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I don't understand why red light is not the default for night lighting and street lamps and maybe even car headlights. Red light allows you to see while still m

I don't understand why red light is not the default for night lighting and street lamps and maybe even car headlights. Red light allows you to see while still maintaining your night vision. Blue or white or whatever other color you use will ruin your night vision and only allows you to see what is decently illuminated and anything outside that zone becomes invisible.

argondonor 3y ago
The blue tint disrupts your sleep cycle and helps keep you awake when driving at night. There's definitely a trade off to be had depending on where these lights are located though.
- TylerE 3y ago
  Red is also really low contrast, at least at non-night-vision destroying lumen levels.
- Galaxeblaffer 3y ago
  says what evidence? it's pretty much been debunked for a long time, and the whole premise is apparently based on bad science. I'm pretty sure i read an article here on hn that showed that this whole blue light scare was based on old science with extremely limited sample sizes and extreme exposure. i tried to link to an article from 2016 that still says that it affects sleep because i hastily read the first part. trying to dig up the article i read seems to be hard, but at least I'm still pretty sure that the science is not settled on the matter at all. earlier posted article https://medicalxpress.com/news/2016-04-debunking-digital-eyestrain-blue-myths.html https://medicalxpress.com/news/2016-04-debunking-digital-eye...
  - mainframed 3y ago
    Do you always link to articles supporting your opponents view? (Hint: read the last section of the article)
    - Galaxeblaffer 3y ago
      touche..
    - joshvm 3y ago
      If you're referring to melatonin then the science really isn't that clear. Most light suppresses melatonin production. One of the biggest arguments against blue light (specifically) being disruptive is that the sky spectrum in the evening is also blue (so naturally you'd be exposed to it). Modern airliners use blue lights for overnight flights with red lights at "dawn". I suspect screen brightness is more of an issue than any particular colour.
      - mlyle 3y ago
        The dynamic range of the eye is confusing for aspects like this. The amount of blue light you're exposed to from the night sky is trivial. Outdoors on a moonless night is 0.002 lux (of which, my understanding, about half is airglow and fairly blueish). Compare to a not-too-bright single blue LED in your bedroom, emitting 0.5 lumens. You could spread that over 2000 square feet of surfaces and still have more blue light around than comes from the night sky.
        TylerE 3y ago
        Lux != lumen. Lux is lumen per unit area.
        BenjiWiebe 3y ago
        Isn't that what they are saying? 0.5 lumen spread out over 2000 sq feet is still more lux than the night sky?
        mlyle 3y ago
        > Lux != lumen. Lux is lumen per unit area. Yes... that is why I divided by area. It's kind of sad how many of us end up so impatient over common mistakes that we screw up just as badly in our eagerness to snap at people. Obviously it's fudged a bit. The LED is not an isotropic emitter, and it's not at the center of a spherical room with perfectly reflective walls. In practice, I suspect the amount of blue illumination from one dim blue LED in a large bedroom and the night sky are pretty much equal.
- TheRealPomax 3y ago
  It's not really the "blue" part. It's the "forcing yourself to be awake when you shouldn't be" part that disrupts your sleep cycle. Driving at night when you should be in bed is so much more the problem than whatever color the light is. For you as human at least =)
  - ketzo 3y ago
    That's the point -- the blue is to help break the cycle further and keep you awake, when your body insists otherwise!
    - gtirloni 3y ago
      I think OP is saying you are in the wrong for being awake during the night.
      - MrGilbert 3y ago
        I'm pretty thankful that firefighters, paramedics and the police choose to break their night-cycle for me.
    - tremon 3y ago
      I'm very thankful that street lighting is helping to keep drivers awake.
GloriousKoji 3y ago
Stop signs will be the same color as everything else.
- Hamuko 3y ago
  Stop signs have a unique shape to them, as well as a big STOP text written on them.
  - excalibur 3y ago
    The white-on-red text is going to be very low contrast under a red light. The shape is still supposed to be unique.
- yurishimo 3y ago
  Jokes on you, there aren't any* STOP signs in the Netherlands! * Okay they do exist but they are extremely rare. I know of exactly 1 within 10km of my home.
KennyBlanken 3y ago
