Light and Color - Mission LC4 Detailed Help

Three colored spotlights - red, green and blue - with equal intensities are used to shine white light upon a cyan shirt. The shirt appears cyan because it absorbs the ____ light and reflects the ____ light.


 
Many students of physics have seen a diagram similar to the one shown at the right. The diagram depicts three circles colored with the primary colors of light - red, green and blue. The primary colored circles overlap to produce other colors of light - known as the secondary colors of light: cyan, magenta and yellow. Complementary pairs of light colors are those colors that are exactly opposite each other on the diagram: red and cyan, magenta and green, and blue and yellow.


 
Color Subtraction and Complementary Colors:
An object that is observed to be a specific color when illuminated with white light has absorbed the complementary color of the observed color. White light or R+ G + B was incident on the object. One or more of the components of white light were absorbed or subtracted and the remaining light colors were reflected to the observer's eye.


 
The color of a shirt is not in the shirt itself, but rather in the light that the shirt reflects. If red, green and blue light shine on a shirt and the shirt appears cyan, then the green and blue light of red, green and blue incident light was reflected. After all, cyan light can be thought of as equivalent to blue and green. So if the green and blue was reflected, then what happened to the red light? It was subtracted or absorbed. So red is absorbed by a shirt that looks cyan. Now think about the color wheel shown in the Dig That Diagram section and you will see the big idea. Red light - the complement of cyan light - is absorbed when a shirt appears cyan in the presence of white light.


 

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