Fluorescence vs. Transmittance


 On the left, the light source is in our line of sight. In this case, what we see is primarily the light emitted by the hot filament of the tungsten bulb that was not absorbed by the chlorophyll.




On the right, the light souce is perpendicular to our line of sight, and we can clearly see the red, fluoresced, light of the chlorophyll. This light is emitted by the chlorophyll molecules after they first absorb light from the lamp.