Our eyes are the least sensitive to it so it requires more light (which means more overall brightness, which actually makes your night vision worse and limits visibility of everything not lit, because your iris closes more) and it provides poor visibility/contrast and no color vision. The only advantage red light offers is not disrupting your circadian rhythm. Airplane instrument panels are lit with white. Saab, Volvo, and plenty of others use white or nearly white light for their dashboards. Blue is used in theater only because it is less noticeable to the audience when it spills or reflects somewhere it shouldn't. The real question is: especially with even 10 year old car headlights being so much better than the utter trash car headlights were 30 or more years ago, why are we still wasting so much energy, and impacting wildlife, and hurting millions of people's circadian rhythms, blasting streets with light all night? There isn't even any argument in terms of public safety; there's never been any proof that lighting reduces crime. Lack of lighting forces people up to no good doing things where they shouldn't be, to use lights themselves - which stands out much, much more than someone doing something they shouldn't be under outdoor floodlights.
- derefr 3y ago
  > why are we still wasting so much energy, and impacting wildlife, and hurting millions of people's circadian rhythms, blasting streets with light all night? For pedestrians? (I agree with your reasoning as it applies to highways, but most of the world's light pollution from overhead street lighting comes from lighting done either 1. within dense cities, or 2. within industrial complexes — in both cases to aid people walking around outside at night.)
  - smolder 3y ago
    Bright night time lighting is often installed here as "security lighting". Meaning the bright light is primarily there to make people uncomfortable and not commit crimes. The pink-orange glow of sodium bulbs was so nice and inviting compared to all these daylight blue parking lot projectors. I wish I lived somewhere where outdoor lighting needed a permit and the issuing authority rejected everything above X lumens or Y color temperature.
  - 3y ago
cronix 3y ago
The US Navy agrees with you, and is one of the reasons why interior lighting in ships/subs is red during battle so you can quickly switch between daylight and red without eye adjustment. Plus it looks cool. https://www.youtube.com/watch?v=oi1R2UK3OTA https://www.youtube.com/watch?v=oi1R2UK3OTA
- spurgu 3y ago
  Yeah I have red LED lighting in my boats for night lighting and also use the red light almost exclusively on my headlamp at night when camping, to maintain my night vision.
munificent 3y ago
> will ruin your night vision But it takes about 45 minutes for your eyes to fully adapt to darkness. So if we were to use red lighting at a level of illumination that assumes fully adapted eyes, it means people won't have sufficient brightneses for the first 45 minutes of their drive, which is likely most of it.
- pastage 3y ago
  I only know that I adapt in about 5min. I read books in fbreader on a black bg and red text. The backlight can be very low in that app, depending on the phone you can read with an almost black screen. I start at 50% in five min I can it down to 10%.
  - munificent 3y ago
    Adaptation begins immediately but takes much longer to reach its full extent. Go out on a very dark night and look up at the stars sometime. After half an hour, you'll be able to see stars that you couldn't see fifteen minutes ago.
rocqua 3y ago
Technology connections (youtube channel) did a video about this. There was a trade-off between night vision and circadian rythm disruption vs driver safety. Cooler light is better at keeping people awake and alert, and people drive safer when they are alert. Given that car accidents are a major cause od death, that is a hard point to compromise on.
AlecSchueler 3y ago
The Netherlands has many streets that are designed as "low car" streets or "bike first" streets. The white lights are important for road safety but the Dutch have developed methods of softly discouraging the kind of traffic that makes the road dangerous. This is especially common in residential areas. Most town centres are pedestrianized but retain brighter lighting as they can still be quite busy public areas in the evening.
jstarfish 3y ago
With red headlights you may see better, but other drivers (and pedestrians) are going to have a harder time seeing you, especially in daytime rain, which is half of their purpose. Use a red flashlight (or filter) if you need to find stuff in a dark room without waking up the occupants.
- sundvor 3y ago
  And you'd be mad to put one at the front of your bicycle. In poor conditions, most any car driver would logically think the rider is travelling away from them. (There are quite a few mad people in this world, having said that).
  - musicale 3y ago
    > In poor conditions, most any car driver would logically think the rider is travelling away from them. I usually can't ride backward fast enough for that to happen. https://en.wikipedia.org/wiki/Redshift https://en.wikipedia.org/wiki/Redshift
Zamicol 3y ago
Why don't we default to the color of the moon? 4000k?
Am4TIfIsER0ppos 3y ago
The color used to be red (almost) before all the eco-commies started conning us all with point light source LEDs.

argondonor 3y ago

The blue tint disrupts your sleep cycle and helps keep you awake when driving at night. There's definitely a trade off to be had depending on where these lights are located though.

