The High Pressure Sodium Light: Ubiquitous, effective, but good?

[@woody5563]

When I was a little kid, maybe 6, my dad worked as a welder. One day he brought me to work. He would to start his drive at 4am. I remember riding through the city on the bench seat of his 80's Mazda B2000 pickup. This is the first time I remember seeing the glow of sodium lights covering everything I could see in a soft, warm orange light. We lived in the country and I had seen singular streetlamps, but never anything like that. Passing under rows of lights on the urban interstate and through the city. That was over 20 years ago and every time I drive on a road at night lit solely by sodium lights it takes me right back there to simple times with my dad, a humble welder, but still my hero. Technology changes, but I hope there is never a night when there is no sodium light remaining. Maybe I'll tell my grandchildren about the warm, calming glow of the past. But words can never convey the magic i felt.

[@LumiKaten]

Man this is a better story than some books

[@Tekape]

I remember that ambience too from my childhood but I always wondered since they made me tired and you don't want sleepy drivers.

[@crazydrummer181]

Interesting coincidence. My dad is a welder and drove a 1990 Mazda B2200 when I was a kid.

[@FreddyThaRipper]

All this from a video on sodium bulbs? Aight lmao!

[@Tazuskii]

@@FreddyThaRipper let the man tell his story it was beautiful

[@khandapwner6805]

1:01- 1:09 is the best explanation on how a lightbulb works that i have ever heard of.

[@mattjw16]

Lol same

[@groggers]

bruh how does your name go all across the screen over everything XD

[@jusa8130]

Dude your username fucks up the webpage width

[@johnlister]

Not quite. Incandescent bulbs were relatively early on filled with inert gases such as nitrogen and argon so that the glass could be made thinner. en.wikipedia.org/wiki/Incandescent_light_bulb#Metal_filament,_inert_gas

[@ChemEDan]

Everyone always asks how lightbulb works, but no one ever asks how lightbulb is :(

[@cameronwilson8561]

As a sparkie (electrician) we were also taught that the orange light is particularly good in areas with fog, similar to the yellow fog lights on cars.

[@InstaLabSparti]

it is. this yellow is very close to the frequency eyes sees best and very penetrative in fog smoke and dust

[@d3sentry]

Then why almost every city is using 5000k-6500k led ? And also cars...

[@kberkstr]

​@@d3sentry many off road and work vehicles these days come with fog lights which are more of a lemon yellow color. As for cities/streetlights, short sightedness perhaps? Or in areas that simply dont get enough fog for it to be a concern.

[@ethansmith9065]

​@@d3sentryone of the videos explains that cooler light keeps drivers more awake and alert

[@bjornroesbeke]

I remember having white street lighting some 20 years ago. Then they changed it to orange. The orange glow makes it "feel" more like nighttime.

[@God-yb2cg]

The orange glow makes it "feel" more like nighmare.* Fixed it for you

[@Blox117]

the orange makes it feel like the 1800s. no thanks

[@wilsjane]

The first generation of discharge street lighting was mercury discharge which was a slightly blue white. They were replaced with high pressure sodium for 3 reasons. More lumens per watt. Less refraction in fog. Lower bulb cost. Because mercury lamps produce a lot of UV and the bulbs are not too bright to stare into, eye damage was always a worry. However, mercury light made buildings look far more attractive.

[@crackedemerald4930]

Because it looks like sunset

[@machina5]

@@God-yb2cg nightmare*

[@TechnologyConnections]

For a channel with an icon of a light bulb, I sure don't do a lot of videos on lighting tech! Time to change that. Added note: the HPS lamp is not the first mainstream discharge lamp. Mercury vapor technology preceded sodium by decades, so we've already done a massive change once before. We'll look a bit at mercury vapor in my next video, and we'll go a bit more into the history of these lighting solutions. But for now, I hope you enjoy this introductory video! EDIT: In the video, I said I wasn't very good at chemistry. Some people have pointed out that this sort of thing is more studied in physics. Aside from proving that I wasn't very good at chemistry, I am genuinely questioning whether or not I first learned about this in Chemistry or Physics. I am _pretty sure_ we discussed electron orbitals and photons produced when electrons jump to lower energy states (plus I know we learned about ionization in chemistry), but I am _certain_ that we looked at gas discharge phenomena in physics class. So both maybe?

[@retired1049]

This video made me think of this: The text for your epilepsy warnings should say something like "It will be safe to look after the tone." Then, you just play a short tone when there's no longer any flashing. That way, anyone who actually is affected by epileptic seizures won't feel as inconvenienced as they usually feel. What do you think? PS: No, I did not come up with this idea.

[@Cheese_1337]

no , keep your lightbulb picture

[@SeanBZA]

Well, also include in the mercury vapour side the self ballasted lamp, especially the interesting changes required to make them run on 115VAC as well. I do have a small collection of carbon filament lamps as well.

[@zick1955]

Soviet union actually used mercury vapor lamps instead of high pressure sodium for street lighting. I remember as a kid, the green white lighting looked very interesting but unfortunately for me they got replaced in 2004/2005.

[@SeanBZA]

MV lighting is still common here, though they are rapidly being replaced with LED over time, but they are still used in a lot of fixtures, and are spot replaced with MV when they fail.

[@ybunnygurl]

Well a few years in and by me the city is switching over to LEDS, but after testing my city is using warm light LEDs, not bright white, or daylight. They cast light like a incandescent bulb. Its wonderful, and really cuts down on light pollution and are easy to see.

[@denisohbrien]

could you ask your city to speak to my city and stop using "hospital waiting room blue" leds .. thanks.

[@volkhen0]

This video is 3 years older then this comment. New street light LEDs are much better than 5 years ago and warmer colors are now available. There new LEDs 3000-3500K are really good and pleasant for eyes.

[@circleinforthecube5170]

@@volkhen0 as long as its orange and retrofitted into old streetlights the vast populace wont know the difference

[@michaelbarry8373]

@@circleinforthecube5170 Not orange, amber.

[@corneliusthecrowtamer1937]

amber isn't a real color @@michaelbarry8373

[@RainWalking]

Love this guys videos. He makes everything feel so Retro but in HD.

[@jimbo5635]

He is pretty cool.

[@ViviSectia]

Yea. It feels like an old PBS show.

[@rjnash2610]

He's sooo camp too :)

[@aidanknoll1019]

His style is similar to Captain Disillusion's. In fact, I think KZbin brought me to this channel because of how much Captain Disillusion I was watching.

[@Warp2090]

"Retro in HD" Wait until you hear about the HD tv sony released in 1989

[@Rikorage]

That random "Yeah" at 12:22 threw me pretty hard, had a good laugh there.

[@MartyMacgyver]

Came here to say that - was quietly listening to this and gaming (also quietly) and yeah, "yeah" made me jump.

