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Comment by terr-dav | Hacker News Reader

An important point in the article is that CRI for LED bulbs does not meaningfully map to the light quality. >Oh, but: Experts agree that the color-rendering index doesn’t really index how colors are rendered. Some bulbs with a 90 CRI make things look wan; some with an 80 are passable. There are better, more useful metrics, but you can’t have them. Nobody puts them on the packaging. One lighting professional — an LED advocate, no less — told me he sometimes calls up the manufacturer and asks to talk to an engineer to get the real specs.

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Yes that's a good point, there's definitely more to it than just CRI. That said, a bulb with very poor CRI definitely sucks, so it's not entirely useless. This seems like one of those things that will suck until it doesn't.

It's interesting how the led datasheets have all the useful information (spectrum, CRI, angular spread). But once manufacturers put them on a bulb, they will refuse to tell even what leds they used.

At this point I believe companies are willfully refusing to inform their customers.

That could be because putting it on the box creates a liability that the LEDs are meeting those specifications -- just because the source LEDs claim to meet those specifications doesn't mean that the enclosure being sold using them as a component will actually produce that. Additionally, any change to LED suppliers/etc now means that the box also has to be changed.

In other words, what they are selling isn't the same as the thing in the box nor the aggregate of all the components (since they interact with one another).

Which means they're selling marginal stuff.

High end museums for example buy bulbs guaranteed to meet their datasheet specs, at a much higher cost of course.

CRI has to do the hard job of describing a spectrum using a single number. It's like looking at the entire menu of a restaurant and having to say how healthy the food there is. (heck, there's probably way better metaphors).

It does! And it seems that CRI is simply not a useful way to characterize LED light sources, as (i assume) it was established when incandescent and other non-semiconductor light sources were the only option.

To expand your metaphor: it's like judging a dish solely on the balance of flavors while not noticing that the restaurants have started changing the smell of the air, the firmness of the seats, the relative humidity and temperature individually.

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