16 December 2016
Uh oh! Blue light, though bright, isn’t better at night.
As cities switch from incandescent or mercury street lights to LEDs they’re saving electricity and money and providing more light. But brighter isn’t better if it’s blue.
The video above shows how the color temperature of light matters to our eyes and sleep patterns. Though the video doesn’t mention it, the color also matters to birds and animals.
It’s possible to buy yellow-toned LEDs but blue, because its bright, has been the default choice for city lights. We didn’t know that color mattered when the world began switching to LEDs and the bulbs have such a long life it’ll be decades before it’s time to replace them. Meanwhile humans, birds and animals will be coping with the change.
It makes me want to close my eyes.
(credits are in the captions)
p.s. Here’s a really helpful video showing the difference between incandescent, compact fluorescent and LED light bulbs in home use (the A19 screw base). You’ll also see the inside of an LED bulb. I was surprised to learn it’s a tiny computer.
Red light is ideal for night vision. It effects our eyes the least as they adapt to the darkness of night. We notice this when following the car in front of us. Their tail lights don’t seem to bother us so much and even when they put on their bright reds when putting on their brakes. But the head lights coming the other way do and especially the ones that have that blue tint. Those blue headlights may look cool but are annoyingly bright at the same time.
LED technology has been around for a little while but it has come a long way in how bright they can now be. This is good given all the new applications they can be applied to like street lighting. In time LED street lighting will probably go to a more amber color giving us the light we need and no more and not so annoying.
Gene
Gene, what you say makes sense of this experience I had recently. At the saw whet owl banding events, Bob Mulvihill used a red light to show us the owl just before he released it. (He used brighter lights during the banding itself.). He said the red helped the owl adjust his eyes before returning to nighttime.
What I find to be UNBELIEVABLE is, in cold climates led traffic lights are not hot enough to melt snow or ice off of them. You could get to a four way intersection and not see if any of the lights are red, green or amber. The powers that be are aware of this but they keep installing them. If people get killled going through a red light, oh well. Led is cheaper to operate. Ahhh the almighty buck.
Wow, Karen, I hadn’t even thought of that. Amazing.