Why does everyone use red and green LED indicator lights when those colors are the worst for colorblind people?
While red and green are the colors of Christmas and holiday cheer, they are actually the colors that are the worst for colorblind people. Roughly 8% of men and 0.5% of women are colorblind, and for them, it can be very difficult to differentiate between red and green. This can pose a serious problem when trying to indicate if something is on or off, as is the case with LED indicator lights.
So why do manufacturers continue to use red and green LED indicator lights when they know that it can be difficult for colorblind people to tell them apart? There are a few reasons.
First, red and green are the colors of the most common type of colorblindness, called protanomaly. This means that people with this condition have a decreased ability to see red light, and as a result, green appears more red to them. While there are other types of colorblindness, protanomaly is the most common, affecting roughly 1 in every 12 men.
Second, red and green are opposite each other on the color wheel. This makes them highly contrasting colors, which makes it easier for people to tell them apart, even if they have a mild case of colorblindness.
Third, red and green are the colors of the traffic lights, which everyone is taught to recognize from a young age. This makes