| Yellow Material. Place a piece of yellow material by clicking on the yellow Material button and then clicking in either the Material A Region or the Material B Region. To see how the percentage of incident light reflected by yellow material varies by color, click the Open Material A Graph or Open Material B Graph buttons. To see the spectrum of light from a particular source reflected by yellow material, use the Spectroscope tool. To model the reflection by a "perfectly" yellow material, use the Ideal Material tool.