TylerE 3y ago
Red is also really low contrast, at least at non-night-vision destroying lumen levels.
Galaxeblaffer 3y ago
says what evidence? it's pretty much been debunked for a long time, and the whole premise is apparently based on bad science. I'm pretty sure i read an article here on hn that showed that this whole blue light scare was based on old science with extremely limited sample sizes and extreme exposure. i tried to link to an article from 2016 that still says that it affects sleep because i hastily read the first part. trying to dig up the article i read seems to be hard, but at least I'm still pretty sure that the science is not settled on the matter at all. earlier posted article https://medicalxpress.com/news/2016-04-debunking-digital-eyestrain-blue-myths.html https://medicalxpress.com/news/2016-04-debunking-digital-eye...
- mainframed 3y ago
  Do you always link to articles supporting your opponents view? (Hint: read the last section of the article)
  - Galaxeblaffer 3y ago
    touche..
  - joshvm 3y ago
    If you're referring to melatonin then the science really isn't that clear. Most light suppresses melatonin production. One of the biggest arguments against blue light (specifically) being disruptive is that the sky spectrum in the evening is also blue (so naturally you'd be exposed to it). Modern airliners use blue lights for overnight flights with red lights at "dawn". I suspect screen brightness is more of an issue than any particular colour.
    - mlyle 3y ago
      The dynamic range of the eye is confusing for aspects like this. The amount of blue light you're exposed to from the night sky is trivial. Outdoors on a moonless night is 0.002 lux (of which, my understanding, about half is airglow and fairly blueish). Compare to a not-too-bright single blue LED in your bedroom, emitting 0.5 lumens. You could spread that over 2000 square feet of surfaces and still have more blue light around than comes from the night sky.
      - TylerE 3y ago
        Lux != lumen. Lux is lumen per unit area.
        BenjiWiebe 3y ago
        Isn't that what they are saying? 0.5 lumen spread out over 2000 sq feet is still more lux than the night sky?
        mlyle 3y ago
        > Lux != lumen. Lux is lumen per unit area. Yes... that is why I divided by area. It's kind of sad how many of us end up so impatient over common mistakes that we screw up just as badly in our eagerness to snap at people. Obviously it's fudged a bit. The LED is not an isotropic emitter, and it's not at the center of a spherical room with perfectly reflective walls. In practice, I suspect the amount of blue illumination from one dim blue LED in a large bedroom and the night sky are pretty much equal.
TheRealPomax 3y ago
It's not really the "blue" part. It's the "forcing yourself to be awake when you shouldn't be" part that disrupts your sleep cycle. Driving at night when you should be in bed is so much more the problem than whatever color the light is. For you as human at least =)
- ketzo 3y ago
  That's the point -- the blue is to help break the cycle further and keep you awake, when your body insists otherwise!
  - gtirloni 3y ago
    I think OP is saying you are in the wrong for being awake during the night.
    - MrGilbert 3y ago
      I'm pretty thankful that firefighters, paramedics and the police choose to break their night-cycle for me.
  - tremon 3y ago
    I'm very thankful that street lighting is helping to keep drivers awake.

GloriousKoji 3y ago

Stop signs will be the same color as everything else.

Hamuko 3y ago
Stop signs have a unique shape to them, as well as a big STOP text written on them.
- excalibur 3y ago
  The white-on-red text is going to be very low contrast under a red light. The shape is still supposed to be unique.
yurishimo 3y ago
Jokes on you, there aren't any* STOP signs in the Netherlands! * Okay they do exist but they are extremely rare. I know of exactly 1 within 10km of my home.

