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Re: halogen lights

Wright Huntley wrote:
> The spectra of incandescent and halogen lights are well known to be pretty
> good approximations to blackbody radiation in the photosynthetically
> interesting part of the spectrum. That is, fairly flat and uniform from IR
> to UV. They are excellent compromises between visibility and action spectrum
> for plants. They just waste energy, like mad.

What is the color temperature of a typical halogen ? A 3000K black-body 
emits about 20 times more photons at 700 nm than at 400 nm. For a 4000K 
black-body the factor is about 4.5. Far from being "flat",  but good 
enough for plants, I guess.

-Ivo Busko