[thelist] [ot] what is Color Temperature ?

[Alessandro]

That's right on, Physics-wise. Color Temperature is a very familiar term to
anyone who does professional photography. Traditional color films are
calibrated to a certain color temperature. Color temperature (normally
expressed in Kelvins) is usually printed on the box or spec sheet of the
film. In more 'common' terms, color temperature is translated into "Outdoors
Film" or "Flash film" or "Fluorescen lights film". You know the color shifts
and variations you get when shooting 'regualr' film indoors? The yellow or
greenish cast... That's because you are not matching your film to your light
source.

My $ .02 (which cost me a lot more in art school)

Alessandro





> 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 first glow
> deep red, the cherry red, then orange until it finally becomes
> blue-white hot.  The color of the light radiated is thus related to its
> temperature.  Therefore, by developing a black-body color temperature
> scale, we can compare the color of a light source to this scale and
> assign to it an approximate "color temperature," that is, the
> temperature to which a black body must be heated to radiate a light
> approximating the color of the source in question."
> the brightness and contrast knob.