How does EnChroma glasses being polarized have anything to do with their possible affect on some symptoms of color blindness? is all colored light polarized?
FYI the other peak in the infrared at 10:00 is another Na doublet at 818.3 nm (3d2D3/2 → 3p2Po1/2) and 819.5 nm (3d2D5/2 → 3p2Po3/2). See "Surrogate measurement of chlorine concentration on steel surfaces by alkali element detection via laser-induced breakdown spectroscopy" in Spectrochimica Acta B by Xiao et al.
7:40 Hey! There's a legit use case for that! People who live near sodium public lighting might want their windows tinted like that, so their room is dark during the night but then in the morning (most) sunlight will filter through and help them gradually wake up!
Exceptionally niche product that could be solved with cheap automatic blinds hooked up to a photoreceptor. And it wouldn't encourage you to be naked in front of your open window by accident
@@skeetsmcgrew3282That use case is pretty niche but the same concept is a big part of why areas around some major observatories still insist on using low pressure sodium lamps for street lighting, because they can use a very narrow band filter to cut out all of the light pollution.
I don't know whether it's the quality of your pedagogy or if we just happen to think alike but whenever I have questions while watching one of your videos you inevitably say, "You might be wondering..." and then answer those questions. It makes your content extremely satisfying to watch. The downside is that since I'm left with no outstanding questions I rarely comment, hurting that elusive "engagement" metric. So here's me making up for that.
When I was learning electronics in the Navy, we used to joke that DS label used for lights in a circuit diagram stood for Dark Sucker. When a bulb blows, all the dark leaks out.
I frequently call power plants with the big steam stacks “cloud machines” and a handful of people take me seriously. I almost always roll with it when they do
The light of the sodium street lamp made me feel nostalgic I associate the freedom of youth with that color, being old enough to walk around with friends at night without my parents, but young enough to have the time and energy to go out and have fun like that
Was going to make a similar comment. Sodium street lighting is liquid nostalgia for me. So warm and comforting, especially in winter. I understand the advantage of near white LED street lights, but it is so cold and harsh. Very unpleasant.
I love sodium street lights. They bring back so many memories of walking around the city and enjoying random bars and restaurants during the good old days.
Only with a very dim sodium doped methanol (or other similarly colorless flame) saber, while battling under an EXTREMELY brightly streetlit night scene
Sodium street lamps were actually way better at controlling light pollution. Because they emit light at such a narrow spectrum, it was possible to make something called a CLS (City Light Suppression) filter that removes the sodium band, but even wearing those glass blower glasses would mean you could actually see the stars, and through a telescope nebula, and galaxies quite well, almost as though you were in a dark sky site with no city lights. The LED bulbs everyone is switching to are horrible because they emit white or blue light broadly, making it almost impossible to filter. Further, these colors also increase the light dome (basically how far light travels away from it's source) over urban areas, meaning that areas around cities that were once dark no longer are. This has forced backyard astrophotographers to switch to narrowband imaging, which is really only useful for nebula, and that's incredibly expensive to get into. To make up for this, some companies sell sodium-like LED street lamps for locations where having dark skies are important, but they are very expensive (basically they are taking advantage of the situation). Personally, I wish we'd just switch back to the sodium lamps, they are as efficient as LED's and they're just better for the night time environment.
Sodium street lights are also FAR better at making colour "blind" people like myself completely miss a red traffic light, because it gets lost in the sea of sodium lights. Sodium street lights are dangerous, & CAUSE conditions that lead to traffic accidents. This is NOT speculation - it is from personal experience! I am very happy they are mostly gone now (despite also being interested in Astronomy) - we are ALL SAFER for it!
@@BrendanBurwoodthat’s an important consideration! I grew up with the sodium lamps, and I never minded them. But they definitely did shift the perception of colors for those of us with “normal” color Vision. I can imagine how terrifying it would be to have nearly every stop light washed out by them! Seems to me we would all do a lot better if we switched to lights that had a SHAPE as well as a color patter to them. Like an arrow up that is also green, vs an X that is also red, and maybe a dash - that is also yellow. This would give people multiple clues to decipher what they mean. In the past, when they were really light bulbs and lenses, it would have been hard to do. But these days, you can arrange LEDs in any pattern you like pretty easily. And I’ve seen plenty of green arrow lights for left turns, so I know it’s pretty easily done. Do you know if anyone has suggested something like this yet? I can’t imagine someone hasn’t already thought of it!
@@DawnDavidson There were arrow lights before LED's were a thing - just a simple screen on the front of the light with the right shape on it. I suspect it's easier to just replace sodium lights with something else as they wear out, rather than attempting to retrain everyone on a new set of signals. Interesting extra aside is that for my type of colour vision some of the lights (MUCH brighter for my vision) that replaced the sodium ones (my mother says they are "apricot" in colour, but I try to not use subjective colour names) get confused with the green traffic lights. This isn't really a problem though, since it doesn't matter if you don't see a green traffic light pointing at you. The red light plus sodium lighting was & is the main dangerous situation - miss a red light can equal a VERY bad day! (also witnessed that happen a few cars in front of me in daylight - 4 car pinball!😮) I have been very happy to see them get mostly phased out in the last 2 decades or so.
Dude the clouds GLOW from reflecting street lights. We went out of town a few years ago near Lake Superior and we could see Duluth because the clouds over top it always glowed WHITE. When I grew up the clouds glowed orange at night, now it is white with the new lights.
I'm really glad you specifically mentioned that color blindness is due to the L and M cones overlapping more than usual! Lots of people seem to think that color blindness is caused by a lack of one or the other, when really it's a mutation. That said, the reason why the literature is inconclusive is largely because there are multiple types and degrees of color blindness. "Red-Green" color blindness is actually a catch-all for the two most common categories: Protan (mutated L ('red') cones), and Deutan (mutated M ('green') cones). Each of those two categories additionally has 'full color blindness' variants: Protanopia (when L cones are mutated to the extent that they behave exactly like M cones), and Deuteranopia (when M cones are mutated to the extent that they behave exactly like L cones). Whenever the mutation doesn't cause them to act _completely_ like the other type, it's called _anomalous trichromacy_, and there are various degrees to that. The terms used are: Protanomaly (when L cones have shifted to behave somewhat like M cones), and Deuteranomaly (when M cones have shifted to behave somewhat like L cones). So, because of all those different types, the way that light filtered by the Enchroma glasses is perceived will differ depending on which type of color blindness a person actually has. Notably, they can *only* work for people with anomalous trichromacy, and it will work better with one type of anomalous trichromacy than the other (though I don't know which one it works better for). People with dichromacy (full color blindness) would have no use for them, and not be able to see any difference. And finally, people with tritanopia and tritanomaly are left without any options because it's already super rare anyway. The only time I've ever even seen a joke or mention of it in something that's well-known, is a subtle jab at tritanopia in the movie 'A Christmas Story', when the father can't tell the difference between the green and blue lights. I've been studying color blindness for several years now, and it was only this past Christmas while watching that movie yet again that I caught that and it made me burst out laughing in front of my suddenly very confused family.
