[ubuntu-art] Is colour useful in high-viz icons?

[Henrik Nilsen Omma]

We are working on the high viz icon theme, trying to make it more 
complete: https://wiki.ubuntu.com/ArtworkTeam/AccessibilityIcons

The original author Jakub Steiner notes in his icon development guide:
http://jimmac.musichall.cz/doc/high-contrast/html/index.xhtml
that the icons have been made black and white in order to get the 
maximum contrast.

However, it strikes me that while this may the case for an individual 
icon, colour cues might be useful in telling icons apart, for those who 
can discern colours.

So I guess my question is: do many/most/few people with blurred vision 
have the ability to see colour and if you cannot see colour are the 
black and white icons very much better than a set with deep primary colours?

It's probably a good idea to keep to one colour when designing the icons 
to make sure they become as simple and clear as posible, but perhaps 
after they are made some could be converted to green+white, red+white, 
etc. (and inverse).

It's not realistic to try this for Dapper; we should just focus on 
completing the existing set, but if colour is a useful additional cue 
then it might be worth adding colour to the set or making a separate set 
with 4-5 base colours. For now I'm just seeking some advice from our VI 
experts.

- Henrik