KennyBlanken 3y ago

Our eyes are the least sensitive to it so it requires more light (which means more overall brightness, which actually makes your night vision worse and limits visibility of everything not lit, because your iris closes more) and it provides poor visibility/contrast and no color vision. The only advantage red light offers is not disrupting your circadian rhythm. Airplane instrument panels are lit with white. Saab, Volvo, and plenty of others use white or nearly white light for their dashboards. Blue is used in theater only because it is less noticeable to the audience when it spills or reflects somewhere it shouldn't. The real question is: especially with even 10 year old car headlights being so much better than the utter trash car headlights were 30 or more years ago, why are we still wasting so much energy, and impacting wildlife, and hurting millions of people's circadian rhythms, blasting streets with light all night? There isn't even any argument in terms of public safety; there's never been any proof that lighting reduces crime. Lack of lighting forces people up to no good doing things where they shouldn't be, to use lights themselves - which stands out much, much more than someone doing something they shouldn't be under outdoor floodlights.

derefr 3y ago
> why are we still wasting so much energy, and impacting wildlife, and hurting millions of people's circadian rhythms, blasting streets with light all night? For pedestrians? (I agree with your reasoning as it applies to highways, but most of the world's light pollution from overhead street lighting comes from lighting done either 1. within dense cities, or 2. within industrial complexes — in both cases to aid people walking around outside at night.)
- smolder 3y ago
  Bright night time lighting is often installed here as "security lighting". Meaning the bright light is primarily there to make people uncomfortable and not commit crimes. The pink-orange glow of sodium bulbs was so nice and inviting compared to all these daylight blue parking lot projectors. I wish I lived somewhere where outdoor lighting needed a permit and the issuing authority rejected everything above X lumens or Y color temperature.
- 3y ago

cronix 3y ago

The US Navy agrees with you, and is one of the reasons why interior lighting in ships/subs is red during battle so you can quickly switch between daylight and red without eye adjustment. Plus it looks cool. https://www.youtube.com/watch?v=oi1R2UK3OTA https://www.youtube.com/watch?v=oi1R2UK3OTA

spurgu 3y ago
Yeah I have red LED lighting in my boats for night lighting and also use the red light almost exclusively on my headlamp at night when camping, to maintain my night vision.

munificent 3y ago

> will ruin your night vision But it takes about 45 minutes for your eyes to fully adapt to darkness. So if we were to use red lighting at a level of illumination that assumes fully adapted eyes, it means people won't have sufficient brightneses for the first 45 minutes of their drive, which is likely most of it.

pastage 3y ago
I only know that I adapt in about 5min. I read books in fbreader on a black bg and red text. The backlight can be very low in that app, depending on the phone you can read with an almost black screen. I start at 50% in five min I can it down to 10%.
- munificent 3y ago
  Adaptation begins immediately but takes much longer to reach its full extent. Go out on a very dark night and look up at the stars sometime. After half an hour, you'll be able to see stars that you couldn't see fifteen minutes ago.

rocqua 3y ago

Technology connections (youtube channel) did a video about this. There was a trade-off between night vision and circadian rythm disruption vs driver safety. Cooler light is better at keeping people awake and alert, and people drive safer when they are alert. Given that car accidents are a major cause od death, that is a hard point to compromise on.

AlecSchueler 3y ago

The Netherlands has many streets that are designed as "low car" streets or "bike first" streets. The white lights are important for road safety but the Dutch have developed methods of softly discouraging the kind of traffic that makes the road dangerous. This is especially common in residential areas. Most town centres are pedestrianized but retain brighter lighting as they can still be quite busy public areas in the evening.

jstarfish 3y ago

With red headlights you may see better, but other drivers (and pedestrians) are going to have a harder time seeing you, especially in daytime rain, which is half of their purpose. Use a red flashlight (or filter) if you need to find stuff in a dark room without waking up the occupants.

sundvor 3y ago
And you'd be mad to put one at the front of your bicycle. In poor conditions, most any car driver would logically think the rider is travelling away from them. (There are quite a few mad people in this world, having said that).
- musicale 3y ago
  > In poor conditions, most any car driver would logically think the rider is travelling away from them. I usually can't ride backward fast enough for that to happen. https://en.wikipedia.org/wiki/Redshift https://en.wikipedia.org/wiki/Redshift

Zamicol 3y ago

Why don't we default to the color of the moon? 4000k?

Am4TIfIsER0ppos 3y ago

The color used to be red (almost) before all the eco-commies started conning us all with point light source LEDs.