Would those glasses work a bit easier, if the left and right lenses blocked different colors? I'd imagine it would be a bit like those old blue-red 3D glasses, but maybe it'd be too annoying and distracting to be practical. 🤔
It's well-known amongst colorblind people that the Enchroma glasses are a huge scam, perpetuated by youtubers who keep lying about the effects. They don't let you see anything you can't, they just make colors "different". They just mess up the colors, and colorblind people can notice when colors are all messed up. The reason they "work" with anomalous trichromacy is that the weakest your colorblindness, the more you perceive how much it's messing up everything. In the end colors end up even less accurate than we see them normally, and yet they falsely claim it makes us see colors we can't see. It's just that, a scam with little to no scientific merit. EDIT: If you want to know more about the massive scam that is Enchroma, there's a very good video on the subject here on TH-cam called "Exposing the Color Blind Glasses Scam". It goes in depth at explaining how it's all BS.
@@retyroni Enchroma glasses are almost always given as gifts and promoted as such. Naturally, most people are not going to complain about a gift to such an extent. Their promotional material targets people with normal vision almost exclusively, probably because they know very well that colorblind people are very well informed about their condition and wouldn't easily fall for this. This means they are deliberately taking advantage of people's ignorance and good faith. This is the very definition of scamming someone, and if you still "think" otherwise, it's a good idea to check a dictionary. Furthermore, this isn't any controversial statement. This is very well-known in the colorblind community, as shown by the video I mentioned in my previous comment.
A fun fact about the sodium light spectrum is Disney created a special process back in the day that worked better than any blue/green screen using a prism. They could get much more detail around a subject without any spill from the screens as well as being able to film sheer & transparent materials. Marry Poppins is the best example of this. The Corridor channel did an interesting deep dive and recreated the effect on one of their channels.
Was this IR screen? I haven't seen the video, but I read about it in the excellent book, _Special Effects Cinematography._ They used it on Wizard of Oz. The way it worked was by using a dichroic filter to split a light source. They used the _light_ to illuminate a black screen that was painted with infrared paint. Then they illuminated the characters with light with IR filtered _out._ Then they split the image coming into the camera using the same type of dichroic filter - the visible light passing through to the film negative, and the reflection landing on an IR sensitive film. By this method, they created the positive and the mask of the characters all in one pass, and one film processing step. This produced far better results than green screen.
As soon as I saw that light it reminded me of the Disney Prism video and I thought 'Somebody else had to mention this in the comments' and sure enough here you are!
Someone else may have already commented about this, but the fact that the light emitted by sodium atoms produces roughly one wavelength of visible light was used in movies for compositing in lieu of greenscreen. This technique known as "Sodium Vapor Process" or informally "Yellow screen" utilized custom-made beam-splitter prisms with embedded notch filters (similar to how EnMouldia glasses work) and Bandpass filters split the image into two parts to create a perfect matte. This process was famously used by Disney in the filming of Bed knobs and Broomsticks as well as Mary Poppins.
And Corridor Digital recently managed to collaborate with an engineer reconstructing such camera setup and made a very interesting test movie with amazing key mattes thanks to sodium vapor!
@@thekingoffailure9967 An ornamental ball on the top of the posts of an old fashioned bed. Loads of wooden furniture used to have knobs, we were just a knob obsessed society 😄
@@The3Sag3 I wouldn't read too much into it. Most viewers are probably going to watch until the end anyway so he might as well put it at a point in the video that is more natural rather than making it prominent and awkward. At the end of the day it was a nice little callout that brought a little joy to a couple of us to see.
@@Alskaskan yea, it would have been weird if he just mentioned it in the middle of the video. he also did it like, "i am mentioned about this because i showed his reaction to the glass i am talking about" kinda nice and casual way. "im not promoting, im proud about him" kinda way.
i have struggled with "Spin" of subatomic particles for years. The "it tells us which way the moving electric charge points its magnetic field" line felt like an epiphany i have waited decades for
Nice, and the reason the property is called "spin" is simply because the magnetic field of the electrons looks as if it was produced by the electrons spinning. Even though they're not, since they're wave functions at quantum level
@@alexeifando747 I've seen their spin episode. While sure it does explain what spin does, even they couldn't make it intuitive. Ultimately the idea of something having angular momentum but also being a point particle that can't actually spin just breaks our imagination. There's a reason even physicists (or even more so physics students) joke about spin.
it's kind of a mislabeling, since the fundamental particles don't have any size, they are points, any "wavelength" is just about probabilities So, they can't "spin" since they don't have any part that could face in different directions.
I find it fascinating and deeply troubling. If there is not a probabilistic fall off between colors of pure wavelengths, what does that say about their ability to capture color in a way that matches our eyes.
It's literally The Darksoul from Darksouls and if you think about it this is really what everything would look like if you were looking from the perspective of the brightest object in existence
The CRI of low-pressure sodium lamps is not just low, not just 0, it is actually Negative. It is so wonderfully efficient at both illuminating as well as destroying any colour recognition.
@@gordonrichardson2972 Yeah, a nice quirk of how that number is calculated. Granted - CRI was never designed for light that does not at least Appear to be white-ish, but still strange.
As I understand it 0 is as bad as it can get while technically being white. For example, a trichromatic light-source with narrow (or single wavelength) red, green and blue peaks would approximate white but it would also make things look as weird as low-pressure sodium lighting. Because sodium street lights are effectively monochromatic yellow this makes them even worse than that. I believe that's why it has a CRI of -44
@@johnydl I was looking for some more information on low-CRI sources buuut seems like nobody wants to create such a useless product. A lightsource having near monochromatic peaks that manage to hit the cones just right to appear white to us. Theoretically just 2 emission-lines should be enough, but i'd guess we can do with 3 :P
About a decade ago, my wife and I were visiting Killarney, Ireland. While we were walking back from the town center to our B&B after sunset one night, we noticed that her bright red raincoat appeared a very dark gray under the streetlights. Turns out, this was the first time we had encountered sodium streetlights in person.
PRACTICAL APPLICATION: I design optics for street lights. With respect to high pressure sodium lamps, we had to make sure our optics did not reflect light back into the arc tube because the sodium would absorb its own light and cause the arc tube to overheat. This would shorten the life of the lamp.
I have the immense joy of being incredibly colorblind. The enChroma glasses did not work for me. However, for $30, I found a particular shade of polarized dark brown cataract sunglasses at CVS (a large chain pharmacy/chemist in the US, for those unfamiliar), which allow me to interpret reds far more easily than I otherwise can. It makes being outside very pleasant, and it's honestly really cool to be able to see the things people have been pointing out all my life that I never understood the interest over. It's a very noticeably subtractive experience, but I find my brain can easily ignore that aspect of it, especially after a few minutes of adaptation, and I get to experience the world slightly darker, and can notice red and red-adjacent things.
I'm not colorblind, but there's a pair of brown polarized glasses I get from Walgreens that makes greens really pop, especially in the sun. I find the shade of green really beautiful, so I just keep buying the same pair when they get worn out.
At least hes honest about it instead of dancing around the topic without being blunt like most people these days (talking about any uncomfortable topic in general). It's refreshing to see
@@SangheiliSpecOp I love the shade (embrace the pun) Steve's throwing at EnChroma here.... "If they pass the happiness versus money test, and you don't care about their dubious marketing practices, and you don't care whether they make you happier than a placebo pair of shades under clinical testing conditions, then maybe EnChroma glasses are for you."
