Why bother ?
"Hmmm ? Never thought about it."
"Why bother going to all that trouble, it’s not like it affects many folk…"
"Well, they can’t see properly, nothing we can do about that, is there?"
"Looks fine to me and that’s what matters!"
Given that you are here, reading this, I assume and hope none of the above applies to you, so let’s get down to business.
Colourblindness is mostly a genetic condition, though injury and old age can bring it on. It is far more common in men than in women, with around 1 in 12 men having some degree of colour perception problems, but only 1 in 200 women. So, from a sales point of view, your clever design could be alienating up to 8% of your male customers. Apparently, though not true colourblindess, when people age their corneas typically turn yellowish, severely hampering their ability to see violet and blue colors. That’s the ‘silver surfers’ ticked off with you too.
The 101 in terms of biology goes like this, it’s down to the mixture of cones in your eyes. People with normal colour perception have three different cones, each cone is tuned to perceive mostly either Long (reds), Middle (greens), or Short wavelengths (blues). If any of these cones are missing or misfiring (has a different peak absorption) then the colours start merging and can be absent completely. At it’s extreme, although phenomenally rare, a few individuals can only see in shades of gray! There’s all sorts of other factors like enzymes and neurology, I’ll leave that to medical sites, eh.
So, in answer to what you can do about it, play with colours and plugins, just as I have. If you have friends with colourblindness, get them to look your work over. See if is it even readable to them. Part of a large company? Discretely ask your staff for help. A typical large office complex or factory can have upwards of a thousand staff – that’s over a hundred people to give you the heads up on your website…
Running a web design agency? You are, of course, aware that colourblindness is a registered disability and as such covered by various acts. It is increasingly becoming a condition and law for commercial websites to comply. I’ll research the legal side another day but at the very least, raising awareness will increase your standing with clients. Put an ad in the local paper and ask for test subjects, offer them a small fee to come in once a month to look at what you are going. Only needs three people, though those with tritanopia will be harder to find.
The bottom line IMHO, forgetting the legal and PR value of remembering disabled visitors, is that it’s the right thing to do!