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Visuals and use of colour

The use of images, graphics and colours can enhance the appeal of online and printed materials and assist communication – but they also introduce some accessibility challenges.

Use of colour

  • Use single colour backgrounds rather than background patterns or pictures and distracting surrounds.  

  • Use sufficient contrast levels between background and text, aim for a contrast ratio of 4.5:1 or higher - the University of Virginia have some helpful guidance on contrast ratios. 

  • Use dark coloured text on a light background. 

  • Do not use colour or spatial position alone to convey information. The University of Virginia has some helpful guidance on using colour or spatial position and accessibility.

  • Avoid the following colour combinations as they are commonly unfriendly to those with colour vision deficiencies: green/red, blue/purple and light green/yellow. 

  • Consider alternatives to white backgrounds for paper, computer and visual aids such as whiteboards. White can appear too dazzling. Use cream or a soft pastel colour. Some dyslexic people will have their own colour preference. 

 

Images and other visuals

Images can be inaccessible in a number of ways, including:

  • Poor image quality.
  • Contain text that is difficult to read.
  • Poor colour contrast.
  • No meaningful alternative text (alt text).

Alt text

Provide alternative text descriptions (alt text) for all images used. The University of Virginia have produced some guidance on providing appropriate alt text for images. Additional guidance is available from the LinkedIn Learning course Teaching Techniques: Making Accessible Learning.

If you have complex visual elements that are used for teaching, you may want to use the Diagram Center's Image description tools which offer guidance and resources for deciding when and how to add alt text to visuals, particularly academic material.

Social media

Additionally, it is possible to provide alt text for images posted to social media. Guidance on enabling this feature is available for:

Selecting images

Images should convey the message you want it to about your content. Is the message made self-explanatory by the image, or is some thought required to make sense of how the image relates to your content? There is nothing wrong with challenging the viewer to think deeply, but you will need to explain the relationship with the content in any alt text or supporting text.

In addition, images should be of good quality with a minimum resolution of 300dpi. Images with high resolutions retain good image quality when they are enlarged.

Colour contrast is also important, it can be difficult for some people to see and read. Where possible select images with good colour contrast.

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