[thelist] [ot] what is Color Temperature ?

Adam Squier asquier at exobox.com
Fri Oct 6 11:45:29 CDT 2000

> straight out of my _Mechanical and Electrical Equipment for Buildings_
> (MEEB as we call it in the industry) bible, page 961 explains color
> temperature:
> "A light source is often designated with a color temperature, such as
> 3400 K for quartz iodine lamps, 4200 K for cool white 
> fluorescent tubes,
> and so on.  This nomenclature derives from the fact that when a
> light-absorbing body (called a black body) is heated, it will 

What's really odd about this quote is that neither of these examples (quartz
iodine or cool white fluorescents) can even be described (accurately) as
having a color temperature because neither of them are examples of black
body radiation. A regular light bulb -- that has something (a filament)
glowing or burning -- can have a color temperature because of this.

Fluorescent tubes and other charged gas have spikes of colors (think
histogram) emitted rather than a curve of all the colors leading up to the
highest color temperature.

Of course, this is all in theory and to most folks it doesn't matter. I just
thought it was odd that the book would use those lights as examples.

At least this is my understanding of it. If there are any physicists out
there that will prove me wrong, please do so before I once again start
spreading incorrect information.


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