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Comment by nine_k | Hacker News Reader

Regarding the LED lights: unless you use a lamp with CRI < 90, you see obvious, glaring color distortions, and some colors just "disappear", cannot be seen, because of the lack of a particular spectrum bands. Sadly, most inexpensive LED lamps have CRI around 80, and that light feeld definitely artificial, even if pleasant to the eye. A lamp with CRI 90 is okay, most things look natural, even though you can notice it's not sunlight. A lamp with CRI 95 is very fine, it's practically sunlight, and most tricky colors are visible well. I've never encountered a lamp with CRI, say, 97, but they exist and cost a lot.

(Source: doing object photography.)

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IME producing artwork that relies on subtle color relationships requires high quality, "full spectrum" illumination. Natural daylight is the obvious canonical option, but of course not always practical.

My studio gets very little natural light, so selecting optimum light sources is crucial. At one time the most practical option was D50 compliant fluorescent tubes, but these were only fairly acceptable.

Situation with LED lamps is also difficult. Even CRI 90 is inadequate, mainly poor red emission and excessive blue radiation. However D50 compliant LED fixtures are available if somewhat more expensive vs. typical LED lamps.

One vendor worth checking out is Waveform Lighting [0]. They offer several types of products with CRI 95 and CRI 99. I've been using their D50 'shop light' for several months and find it very satisfactory.

[0] https://www.waveformlighting.com

Surely an incandescent bulb, being a black body radiator, has a CRI of 100? Yes, the temperature is low compared to sunlight, but the rendering is theoretically perfect.

I suppose if you want to get closer to sunlight, you need a carbon arc, which is only a few hundred degrees cooler and again, a perfect black body emitter.

Yes. An incandescent bulb is basically the reference for CRI 100. The parent of your poster is explicitly discussing non-incandescent technologies.

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