

Imagine your content is being printed in black and white.

This is a great way to replicate colour blindness or colour vision issues. Is it still understandable without the need for seeing colours?

For example, you may have a graph using two different colours for positive results and negative information.

Without labelling the information, how would you know which was green for positive and red for negative in the black and white version?

The Microsoft Office Accessibility Checker will list any accessibility issues in your document, including insufficient colour contrast. You can also manually look for text in your document that’s hard to read or to distinguish from the background.

Tools for checking colour and contrast

• Colour Contrast Analyser
• Siteimprove Colour Contrast Checker
• WebAIM Contrast Checker

Video: the importance of colour contrast