An ideal street lightning

[Moreno]

What color of light would you prefer for street lightning and what color is the best for human eyes and psychic? Currently they replace high and low pressure sodium lams which produce light of orange-yellow color with LED lamps in many countries. Some people complain harshly about that. I think light color of LEDs can differ from city to city. In my city they are of yellowish white color mostly. Personally I dislike orange light produced by sodium lamps and almost comfortable with LEDs. Some studies claim LED light is harmful to eyes. I think ideal color should be something similar to Moon light (pale yellow) or closer to incandescent lamp light for general street lightning and warm yellow for an occasional decorative lightning.

[Strange]

3 minutes ago, Moreno said:

Some studies claim LED light is harmful to eyes.

Reference?

[StringJunky]

1 hour ago, Strange said:

Reference?

Put an LED light onto a glow-in-the-dark object and it will shine.  There is UV but it is very short range. Streetlights won't be an issue. 3000K would probably be ok with most people for general night lighting where colour rendition is not important.

Edited November 16, 2019 by StringJunky

[John Cuthber]

5 minutes ago, StringJunky said:

There is UV but it is very short range.

How?

[StringJunky]

34 minutes ago, John Cuthber said:

How?

Air probably and being of low emission level but it is there..

Edited November 16, 2019 by StringJunky

[Moreno]

1 hour ago, Strange said:

Reference?

https://www.cnn.com/2019/05/16/health/blue-light-led-health-effects-bn-trnd/index.html

[mistermack]

I personally would opt for daylight white every time. I find it a huge improvement over the old sodium lights, or incandescent light bulbs. 

The old orange sodium colour is unnatural, the only time you get anything like it, is just before a thunderstorm, or maybe in a sandstorm. It gives off an ominous feeling, to me. 

The health effects should be rated against the health effects of normal bright daylight in my opinion. If it's worse, it needs looking at. If it's better, then I can't see the problem.

[StringJunky]

Here's a paper on possible effects explored:

Quote

Potential risks to human health of LEDs     Final Opinion

Abstract

Following a request from the European Commission, the Scientific Committee on Health,
Environmental and Emerging Risks (SCHEER) reviewed recent evidence to assess
potential risks to human health posed by Light Emitting Diodes (LEDs) emissions.
The review of the published research conducted by the SCHEER has led to valuable
conclusions and identified certain gaps in knowledge on potential risks to human health
from LEDs.
The Committee concluded that there is no evidence of direct adverse health effects from
LEDs emission in normal use (lamps and displays) by the general healthy population.
There is some evidence that exposure to light in the late evening, including that from
LED lighting and/or screens, may have an impact on the circadian rhythm. At the
moment, it is not yet clear if this disturbance of the circadian system leads to adverse
health effects.
Vulnerable and susceptible populations (young children, adolescents and elderly people)
have been considered separately. Children have a higher sensitivity to blue light and
although emissions may not be harmful, blue LEDs (between 400 nm and 500 nm)
including those in toys may be very dazzling and may induce photochemical retinopathy,
which is a concern especially for children below three years of age. Older people may
experience discomfort from exposure to light that is rich in blue light.
Although there are cellular and animal studies showing adverse effects raising concerns,
particularly in susceptible populations, their conclusions derive from results obtained
either using exposure conditions that are difficult to relate to human exposures or using
exposure levels greater than those likely to be achieved with LED lighting systems in
practice.
Some LEDs present potential health concerns due to temporal light modulation (flicker)
at frequencies of 100 Hz and above.
Reliable information on the dose-response relationship for adverse health effects for the
healthy general public is not available in the scientific literature for all wavelengths
emitted by LED devices.
Since the use of LED technology is still evolving, the Committee considers that it is
important to closely monitor the risk of adverse health effects from long-term LED use
by the general population.

https://ec.europa.eu/health/sites/health/files/scientific_committees/scheer/docs/scheer_o_011.pdf

 

[dimreepr]

I personally would opt for no street lighting, if you want to see at night, buy a torch. 

Edited November 16, 2019 by dimreepr

[John Cuthber]

42 minutes ago, StringJunky said:

Air probably and being of low emission level but it is there..

Air is transparent to any wavelengths of UV that would escape the plastic package of an LED.

Incidentally, as far as I can see, nobody has mentioned purchase and running costs (except, arguably, Dimrepr).

[mistermack]

12 minutes ago, StringJunky said:

Some LEDs present potential health concerns due to temporal light modulation (flicker)
at frequencies of 100 Hz and above.

I've noticed that if you shine an LED torch on a rotating object, like a fan, you get the common effect you see in the movies, where a planes propeller can look like its stationary, or starting to go backwards, or just going very slow. The torches flicker at high rates, and that's how you can dim or brighten them, by reducing or increasing the frequency. It was quite confusing, the first time I saw it. 

