Red Material. Place a piece of red material by clicking on the red 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 red 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 red material, use the Spectroscope tool.

To model the reflection by a "perfectly" red material, use the Ideal Material tool.