[VBprogrammer]

Unfortunately it is rarely that simple. For example I can easily spot 'pillar box' red and have no difficulty telling it apart from 'snot' green. In fact, its only in strange or low lighting that I generally have a problem telling red and greens apart. Green, Orange and Yellow; Purple, Pink and Blue; Red and Brown all can occasionally catch me out.

The effect of colour-blindness can also vary hugely from person to person. Even when they share the same type of colour-vision impairment.

Personally, I believe I tend to avoid relying on information coded in colour through habit, even when I can identify with reasonable accuracy the colours involved. Just as someone who is left handed will avoid complex tasks with their right.