Most awesome lightbulbs

Most awesome lightbulbs

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Alzo Digital 5500K 91CRI Compact FLuorescents.

Absolutely instant on. Disappointingly audible buzz.

I'm sure you've heard that a 22 watt CFL (Compact FLuorescent) lightbulb puts out as much light (lumens) as a 100 watt incandescent bulb, and they live a lot longer. That's about 1/5th the power (electrical cost) for the same brightness.

You might not know that the color of white light is relative. While an incandescent lightbulb makes everything look yellow, it is technically as white as the mid day sun. Your brain compensates.

So when I decided to replace all the lightbulbs in my house with one color, I had some difficulty with the absence of a One True White (which does exist in pigments, just not light). But 5500 Kelvin color temperature turned out to be mostly standardized. (Apparently some guys in Cambridge went outside one sightly overcast day and picked one.)

Then it turns out a lot of fluorescent lightbulbs reproduce colors poorly. This is measured with the Color Rendering Index. Smooth color spectrum = high CRI, spiky color spectrum (like sodium street lights) = low CRI. The best CRI is 100. So I got the 5500K lightbulbs with the highest CRI, these from Alzo: 91 CRI. (From all bulbs, not just CFLs.)

This is the same stuff used anti-SAD light boxes, and qualifies as "full spectrum" "daylight" bulbs. But since nobody regulates these terms, be sure to check for the 5500K and 91+CRI.

CFL bulbs that mention their CRI at all are hard to find. I have yet to find one in a physical store, and I regularly check. (Of course the rest have something to hide.)

The CRI measurement sucks. It only uses 10 or 15 reference swatches. They're working on it.

The other bulb in this photo is a CFL that came with my house, half the watts, no color temperature or CRI listed, clearly intended to avoid looking wrong to people accustomed to the yellow light of incandescent tungsten.

Yes, I white balanced the picture off the 5500K bulb alone. And that's also really what it looks like.

I am still amused by the possibility of gelling a 100 CRI ~3100K halogen to 5500K.

I also really want CIE Illuminant E emulators for lightbulbs. An equal energy radiator. Flat spectrum. Imagine the color separation.

Update (2010-07-15): Some buzzing is apparently normal for this batch and "is something we need to address in our next round of bulbs".
  • Wow.. I like the color of the one on the left better.

    What're you going to do with all the old bulbs? :)
  • Indeed

    CFL bulbs that mention their CRI at all are hard to find

    I've never found one. We just tend to buy brands we've used in the past and hope for the best.
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