I'd prefer it if he straight up voiced his opinion on EnChroma glasses. Most TH-camrs love controversy in their comments. Was Steve more worried about being shouted at, or litigation? As a colourblind person, EnChroma makes me angry. Basically a scam.
0:12 I mean we did that in chemistry class as a matter of fact, everyone should have since your chemistry teacher should warn you not to do that, as an invisible flame is very dangerous because, well you know you don't see it.
Chemistry like drivers Ed is not only optional but not the main core of education in America. I only took chemistry because I wanted to. Most people didn’t. Most of the kids who were interested watched a lil too much Breaking Bad and that was the only thing that got them interested.
@@dannyhothrikker4783 that's crazy, it's defenitly mandatory in high school over here you have to follow it for like at least 3 years I think with a maximum of 4~6 years depending on the level of education.
Wow, came here for a black flame (which I knew would be about sodium absorption lines) and learned about glass blowing, colour blindness and - finally - a good explanation of an electron spin.
You might not like being shouted at, but how about some praise? I highly appreciate you doing resarch into the glasses before shouting them out in any way, even more so that you actually share the controversy, instead of just saying it's bs or 100% fact. That's exactly what I want out of a science channel!
One guy did a series of videos on these glasses, claiming that because they are purely subtractive, they cannot enhance colour perception. I don't think that's actually true, but it takes rather a lot of reasoning/explanation. Ultimately I think it comes down to the fact that colours are determined by the _ratios_ of the components, and a subtractive filter can indeed change the observed ratios in real world scenes, leaving open the possibility of perceiving a wider range of colours. I don't know whether or not they help people, I think that would need to be determined empirically using real-world scenes and some kind of blind glasses, but it was what I considered an overly-simplistic statement I objected to, so I'm glad Steve takes a more measured approach.
No, if the glasses are strictly subtractive (which they are), then it would be impossible for a person using them to see new colors. The explanation is quite simple and logical, too: when you’re subtracting colors on the visible spectrum and are left with a new, altered spectrum, it’s the same as looking at something *without* that filter that already omits that particular spectrum. In other words, since every post-filter spectrum can also be created without the filter, then obviously adding the filter cannot create a “new” spectrum. Put in mathematical terms, if we say that A is a set containing all possible spectrums that can be found naturally, and B is a set containing all possible resulting spectrums after applying the filter, B is a subset of A, which means that by definition it’s impossible for B to contain a value outside of A. That’s not to say that Enchroma glasses don’t do anything. In fact, I think it’s pretty obvious (and not really at all disputed) that they help colorblind individuals distinguish reds and greens better, specifically by blocking out the confusing color, so something might look more green or more red. But the idea that they allow you to see “new colors” is ridiculous and as of yet has no logical or scientific evidence to support it.
@@openfire2691 There's a fault in your logic, which is easy to demonstrate by counterexample. If A is the set of all greys in a colour space, subtractive filtering can produce non-greys in B. Non-greys are not a subset of greys. This is why I specifically limited my comments to real world scenes. If they occupy a limited part of the colour space, we can always generate additional colours by subtractive filtering.
I'm diagnosed with deuteroanomaly, and I've had opticians really push the enchroma lenses. "You'll see what everyone else can see!" they cry. But what will I lose? I seem to see things in nature they don't. I'm not convinced. Thanks for the very balanced perspective on a somewhat contentious issue. Well Done!
My brother was convinced to get those glasses by some TH-camr when he was young. My dad saved up for it and they eventually arrived. No different. Broke my brother’s heart. He moped for weeks, the TH-camr had really convinced him he could see like other people.
@@lux_fero Indeed, it was used over here because of the nearby observatory, as it's easy to filter since guide stars (ie. "their laser pointer") use the same wavelength (or very similar)
As someone with mild red-green colorblindness and a pair of Enchromas, I feel like I should say that they do work, but not to allow me to "see colors I couldn't see before" Mostly what they do is allow me to distinguish shades of green and red that my eyes have trouble picking apart from the background by cutting out the duller shades of those colors and making them more vibrant. Like, say, a green bush full of red flowers. Without Enchromas I might be able to tell that there are red flowers, but unless I got up close to the bush and searched for them, I wouldn't be able to just distinguish the red flowers at a glance. My Enchromas allow me to do just that. And the same goes for different shades of green. I could physically see those colors already, my eyes just sucked at picking them out from each other when they're all mixed up. Kinda like the colorblindness tests with the different colored dots. They do make blues a bit purpley, though.
Thank you for this comment! I think I have nearly the same amount of red-green deficiency and I wondered if they would do anything at all. Distinguishing a red berry in a bush is trivial if I'm looking at it, but from a small distance away or at a quick glace it's nearly impossible. I'll have to try and find a pair just to try it out.
I have some Enchromas and mild colour blindness. Whilst wearing them, everything looks a bit weird and fake, BUT I am able to distinguish between colours that I otherwise wouldn't be able to. My main for use for this at work when reading things that have legends with colour categories - I can actually distinguish between things when using the Enchromas.
Please stop perpetuating the lie that is enchroma glasses. It's been proven that they are a complete and utter hoax... Look up MegaLag's video about them.
So it would be more correct to say the glasses are not about fixing the color blindness, but about fixing the uneven color distribution it brings? Because I can see how it would help the dynamic range of your vision.
i have to hand it to you, its great to make a video that is clickbaity like 99% of videos on here, but then actually gives incredibly detailed, interesting and educational information that could genuinely spark someones interest in science. Fair play.
Here in Sweden, I miss the highway sodium lights upon startup (I remember them shifting from purple/blue/yellow/deep red/orange to the final yellow light). A late summer evening with a clear, rather dark sky, seeing the sodiums start up into the distance... awesome.
@@TeddieBean Colors are the keys. When I was 7 my parents shipped me off from Seattle to visit relatives on the east coast. Over 3+ weeks of constant entertainment, I remember exactly three things. The birds Connecticut (the only bright red, yellow, or blue birds in the northwest are found in zoos), a blue lobster in Maine, but mostly I remember flying into Chicago at night. My parents had no idea what the hell I was talking about, so I didn't find out until years later that Chicago was the first city in the country to switch every street light over to sodium vapor. I just happened to pass through shortly after, and it looked absolutely amazing.
I'm from USA, but I vividly remember light being different as a child. The sun was less white, more yellow. And the street lights were a hazy sunset color, amazing memories. Those industrial white buzzing lights were way too sharp. Nowadays either my senses have changed or light is different.
@@litttoe Most likely your memories are faulty. The sun is often portrayed as yellow because we know it's made of something like fire and the only time of day you can safely look at it for a second or two the light that gets through is either yellow or red, but the actual light emission from the sun is white. So unless you grew up in LA when there was visibly yellow smog, you're just remembering things wrong.
