Ack, I had one more lighting article kicking around…and here it is.
Color temperature is one of those topics everyone will be familiar with, but not understand. And you don’t really need to understand it, but if you’re discussing lighting and light quality, then color temperature will come up. The radiation mechanics and what not aren’t so important for average homeowners as realizing that an LED bulb which produces 2700 K amber light is a good thing.
Color Temperature – Technical
The technical definition means almost nothing to us. And courtesy of Wikpiedia here it is:
“The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of comparable hue to that of the light source. Color temperature is conventionally stated in the unit of absolute temperature, the kelvin, having the symbol K.”
Wow, that means nothing to me. Let’s instead look at the practical meaning of all this.
Color Temperature – Practical
The practical upshot is that color temperature is an effective way for homeowners to gauge the hue of lighting. Flame, natural sunlight and most incandescent bulbs register much cooler light temperatures (from around 1800K for flame to 2700K for whiter incandescent lights). These are the softer, warmer lights our eyes are accustomed to for most of daily life.
Compact fluorescent and white LEDs are much harsher and in color temperature parlance, much hotter. Their light ranges from white to blue-white and are famous with cubicle dwellers for their headache-inducing glare. When my wife and I discussed the CFLs around our house, the harsh white light was one of the first things. Here’s a little chart of color temperatures and human reactions to them:
CFLs struggle with color temperature enormously, though LEDs show some promise in producing cooler lighting. CFLs can change tints or glazes, but the naturally ‘hot’ light produced by the mercury vapor hamstrings those attempts. LEDs have much more flexibility as the light color and color temperature are determined by the LED’s semi-conductor.
While the definition of color temperature may not have great resonance with most homeowners, its practical applications do. Their harsher color is one factor that has held back wider adoption of CFL bulbs. Reproducing the color temperature characteristics of an incandescent in a bulb with the efficiency of an LED or CFL is the Holy Grail of efficient lighting.
Once the new efficient lighting guidelines take effect, manufacturers will have to make more efficient lighting but customers will be shopping for the warm amber color temperature to which they’re accustomed.