A quick and simple way to roughly check the calibration of a spectrometer is to point it at the ceiling. Fluorescent lights put out a particular spectrum, and by comparing the colors the spectrometer senses to the colors you know the light emits, you can see if your spectrometer is accurate to a first approximation. I did this very thing yesterday, with the following result:
This is about what we expect to see. Fluorescent lighting consists of a relatively discrete set of colors compared to the broad Planck’s law emission of a hot incandescent bulb. The central peak in the florescent spectrum is in the yellow region, the sharp peak to the right is in the orange, the spike near the other end is in the blue, and so forth corresponding to the colors of a rainbow with red -> blue running from right to left. But there are slices of the spectrum that aren’t well-represented. This means that some colors aren’t rendered very well to the eye and accounts for the somewhat “unnatural” feel of fluorescent lighting.
This was a problem for the widespread adoption of CFL bulbs in the home. People tend to prefer the broad spectrum of incandescent bulbs, which looks more like a smooth and vaguely bell-shaped curve centered perhaps around 680-700 nm. Modern CFLs have a more complex internal chemistry which makes their spectrum look more like an incandescent bulb than a traditional fluorescent light.
Personally I’ve never been too impressed with CFLs as a technology. They’re nice and I use them, but their electronics are more complicated and fragile than a bulb can justify, they take time to warm up, and I’m not a fan of the (admittedly slight) mercury risk. As such I’m excited about the rapid progress in LED lighting. LEDs are light-emitting diodes, and until recently their problem was much the same as fluorescent lighting: they only emit in a small slice of the spectrum, and even if you combine red, green, and blue LEDs into one fixture the color rendering is still not so good. All of these problems are rapidly falling to technological advance, in particular the organic-chemistry based OLEDs and comparatively broad-spectrum quantum dot LEDs.
Though unfortunately OLEDs are rather unstable at the moment, in general LEDs are very electronically simple and astonishingly robust. In terms of efficiency and lifetime they could be practically as much of an improvement over CFLs as CFLs were from incandescents. Not only that, but they’re potentially much more versatile in their colors, they’re safe and easy to dispose of, and as a bonus they don’t have the warm-up issues that tends to plague CFLs. Bring ’em on.