[@adnanabdillahghifari720]

it's actually at 12:24

[@SwokTaronyu]

Waited the whole video so i could experience it myself, was not disappointed

[@BeachLookingGuy]

it scared the crap out of me i thought it was a roommate at my door

[@eksboks148]

My response to this comment: 12:24

[@avenged110]

I loved these lights. In my city, they would cast a warm glow that covered pretty much everything in a pleasant, relaxed light. Now that they all got replaced with LEDs, there's a tiny cone of very dim white light under the poles and total darkness in between, making them relatively worthless at actually lighting the streets.

[@kevinmencer3782]

There are few things quite as beautiful as fresh snow under that orange-red glow.

[@sodaodaoda]

@@kevinmencer3782 God, I love that, it was my favorite part of winter. Unfortunately, in my town, almost all of the lights have been replaced by those white LEDs, so I really miss that image.

[@johnmickey5017]

@@fitz394 Light has an important function for life, including managing circadian rhythm, so, yes, the pleasantness of light is actually fundamental to how good they are. Second, the directionality and high intensity of LED lights actually creates higher contrast (blacker blacks) in less illuminated areas, which also means they function less effectively for area lighting.

[@avenged110]

@@fitz394 Idk about anyone else, but where I am, the LEDs appear significantly dimmer (whether or not they actually are) and provide very little street lighting at all. Compared to how it used to be, it's almost comical and seems to mostly defeat the purpose (by comparison).

[@MegaPompoen]

IDK man, where I live they have replaced almost all lighting with LED's and the change isn't in how much of the ground is illuminated, the change is in how much of that light goes into the sky (less light pollution, and you can still see the road). So this might just be a lamp design thing instead of a LED thing

[@EVRLYNMedia]

Today i learned that my teacher in 2nd grade wasnt talking bs when she told everyone to never shut off the metal hallide lights in our gym

[@vamul1]

why?

[@glasseyebird]

I guess because they have such a long warm up time?

[@dogwalker666]

@@vamul1 they need about 30 minutes to cool before they can re ignite then they take about 5 minutes to get back up to full output

[@groggers]

I remember when this happened once in an activities centre on a school trip, now I seem to have found a resonable explanation!

[@xHadesStamps]

I have firsthand experience with metal halide lights being shut off on me

[@zekefleming1]

We have a sodium light above our barn, dusk to dawn every night it’s on. The same bulb has been in place sense 1983. Pretty impressive!

[@genediggins8331]

What size bulb/watts for the high pressure sodium? I too like the color produced

[@yammmit]

@@genediggins8331I guess he doesn’t know

[@Warp2090]

Yet some LED streetlights in my town (brand new) Are already doing weird things like turning purple and flashing

[@nickweir5086]

​@@Warp2090 It's probably because they went with cheaper units to save money but it's actually just going to cost more in the long run.

[@Warp2090]

@@nickweir5086 yeah

[@Doggieman1111]

Keep in mind, too, that these orangey lights are more akin to the light coming from the really old gas lights that dominated the scene for decades before. The whiter LEDs are harsher on the eyes at night.

[@flat-earther]

I agree. BTW doggieman I suggest watch a 13 part series called _What on earth happened_ by Ewaranon to learn that the earth is not a globe. I got it in my about tab.

[@the_undead]

There is no actual evidence to suggest that they harm your eyes or whatever, do they appear brighter at night yes absolutely but your eyes were built to take much more light than that

[@rizalmuhammad1141]

the stuff I watch instead of sleeping

[@apenasmeucanal5984]

Rizal, Muhammad yeah 5 am now...

[@TheReaverOfDarkness]

Must be all that light pollution affecting your circadian rhythm.

[@millbrick]

nice

[@AmrAlOmari]

The stuff I watch to sleep 😴

[@Bearbytez]

Went to bed almost 5 hours ago. You caught me.

[@videolabguy]

I parked my fire engine red bicycle against the lamp post in front of my friend's house when I was about 8 years old (1963 or 4). I stayed until after dark. When I came out, someone had stolen my bike and replaced it with an identical bright purple glowing one! I squalled all the way home! Dad came back with me to see what the fuss was all about. Yep. I caught a case of the Sodium Vapours! If he were still alive, Dad would still be chuckling at me!

[@raafmaat]

haha i cant help but think you must have been a slow child :P

[@Blox117]

sounds like someone gave you an even cooler bike :D

[@raafmaat]

aaron, wait really you didnt get his post? wth man, learn to read

[@PSKResearch]

A sodium vapor light would have made the red bike look reddish orange. A mercury vapor light would have made it look purple.

[@Sashazur]

PSK Research Mercury street lights probably wouldn’t be in use anymore due to the toxicity of mercury. But it wouldn’t surprise me if those kinds of lights were in use in the 60s.

[@TimurTripp2]

In my neighborhood they recently replaced all the sodium bulbs with modern white LEDs. Was kind of disappointed to lose that nostalgic orange glow.

[@James1095]

It's funny to hear someone refer to the orange glow as nostalgic. The lights used to be white mercury vapor lamps, then in the mid 80s those got replaced by yucky orange sodium lights that make everything look muddy and gross. I've always hated HPS.

[@thom1218]

@@James1095 It's literally the same spectrum of light as early dawn - I mean I don't have anything against basement dwellers that hate sunrises, but I guess it's just to each his own.

[@rastislavstanik]

@@thom1218 it's nothing like that spectrum

[@billybassman21]

@@James1095 I hated them too, but the colors have improved and they tend to be a more amber color than orange. What I like about them for street applications is they produce less glare. The neighborhood next to mine switched to LED and while the color looks nice, it hurts my eyes.

[@Equinox866]

They replaced our street lights with the new white LED one's, now we get that nice purple glow on everything at night

[@abborne1]

I don't know if it's just me or if you're getting to the science behind it, but every LED street light I've ever encountered was real good at illuminating a one-square-foot patch of road directly beneath it. But with all that extra color accuracy, I can definitely sort of tell the road surface is approximately black and the curb is approximately white.

[@kennethmiller3802]

We have one out of every 40 lights with some blue-purple light. Not UV, it's visible, not incredibly dark, not blinding bright. I see more than a 1sqft though, these ones seem to accentuate certain paints.

[@James1095]

The issue is not the light source but the regulations that mandate no light emitted above 90 degrees. This forces luminairs to create a pool of light under them, because if you have a drop lens that spreads it out more evenly that will result in some amount of light going upward.

[@dsandoval9396]

"Not exactly the safest thing in the world, but it does work." Hehe, my boss says the same thing about me.

[@Cra3ier]

D Sandoval you? Hehehehe

[@Corvus__]

Sounds like your boss has a good sense of humor!

[@secondace9495]

So i can guess..you did something memorable?