I'm colorblind and have a pair of Enchromas. They do make it much easier to distinguish reds and greens, but they're not magic and I certainly don't see "new colors" I couldn't see before, although my colorblindness is not that severe either so I won't discount other people's experiences. But the best demonstration I've been able to find of their effectiveness is rose bushes. For the most common types of red-green colorblindness, the red polka dots on a green background look that rose bushes have is especially problematic. From any sort of distance away, the roses lose their definition and start to just look like darker parts of the bush. But with the Enchromas, they pop out really strongly from the bush, even from quite a distance. So it's not so much that they help you to see new colors, as much as they improve your ability to distinguish and apreciate colors you could always see. It's not like (most) colorblind people can't see red or green at all, it's just a lot harder to distinguish them from each other in most situations. Additionally, for all people (including normal-sighted people) they generally improve contrast and make all colors seem a bit more vibrant. I'm almost surprised that they haven't caught on as a luxury glasses brand just for the way they make everything look "more vibrant than real life". Although, that effect is really only true in especially good lighting.
Regarding how Enchromas work. Given that computer and phone screens use RGB leds, i.e. they are specific colors that "trick" our brain into thinking we're actually seeing all the colors, do colorblind people have an easier time discerning colors in a screen vs. real life? If all Enchromas do is to supress the overlapping, then there shouldn't be any overlapping in screen leds.
I have to wonder why they don't just take advantage of stereoscopy, like there's this meme of "impossible colors" created by seeing one color in one eye and one in the other. You'd think technically it'd be possible to give difficult colors a stereo difference (maybe that's uncomfortable though)
@@Nico_M. I've never actually thought about this before. It kind of makes sense, but I definitely still have trouble with colors on screens sometimes. I don't think it's any less, but I couldn't tell you why.
My physics professor once bemoaned sodium street lamps getting phased out. Apparently, it's extremely useful in astronomy, as you can't normally see the stars because of light pollution. Yet with sodium street lamps, all you needed to do to make your telescope work was to put on a filter, blocking sodium's emission.
Back in my physics days, you could look up all of these lines and transitions in textbooks. Or on NIST, but that page seems to be strugging. I did the looking up for you: The 819nm transition is a 3d-3p transition. The other ones are from higher orbitals, 5s-3p for 616nm and 4d-3p for 569nm.
That peak in the IR is actually another doublet at 818.3 nm (3d2D3/2 → 3p2Po1/2) and 819.5 nm (3d2D5/2 → 3p2Po3/2). See "Surrogate measurement of chlorine concentration on steel surfaces by alkali element detection via laser-induced breakdown spectroscopy" in Spectrochimica Acta B by Xiao et al.
15:22 Dammit, Steve. I can't believe you've done this. By the way, your description of spin & quantized angular momentum was one of the most interesting one's I've encountered. I'm definitely going to have to keep coming back and rewatching that segment to wrap my head around it.
Those old street lights are nostalgic af... All the memories of being driven back home from visiting family, late at night and falling asleep to the sound of the moving car and the atmosphere created by those old street lights. 🌃
Reminds me of coming late in the winter evening from the university, passing through a dim park with big yellow spheres as lanterns... A bit eerie, uncomfortable, but also dreamlike...
@@SuperAWaCit's good that LEDS replaced sodium in some ways though, the monochromatic color completely removes your color vision, so it might be hard to identify some street signs.
"How can a point-like particle have angular momentum?" (at 11:35) I think is because it's a vector rather than a point. It has a a location and also a direction and rate conveyed into reality as a location over time with the rate being set to "infinity" which is not possible so it hits the universal speed limit instead. You can essentially think of it as a fundamental aspect of spacetime, not just space, and you can think of it as a particle that moves on the smallest possible scale every universal "frame" (in video game terms), meaning it is so fast it updates its location faster than everything else but no faster than the computer (the universe) can process its movement. The reason it applies to very well to computer programmed hit scan lines is one of the many reasons very smart people think we may be living in a simulation. But this is only one interpretation and it's very possible that we're viewing it through the lens of the current information age which is programmed to simulate real world concepts and so of course the simulations work like the real world. But do our simulations work the same as the real world from an extradimensional creature gazing into our universe like a child with an ant colony? Probably not, and it's equally possible we are not living in a simulation at all. The result (virtualized digital simulations based on reality as we know it) cannot be used as data (scientific measurements of reality) to determine how reality works. Not without a control of course, among other things.
Corridor Crew also did a video where they used a set of sodium lights to essentially re-create vfx similar to what was done on films like Marry Poppins. It involved an interesting camera set up, but resulted in a more defined chroma-keying to where you don't have to worry about other colors bleeding into the void.
Yeah, you need to split the incoming light so you can get the image without the sodium color, and the image with just the sodium color. Then you can invert the sodium-only image to use as a matte for the non-sodium image. Since it’s all achieved optically, background replacement can be done entirely with film and an optical printer. And since sodium light is such a narrow wavelength, it doesn’t bleed into anything you want to keep and you get near-perfect transparency.
Moving from sodium lights was a real problem for astronomers as narrow band filters were common and cheap, the LED lights are much harder to filter out due to having multiple peaks and the phosphors not being to a standard chemistry resulting in different lights having different frequency outputs.
@@SteveMould Might be sad from a normal colour vision person's perspective, but from someone (like me) with Protonomalous colour "blindness" the disappearance of Sodium street lights has made EVERYONE SAFER on the roads at night! Why? Because if we don't see a traffic light change from orange to red on a street with Sodium lights then we can very easily completely miss the red traffic light, possibly causing an accident! Especially so if we aren't familiar with the area, or a new set of traffic lights have been installed - a situation which actually happened 30-odd years ago when my brother (also with similar vision to me) missed seeing a new set of lights in a very familiar area lined with Sodium street lights. Fortunately we had my older sister in the car who realised in time that neither of us had seen the red light. She got our attention in enough time for my brother to stop the car with the nose over the line. Fortunately it wouldn't have caused an accident on that occasion as there were no other cars nearby, but there easily could have been. I for one do NOT miss Sodium street lights (despite also being interested in Astronomy). We are ALL safer from their disappearance.
Your sodium lamp isn’t pure sodium. There is at least a hint of neon in there for arc initiation, and I wonder if that is part of your spectrum impurity. Take another spectrograph of it when first cold lit, and I’ll bet that highlights the non-sodium component.
Yes. But no. The sodium overpowers all other gases in the lamp by a LARGE margin. Brainiac75 just did another video on this. He does a good explanation and also a spectrograph so you can see where the lines are.
Nope. All the peaks he's seeing when the lamp is at full brightness are from sodium. The other prominent peak in the infrared at 10:00 is another Na doublet at 818.3 nm (3d2D3/2 → 3p2Po1/2) and 819.5 nm (3d2D5/2 → 3p2Po3/2).
@@dreamyrhodes Completely false. All the lines visible here are due to Na and a single sharp peak in the infrared is not "just heat". That's not how it works, that's not how any of this works.
@@dreamyrhodes Heat is chaos and chaos doesn't produce sharp emission peaks. Look-up 'black-body radiation' if you want to know, what kind of spectrum is produced by heat.
Please never stop doing these kinds of videos. You are literally broadening my horizont. There are many things that are far out of my reach, knowledge wise, and you tap into them, but you also make me understand enough. It really is fun and exciting to watch videos like this. Not necessarily because of the topic, but because of how you are driving us in your bus through knowledge town. Sightseeing with you is fun, not boring. It's pleasant and exciting to learn more and to see the world a little bit through your eyes. (Or rather mind really lol). Thank you for putting this effort into your videos!
