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Re: Tritons vs Chroma 50s

"Alan Kaufmann" <Alan4ever at worldnet_att.net wrote:

> Hi Don,
> I was at a SFBAAPS meeting Friday where Claus Christensen talk about raising
> plants.  He knows a little about it as he is the head of Tropica
> International, the largest aquarium plant growers in the world.  He
> explained that the reason Chroma 50s look so bright is because much of their
> light is in the green spectrum.  Plants use (absorb) the red and blue
> spectrums and reflect the green spectrum (which is why plants look green).
> Green is in the middle of the spectrum in which we see, so it appears much
> brighter to us then either red or blue lights.  However, for plants it is
> the opposite, so what is bright looking light to us may, in effect, be
> rather dim for them.
> Hope this helps,
> Alan

It doesn't matter how the spectral distribution of the light is, as long as
we use lumens to quantify the light. 2000 lumens, say, coming out from a C50 
or a GE Fresh & Salt bulb (the subject of the original post) should create
a similar level of *perceived* brightness, because the lumen measure already 
takes into account the photopic response of the visual system. C50s and the 
GE Fresh & Salt bulbs have similar initial lumen ratings, so brand new bulbs 
put side by side shouldn't look that different.

-Ivo Busko
 Baltimore, MD