[@brovid-19]

Same here

[@targetbuddy5]

They say "it"? How rude

[@Creeperboy099]

There’s something nostalgic about sodium lighting Perhaps the memories of road trips to Illinois through the night, or how the property at my summer camp was lit up with these at night, providing a 60hz hum with the cricket ambience

[@thomashernandez4027]

I love sodium lighting. So easy on the eyes and lights up everything.

[@locke103]

there's a certain aesthetic to it i honestly enjoy.

[@jessdoritowhale]

My salt lamp gives off a orangeish glow from the salt rock itself excatly like sodium light and my eyes and study sessions are so so chill

[@hakim567]

@midnitesquirldog1 HMMMMMM

[@anishkumbhar4962]

@@locke103 yeah also gives spooky feel specially when you are walking at night alone

[@TheIcpfan23]

@@anishkumbhar4962 Why would you be walking alone or be outside in the first place

[@Larry]

My local council has just changed the bulbs in out area to bright white LEDs, they're way to bright and give everyone headaches.

[@junienet]

i feel you

[@lucasc5622]

i feel you

[@tannerl4143]

i feel you

[@Oystein87]

Love the LED lights :P Very efficient and great light! But however some installations have the light spreading wrong and the worst is if they have a bit too cold light. THAT is what CAN give some few people headaches. That's why warm white is better for home use and more than cold white is.

[@Harlem55]

Because it's not just white light- LEDs have a tendency to throw off UV.

[@xINVISIGOTHx]

Theres a place near where I live that has red street lights. I dont mean they have a red tint to them, I mean pure, bright, ruby red, demon eyes red

[@macdaniel6029]

I really love this old style of light. The new LED lamps are too cold. Even the warm ones.

[@TheCandoRailfan]

I usually prefer white white, not orange "white".

[@Berniebud]

@@TheCandoRailfan "White white" you mean basically blue? White white is absolute shit for night time. Warm tones help people maintain their circadian rhythm.

[@Ely-zf4yt]

@@Berniebud only if you sleep with the lights on

[@willpower3544]

and they last about a month

[@thecommenter578]

According to some studies, white light is better for mental health and even reduces the chances of suicide, meanwhile, the warmer light increase it

[@KurNorock]

before watching the video, I am going to say from my experience offroading in the desert, the orange (amber) light does a MUCH better job of cutting through fog and dust. White light just reflects off of the dust/fog and blinds you. Amber light shines through so you can see the road.

[@Nostalg1a]

Yes, lights should be placed taking into account their location. Foggy areas with these new LED’s are awful at night.

[@dingusmann3003]

I absolutely adore that shade of light tbh It has such a nice, almost nostalgic feel

[@KylesDigitalLab]

This is a really good channel, love your work

[@KylesDigitalLab]

Maybe do a video on the failure of HD DVD?

[@marktubeie07]

YES AGREE, that would be great. _And yes, I was an early adopter and got burnt :(_

[@Dragonfire511]

nice profile pic. oh those times... heheh

[@eng3d]

I agree

[@PracticalAI_]

me too, I like your style

[@Stormy2142]

Best 13 minutes about light bulbs I've ever seen!!

[@gentillydanny]

When I was a kid the Interstate system was still being built. I was twelve (1969) when the section near our house was first lit at night and I was amazed how the hundreds of birds that had nested there were so restless and noisy. This went on for awhile until they'd all moved on or died from exhaustion. Circadian cycle into chaos.

[@AloofObserver]

I prefer the orange glow of HPS over the LED's they're installing atm. I find it easier on the eyes at night. The best option would be for warm (like 2200k-2700k) LED's to be installed, but the idiots who purchase them always seem to choose disgusting 5500k lights.

[@oddieboi]

It has nothing to do with people being "idiots" and buying the wrong color LED fixtures. Lower color temperature LED's like you're suggesting are not much more efficient than current quality HPS lamps. By the time you factor in the cost to replace all the street lights in a given municipality, it's not longer viable to replace them with LED's for minor increase in energy savings.

[@HDestroyer787]

My street became too dark at night because of those LEDs

[@arnemaeschaelck5012]

They switched to a warm white kind of LED in Europe, which doesn't look orange like the older lights, but very natural. Pedestrian crossings always have bright, cold, white lights above them. In cars I actually prefer a warmer tone headlights as well over those snow-white LED's.

[@bromidedrag]

I agree. I think it has something to do with the wavelength being easier on your eyes when they’re dilated... night vision. You know how hunters and others use red lights at night so that when you turn the light off your night vision is less disrupted. The whiter or cooler the temp, the more harsh it is on your eyes and they adjust, then when you look or drive in a dark area, they have to adjust back.

[@Alaprine]

I get blinded by cars with LED headlights. Seriously, it's almost a hazard.

[@bryanmartinez6600]

Let's set the mood to get mugged in an alley. *Flashing Orange Light*

[@kacey797]

( 103 likes ) and this is the first comment 😂😂✌🙂

[@mevoogle]

@@kacey797 what?

[@kacey797]

@@mevoogle 😕 I edited the comment and now it's clearer

[@RobotacularRoBob]

In case anyone isn't aware, there is a definite effect on human behavior based solely on color spectrums. In LA some years ago for example, crime was reduced after switching from orange to blue street lights. From irritable to calm all from a change of color.

[@reggiestickleback7794]

Robotacular >desk lamp is orange *Intense urge to rape and murder intensifies*

[@3AST-PARK]

I personally love the hue this type of light puts off. Some people I know have started putting led bulbs in their house. It makes it feel so “unhomey” and more like a doctors office the warm vibrant light from the incandescent bulb is the way I’ve seen lights for so long the only thing I’d want to use led for is my headlights in my car and possibly the kitchen since I’d want good visibility for what I’m doin just my opinion tho 🤷🏼‍♂️

[@account-now-closed]

Can't you buy Warm White LEDs?

[@gakulon]

Your wallet would prefer the LEDs

[@stephensnell5707]

​@@account-now-closedyes you can,that type of L.E.D. bulb does exist

[@account-now-closed]

@@stephensnell5707 I know

[@dakel20]

Another advantage, and why I really miss sodium vapor lamps, is because broad spectrum LEDs are basically impossible to filter out with astronomy gear. Sodium lights? Nice and easy, pop a filter in and I'm good to go.

[@raafmaat]

yes i dont think city hall takes into consideration people with astronomy as a hobby xD

[@Eletronicafg]

Low pressure sodium lamps only.

[@keiffitz689]

Clear mercury vapor is great for this too.

[@CZbanhof]

raafmaat Well it's not like professional astronomers can filter unwanted light any better. I talked to one and LEDs are a serious issue.

[@cb1671]

raafmaat They don't, but I think they should. Obviously hobbies take a backseat to safety and energy efficiency, but if it's disrupting the enjoyment of the night sky for astronomers (amateur or otherwise), maybe they can find a different solution that would be more effective for everyone next time these bulbs need replacing.

[@terencerudkin6425]

as a 'wet' darkroom photographer LPS lights are great because Black & White Paper (not most films) is made to ignore its wave length allowing for a bright room without fogging the paper

[@Pjazerlazer]

Alec: "Drum-roll please" *Me: "20?"* Alec: "21" *Me: Dang it*

[@aflockofseacowsesquire]

I love the orange. Very romantic. Especially in the winter. Also, the light seems to do a better job at lighting stuff than the whiter lights.

[@ABaumstumpf]

The orange light due to being such a narrow band only stimulate the red and a bit of the green cone cells and do not stimulate the cone cells - that means your eyes do not adjust as much to the light and the cells them self don't work so hard, giving you far better night vision when looking away.

[@plushifoxed]

my favorite thing is when orange light saturates an overcast/rainy night sky and makes it look purple-y and orange-y all at once

[@nickwallette6201]

I love LEDs for most lighting, but I think I will miss all the warmth when they've totally replaced incandescent and sodium lights.

[@ggesdsdsdsd]

Yeah i really like the pinky/golden/orange light better.

[@rars0n]

Okay, I thought one of the reasons sodium bulbs were used for street lights was that the yellowish color was better for enhancing the contrast of items being lit up. I mean, in Europe fog lights were usually tinted yellow for this reason. Likewise, the silly trend of putting blue headlights on your car is stupid because blue light makes less contrast, therefore objects are harder to distinguish than yellow, or something. So I found this video quite interesting. I was in the Navy and one of my jobs was to monitor personnel dosimetry (radiation levels). We had devices that each person would wear on their belt called a TLD (thermoluminescent dosimeter). There was an element in the cap to absorb neutrons, but what we mainly focused on was the glass capsule stored inside the case. It was basically a wire with some calcium flouride crystals attached to it, and when photons hit the crystal, it would send electrons into an excited state. So every quarter, we'd read the dosimeters by inserting them into this machine, which kept them in darkness and would apply a voltage to the dosimeter which would result in the electrons returning to their normal state... which produced light. So the machine would calculate the dosage received based on how much light was emitted. I was reminded about that when you started talking about electrons. I didn't realize how similar they were. Great stuff!

[@Elleaf1]

Curious if you watched his next video which seems to suggest that bluer light is superior for night time vision. Yellow/orange light is more pleasant, but it looks like bluer light is safer

[@yeahnoway111]

i'm european and fog lights can not be yellow here, has to be white 🤔

[@notmenotme614]

No car is sold in the UK with yellow lights. The best lights Ive used for driving at night were LED headlights.

[@iDriveDaily]

French cars were sold starting in 1937 with yellow lights and while it was stated as safety, it had more to do with recognizing who was driving up on you in the night during WWII. Yellow is actually worse for night time driving, but the French government could certainly pick a French car out in the night. This was phased put in 1993 when France conformed to the EU.

[@johnsiders7819]

A lot of guys put the blue headlight bulbs in to make people think you have the high discharge headlights that come in cars like a Mercedes .

[@kkupsky6321]

Forreal. In my neighbourhood we tell the distance down the streets by the white and yellow lights. I’ll never forget those lights and when they came on.

[@daveb5041]

The easiest way to think about how gas discharge lights work is electrons of the atom re bumped up into a higher electron orbital. As they jump back down to their ground state they emit a photon of light at the wavelength directly proportional to the distance it jumped. The bluer the light the more energy the longer the jump. This is why you can't get gamma rays only up to Xrays using electrons there isn't a long enough jump for gamma rays. Also shorter paths have a limit and is why you don't see too far into the infra red. To go lower you need a wire where AC goes down: Hence a 1 meter antenna makes a wave length of 300MHz. The electron orbital acts as a nanometer length antenna.

[@awfuldynne]

Dave B Fun fact, unless I was misinformed: You can have gamma rays of a greater wavelength (yes, lower energy) than some X-rays, because when it's known whether high-energy EM radiation came from an electron or nucleus, this information "overrides" whether the radiation is categorized as gamma or x-rays.

[@daveb5041]

What defines a gamma ray is that it has a shorter wave length and therefore higher energy then Xrays. Energy is DIRECTLY proportional to wave length. The SI standard is frequency/energy. If it came from an electron jumping it's always xrays the longest path is the balmer series (I think it called that) which emits the hardest xrays. After this electrons can't jump any further so gamma rays are impossible by quantum physics. Any other classification is outdated or wrong.

[@Blox117]

the specific wavelengths is why they have such bad color rendering.

[@daveb5041]

Yes instead of a broad flat convex curve on a intensity vs wavelength chart they have sharp peaks at specific wavelengths. Totally missing some colors entirely. No green and very weak blue. The highest efficiency lamp is the low pressure sodium but the CRI is so bad that it's hard to see even when it's bright. Those are the dull reddish orange lamps you sometimes see used in military bases. The light makes everything look black and orange no colors to see. About as close to seeing gray scale as possible. Would be cool to see a gray scale lamp or scene.

[@Josh_Fredman]

Sodium lamps are one of my favorite things in the world, and their gradual replacement by LEDs in Washington State is the hill I've chosen to die on. I've sent letters to city councils, newspapers, power companies...all to no avail of course. But to me the orange glow of a sodium lamp at night is the very embodiment of peace. There's a lot I'm willing to let go of because of changing times, but this ain't one. ALSO! They're super rare nowadays, but I once lived in a town with low-pressure sodium lamps. It surprised me because my girlfriend's red car was jet black at night. Actually kinda cool.

[@Blox117]

you can buy your own sodium lamp if you really like them so much

[@user-lq1dk6gr3p]

Sodium lamps don’t save hundreds of thousands of dollars

[@danieldaniels7571]

Pete S. As a Phoenix cab driver in the 90s, that orange glow was how I knew I’d entered Glendale at night

[@soylentgreenb]

@@user-lq1dk6gr3p LEDs are less efficient and don't save any money. The only way to be able to claim higher efficiency is by having a light cone that is too narrow to fulfil its purpose and chosing a very harsh colour that fucks with people's circadian rythm. Since the light cone is too narrow, they often obfuscate pedestrians and bicycles (they're supposed to have a which lamp in the front and a red light at the back, but they almost never do...); if they're outside of the light cone and there is no snow the dim indirect lighting is *much* weaker than the harsh glare of the LED lamp. I'm not sure they are better than not having street lights at all. LEDs save money by doing less with less. You can do less with sodium lamps too and save energy; that's not efficiency.

[@Mohammed43287]

Go live in H$ll if you like these lamps because it's this orange color

[@Gebieter]

I think they give the night a very unique feel. They aren't too obstructing or bright either. I don't want to loose this warm atmosphere. If LEDs take over for economic reasons, I hope we stick at least with the exact wavelengths and illumination patterns we are used to. The technology can change, but the results shouldn't.

[@Ribeanie]

They are removing them all in the UK in my area they are replaced with miserable bright cold white LEDs

[@handanyldzhan9232]

Especially considering warm colors are better at night.

[@fen7662]

Perhaps it's intentional, perhaps not, but limiting the colors, particularly to low wavelengths (Yellow/Amber and lower into Reds) can diminish the interference of light on night vision. Reds are more difficult to see, making Amber/Yellow lights a safer balance once you reach a poorly lit street or the edge of town (because your eyes need less time to adjust). You can literally output more light and it'll be less disruptive to human nighttime perception than anything in the Green+ range.

[@giann3021]

So far, implementations of LEDs I've seen have been spotty and blinding bright white. I'm looking forward to different proposed solutions. The studies on vision he mentions seem like a good starting point to judge whether the efficiency of HPS is real, and the effects each type might have on night visibility. Perhaps some warm white LEDs with diffusers might improve CRI and save us a few bucks in the process. Another thing people haven't mentioned much is how many more insects white light attracts vs mostly orange.

[@TomTravelling]

There are no "white" LEDs - like fluorescents, they emit ultraviolet & a phosphor mix makes the white.

[@TomTravelling]

If outdoor lights didn't affect our night vision, we could see better beyond the reach of the light.

[@giann3021]

+tOM Travelling I know getting "white" out of LEDs is a challenge and that they also tried using RGB instead of phosphor coatings, but why is that relevant to these comments?

[@nthgth]

Try getting a municipality to defer to common sense like that though

[@jonathanlanglois2742]

My town has slowly been replacing the old sodium light with LED as they burn out. The first few were white, but the ones they are installing now are the amber color we are used to. Amber leds do cost more, but there are multiple reason to use them instead of a pure white led lamp. There's an observatory about 50km from my city which makes bright white light a problem. It obscures the night sky. It's also a fact that personally, bright white led lamp make me feel like a deer in headlamps. They are so bright that my eyes have a hard time adjusting between the bright light and the dark surroundings. Bright white light also has been shown to have an effect on sleep patterns. Edit: I made that comment as I was watching. I see that at the end, you mention you'll be addressing that in your next video.

[@Zaltic]

I love the yellow look. It feels relaxing to me.

[@stephensnell5707]

The white L.E.D. Lights are way better and orangy-yellow lights look awful

[@Sneaky_Snivy]

sadly the city recently replaced the sodium vapor lights in the streets around me, with cold white LEDs. I like LEDs, they're great, but a cold white just isn't a good colour for nighttime street lamps. especially in the Winter, which is when they replaced them. You almost couldn't distinguish slippy snow from concrete floor.

[@Blox117]

if you cant distinguish between snow and concrete I'd say either you are blind, or your city keeps the sidewalks ultra clean.

[@senateb]

In the future, historians will cite this channel in their research of our times. Making the Patreon credits some of the most valuable real estate on the internet. And your bizarre sense of humor will probably be impenetrable to them.

[@h10hunter]

Modern humans won't be baboons which will forget what internet is and will have to re-discover fire

[@Chase0The0Bass]

@@h10hunter That is literally the best case scenario. Us having the ability to retain our vast amounts of knowledge and data and also the means to apply it. There exists the possibilities for absolute global catastrophes to send many generations of us into pure survival mode in a new landscape and then having to bring this knowledge back into the fray on mostly fresh eyes. Incredibly rare they may be but it does make for a good movie or show.

[@robertmartindale563]

When they started replacing sodium with LED, one thing I noticed was how the light seemed to "flow" between the sodium lamps, appearing to leave very little unlit space, whereas the light from the LED units seems more focused, and left very clear delineation between each pole, I tried to make that as clear as possible.

[@CortezEspartaco2]

They still use sodium lamps in my town in southern Spain and, from my experience, pretty much everywhere in Spain. I think there might actually be rules that limit which colors you can use in certain historical areas, as orange-peach light makes stone architecture look way better at night than white light does. I personally like it, even though I chose 5000K LEDs for my home. For street lighting, sodium does a great job of making an area look cozy and is gentle on the eyes, all without the horrendous inefficiencies of incandescent lighting. (Incandescent lights are no longer available in most of Europe, and for good reason.) LEDs, I think, make historic streets look dull while making modern urban areas look more striking. LEDs certainly work for outdoor lighting in non-historical city areas.

[@jonahbento7649]

Technology Connection: “Discharge Lamp” Me: Then Recharge It

[@PrivateMcPrivate]

Lol

[@Hagemann666]

I absolutely love your videos. You tackle a lot of stuff that I've always wondered about (like how VCRS, sprinkler heads, and - yes - high-pressure sodium lighting work). And you do so in an easy to follow, thorough, friendly, and humorous way. You really speak to my inner nerd. Keep up the fantastic work and thank you for so much entertainment and knowledge!

[@42luke93]

I miss when they used high pressure sodium lighting. They were so calm on your eyes! I hate the blue LED ones.

[@42luke93]

Mahdi RANA It’s so annoying! I wish they could just make them the color of Hps lighting! HPS is my favorite! The light fixtures themselves look cooler compared to led as well.

[@42luke93]

Mahdi RANA I concur! I miss when it used to be night time where I live.

[@tejasbhandare251]

Here in india they replaced HPS lamps with a similar temperature LED lamps

[@mpred8606]

@@tejasbhandare251 I wish we could change ours to be warmer too

[@42luke93]

@Rowdy Everywhere else uses the higher Kelvin lights. At least some places seem to use lower Kelvin variants. I wouldn’t mind LED so much if they were just lower Kelvin.

[@WilliamTermini]

Thanks for shining some light on this subject :).

[@TechnologyConnections]

I hope you found the topic enlightening!

[@m-th]

Those jokes really brighten my day.

[@jameslaidler4259]

Technology Connections One could say it was illuminating.

[@DMack6464]

This is a very bright comment thread.

[@benderrodriquez]

Yes, it has shone some new light on the topic.

[@henrycalde1991]

I like the Mercury Vapor lighting, the moonlight glow it gives off while illuminating its surroundings

[@5roundsrapid263]

We had a mercury vapor light on our porch when I was a kid. It really was a nice cool glow.

[@alahollywood]

I really miss the HPS street lighting. Here in LA switched to effing LED.

[@EdmontonRails]

Same thing in my city. It looks like a cold, barren wasteland outside with this LED trash, which doesn't help when it's -30 in winter and you want to feel warm.

[@m2heavyindustries378]

Go and moan to a retirement home nurse old man, who cares

[@Skyhawk1998]

@@EdmontonRails Not so much the lighting technology as it is the color temp - although for a long time lighting LEDs were mostly the cringe-inducing cold white that you speak of.

[@EdmontonRails]

@@Skyhawk1998 There are warmer LEDs for sure, but there's catches. Warmer LEDs are less efficient, practically tied with HPS. They also often have bad tints. The blue-orange color temperature scale is only half the picture. There is also a green-purple tint scale that completes the chart. HPS lights have a nice purple tint to their orange. A lot of warm LED lights have a nasty looking green tint. The LED light panels don't look as nice as the HPS bulbs either.

[@uvwuvw-ol3fg]

@@EdmontonRails Higher efficiency doesn't mean higher CRI. What's the point of higher efficiency in cool white 6000k LED's if the reduce depth perception, increase glare and eye strain. Even at 5000k LED's can have rosy tint which leads to higher CRI.

[@EpicLPer]

Love the good and interesting content, you make me interested in stuff I never thought about before.

[@DMack6464]

We meet again..

[@BorkBorkDoggo]

I always see your comments in the most random places.

[@gaytoaster]

I saw you on gbatemp a while ago

[@Valery0p5]

'temp strikes again!

[@ignasanchezl]

lol u here too

[@jorrit_o]

In my village we have orange led lights in more inhabited areas and white led lights for the main streets. We also have a few of those lamps mentioned in the video. But those are the old ones.

[@thelightingenthusiast]

What area do you live in?

[@jorrit_o]

@@thelightingenthusiast I’m living in a residential area of a small village in central Germany...

[@munjee2]

12:24 That scared me , wearing headphones and it's like 3 I had to turn around to see if someone else was up

[@AlessandroRodriguez]

your passion for lightbulbs in remarkable, congrats for your video

[@captaintruth3219]

I bought four of these type of lights back in 1991 pretty pricey at the time but best investment I ever made. I had low pressure sodium but I changed to the high-pressure sodium When they became available. installed them 35 feet at the top of the house I have 2 acres and they light up the whole place. Much better than anything else out there. I don’t use them every night only when I’m gone or if I’m working outside so far 32 years and they’re still working great just as bright as the day I bought them

[@gabevee3]

What I remember in the 1970s, the reason for going to the amber (yet another definition of the color! WOOHOO!) street lamps replaced the white because the white street lamps did not cover as much area. There were dark spots where muggers and other criminals could hide. The change did reduce some of the crime.

[@aldrinlimos5159]

We still have a few of these where I live, and they make it feel more like "night". Any other color lamp besides maybe white and I'd think I was in a horror movie.

[@PeterShieldsukcatstripey]

I love the amber street lamps. they make the city at night and the shadows so beautiful.

[@dzymslizzy3641]

I remember as a child, coming home from visiting relatives in Marin County, CA, to our home in San Francisco, the lighting on the Golden Gate Bridge was always a definite orangey color. My parents knew then, and told me, that they were sodium vapor lights. It's one of those bits of trivia I learned at a young age, and that has stuck with me these 6+ decades later...

[@James1095]

The lights on the Golden Gate bridge are (or were) low pressure sodium. Those produce a monochromatic gold light which is quite different from the much more common high pressure sodium lights.

[@willmetz1490]

Some of the lights still are and it’s funny but for me it was heading the opposite direction

[@10p6]

Because astronomers love them as it is easy to filter the light out compared to white light.

[@soaringvulture]

That's low-pressure sodium, which has a nearly monochromatic output. As noted in the video, the high-pressure sodium lamps have a broad-spectrum output although the CRI is low. San José, California uses low-pressure sodium street lights for the benefit of the nearby Lick Observatory. These lights have, as was noted in the video, horrible color rendition and make it impossible to, say, find your car in a parking lot at night because they're all gray.

[@NickBoston]

You have an art for making the most mundane things seem seriously interesting. Thank you.

[@emiliolopez2023]

There is another really awesome thing about sodium vapor lamps it was used in visual effects compositing. It is a technique pioneered by "Petro Vlahos" for Walt Disney Productions. The technique involves using a prism tuned specifically to omit the orangy color that the lamps give off creating a black mat for compositing. The technique is actually superior to blue screen an produces better quality images with no visible mat lines. A good example of it is Marry Poppins and Bed nobs and Broom Sticks. the only reason the technique was not used more in other films is the fact that Disney own the rights to the process,

[@animaToy]

I was also used in Alfred Hitchcock's "The birds".

[@what-uc]

You just sent me on a KZbin detour, very interesting. A video called Hollywood's History of Faking It by Filmmaker IQ is particularly good.

[@TheSpliceofLife]

I also remember it could not be used in anamorphic processes.

[@justanotheryoutubechannel]

Beautiful. I love these things, so much, now that I know about them. That orange glow is so beautifully nostalgic. Nowadays, almost everywhere around where I live has switched to white lights for street lighting, however, in the past it used to be low pressure sodium streetlights everywhere. If I had the choice, I’d light my house with these beautiful orange bulbs. Not everywhere, as the colour index is pretty bad, but I’d use them for some places where I don’t need colours.

[@coolboy5428]

You can, you can buy 150w setups and higher online. Try it, just don't get the dual spectrum.

[@3Cr15w311]

I remember watching this video when it first came out and now I came across it again and in the last 5 years since this was made, 70 percent of the street lights in my neighborhood have been changed to LED types. Many street lights in a lot of towns have changed this way as well, including interchange lighting on Interstates in a lot of places.

[@centurybug]

This is the best explanation of how a light bulb works I've heard to date.

[@giann3021]

Me too. Including the description of electrons jumping between atoms from Wikipedia, which I had never read.

[@ashtonsopher29]

I just came across this channel, and have finally gotten the answer to a mystery of life that I've wondered about for literally as long as I can remember. Idk if this is a thing in other places, but when you drive on the Paris périphérique, some of the tunnels/underpasses you go through are lit entirely by what I'm now guessing are some such sodium lamps. What made those tunnels unique though was that everything looked greyscale (well, with a yellow tint) when you went through--and I mean *fully* greyscale, absolutely no colors visible, not like the example of the colorful objects in this video. That was always my favorite part of car rides as a kid, and honestly I still get unreasonably excited when going through those tunnels. It's so cool to finally learn why that happens! Unfortunately these tunnels are way less common now than they were a couple decades ago; many tunnels now alternate between the sodium lamps and a boring white lamp, so you can vaguely see colors even if they're a little wonky.

[@mfbfreak]

If it looks fully monochrome, it was a low pressure sodium lamp. The high pressure ones are a lighter, golden color with a tiny bit of color rendering

[@perhir01]

Late to the party, but as a person 1 year away from my masters degree in physics, I would like to add that the Sodium D line is actually the Sodium d lineS, there is two of them. The lines are very close to each other in wavelength, about half a nanometer. This makes low pressure sodium lamps useful as a reference source if you need to calibrate a spectrometer or something :)

[@Empire526]

I just watched a sodium vapor light turn on during my walk and it reminded me of this video.