I once gave blood at a Cambodian hospital, and I read that the name of the male phlebotomist was Bun Sen. It took me 5 minutes to stop giggling enough so he could get the needle in.
Disney used "amber screen" in Mary Poppins , that predated green/blue screen special effects, back in the 1950s . It used sodium lamps. And it is superior in many ways to green screen and blue screen. It's even possible to do transparent things like water and fine hair, which has proved very difficult to do in green screen.
Green screen, blue screen, black screen, and white screen all predate the sodium lamp amber screen technique by many decades. Mary Poppins is one of the only examples of amber screen because it's not nearly as reliable as the other chroma techniques
A modern way to do scary clean colour key composite is to have the background of retroreflective material (3M Scotchlite) and place a green non-diffuse ringlight on the lens. You also lose all colour key spill this way. If you're dealing with green items, you can also use RGB ringlight and switch to a different colour. But due to how saturated the colour is, you usually don't even need to, because real world pigment greens can't compete with the LED on saturation. One could potentially enhance it by going complimentary, switching the ringlight frame synchronously between green and purple every frame. Of course only for cameras that record in non motion estimated CODECs. But this is also largely unexplored territory, because i guess standard colour key works well enough. Still having a near-true moving matte from sodium light does have advantages!
This is the comment I was looking for. The TH-cam channel "Corridor Crew" did a video not long ago where they resurrected the technology, showing off just what it can do that a green screen can't.
@@SianaGearz with the advent of machine learning/AI , amazing things become possible. The ability of the AI to distinguish what is background to remove/replace is uncanny, and it's only getting better by the second! It's starting to make chroma key look like old hat.
@@MyProjectBoxChannelSure, but if you look at the demo on Corridor's channel using a modified version of the sodium lamp setup it's pretty much flawless, far outperforming any other process available today including current AI based systems. I'm sure future AI vision setups will eventually be able to just about match it, but doing it with a near perfect optical process is going to be very reliable and simple to implement, whereas AI systems are always going to have glitches and edge cases, not to mention being a lot more expensive to run for the foreseeable future
Wow, I can't believe that I've never put two and two together, but I honestly didn't realize until now that sodium street lamps render color useless. It's not that I'm color-blind or anything; it's just a sort of conceptual understanding I've not stopped to consider enough for it to sink in. Always just thought of it as 'weird orange.' Amazing what you can miss! Thanks.
Low pressure sodium lamps are really rare in my country (these days?). The first time I drove through an area that had them, it really threw me for a loop. I could not understand why all the normally red or blue signs were grey.
I’m a welder and always find it really fascinating when I’m looking at what I’m welding through my hood. Or when I’m cutting some steel with oxy/acetylene torch or using a plasma cutter.
I wish we still used sodium streetlights, the modern streetlights are far too bright, it doesn't feel like night-time at all. I wondered why night-time actually felt like night time as a kid, it was because of the street lights.
Where was thet? I was wondering about top raw middle to the right image that I can not understand at 15:37. Is that it? Or do I have a color blindness?
I saw a misconception in this video which keeps getting spread, mainly because the actual explanation is a lot trickier and weirder to understand than the actual reasoning. In the video, Steve says that the reason there are two lines is because the electron spins are either in the same direction or different direction from the orbital angular momentum. But, this is not true. Rather, it is because of statistics and the Pauli exclusion principle. The Pauli exclusion principle says that an electron cannot be in the same quantum state as other particles. As it turns out, there are 4 different options for spin orientation: both spinning in the same direction upwards, both spinning in the same direction downwards, one spin up and the other spin down, and then vice versa. We then write these as a math statement. The first one is written as ↑↑, the second is ↓↓, the third is ↑↓, and the last is ↓↑. HOWEVER, as it turns out, ↑↓ and ↓↑ are not actual "good" states. For those who this word means something to, they aren't eigenvectors of a 2x2 matrix -- which is necessary for a state to be physically possible. So the solution is to change the set of states we work with to: {↑↑, ↓↓, ↑↓+↓↑, ↑↓-↓↑}. This is the set of all possible spin states. Now onto the Pauli exclusion principle. Because an electron is a "fermion," when you swap two electrons, all that should change is the overall quantum function -- the thing which describes the electron -- should have a negative sign. Let s be the spin state, and p be the rest of the function -- describing which orbital the electron is in. We write that the whole function P is a function of particle 1 and 2, written as P(1,2) and equaling s(1,2)*p(1,2). In other words, P(1,2)=s(1,2)*p(1,2), with * just meaning multiplication. The "fermion" statement I made means P(2,1) = -P(1,2). So, s(2,1)*p(2,1) = -s(1,2)*p(1,2). Now, we will look at each of the spin states. Note that when you swap the order of the first three spin states, we get ↑↑, ↓↓, ↓↑+↑↓. The last is identical to ↑↓+↓↑ because you can swap the order of addition. HOWEVER, the last state becomes ↓↑-↑↓ = -(↑↓-↓↑). This means if the particle is in the first three states, then we have to say p(2,1) = -p(1,2), and if the particle is in the last state, p(2,1) = p(1,2). This property is what causes the electron to have different energy levels. If the particle has the first property p(2,1) = -p(1,2), the particles tend to be repelled away from each other, and we say that the position function has a "fermionic" behavior. In fact, THIS is why solids are solid. It's not that there are electromagnetic forces repelling electrons from electrons. Rather, it's because of this fermionic behavior of matter. Neutrons do the SAME exact thing, which is why neutron stars are a thing. They are held together and kept from collapsing by this pressure called "degeneracy pressure," despite having a neutral charge. If a particle has the second property, p(2,1) = p(1,2), the particles tend to be attracted towards each other, and we say that the position function has a "bosonic" behavior. Light is a boson. A bosonic particle tends to be attracted to other of the same type. I will make an important distinction: the repulsion of fermions and the attraction of bosons ONLY happens because the particles are EXACTLY the same. All electrons are 100% completely indistinguishable, there is no way to know for 100% certain one electron is not another electron or one photon is not another photon. Fermions are ONLY repelled from other fermions for which they are 100% absolutely identical to, and bosons are ONLY repelled from other bosons they are 100% absolutely identical to. Protons, neutrons, and electrons, for example, are not repelled from each other by this degeneracy pressure. FINALLY we can get into why the energy levels are different. If they are in the fermionic position state, we call this state the "triplet" state, and the position function needs to be of a higher energy because of the degeneracy pressure pushing the electron further away. And, if they are in the bosonic position function, we call this state the "singlet" state, and the position function needs to be of a lower energy level. Now, I will admit, I feel like there is something slightly wrong here. I believe an important statement is I need to say magnetic fields show up someplace in here because iirc, splitting of the singlet and triplet state don't occur unless if there is a magnetic field. Iirc, this magnetic field is due to the nucleus's spin (?). I am willing to correct myself if I made any mistakes. At the very least, the misconception which keeps getting spread is that objects are solid because of electromagnetism, which isn't true; it's because of spin statistics.
