Visible light has a higher energy than microwaves. For a material to absorb energy, a condition called resonance must be met. In visible light, a simple example of resonance would be from recognizing that different colors of light possess different energies. Red light is absorbed by a green material because there is a resonance condition between the color of the material and the color (energy) of the light. Green light has higher energy than red light, but green light is not absorbed by a green material causing it to stay green. A microwave has a resonance condition for absorbing the water in order to heat an item, however, this is done with energy in motion and there is no resonance condition for color to absorb visible light and turn it into heat.