81–90 of 108 posts
Meanwhile, the “dark sky” movement criticizes LEDs as a major contributor to what it calls the “light pollution” that humans cast into the night sky. As a former, quasi-astronomer, nothing at night is more impressive than a star lit sky. My first night in Colorado was unbelievable.
Let's break down their claims. > unseen blue light I have unread negative comments about this sloppy writing. They also repeatedly use the word "intense" incorrectly. Intensity refers to candela. Not lumens or temperature. > The original LED streetlights had temperatures of at least 4000K, which produces a bright white light with a high content of unseen blue light. 4000K is actually considered fairly mellow. Above 6…
I would also submit that Kelvin is not an appropriate reference for the colour of LED lights. Kelvin only makes sense when discussing blackbody emissions, it is essentially a description of temperature. LEDs do not create light via simple heating. Their spectrum is not the smooth blackbody curve that the kelvin scale suggests. It is in fact a combination of several strong emissions at narrow wavelengths that combine…
I'm head of engineering for a company that designs outdoor luminaires for industrial environments, but not street lights. We use LED and other technologies. Like so many things in life, there are aspects of the AMA directive with potential cause for concern, but also combined with a mixed bag of scientific underpinnings. If you have specific questions about LED physics or human vision, I'm happy to give them a go. I…
What temperature LED light should I have for my bedroom?
Let's break down their claims. > unseen blue light I have unread negative comments about this sloppy writing. They also repeatedly use the word "intense" incorrectly. Intensity refers to candela. Not lumens or temperature. > The original LED streetlights had temperatures of at least 4000K, which produces a bright white light with a high content of unseen blue light. 4000K is actually considered fairly mellow. Above 6…
It is a confusing story, and not well supported by actual facts or studies. So I wonder about these things, who has it in for street lights? Crooks obviously it makes their life harder (and it mentions in the article that police are getting better witness descriptions under LED lights). And presumably the folks who made the old Mercury Vapor lights. Which happen to have about 1/10th the cost to make as LED lights but…
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The light has an effect during the night as it blocks the melatonin hormone from kicking in. It takes about an hour of darkness for the hormone kick in and make you sleepy. On very long occasional drives it's probably safer to trade some sleep disturbance for a more wakeful drive. If it's your daily commute it'll probably mess up your sleep.
And if it's on your residential block, it'll definitely mess with your sleep.
Yeah about that. Seems we have a ways to go still wrt nocturnal blue light usage and health advocacy.
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I thought this was already common around the world, say in Europe. Where 4 lane / artery / highways get brighter, whiter (bluer) lights, while 2 lane feeders and smaller roads have warmer yellow lighting. It produces an interesting nighttime aerial effect as the color indicates the nature of the street. I can't find any source to corroborate so I'd love if someone with more worldly travel experience could corroborate…
IDK, but this could simply be an effect of bigger roads getting more frequent upgrades, and/or bigger roads tolerating a larger cost per light since the total cost per meter of road is already higher.
There are 9 grades of lighting, ranging from that required on a motorway interchange, through urban motorways, rural motorways, major roads, etc, to residential areas.
Here's the relevant standard: http://vili.pmmf.hu/~mate/oktatas/VilTech_levelez%F5/EN13201... (BS = British Standard, but EN = European Norm, so the British Standard implements the European Standard. [I think that's how it works.])
This is the code of practise for Britain: http://persona.uk.com/orga46newark/ha_docs/disposit_docs/dd1...
The "Manual for Streets" has an overview, from p120: https://www.gov.uk/government/uploads/system/uploads/attachm...
(Similar documents should exist for every EU country, but the British ones are in English and easiest to find with Google.)
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A quick goog of blue+light+retina+study brings up quite a few legit sites. The one I am going to read for my edification on the subject: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144654/
I think there's some miscommunication here. Certainly, it's possible for light to damage the retina. It's likely that blue light is more apt to cause damage because it's higher energy. This doesn't mean that LEDs producing a larger blue component are more damaging than LEDs (or other lights) with a smaller blue component. It's entirely possible that at the intensity artificial light is used for indoor and street ligh…
Edit:Adding LED to the search results in many spurious sources in 1st two pages, with a single NIH study. Again, more reading required: http://ehp.niehs.nih.gov/122-a81/
This particular topic falls into the same category as 'phone radiation & brain cancer' news, where claims are made, proven, disproven and so on. If either proves true enough, we'll all be in the same boat together, I guess.