The main point is that electromagnetism plays little to no role in this, and the role it plays is weirder than you think. It's not "spins in same or opposite direction" but much weirder.
As @yorickandeweg2134 pointed before, it's spin-orbit coupling, so speaking about 2-electron behavior (fermionic/bosonic states) is incorrect. However, (somewhat miraculously) it turns out that the addition of spins of 2 electrons obeys the exact same mathematical rules as addition of electron spin and its angular momentum! Thus your description is largely correct. The key difference is that angular momentum on P orbital is 1, so instead of 1/2+1/2 addition (described by your arrows) we get slightly more complicated 1+1/2.
i genuinely don’t get this but now i’m determined so im commenting so i can come back to it later. to be fair i just woke up and haven’t gotten to this part of the video yet
@@yorickandeweg2134 Ok, yes, I agree! I think I got excited because the hyperfine and spin-spin coupling tends to be rather misunderstood too often as being an EM effect and not just a pure quantum effect. But, I humbly admit I was wrong!
Posting for everyone else who doesn't have patience - he doesnt have the camera set to full color (natural color), he's disabled auto white balancing on the camera, and he's shining an incredibly bright sodium street light on the scene.
I'm pretty sure we used those same glasses in a class of mine for brazing copper pipe. Our teacher was very clear in stating these are NOT a pair of sunglasses and to use them on the road is VERY BAD. Those glasses are blocking the red/orange spectrum and apparently a couple students wore them out of class and rear ended a guy because they couldn't see their red brakelights.
Wow! Most science videos manage to teach you one amazing fact - this one just kept coming and coming with more and more answers to questions I've always wondered about. It's like a 6 month science course crammed into 20 minutes!
Someone I know recently combined Maple Syrup & buttered Popcorn thinking it would taste like caramel popcorn. It didn’t and they don’t recommend anyone else do it either.
About the enchroma glasses, a youtuber "megalag" made a few episodes exposing the whole color correction glasses industry, you might find it interesting
I think that's exactly his point when he refers to the topic being "weirdly polarised". Megalag presumed bad faith on some of the sponsored influencers and some of his viewers have become toxic and attacking the influencers.
@@Karavusk They do work though. Not nearly as well as they advertise, but they're still effective. I bought them as a gift to my father - and while they didn't provide immediate WOW effect, he would often write me something like: "Oh I didn't know those were actually red before"
the way you explained how certain waves of light is produced was far more understandable than what my high school physics class taught me, it actually kinda annoyed me how well you explained it
I'm seriously impressed by how accurate, yet accessible, this video is. The relation between light spectrum and atomic orbitals is the heart of Quantum Mechanics; it's what drove its development historically and it's where the theory makes predictions that stumped the rest of physics. It's also the foundations of just about all of chemistry, material science, and the starting point of nuclear physics. I'd so far as to say that it's the most important development in the last 200 years of physics. And this madman casually explains it in 15min in a stunningly visual way.
Hey Guys. @15:31 There is a set of Color blind tests. I'm not previously had issues with color blindness, But I cant tell if one of these tests are a control or not. From the top left to the top right. The numbers are | 45 | 2 | [Squiggly lines] | 42| For reference if anyone is curious the bottom row from left to right is | 74 | 97 | 6 | 3 | Is the second from the right on the top just squiggly orange, brown, and green lines for you too? Edit: Its apparently 15:31, I missed a 1
I too saw just those three colored squiggles in the third-from-left-on-top image. I paused and looked at it sfor a while. I also have not had issues with colorblindness. Whatever the situation, you and I are both in it.
Slight correction: It’s actually at 15:31 (took me a while to figure that out!). I also see a bunch of squiggly lines on the top line, second from the right. It is probably a control, as others have said. Otherwise, I see 45 / 2 / squiggle / 42 74 / 97 / 6 / 3
@@DawnDavidson yeah, i do think its for a control, so people cant fully guess their way through the test. for those with normal color vision its easy to tell its squiggles, but with slight color issues they would be able to tell there is something there but could have issues seeing the full squiggles.
Small correction about the streetlights. Most lights you'll find outside use high pressure sodium, which has a CRI of about 25. What you are using here is referred to as low pressure sodium, which has a monochromatic light with a CRI of about 5.
Incredible episode Steve, one of your best yet. I’ve seen a dozen efforts at explaining the black sulfur flame over the years and none have been as clear and complete as yours. Great job.
Back in the early 1980s, after I acquired my driver's licence, I ran a red light on a section of roadway lit by sodium street-lighting because I happened to approach the lights after they'd turned to amber, perfectly camouflaged amongst the sodium lights. Fortunately there were no other vehicles around as it was very early in the morning!
Bingo! Exactly the same thing happened while my brother was driving in the late 80's/early 90's, but fortunately without actually running the red light (newly installed lights on a very familiar road lit by sodium lights) since we also had my older sister in the car who called out "red light" when she realised neither of use had seen it. Stopped with the nose over the line. No cars nearby (~9pm), but easily could have been. The traffic lights were visible from over 200 metres away, but like your experience had already changed to red before they were in our view, so were lost in the sodium lights. For that reason I do not miss the sodium street lights - we are all safer from their disappearance.
Oh, wow, you perfectly explained something that i totally flunked at/failed at explaining years ago to others. At the time i had known most of this, but, really struggled in expanding on this explanation, because, i struggled with condensing this information down into something bite size like this. Awesome video.
It’s a lighting trick based off of the camera’s auto balancing, i.e., a camera trick. And no, it’s not what the eye sees. The opening frame at 1 second looks like a white room with white light, and an obsidian flame, all because of auto balance. With the auto balance turned off, it would look to the eye more like frame 31 seconds, which is a lot less impressive: a yellow washed room in mono light with a tuned-out flame.
Wow! WOW! This is instantly one of my favourite videos online. So much good stuff - told without equivocating, yet just deep enough to get what you need and then move on. I'm going to suggest this to so many people. Thank you for an interesting, broad, focused (yes) and intellectually honest work of art and exposition.
You can also get a "light pollution filter" from an amateur astronomy shop which also blocks the sodium lines. Unfortunately it doesn't work well for the intended purposes anymore because most sodium streetlights are being replaced by white LEDs.
I really liked the glow of sodium streetlights, there's some nice sides to really white leds (they make plants look magical during nighttime), but otherwise it was nice for the night to look like the night.
@@unatwomey7112 Live near a corner and have 2 out from and one to side. Can basically read a book out back garden in the middle of the night with the amount of light pollution. Terrible for just looking at the stars. When they used sodiums they designed the shroud to reflect as much light downwards as possible. With the Leds it's like they barely bother.
this is the closest thing to black light & black lightening that i wanted to see as a kid 🖤🖤🖤🖤🖤🖤 i had a dream about it that's why i always imagined black flames Amaterasu just fueled that more😂 black lightning & black light 🖤
one of the most beautiful sights I have seen was after a night of LSD, the earliest morning twilight above, sodium lamps below, and pure darkness of city buildings between. the differences between that single wavelength light at the bottom and the glorious full spectrum yellow-blue sky was insane
Very nicely done, good explanation of subatomic photon production (and absorption). As a theoretical concept, I had thought about "dark light", but had never seen an example of such as being demonstrated via a black flame. Of course, there are well known examples of "invisible" flames (partially a function of the flame temp, and the relative energy levels of the electron orbits), a terrifying example of which is the methanol fuel used in race cars. It has happened when a driver is being burned with a flame no one can see, but the process of being burned becomes extremely apparent.
