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[APD] Optical Psycho
Where's that psycho-optics fella when we need him?
He's here, and driven around the bend by some of the misinformation in
this thread. :-) The terrible thought is that some of it gets passed on
Color temperature is a psycho-physical measurement that says how the
light "looks" to a "standard observer." The International Committee on
Illumination (ICI in English and CIE in French) tested a large number of
individuals and found averages as to how certain nominally white colors
appeared when compared to blackbodies at various temperatures. The scale
actually ends at around 10K and higher numbers are just marketers trying
to foist off non-white tubes (usually very blue).
A 10K with high CRI can look very white. If CRI is down around 80 or
below, it will be blue.
Basically Color Temp. tells you little about the spectrum or usefulness
in unintended applications. It was a standard to get store show windows
to look right, and (sometimes) to make meat look fresher in the display
Applications to aquarium illumination are a true stretching of the
A true spectral energy distribution plot would be far, far more useful,
both for predicting photosynthesis efficiency and apparent color
fidelity and intensity to your eye. Those are what we want.
In LFS lamps, Color Temp. holds about the same place as Megapixels in
cameras. That is, a great marketing hook, but with little real value to
Your friendly Optical Psycho
Wright Huntley - Rt. 001 Box K36, Bishop CA 93514 - whuntley at verizon_net
"I cannot undertake to lay my finger on that article of the Constitution which granted a right to Congress of expending, on objects of benevolence, the money of their constituents...." --James Madison
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