Things appear different colors because the substance they are made out of absorbs all colors of light except the one that we see. So a blue car would appear blue because the paint absorbs all of the yellow and red light. A red car appears red because the paint absorbs all of the blue and yellow light, and reflects the red. BTW sun light is known as white light, which contains all of the colors into one. if you shined a red light at a blue car in absolute darkness, it would look black because it isn't reflecting anything back.