I can imagine somebody putting their hand on a rotating fan, under unlikely but possible conditions, thinking it had stopped. 

[dimreepr]

Its a fooking stupid idea on the face of it... 

9 minutes ago, John Cuthber said:

Incidentally, as far as I can see, nobody has mentioned purchase and running costs (except, arguably, Dimrepr).

that was my point.

[Phi for All]

What's the purpose of street lighting? If it's supposed to illuminate so people can be vigilant as they go about at night, you should have light above the 5000K range, which is closer to sunlight. Light under 5000K is cozier and more calming, so I don't think that serves the purpose as well. You don't want light so warm it makes drivers fall asleep at the wheel.

One of the best things about this technology is that you can be much more precise about how you throw light. LED street lights can distribute in patterns, unlike the old Cobra heads that only light a circle.

[StringJunky]

24 minutes ago, Phi for All said:

What's the purpose of street lighting? If it's supposed to illuminate so people can be vigilant as they go about at night, you should have light above the 5000K range, which is closer to sunlight. Light under 5000K is cozier and more calming, so I don't think that serves the purpose as well. You don't want light so warm it makes drivers fall asleep at the wheel.

One of the best things about this technology is that you can be much more precise about how you throw light. LED street lights can distribute in patterns, unlike the old Cobra heads that only light a circle.

OK, but then you'll alter circadian rhythms of plants and other organisms in the vicinity. Someone needs to invent full colour night vision goggles.

44 minutes ago, John Cuthber said:

Air is transparent to any wavelengths of UV that would escape the plastic package of an LED.

Incidentally, as far as I can see, nobody has mentioned purchase and running costs (except, arguably, Dimrepr).

But in the centimetre range or two an  LED will cause a glow in the dark object to glow. What wavelength is causing that?

Edited November 16, 2019 by StringJunky

[dimreepr]

6 minutes ago, StringJunky said:

OK, but then you'll alter circadian rhythms of plants and other organisms in the vicinity.

not If you distribute the patterns locally, like a torch. 

[StringJunky]

2 minutes ago, dimreepr said:

not If you distribute the patterns locally, like a torch. 

Then you need more lights for continuity and you've light spill to deal with still.

[iNow]

I think we can safely assume for purposes of this conversation that we’ll be keeping streetlights and won’t be asking everyone to instead light their way with flashlights, so recommend focusing on which light to use instead of arguing for no lights at all.

[StringJunky]

1 minute ago, iNow said:

I think we can safely assume for purposes of this conversation that we’ll be keeping streetlights and won’t be asking everyone to instead light their way with flashlights, so recommend focusing on which light to use instead of arguing for no lights at all.

The discussion is not about that but the ideal colour temperature.

[iNow]

2 minutes ago, StringJunky said:

The discussion is not about that but the ideal colour temperature.

Even better

[Moreno]

Moon light spectrum 

LED spectrum

Street light LED spectrum

 

[John Cuthber]

1 hour ago, StringJunky said:

OK, but then you'll alter circadian rhythms of plants and other organisms in the vicinity. Someone needs to invent full colour night vision goggles.

But in the centimetre range or two an  LED will cause a glow in the dark object to glow. What wavelength is causing that?

How have you ruled out blue?

[Phi for All]

47 minutes ago, StringJunky said:

OK, but then you'll alter circadian rhythms of plants and other organisms in the vicinity.

You could be right, moonlight is around 4000K. Hopefully there are some studies addressing this, since many of the LED street lamp replacements I see are a much higher color temp. Of course, you could argue that any city is going to have way more light at night than is natural even if it is a warmer light, so how how important is maintaining those rhythms?

[Danijel Gorupec]

I heard some amateur astronomers complaining more about bluish light than about reddish light when making observations (I guess, blue disperses more causing more light pollution).

I also heard somewhere, but I cannot remember how much was this reliable, that night animals might get disturbed more by bluish light than by reddish light. Anyone heard about this?

For me, the ideal street lighting would adjust its intensity during the night - decreasing its power and shifting more red after 23:00h... I guess it might also adjust to foggy conditions somehow... or even to moonlight intensity.

[StringJunky]

30 minutes ago, John Cuthber said:

How have you ruled out blue?

Is visible blue energetic enough?

31 minutes ago, Phi for All said:

You could be right, moonlight is around 4000K. Hopefully there are some studies addressing this, since many of the LED street lamp replacements I see are a much higher color temp. Of course, you could argue that any city is going to have way more light at night than is natural even if it is a warmer light, so how how important is maintaining those rhythms?

In my area in a city, minor streets are in the dark after a certain time. Taking a broader view: with the advent of widespread LED use,  urban planners are on a learning curve now they have colour temperature options that weren't there before.

[mistermack]

Maybe it will end up that they are all controlled by motion detectors, so they only light what's necessary. Or with driverless cars, there will be no need for street lights or headlights.