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Colours and colour contrast

Around 4.5% of our UK population are colour blind or colour vision deficient. In the world this is estimated to be about 300 million people. Find out more at colour blind awareness.

There are also around 2 million people living with some form of sight loss or vision deterioration. Further details can be found at NHS blindness and vision loss.

Use of colour

If you just use colour to identify objects, those with colour blindness may not easily be able to see the difference between items.

The most common colour blindness is green/red. So imagine having a green button and red button, that through the eyes of someone who is colour blind may look similar in colour. Without labels it is hard to know which button is which.

Beyond colour blindness, this can also impact everyone:

What if your content was printed out in black and white. This is a great way to demonstrate when using colour alone to identify things doesn't work. Does referring to colour alone still make sense, or like our image does it need labels?


You can help by either:

  • labelling your content

  • use shapes or patterns to make them appear different

Image that says Make sure you click on the green button. Image first shows two grey boxes to simulate colour blindness. Then shows two others with the labels of red and green so they boxes are labelled

Colour contrast

Good colour contrast can help those with poor vision see things more clearly, it can help people see things more easily from a distance and it can also help those with colour blindness.

However, using good colour contrast isn't just about people with poor vision.

Have you ever had the sun glare onto your mobile phone screen, or had a bulb go in your classroom projector. In this circumstance, using good colour contrast means its still more visible even in bright or distorted light.

The video below explains how using strong colour contrast is useful to everyone.

Always make sure you:

  • have strong colour contrast between your text and background colours

The words poor colour contrast in white writing on a light blue background and the words good colour contrast in white writing on a dark blue background
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