Why can't color blind people see any colors?
Most people with color blindness can see almost all colors. They are typically only blind to a few colors. Furthermore, they are not completely blind to those colors, but are only partially blind. The human eye contains three types of color detecting cells: red-detecting cones, green-detecting cones, and blue-detecting cones. Each cone cell can detect many colors in addition to its main color. For instance, the cone cells in the eye that can see red light can also see orange and yellow. The red cone cells just see red the best, and that is why they are called the red cones. Similarly, the green cones can also see orange, yellow and blue. This overlap is what allows humans to see so many different colors. Humans can see the color yellow, for instance, even though there are no yellow receptors, because of this overlap. When you look at a yellow flower, the yellow light stimulates the red and green cells in your eyes, and your brain interprets a little bit of red plus a little bit of green as yellow.
