4 ms·

I think she has a good point about how too much blue light might not be very good for us. There has been interesting research in this are. It's true that tradi

by jonex 8y ago

I think she has a good point about how too much blue light might not be very good for us. There has been interesting research in this are. It's true that traditional street lights (sodium vapor lamps[1]) are warmer, but they also provide more limited light spectrum (only one frequency of yellow) for this reason they are mainly used where the price and power efficiency outweighs the limited visibilty. So it's not strange that given the option to get better color rendering at a good price, LED technology using full spectrum light has been prefferd. However, there's nothing stopping us from using LED lights with warmer spectrum, and that argument is probably good to raise. With the higher control of the spectrum that LED gives us compared to the previous street lights we might even be able to create a good compromise using warmer but still wider spectrum lights. [1] https://en.wikipedia.org/wiki/Sodium-vapor_lamp https://en.wikipedia.org/wiki/Sodium-vapor_lamp

graeme 8y ago
Do any LEDs match the spectrum of those sodium vapor lamp? The ones I looked at had a higher blue profile even if the output colour matched the yellow.
- asteli 8y ago
  In fact, yes. The illumination spectrum of sodium vapor lamps is very specific -- they emit almost all of their light around 589nm (amber) [1]. You could easily replace the light from a sodium vapor lamp with an LED lamp outfitted with LEDs manufactured to emit that particular frequency of light. The LEDs themselves are not particularly expensive either. Linked a digikey page with a potential part you could use.[2] 1:https://commons.wikimedia.org/wiki/File:Low-pressure_sodium_lamp_spectrum.svg https://commons.wikimedia.org/wiki/File:Low-pressure_sodium_... 2:https://www.digikey.com/products/en?keywords=XPEBAM-L1-0000-00601CT-ND https://www.digikey.com/products/en?keywords=XPEBAM-L1-0000-...
floatrock 8y ago
My house's front door faces a street lamp, and ever since the town replaced it with a white LED, it's terribly blinding to walk by in the evening. I wish my door came with flux or nightshift. That being said, I wonder how much of this is marketing the wrong product. When I see towns or cities advertising the shift, they use phrases like "more natural lighting" (yes, cool white is closer to daylight) and "brighter" (a messy concept when including colors, but I think they mean perceived brightness which again goes back to cool daylight temperature). Those sound like Good Things for a city (which I imagine is why they're buying these things), but really we're being marketed the wrong things. I don't want "more natural" daylight lighting at night, because it's night and I want to sleep. It may make drivers slightly more alert, but it comes at the cost of polluting everyone else's house (like my front door). So the people being marketed these lights hear things that sound good and sound like they make our communities safe, but really these are features we don't actually want for nighttime lighting... we need to realize we need different solutions for this problem.
fyfy18 8y ago
> for this reason they are mainly used where the price and power efficiency outweighs the limited visibilty I always thought these lamps were inefficient, which is why they are being replaced with LEDs, but apparently they output up to 200 lumens per Watt which is better than most household LEDs.

by jonex 8y ago

graeme 8y ago

Do any LEDs match the spectrum of those sodium vapor lamp? The ones I looked at had a higher blue profile even if the output colour matched the yellow.

asteli 8y ago
In fact, yes. The illumination spectrum of sodium vapor lamps is very specific -- they emit almost all of their light around 589nm (amber) [1]. You could easily replace the light from a sodium vapor lamp with an LED lamp outfitted with LEDs manufactured to emit that particular frequency of light. The LEDs themselves are not particularly expensive either. Linked a digikey page with a potential part you could use.[2] 1:https://commons.wikimedia.org/wiki/File:Low-pressure_sodium_lamp_spectrum.svg https://commons.wikimedia.org/wiki/File:Low-pressure_sodium_... 2:https://www.digikey.com/products/en?keywords=XPEBAM-L1-0000-00601CT-ND https://www.digikey.com/products/en?keywords=XPEBAM-L1-0000-...

floatrock 8y ago

My house's front door faces a street lamp, and ever since the town replaced it with a white LED, it's terribly blinding to walk by in the evening. I wish my door came with flux or nightshift. That being said, I wonder how much of this is marketing the wrong product. When I see towns or cities advertising the shift, they use phrases like "more natural lighting" (yes, cool white is closer to daylight) and "brighter" (a messy concept when including colors, but I think they mean perceived brightness which again goes back to cool daylight temperature). Those sound like Good Things for a city (which I imagine is why they're buying these things), but really we're being marketed the wrong things. I don't want "more natural" daylight lighting at night, because it's night and I want to sleep. It may make drivers slightly more alert, but it comes at the cost of polluting everyone else's house (like my front door). So the people being marketed these lights hear things that sound good and sound like they make our communities safe, but really these are features we don't actually want for nighttime lighting... we need to realize we need different solutions for this problem.

fyfy18 8y ago

> for this reason they are mainly used where the price and power efficiency outweighs the limited visibilty I always thought these lamps were inefficient, which is why they are being replaced with LEDs, but apparently they output up to 200 lumens per Watt which is better than most household LEDs.