text: why is it that the only colors that we can see happen to be the same light frequency used in photosynthesis?   the reason our eyes are sensitive to the visible light spectrum that they are is because that is the same spectrum over which our star has the greatest output that our atmosphere doesn't absorb. there are more visible light photons (if i remember correctly at a range of ~400-750 nm) bouncing off and being absorbed by objects (to give them color) then any other natural form of radiation.  i'm no botonist, but i believe that although plants may utilize other wavelengths of light (since all light travels at relatively the same speed, the wavelength is proportional to the frequency (frequency = constant/wavelength)) they are optimized to absorb visible light, which is why they appear green - they absorb blue and red light for photosynthesis. they use the same range for photosynthesis as we do to see because they reside under the same sun.