Quite a few inaccuracies in the article which indicate misunderstanding of how additive light temperature works.
You don't want to "cool it" - that means more blue! You want to warm it with less.
Doctors issue warning about effects of LED streetlights on health
31–40 of 89 posts
Re: Doctors issue warning about effects of LED streetlights on health
#32Color temperature of "white" LEDs is due to the amount and type of phosphor to downconvert the blue LED spike to warmer colors. The more phosphor and conversion that goes on, the less total output (no free lunch in physics). So in markets where amount of light (like exterior lighting) is a selling point, vendors sell their cooler temperature LED's for performance.
Re: Doctors issue warning about effects of LED streetlights on health
#33Title is misleading; it's not LED streetlights, it's the color temperature of LED streetlights. While the article raises a few good points, color temperature isn't new; it's not like LEDs have some inherent issue that impacts health.
True, but there's a real problem with people and places using lights with far too high a temperature, and even when shopping for home LED lights it's surprisingly difficult to find low temperature lights that aren't low on lumens output.
Pretty much anything over 3000K looks horribly blue at night, and if it wasn't such a massive pain to find them I'd prefer <2000K.
Re: Doctors issue warning about effects of LED streetlights on health
#34Quite a few inaccuracies in the article which indicate misunderstanding of how additive light temperature works. You don't want to "cool it" - that means more blue! You want to warm it with less.
"Hot" and "cold" have different meanings in different contexts. In the article, they're referring to color temperature, which is about the temperature of the source, and assumes black-body spectrum. So 3000K means a source at 3000 Kelvins. Light from a 5000K source has more blue, and so is cooler. But the color temperature is higher (5000K vs 3000K).
Re: Doctors issue warning about effects of LED streetlights on health
#35The article is saying "cool it and dim it" but I think they mean to say "warm it and dim it". They suggest the temperature should not be above 3000 kelvin.
Re: Doctors issue warning about effects of LED streetlights on health
#36Could we just place a lens of some sort on pre existing led street lights to decrease the amount of blue light emitted?
How about an add-on cover with "phosphor to downconvert the blue LED spike to warmer colors" [thanks, nickhalfasleep]?
Re: Doctors issue warning about effects of LED streetlights on health
#37And what about laptop monitors?
Re: Doctors issue warning about effects of LED streetlights on health
#38I would argue that people with those crazy LED headlights are even worse. Since I often work late, I get the pleasure of being temporarily blinded as a white dwarf passes by at 45mph regularly.
And don't even get me started on the LED eye melters that cyclists are running these days. Some are about as bright as car headlights, but the spread and aim are inferior - especially since the folks that run those invariably seem to point them up from the horizontal. I keep thinking about mounting a 8 D cell maglight on a gimbal on my handlebars to give them a photon in-kind response.
Re: Doctors issue warning about effects of LED streetlights on health
#39The article is saying "cool it and dim it" but I think they mean to say "warm it and dim it". They suggest the temperature should not be above 3000 kelvin.
That is because redder colors correspond to a cooler or lower color temperature. Colloquially, we think of blues as cool and reds as warm, but blue light is actually more energetic (or "hot") than red light.
Re: Doctors issue warning about effects of LED streetlights on health
#40The article is saying "cool it and dim it" but I think they mean to say "warm it and dim it". They suggest the temperature should not be above 3000 kelvin.
Yes. It's the blue component (large with high color temperature lights) that is thought to most strongly affect human melatonin secretion and sleep. Here's one of many studies that indicate this: