Purple Lights

[steve66]

I saw a news article about purple street lights, and thought I haven't seen any.

https://www.cbc.ca/news/canada/british-columbia/purple-street-lights-vancouver-1.6604599

Then I'm driving home and I see this: An entire parking lot full of them:

 

[LarryFine]

My son and I just saw some blue lighting in a school parking lot. I think the blue gives more lumens per watt.

 

[steve66]

My son and I just saw some blue lighting in a school parking lot. I think the blue gives more lumens per watt.

Blue is basically the cheapest way to do LED's.

If you get any cheap LED flashlight, they are usually pretty blue also.

These lights have had a layer delaminate, causing them to turn purple.

 

[SceneryDriver]

Blue is basically the cheapest way to do LED's.

If you get any cheap LED flashlight, they are usually pretty blue also.

These lights have had a layer delaminate, causing them to turn purple.

"White" LEDs are actually deep blue, with a layer of phosphor over top. The phosphor absorbs the blue light, and re-emits the light across a broad spectrum we see as "white." By adjusting the phosphor recipe, the color temperature of the emitted light can be adjusted. When the phosphor layer fails, almost always because the LEDs are driven too hard and get too hot (ocassionally because the LED chip itself gets wet), we get the blueish/purple light underneath.

Reputable manufacturers don't drive the LEDs in their fixtures so hard as to damage them from overcurrent/overheating, but that makes those fixtures more expensive because you need more LEDs for the same amount of light. Many cheaper fixtures "only have to last for the 1yr warranty period" but make more light with fewer LEDs. Cheap is expensive - someone is going to have to replace all those fixtures at some point.


SceneryDriver

 

[James L]

KCMO has some very blue lights on I-35 coming into downtown from the north. But my guess is the fixtures are cheap while the money they spent was a lot.

We have an array of shoebox lighting on I-670 under Bartle Hall that makes the sun look dim. They spent $7.5 million to have 1,800 fixtures installed. That's a whopping $4,200 each.

I read somewhere that purchase price for each fixture was $1,500. Wish I owned a lighting store

LED lights under Bartle Hall too bright for some

The Interstate 670 tunnel underneath Bartle Hall is much brighter than it used to be, but not all drivers believe it's a positive change.

www.google.com

 

[ActionDave]

KCMO has some very blue lights on I-35 coming into downtown from the north. But my guess is the fixtures are cheap while the money they spent was a lot.....

They weren't cheap, they were made by Acuity. The outfit that Acuity subbed to was the cheapskate.