Best Answer: I have never heard the question put like that before, but I would say it is the color of the pigment that determines what wavelength of light is absorbable. Light has what is called 'color temperature', or Kelvin temperature. Depending on the wavelength of a particular light source, the light will have a different color (temperature). The reason a plant looks, say, green, is because chlorophyll absorbs all the colors but green (roughly), and reflects the green color away.