This video is amazing. Your casual explanation of spin to get to the why of the double lines emmiting form sodium was marvelous, I love when I get answers to questions I didn't know I have. And I'm totally using that orbit analogy to explain this. Thx for your content, cheers Steve
Awesome science still after so many years of youtube. Thanks Steve. I've been watching only occasionally but for long enough to have noticed we both have gotten visibly older. You've built something great here in that time. Keep up the good work teaching us new amazing science things...well, at least new concepts to me, and probably most of the viewers. Cheers to many more years to come doing what you so pasionately love to do.
@@dmytrog6127 The third image on that test only shows numbers for certain color blind people. If you can read numbers there, you might want to consider visiting an eye doctor!
It might have something to do with the monitor, but I had to copy it into a editing software and turn the contrast up almost to the maximum to see it, but it is there.
Awesome video, wish I had the setup to do this sort of thing. I'd never get anything else done! For the enchroma glasses, I'd refer you to "Megalag", he did/is doing a deep dive series into them. Very well reseached and definitely worth the watch.
There's so much more I could say about EnChroma but it's already 19 minutes long!
The sponsor is Odoo. Try it for yourself today: www.odoo.com/r/kYo
Isn't that a scam, though? (EnChroma)
source: MegaLag has quite a few videos on it...
For people interested in how EnChroma glasses DON'T work, a TH-camr called 'MegaLag' made a few Videos about them.
How does EnChroma glasses being polarized have anything to do with their possible affect on some symptoms of color blindness? is all colored light polarized?
@MegaLag has done a fair amount on enchroma.
Maybe consult/collaboration would be beneficial
FYI the other peak in the infrared at 10:00 is another Na doublet at 818.3 nm (3d2D3/2 → 3p2Po1/2) and 819.5 nm (3d2D5/2 → 3p2Po3/2). See "Surrogate measurement of chlorine concentration on steel surfaces by alkali element detection via laser-induced breakdown spectroscopy" in Spectrochimica Acta B by Xiao et al.
7:40 Hey! There's a legit use case for that!
People who live near sodium public lighting might want their windows tinted like that, so their room is dark during the night but then in the morning (most) sunlight will filter through and help them gradually wake up!
Exceptionally niche product that could be solved with cheap automatic blinds hooked up to a photoreceptor. And it wouldn't encourage you to be naked in front of your open window by accident
But how expensive would that glass be?
they dont use sodium lamps any more
@@skeetsmcgrew3282That use case is pretty niche but the same concept is a big part of why areas around some major observatories still insist on using low pressure sodium lamps for street lighting, because they can use a very narrow band filter to cut out all of the light pollution.
@@skeetsmcgrew3282 even if it's a costlier solution, it's much more elegant than the automatic blinds.
I don't know whether it's the quality of your pedagogy or if we just happen to think alike but whenever I have questions while watching one of your videos you inevitably say, "You might be wondering..." and then answer those questions. It makes your content extremely satisfying to watch. The downside is that since I'm left with no outstanding questions I rarely comment, hurting that elusive "engagement" metric. So here's me making up for that.
Goddamn that's a good comment. One of very few around TH-cam. I had to join the metric here 😂
I was wondering if someone was going to make that comment.
and this comment has done the exact same thing lol
spot on!
Great content makes the viewer think and ask questions, and even better content anticipates those questions and answers them.
When I was learning electronics in the Navy, we used to joke that DS label used for lights in a circuit diagram stood for Dark Sucker. When a bulb blows, all the dark leaks out.
Douglas Adams and Terry Pratchett would be proud of you.
Lol
I frequently call power plants with the big steam stacks “cloud machines” and a handful of people take me seriously.
I almost always roll with it when they do
As a mm electronics had magic smoke and if it was released it was the em problem
Are there refills for the dark, like there are refills for the magic smoke?
The light of the sodium street lamp made me feel nostalgic
I associate the freedom of youth with that color, being old enough to walk around with friends at night without my parents, but young enough to have the time and energy to go out and have fun like that
Was going to make a similar comment. Sodium street lighting is liquid nostalgia for me. So warm and comforting, especially in winter.
I understand the advantage of near white LED street lights, but it is so cold and harsh. Very unpleasant.
@@lmf8503 finally. Somebody sane on this fucking rock
I love sodium street lights. They bring back so many memories of walking around the city and enjoying random bars and restaurants during the good old days.
They are still common in my city
I'm with ya'll - I love a street flooded with that light.
Now someone can make the REAL Darksaber!
Ah yes, You right!
I came here to say this!!
But you have to live on the planet with a sodium sun.
@@manabellum Ok, so first step, we can find sodium in salt, so now we juste have to build a sun with!
Only with a very dim sodium doped methanol (or other similarly colorless flame) saber, while battling under an EXTREMELY brightly streetlit night scene
Sodium street lamps were actually way better at controlling light pollution. Because they emit light at such a narrow spectrum, it was possible to make something called a CLS (City Light Suppression) filter that removes the sodium band, but even wearing those glass blower glasses would mean you could actually see the stars, and through a telescope nebula, and galaxies quite well, almost as though you were in a dark sky site with no city lights.
The LED bulbs everyone is switching to are horrible because they emit white or blue light broadly, making it almost impossible to filter. Further, these colors also increase the light dome (basically how far light travels away from it's source) over urban areas, meaning that areas around cities that were once dark no longer are. This has forced backyard astrophotographers to switch to narrowband imaging, which is really only useful for nebula, and that's incredibly expensive to get into.
To make up for this, some companies sell sodium-like LED street lamps for locations where having dark skies are important, but they are very expensive (basically they are taking advantage of the situation). Personally, I wish we'd just switch back to the sodium lamps, they are as efficient as LED's and they're just better for the night time environment.
Sodium street lights are also FAR better at making colour "blind" people like myself completely miss a red traffic light, because it gets lost in the sea of sodium lights. Sodium street lights are dangerous, & CAUSE conditions that lead to traffic accidents. This is NOT speculation - it is from personal experience! I am very happy they are mostly gone now (despite also being interested in Astronomy) - we are ALL SAFER for it!
@@BrendanBurwoodthat’s an important consideration! I grew up with the sodium lamps, and I never minded them. But they definitely did shift the perception of colors for those of us with “normal” color
Vision. I can imagine how terrifying it would be to have nearly every stop light washed out by them! Seems to me we would all do a lot better if we switched to lights that had a SHAPE as well as a color patter to them. Like an arrow up that is also green, vs an X that is also red, and maybe a dash - that is also yellow. This would give people multiple clues to decipher what they mean. In the past, when they were really light bulbs and lenses, it would have been hard to do. But these days, you can arrange LEDs in any pattern you like pretty easily. And I’ve seen plenty of green arrow lights for left turns, so I know it’s pretty easily done. Do you know if anyone has suggested something like this yet? I can’t imagine someone hasn’t already thought of it!
