What does "K" stand for in lighting

[Turf]

if you have 20K bulbs what does the 'K' stand for. I know it is spectrum and light temp etc etc etc. Just need to know what it actually means. Thanks a ton.

[Amphiprion]

It is referring to the color of an ideal metal when heated to approximately 20000 Kelvin. When this theoretical ideal metal is heated to this temp, it is a relative blue color (hence 20K halides are blue). But since this is theoretical, the measures for color temp are approximate (or even subjective) at best. This is it (in very basic format) in a nutshell. Hope it helps.

[tag]

ok, what does the nm stand for in actinic bulbs? say a 420nm bulb.

[orlenz]

nanometer

[Turf]

thanks a bunch it is just what i was looking for.

[WaterKeeper]

Hi Turf,

I think you are really in need of this The Lighting Thread (http://www.reefcentral.com/forums/showthread.php?threadid=550860). Even Lord Kelvin has read it. :D