Color Blind Web Sites: And other design decisions

I've been doing some thinking about color blindness recently (I posted about the perception aspects of this over on my arts blog). As a color blind person I have often thought about this question: Should product designers cater to the color blind?

FYI, the cube on the left shows "normal" vision while the one on the right simulates what the same colors look like to someone with color deficiency.

By some estimates as many as 1 in 12 people have some form of color deficiency (although total color blindness is quite rare). Is that too small a minority to care about? After all, 1 in 12 people are left-handed and very few designers adjust their designs to accommodate lefties. But consider this, if you are designing technology for men, the incidence of color defectiveness is higher in men (as is, coincidentally, left-handedness--I'm not sure of the incidence of left-handed color blind men, but I am one).

What does it mean to design for color deficiency? I recently found an article in Dr. Dobb's that gives some good ideas for web designers looking to adjust designs for color deficiency. I have not yet found anything about "color-adjusting" products like electronics. One design choice that irks me, as a color deficient user of electronics, is the two-color LEDs like the ones that switch from red to green to show different states, for example, to show connected and not connected. Given that the most common form of color deficiency is referred to as "red/green deficiency" this might not be a smart design choice. You run the risk that as many as 1 in 8 of your customers a. won't be able to figure out that LED, and b. will get frustrated and disgruntled. You don't want to be the customer service person who asks "Is the LED red or green?" when the person on the other end says "I have no idea, I'm color blind."

How much more would it cost to have two LEDs? That arrangement gives you location and On/Off states to work with, which color blind people can handle (when the top traffic light is brightest it means stop, when the bottom one is brightest it means go, and so on). Then you can ask "Is the LED on the left on?" and get an accurate answer.

To be honest, and speaking as a businessperson, I don't know if catering to the color blind is a profitable path to take. But product designers might want to try it. You might be surprised how many people appreciate it.

P.S. If you are wondering about your own vision there is a site where you can do some basic tests of your color perceptions.