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).