[@kenstorm4591]

I'm gonna miss that lovely yellow colour in cities when they are all replaced with harsh LED streetlights. There is one in front in my house that blinks off once in a while. I won't call the city about it because I know "fixing" it means replaced with LED.

[@tejasbhandare251]

Thankfully in my city they replaced sodium lamps with similar temperature led lamps

[@m2heavyindustries378]

The sooner we get rid of this inefficient boomer crap the better

[@marcusborderlands6177]

@@m2heavyindustries378 but it's the same efficiency for the amount of light?

[@Zimmy_1981]

I am.in the monority here but I rather the brighter lights

[@bleack8701]

@@m2heavyindustries378 boomer crap lol. Spoken like a preteen than has never driven at night. LEDs suck and barely illuminate anything while they irritate the eyes

[@anthonywilliams8956]

I love these lights. They don't hurt my eyes like the newer cold white LED streetlights.

[@stephensnell5707]

L.E.D. lights have basically replaced HPS AND LPS LIGHTS AS L.E.D. lights are extremely long lasting and 100% efficient and don't produce no heat

[@anthonywilliams8956]

@@stephensnell5707 every LED I've seen except for the small Holliday ones get hot!

[@stephensnell5707]

​@@anthonywilliams8956 L.E.D lights don't get hot unlike older lights

[@anthonywilliams8956]

@@stephensnell5707 the LEDs don't get hot but some of their power supplies do!

[@stephensnell5707]

​@@anthonywilliams8956absolutely bullshit that is,L.E.D. Power supplies won't get hot,no L.E.D. power supply would ever get warm as they are made to stay cool the entire time

[@juhailmarisalminen]

The streetlight bulbs of my homestreet got replaced by LEDs and the warm orangey yellowish color got replaced by cool cold white. It honestly took some of the warmth away from our street. I dont like em. Even if they are slightly more efficient.

[@Distress.]

Piste Itse maybe if they replaced them with warm white LEDS?

[@raafmaat]

some towns actually use yellowish leds, its a good alternative, but i think alot of towns choose white because its supposed to be safer for traffic

[@juhailmarisalminen]

Yeah replacing cold ass leds with warm ones would be an awesome compromise.

[@mmushler5887]

Same here, and I hate the white LEDs, I feel they only blind you. The sodium lights were maybe not that bright but they allowed you to actually see much better and further. Besides I liked the yellowish color, you don't need to make night look like it would be a day. Maybe it's just my eyes.

[@Lunar_Capital]

m mushler Not to mention these white LEDs do a horrible job at lighting a roadway while it raining.

[@DeadlyAviator]

As someone with an interest in lighting technology, I find it crazy how uncommon enthusiasts are to find for it compared to other things, given how it's absolutely everywhere, and essential to modern life. It's great to see someone with an audience that isn't weed growers make videos on the subject, thank you! :p In central London where I live, ceramic metal halide (my favourite light source) has largely replaced HPS, though LED is creeping in too, with mixed levels of effectiveness and aesthetics. I was thinking, why didn't you get a second hand street or floodlight for your HPS lamp, but I suppose that would not have looked as professional/neat as having it in a desk lamp!

[@thunderbear0]

That amber colour is the best. Nowadays my town is moving to white neutral colour LED lights and i hate them. The vibe you get from these sodium bulbs, its just amazing.

[@stephensnell5707]

Well L.E.D. Lights are now permanent so you will have to accept it

[@istvankovasznai]

"No matter what I say, I'll be wrong" 1:06 - The inside of an incandescent bulb is not vacuum, it's actually a low-pressure noble gas - usually Argon. I guess you were right :)

[@thekinginyellow1744]

And IIRC tungsten was chosen not so much for it's high temperature tolerance as for it's low vapor pressure "One atom per universe"

[@42luke93]

I live that color because It’s good fo you’re eyes at night. Meaning it is calm on you, and you will get rest from day light.

[@mattjw16]

*love *it’s *for *your *daylight

[@mozarteanchaos]

@@mattjw16 you must be fun at parties

[@RichieRouge206]

Really find your presentation style so easy to watch and your explanations very concise! Great video dude.

[@themaritimegirl]

My city is mostly LED now, and I actually greatly prefer it to the sodium vapor. The color reminds me of the old DX phosphor coated mercury vapor lamps. Something you didn't mention (maybe on purpose, I don't know) is that while the lamps themselves are quite efficient, the ballast wastes a portion of power as heat. Significantly so, in autotransformer ballasts for larger lamps. But modern electronic ballasts mostly mitigate this.

[@thom1218]

Agreed - not to mention HPS's huge market as grow lights.

[@5roundsrapid263]

We had a mercury vapor light on our porch when I was a kid. I’ve preferred white lights ever since.

[@culturelab9679]

Recently all of the street lights over in the uk have been switched to bright, white leds which darken during the early hours of the morning in an attempt to save energy. They're awful.

[@Nevexo287]

Worst lights possible, they don't light up the damn road.

[@InsaneGamersOfficial]

In my area they moved the streetlights while installing the leds so they actually do light up the road.

[@MichaelFlatman]

Ik they are awful. Not all of them, I've still got some lovely sodium lamps. But there is one lamp recently put in under a bridge which is a ghastly 6500K Cold white. Looks silly in comparison to the surrounding warm look.

[@C.I...]

They are just so terrible. When you close the curtains to them it looks like daylight! The birds think so too - since LEDs were installed near me they sing all through the night. Also they completely deaden any night vision sodium lamps allowed.

[@MichaelFlatman]

yeah, the blue light emitted from the LEDs will destroy your circadian rhythm

[@soylentgreenb]

The low pressure sodium light is even more amazing. It's two close spectral lines so you can filter that shit out when taking astrophotos and it has amazing efficiency for putting out a lot of mellow light that doesn't fuck with your circadian rythm.

[@TheHortond]

I can heat my living room with incandescent lights during the winter.

[@m2heavyindustries378]

Do you live in a closet? Lucky you

[@FSM_Reviews]

I use my old laptop. _Beat that, mate_ .

[@jasonvee34]

Just play PUBG full brightness while charging your Samsung

[@PrivateMcPrivate]

@Tom Garbo That means they can have DOUBLE uses.A light emitting heater!

[@Atlessa]

@@PrivateMcPrivate No joke: there are applications where incandescent bulbs are used for exactly that reason. Terrariums and Lava lamps come to mind.

[@BigRedJed]

They got rid of our orange lamps a couple of years ago in my village in Scotland. On foggy nights the atmosphere is gone. I no longer fear that there could be a ripper around the corner with these white LED lights.

