Sunlight has all colors of visible light in similar proportions. When light passes through a leaf, more blue, orange and red wavelengths are removed by chlorophyll and carotenoids and more green-yellow and far red wavelengths are transmitted. Therefore, the shade of a tree is richer in green-yellow and far red wavelengths. Plants are partially "color blind" to the light in the shade.
Light
Quality from Artificial Light Sources
Artificial
lights emit different wavelengths (colors) of visible light. Fluorescent
light are highest in the blue and yellow-orange region of the spectrum.
Incandescent (tungsten) lights are poor in the blue region, moderate in
the green region, high in the red and far red region of the spectrum, with
up to 50% of their output in the infra red region (that's why they're hot).
