05 Oct 2003, 04:58, Roy J. Tellason (1:270/615), wrote to Charles Angelich:

Hi Roy.

 CA>> How many people look for 'temperature' when they purchase a bulb?

 RJT> I'd say it depends on how specialized the application is.

 CA>> I realize that the decision to apply 'temperature' to color was 
 CA>> not made here at FIDO but reasonable people can grasp the fact 
 CA>> that there is no 'temperature' that would apply to color in any 
 CA>> meaningful way.

 RJT> No?  Take a hunk of steel or iron,  and heat it up.  At some 
 RJT> temperature,  it starts to glow red.  Get it somewhat hotter,  
 RJT> and the color changes.  I'm not 100% sure that it was this where 
 RJT> it came from,  but it may very well have been something similar, 
 RJT>  perhaps some other material...

Here's a bit from a 'Photo site':

Color Temperature:

Color temperature is a term that is borrowed from physics.
In physics we learn that a so called "black body" will radiate
light when it is heated. The spectrum of this light, and therefore
its color, depends on the temperature of the body. You probably
know this effect from everyday life: if you heat an iron bar, say,
it will eventually start to glow dark red ("red hot"). Continue to
heat it and it turns yellow (like the filament in a light-bulb) and
eventually blue-white. Be careful with the terminology here! The
hotter the body gets (measured as the temperature in degrees Kelvin)
the more the color moves from red towards blue. But we say that red
is a "warmer" color than blue! So a warm body radiates a cold color
and a (comparatively) cold body radiates warm colors. I know, it's
confusing...

The photographic color temperature is not the same as the color
temperature defined in physics or colorimetry. As mentioned above,
the photographic color temperature is measured only on the relative
intensity of blue to red. However, we borrow the basic measurement
scale from physics and we will measure the photographic color
temperature in degrees Kelvin (K).

The following table should give you some feeling for the scale.
These are of course not exact numbers but rather typical values.
The list is not a substitute for a color meter.

Temperature  Typical Sources
1000K        Candles; oil lamps
2000K        Very early sunrise; low effect tungsten lamps
2500K        Household light bulbs
3000K        Studio lights, photo floods
4000K        Clear flashbulbs
5000K        Typical daylight; electronic flash
5500K        The sun at noon near Kodak's offices :-)
6000K        Bright sunshine with clear sky
7000K        Slightly overcast sky
8000K        Hazy sky
9000K        Open shade on clear day
10,000K      Heavily overcast sky
11,000K      Sunless blue skies
20,000+K     Open shade in mountains on a really clear day


     Good luck...  M.

--- Msged/386 TE 06 (pre)