Wheel of Color

In World War II, when airplanes flew bombing runs over camouflaged Nazi camps, the pilots were faced with a problem---they couldn't see the enemy. The camps were camouflaged well enough to be nearly invisible. Technology wasn't available to solve the problem---while heat-sensing goggles would surely have been nice, they were hardly available. So who came to the rescue?

Color blind people.

Before I explain, let me point out one thing you might not know about color blind folk: they are often not totally insensitive to color---they are really color "different". Many color blind people, myself included, have all the sensors needed to detect color (red, green, and blue), but the wavelengths of some of these sensors are different than normal. For example, my red sensors are geared more towards orange.

By the same token, light is not necessarily defined in terms of red, green, and blue---it is a continuous spectrum. In computer monitors, we use red, green, and blue to simulate all the colors of the rainbow, but that is only because we sense the world through those three particular wavelengths. A true orange color stimulates both green and red cones, so a computer can imitate a true orange with varying degrees of the component colors. But real-world pigments and colors are more complex than can be shown through a computer screen.

With that, let's go back to World War II. When the Germans chose colors for their camouflage, they evaluated the color scheme with their "normal" eyes, choosing the colors that hit their eyes' light sensors the same way the landscape would. Seen at a distance against a dark forest, such camouflage should be invisible. But since color blindness is a difference in light sensor wavelengths, the camouflage colors would not necessarily strike the eyes of color blind soldiers quite the same. Additionally, people who are color blind often focus more on texture than on color. This discovery gave the Allies a valuable weapon in the war against Nazi Germany.

Maybe that's why there are color blind people around still.