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| RichC:
--- Quote from: Rick Law on May 14, 2021, 08:31:04 pm ---The most common color blindness is red-green (8% of male, 0.5% female for Northern European descent according to Wikipedia), next to that is blue-yellow. Yellow, orange, amber are colors are a mix of red and green, so it is unfriendly to decreased sensitivity to red-green. The traffic light colors are even less friendly to them, yet red-green insensitivity appears to be the most common. It may not make any difference to most of us, but I guess only until someone runs over your dog because the street is lid with yellowish lamps. --- End quote --- Sodium lamps are not a mix of red and green, they are a pure yellow (sodium lights have probably the narrowest frequency band of any lights in fact). Also as mentioned colour blindness is about being unable to tell colours apart not being unable to see them at all. |
| james_s:
--- Quote from: RichC on May 16, 2021, 12:59:56 pm ---Sodium lamps are not a mix of red and green, they are a pure yellow (sodium lights have probably the narrowest frequency band of any lights in fact). Also as mentioned colour blindness is about being unable to tell colours apart not being unable to see them at all. --- End quote --- Remember that there are two types of "sodium lamps", low pressure sodium and high pressure sodium. The low pressure sodium lamps produce an extremely narrow band monochromatic yellow light, they have been very common in Europe and UK but are extremely rare in North America, they just never really caught on here at all. http://lamptech.co.uk/Spec%20Sheets/D%20SLP%20GEC%20SOX90.htm High pressure sodium lamps produce an orange colored light but it is fairly broadband, this is what almost anyone in this part of the world will think of if they hear "sodium lights". http://lamptech.co.uk/Spec%20Sheets/D%20SHP%20Sylvania%20LU200.htm |
| Siwastaja:
Good riddance. LED streetlights are superior in almost every imaginable way, including the fact you see so much better with the same number of lumens. Plus, you clearly are young and only pretending to be old and grumpy. The orange glow era was short. Before that, the dim cold white mercury vapor lighting was the norm. |
| Red Squirrel:
I don't think LED lighting itself is bad, but I don't get why they could not stick to orange/yellow for street lights as it's less harsh as far as making light pollution, and also keep the glass diffusers in place. The orange light still lit up the streets without being harsh, and the diffusers made the light more spread out instead of lot of harsh spots. My city switched to LED years back and one thing I find is the light is more directional due to lack of diffusers so it's well lit under the street light but the spaces between are not lit as well. The white light is brighter though, so there's that, but I don't think the purpose of street lights should be to try to make it super bright, but rather brighten up the area slightly enough to see. |
| james_s:
--- Quote from: Red Squirrel on May 16, 2021, 06:14:34 pm ---I don't think LED lighting itself is bad, but I don't get why they could not stick to orange/yellow for street lights as it's less harsh as far as making light pollution, and also keep the glass diffusers in place. The orange light still lit up the streets without being harsh, and the diffusers made the light more spread out instead of lot of harsh spots. --- End quote --- The orange light was a bug, not a feature. It was something people lived with in order to get the high efficiency offered by a sodium discharge, it was never considered desirable and nobody thought it was an improvement over the nice white mercury vapor light we had before the switch to sodium. If the white light looks harsh it's probably because it's too bright. That awful orange light never really lit anything up properly so they used a LOT of light, and the LED replacements were sized to provide similar lumen output when in most cases they should have dropped it down a notch. The orange HPS light also does nothing to reduce light pollution, it's not monochromatic like LPS, and it's the monochromatic light that helps reduce light pollution because it can be easily filtered out. The diffusers went away because of legislation meant to reduce light pollution by requiring FCO luminaires that do not emit any light at all above 90 degrees. This brings the unintended consequences of uneven lighting, hot spots and glare. IMO a better solution to light pollution would be to reduce the total amount of light emitted and try to have it as even as possible. |
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