[@TheJestersDoor]

I grew up in a backwoods village in TX. We had 1 street lamp for about 70 miles of country roads that was 6000 Kelvin. It gave off a creepy ice blue light that was the opposite of warm or inviting. Story over lol

[@justanotheryoutubechannel]

Did anyone else hear a “Yeah” when our host said “should they be replaced?”

[@aidanknoll1019]

Yes, I'm quite sure that was intentional.

[@charlesslaton5924]

@@aidanknoll1019 It made me pause for a second. lol

[@srcarter2012]

Not gonna lie. It kind of scared me. Thought someone was in my room

[@gundaniumdovah]

I thought I was crazy for a sec

[@01superduty89]

Sounded like archer

[@edwardblair4096]

I was a kid when they switched the lights TO sodium vapor from mercury vapor lights. I liked the mercury vapor lighting better because it seemed brighter and "whiter". I guess the problem was that it was too "harsh", caused more light pollution, and was more expensive to operate. I don't remember it, but I have heard that mercury had two peak light frequencies that would cause strange "doubling" effects when it passed through glass.

[@TheRealMikeWilly]

I have been using 1000w high pressure sodium bulbs for indoor grow lights since 1999, so roughly 22 years now. One thing that's super awesome about HPS bulbs, especially when you have an affection for knives like myself, the sodium oxide tube inside makes a better final sharpening tool than a Whetstone. After about 45 minutes to an hour on the Whetstone I'll use the sodium tube from an old HPS for 10 to 15 minutes for a blade so sharp I can drop a piece of standard computer paper held vertically on a knife held stationary and the weight of the paper alone, falling roughly 2-3 inches is enough to cut it about 8 inches before it stops on the knife (depending on blade thickness)

[@swinde]

The worst side effect of outdoor and street lighting is that it takes away our view of the night sky, and sadly the public at large doesn't care. A simple shade on this lighting to direct the beams to the ground would solve this problem. It would also improve the efficiency of the lighting and require fewer fixtures. All of the light that is directed upward is wasted, it this is the light that ruins the sky. The reason the shades would help is that reflected light from the ground that goes into the sky is only about 10% while misdirected light that is wastefully directed at the sky is 100%. We have a few of the correctly designed fixtures here that are used to illuminate ball fields, but most street lighting and the horrible "security lights" that have inundated neighborhoods have destroyed the night sky. The limiting magnitude where I live is about 2nd. It would be 6th if there were no outdoor lighting and no worse than 4th with properly designed lighting.

[@raafmaat]

a cover over the lamps would do nothing, most of the issue you talk about is actually from light reflecting from the ground! think about it, even though the ground maybe isnt that bright, the area is millions times larger than those silly tops of lamps!

[@swinde]

No, the direct light from a fixture aimed at the sky does far more damage to the sky "darkness" than the light reflected from the ground into the sky.

[@raafmaat]

yeah thats what you would think if you dont know any better ;)

[@swinde]

I know better, while you simply pulled an opinion out of someplace i would rather not mention. Try this. Get a good flashlight and take it into a dark room and shine it on a white wall. Note the brightness. Now, without moving the flashlight look at the wall behind you and note the brightness.

[@raafmaat]

anyway, it comes down to this: even if you capped off all lights with shades, there would be minimal change to the issue of night sky bleeding, since the surface of lit up area is just so rediculously large

[@dbmail545]

I remember the first mercury vapor street lights that I saw in the 60's. Turned my father's cherry red Barracuda a VERY strange color. HPS has become the lamp of choice for hydroponic farmers.

[@spm1209]

Do i care about lightbulbs, dish detergent, or gas burning furnaces? Not even a little. Am i going to bingewatch all of this guys videos cause they're wildly informative and enjoyable? You're god damn right I am.

[@robtyman4281]

Increasingly no longer the case in the UK. Where once we had 'soft glow' orangey or 'off white' street lights, we now have super bright 'bluey white' LED street lights. These are super bright, and very dazzling if you look straight at them. I much prefer the old style soft orangey glow of sodium street lights. But they are being gradually replaced all over the UK.

[@donaldasayers]

In the UK it's ages since I have seen sodium streetlights. My Dad would not drive a red car, because the sodium light makes them effectively black and harder to see.. The yellow of the sodium also masked yellow indicators quite well.

[@flat-earther]

Hi donaldasayers have you become a flat earther yet? If not I suggest watch a 13 part series called _What on earth happened_ by Ewaranon to learn that the earth is not a globe. I got it in my about tab.

[@donaldasayers]

@@flat-earther Go away nutter.

[@VoidHalo]

Best part about sodium lamps is the way the yellow light reflects off of snowy ground back into a cloudy sky and gives the sky this yellowish glow. It incredibly beautiful. Probably not so much to astronomers, though.

[@albert-johnfreeman1484]

I feel the opposite about it; the orange-yellow glow makes me think of wildfires.

[@valerianmp]

LPS is good for use near observatory since its monochromatic nature means it is easier to filter

[@JuxtaposedStars]

High Pressure Sodium lighting is also extensively used for indoor gardening. Metal Halide lights are also used and they even make a dual element MH/HPS bulb now. There is and unsubstantiated belief that the bluer light is better for the growth/vegetative phase of plants and the redder light for fruiting/flowering. Most studies have shown the amount of light matters more than the color to the growth of the plant but some anecdotal claims are still made suggesting otherwise.

[@gaetansimard1594]

Just want to say that I literally love your Chanel and your work. I know I am not the only one saying this but I must thank you for the increase the knowledge of people (like me) in things and technology that surround us. 🎉

[@MuZiKiNmYMiNd]

It's unfortunate that the video about Low-pressure Sodium lamps never came to fruition. I was looking forward to learning more about that specific type of bulb and its applications.

[@rdrrr]

One of the major ones is around observatories. LPS lights have a much narrower frequency band than HPS lights, so it's easier to filter out the light they cast. I don't know if they're still commonplace in that context. Might be obsolete now LED lighting is commonplace; because LED lighting is much more directional, LED light fixtures won't cast so much light into the sky.

[@Darkestestmatter]

I remember my city at night, quiet, covered by a thick coat of snow under the orange glow of the sodium lights. Then it started snowing gently. That's what heaven must feel like :)

[@rdaltry777]

Double thumbs up for The Engineering Guy link. He was great while posting, shame he hasn't in so long. We really appreciate you, Alec. Keep up the great work!

[@Skeleton-wn2zu]

3:48 Technology connections: "Sodium vapor lamps rather than using mercury use..." Me: "cobalt!" Technology connections: "Sodium! You guessed it." Me: "Dang it."

[@googiegress]

Nutmeg?

[@Skeleton-wn2zu]

@@googiegress possibly

[@wta1518]

​@@googiegressNo, it's a dash of cinnamon mixed with crushed pecans.