Designing for Colour-blind Users

(Previously: “Safe web colours for colour deficient vision”)

Colour is used more and more these days to help convey information. When one in twelve men have some measurable degree of colour vision deficiency, the use of certain colours in certain ways can cause difficulty when navigating web pages or software, and even total illegibility in some cases.

The key issue is to know when you are using colours which some people will not be able to differentiate – because that (for them) removes the benefit of using colour for visual cues. Sometimes it can even make what you want visible, to be invisible. Colour scientists have long known which colours are confused by colour blind people, but this tends to be expressed in a way difficult for designers to utilise.

Back in the mid to late 90s, most browsers could only display 216 colours. If there were more colours than that, they would be speckled as the hardware tried to approximate the intended colour. When one of the 216 colours were used, then they would be displayed as a solid colour. I refer to these as ‘safe colours’ in this context, though any colours that colour blind people can tell apart could also be considered ‘safe’.

I’ve done a ‘translation’ of all the colours in the old standard 216-colour web-safe palette. The colours may not show you exactly what dichromats see, but will help you to understand which colours are easily confused. This can help you to ensure that important colour cues are not lost.

The pages in this section are being moved from html
to WordPress, as well as updating the content.
Apologies for the delay in completing.