Comment by jwr | Hacker News Reader

Comment by jwr | Hacker News Reader

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I've been working on designing my lighting system for home. I find these reports annoying: without specifics, it's really just FUD. I am looking at datasheets for various LEDs, comparing CRIs and spectral distributions and I know already that my lights are going to be as "warm white" as possible (e.g. close to 2700K with a mix of higher-K added only during daytime) with the blue peak being as small as possible.

Incidentally, I actually DO want to add blue at times, because at my latitude days are short and dark during winter time and daylight temperature lighting seems to be beneficial during daytime hours.

How do I make use of "information" in this article? Do I reject LEDs altogether? Do I look to minimize certain frequencies? If so, which ones specifically? Do I avoid exceeding certain intensity? (then give me at threshold for Lux at eye position) Or do I avoid exceeding certain energy radiated within a specific band?

It's frustrating, because apart from the FUD, there is little to go on.

Its the blue light, when I worked with "hard" blue LEDs (~460nm), I had to wear special glasses or I could literally feel my retinas melting.

Just stick with warm white and you'll be good. Warm white still emits a fair amount of blue light, but its approximately around 1/3 that of cool or daylight white LEDs.

Remember that natural sunlight is many orders of magnitude stronger than any 5000K LED and unlike LEDs has tons of UV as well. You could likely offset any damage and then some just by wearing sunglasses anytime you are out in the sun.

Are you sure of that?

I believe humans have evolved to accept certain damage as natural and it just repairs itself.

When I expose myself to moderate amounts of light, my body reacts making my skin darker, which protects my skin against light.

Think for example gravity, that is exerting acceleration that damages our bodies, so our body has to react making bones and muscles. If we go to space and do not apply damage, the human becomes weaker, as it atrophies.

If we make a person to breathe in a total clean environment(filtered air), the immune system atrophies, then if you make the person breath normal air, you can kill her.

Of course we also know that too much is very bad, because it exceeds the limits of the human body to repair and something breaks down.

Common sense is key. If you go to the mountain or the sea in summer in Spain, Italy, Greece, Morroco, New Zealand... you should be extremely careful. This exposure in thousands of times more than indoors(or countries like UK) and UV light skyrockets.

Same here, I live in a dark country. I use cold white where I work and warm white where I sleep, eat, watch tv. Basically evening time.

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