This post is a follow-up to one I made last week – Don’t be blind to colour. You might have spotted a comment on this post from D Overton, a spokesperson for the Colour Blind Awareness and Support Group, Australia.  Mr Overton has quite literally enlightened me on several fronts and I encourage you to have a look at his website which includes a lot of interesting information and links to some fascinating resources.

Of particular interest to me was a link to some interactive java applets that let those with normal colour vision experience things from the perspective of someone with Colour Defective Vision or CDV.  Mr Overton points out that CDV is the terms we should be using and quite reasonably explains that Colour Blind is a term that implies the viewer “cannot see colour or is blind” which is of course not the case at all.

This extract from Mr Overton’s website hits home I think

Our sunrises and sunsets are not interesting; Our rainbows are plain; Our fruit is not ripe; Our meat is not cooked; Our  clothes do not go together; Our paint charts are a blur; Our printer/camera batteries are never low; Where are the flowers on the Christmas bush? We all have a box of 24 different coloured pencils we never use? Red and green dot clearance sales are great; Travel route coding and signs are a waste of time; We can not even see when we are sun burnt; I could go on, yet today, children and adults are still being told, when diagnosed with colour blindness, you will adapt and that’s it!

Dennis sent through a huge series of leaflets (24 I think) which took me a fair while to get through.  In amongst them was this list of suggestions and things to consider if you want your content to be more readily perceived and understand by everyone, including those with CDV.

• Some colour-blind people may like bright colours because they can detect them more easily. Use blue, yellow, white and black
• Use clear, recognisable and meaningful navigational clues on information to stop people turning off searches
• Use textures or line shading instead of colour. Consider additional labels or the pattern function on the computer, especially for maps and charts
• Text must be pleasant and easy to read.
• Use small range of colours.  Associate colour choices with each message or piece of information.
• Do not use washed or low intensity colours particularly on small bands, lines or text, as this will cause difficulty in colour discrimination.
• Do not use red, green, brown, grey and purple next to / on top of / or changing to red, green, brown, grey and purple
• Do not use light pastel colours in low light or bright light conditions.
• Do not rely on colour alone to convey a message – give some other visual clue.
• Do not use colours from the same part of the colour spectrum.
• Beware some colours may be perceived to look differently when placed on top or behind some other colours.