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 == Incandescent == 

 I have a question about the following statement made in this article. 

 ""The power of a lightbulb (20 or 100 W) seems to change its color but in reality it only affects its luminosity (luminance) to which our eyes are very sensitive."" 

 Is there a reference for this?  This doesn't seem to agree with a statement in the Incandescent Light Bulb entry (see quote below), which infers that color temperature of tungsten lighting is variable. 

 ""The current heats the filament to an extremely high temperature (typically 2000K to 3300K depending on the filament type, shape, size, and amount of current passed through). Heated atoms within the filament intensely vibrate. The electrons, which are charged particles now strongly oscilating, radiate excess energy in the form of black body radiation, according to Maxwell's equations."" 

 I'm not saying that a 20W bulb and a 100W bulb couldn't have the same color temperature, it just means that they aren't necessarily the same since there is a lot of variability in filament temperatures for tungsten bulbs. 

 Furthermore, I have seen many photography websites which list color temperatures for tungsten lighting as a range, rather than a single value. 

 On a different (but related) subject, I would infer from the Incandescent Light Bulb entry that a dimmer switch will vary not only the luminosity of the bulb, but also the color temperature.  This might be worth mentioning in this article."