Perception

When the primary colors of light, red, green, and blue are mixed, white light is produced. By looking at the shadows cast when an object blocks one or more of these color components, you can observe both the additive and subtractive processes of color mixing. Instead of subtracting light via an absorbing pigment, the object's shadow "removes" the component color from the "white" light. For example, the yellow shadow is the result of blocking the blue led and only allowing red and green to mix. Similarly, yellow pigment absorbs blue light and reflects red and green.