What you perceive as an object's color is actually a section of the light's wavelength being reflected by the object. Remove that wavelength from the light, and you'll no longer "see" the object's color. Sounds crazy? Step into the "color room" and see for yourself. Adjust the amount of red, blue or green in the room's light. What happens to the circle marked "BLUE" when you take out the blue light? You may not believe your eyes.