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How The Human Eye and Brain Work Together To See Color
Cones require a lot more light than rods and they are used to see color. The human eye only has about 6 million cones. Cones are packed into the back of the eye to produce sharpness and detail of images. We have three types of cones: red, green, and blue. Since the three types of cones are commonly labeled by the wavelength of color at which they are most sensitive (blue - long wavelengths , green - medium wavelengths and red - short wavelengths ) you might think other colors are not possible. But it is how the brain interprets the signals sent by the individual cones that allows us to see millions of colors. Here is how cones work together to produce color.
Look carefully at the picture of the snowman. Starting first with his hat, you will learn how each of the three retinal cones work together to produce the colors that you see. • The Snowman's Black Hat - The red, green and blue cones do not react to the color black. No signal is sent to the brain. • The Snowman's White Body - The red, green and blue cones all react to the color white. All 3 cones sen d signals to the brain. • The Snowman's Red Mittens - Only the red cone reacts to red colors. The red signal is sent to the brain. • The Snowman's Carrot Nose - G reen cone s reacts a lot to orange light. Red cones react less . Blue cones do not react at all. • The Snowman's Yellow Belt - Red cones react a lot with yellow light. Gree n cones react a little bit. Blue cones do not react at all. • The Snowman's Blue Shorts - Only the blue cone reacts to blue colors. The blue signal is sent to the brain.
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