Colours for colour blindness

Title of the blog article using light blue and dark blue colours.Colour is often used in charts, maps and infographics, but what if you can’t see some colours? One in twelve men are colour blind, but not for all colours or the same colours. Infographics are becoming more popular as a means of explaining things. So choosing the best colours is to everyone’s advantage. Venngage website has an good guide and lots of tips on making charts more accessible. It shows the three types of colour blindness and compares them with normal vision. Different colour palettes are provided along with templates. The blog page includes links to other resources. Colour combinations to avoid include:

    • Red & green
    • Green & brown
    • Green & blue
    • Blue & gray
    • Blue & purple
    • Green & gray
    • Green & black

Most colour blind people can detect contrast, so as a last resort, if you must use these colours, make the contrast as strong as possible. Patterns and textures also work. The article is titled, How to use color blind friendly palettes to make your charts accessible.  Colour blindness is technically referred known as colour vision deficiency (CVD). 

Another resource for map colour by Tedora Zareva is useful too. You can also find out more about CVD or colour blindness from going to the National Eye Institute website

Four circular charts showing how people with colour deficiency see different colours on the colour wheel

 

Which colour to use – a new standard?

part of a London underground transport map.There is a growing body of science on the topic of colour use and choice. On the second page of the International Ergonomics Association newsletter there is an item advising that in developing an international standard (ISO 24505) for colour use, accessibility needs to be considered. In four parts, the first part of the standard has been published for older people taking into account age-related changes in human colour vision. The remaining three are under development. Here is a snippet from the newsletter:

“The “colour category theory” tells us all the colours are perceived in groups of similar colours at the central level of the brain (not in the retinal level), such as red, green, blue, etc. According to the theory there are a limited number of colour categories (groups), 11 to 13 depending on the studies, in each of which colours are perceived as a group of similar ones. For example, an orangish-red and a purplish-red are both perceived in the same colour category labelled “red”. As intuitively understood from the theory, colours within a same category are apt to be confused, but on the contrary colours belonging to different categories can be easily differentiated. This idea could be applied to the choice of colors for color combinations. The problem is which colours belong to which categories.”

The aim of the International Ergonomics Association (IEA) Ergonomics in Design for All Technical Committee is to promote Ergonomics in Design-for-All (the European equivalent of universal design).