Austine Wood Comarow creates lovely pieces like "Garden Gold," which shift in hue as the pieces move. The materials themselves have no colors:
We perceive the color as a result of the interaction of polarized light and certain optically active materials such as cellophane. The image is created by cutting and laminating thousands of tiny pieces of this colorless material to polarizing filter. This work is presented here in a special light box incorporating a motor and rotating polarizing filter which gives the work it color and causes it to continually change.
For those who are curious about how it works, she also has an interesting white paper on the physics of the art form.
Image: YouTube/ Austine Studios