@@DawnDavidson There were arrow lights before LED's were a thing - just a simple screen on the front of the light with the right shape on it. I suspect it's easier to just replace sodium lights with something else as they wear out, rather than attempting to retrain everyone on a new set of signals.
Interesting extra aside is that for my type of colour vision some of the lights (MUCH brighter for my vision) that replaced the sodium ones (my mother says they are "apricot" in colour, but I try to not use subjective colour names) get confused with the green traffic lights. This isn't really a problem though, since it doesn't matter if you don't see a green traffic light pointing at you. The red light plus sodium lighting was & is the main dangerous situation - miss a red light can equal a VERY bad day! (also witnessed that happen a few cars in front of me in daylight - 4 car pinball!😮) I have been very happy to see them get mostly phased out in the last 2 decades or so.
Dude the clouds GLOW from reflecting street lights. We went out of town a few years ago near Lake Superior and we could see Duluth because the clouds over top it always glowed WHITE. When I grew up the clouds glowed orange at night, now it is white with the new lights.
We really cant understate light pollution...
I'm really glad you specifically mentioned that color blindness is due to the L and M cones overlapping more than usual! Lots of people seem to think that color blindness is caused by a lack of one or the other, when really it's a mutation.
That said, the reason why the literature is inconclusive is largely because there are multiple types and degrees of color blindness. "Red-Green" color blindness is actually a catch-all for the two most common categories: Protan (mutated L ('red') cones), and Deutan (mutated M ('green') cones).
Each of those two categories additionally has 'full color blindness' variants: Protanopia (when L cones are mutated to the extent that they behave exactly like M cones), and Deuteranopia (when M cones are mutated to the extent that they behave exactly like L cones). Whenever the mutation doesn't cause them to act _completely_ like the other type, it's called _anomalous trichromacy_, and there are various degrees to that. The terms used are: Protanomaly (when L cones have shifted to behave somewhat like M cones), and Deuteranomaly (when M cones have shifted to behave somewhat like L cones).
So, because of all those different types, the way that light filtered by the Enchroma glasses is perceived will differ depending on which type of color blindness a person actually has. Notably, they can *only* work for people with anomalous trichromacy, and it will work better with one type of anomalous trichromacy than the other (though I don't know which one it works better for).
People with dichromacy (full color blindness) would have no use for them, and not be able to see any difference.
And finally, people with tritanopia and tritanomaly are left without any options because it's already super rare anyway. The only time I've ever even seen a joke or mention of it in something that's well-known, is a subtle jab at tritanopia in the movie 'A Christmas Story', when the father can't tell the difference between the green and blue lights. I've been studying color blindness for several years now, and it was only this past Christmas while watching that movie yet again that I caught that and it made me burst out laughing in front of my suddenly very confused family.
Would those glasses work a bit easier, if the left and right lenses blocked different colors? I'd imagine it would be a bit like those old blue-red 3D glasses, but maybe it'd be too annoying and distracting to be practical. 🤔
Thank you for sharing this! Didn't think I would be learning this much about color blindness tonight but that was fascinating to read
It's well-known amongst colorblind people that the Enchroma glasses are a huge scam, perpetuated by youtubers who keep lying about the effects. They don't let you see anything you can't, they just make colors "different". They just mess up the colors, and colorblind people can notice when colors are all messed up. The reason they "work" with anomalous trichromacy is that the weakest your colorblindness, the more you perceive how much it's messing up everything. In the end colors end up even less accurate than we see them normally, and yet they falsely claim it makes us see colors we can't see. It's just that, a scam with little to no scientific merit.
EDIT: If you want to know more about the massive scam that is Enchroma, there's a very good video on the subject here on TH-cam called "Exposing the Color Blind Glasses Scam". It goes in depth at explaining how it's all BS.
@@dantemeriere5890 Enchroma has a 60 day money back return policy. I don't think "scam" means what you think it means.
@@retyroni Enchroma glasses are almost always given as gifts and promoted as such. Naturally, most people are not going to complain about a gift to such an extent. Their promotional material targets people with normal vision almost exclusively, probably because they know very well that colorblind people are very well informed about their condition and wouldn't easily fall for this. This means they are deliberately taking advantage of people's ignorance and good faith. This is the very definition of scamming someone, and if you still "think" otherwise, it's a good idea to check a dictionary.
Furthermore, this isn't any controversial statement. This is very well-known in the colorblind community, as shown by the video I mentioned in my previous comment.
Amaterasu 😮
Can't believe it took me two pages of scrolling to find this. Thank you.
Itachi
Lol😂
Who is that?
Took to long to find this comment
A fun fact about the sodium light spectrum is Disney created a special process back in the day that worked better than any blue/green screen using a prism. They could get much more detail around a subject without any spill from the screens as well as being able to film sheer & transparent materials. Marry Poppins is the best example of this. The Corridor channel did an interesting deep dive and recreated the effect on one of their channels.
Was just commenting to say the same thing :D th-cam.com/video/UQuIVsNzqDk/w-d-xo.htmlsi=xi6Eh5vvBBpQyNie
I was also thinking of the same video!
Was this IR screen? I haven't seen the video, but I read about it in the excellent book, _Special Effects Cinematography._
They used it on Wizard of Oz.
The way it worked was by using a dichroic filter to split a light source. They used the _light_ to illuminate a black screen that was painted with infrared paint. Then they illuminated the characters with light with IR filtered _out._
Then they split the image coming into the camera using the same type of dichroic filter - the visible light passing through to the film negative, and the reflection landing on an IR sensitive film.
By this method, they created the positive and the mask of the characters all in one pass, and one film processing step.
This produced far better results than green screen.
As soon as I saw that light it reminded me of the Disney Prism video and I thought 'Somebody else had to mention this in the comments' and sure enough here you are!
was looking for this comment! good stuff!
Someone else may have already commented about this, but the fact that the light emitted by sodium atoms produces roughly one wavelength of visible light was used in movies for compositing in lieu of greenscreen. This technique known as "Sodium Vapor Process" or informally "Yellow screen" utilized custom-made beam-splitter prisms with embedded notch filters (similar to how EnMouldia glasses work) and Bandpass filters split the image into two parts to create a perfect matte. This process was famously used by Disney in the filming of Bed knobs and Broomsticks as well as Mary Poppins.
And Corridor Digital recently managed to collaborate with an engineer reconstructing such camera setup and made a very interesting test movie with amazing key mattes thanks to sodium vapor!
Wasn't it also used in The Birds?
The f is a bed knob
@@thekingoffailure9967 An ornamental ball on the top of the posts of an old fashioned bed. Loads of wooden furniture used to have knobs, we were just a knob obsessed society 😄
@@matthewstarkie4254 I have those on my metal bed frame but I didn't know that was what bed knobs were lol
16:12 From one uncle to another, this is top notch uncling giving your nephew's TH-cam a shoutout. Bravo.
I noticed that too, one more reason to wanna marry the guy
@@The3Sag3 He usually puts his sponsors at the end. Clearly the little guy is the actual sponsor of this video!
@@The3Sag3 I wouldn't read too much into it. Most viewers are probably going to watch until the end anyway so he might as well put it at a point in the video that is more natural rather than making it prominent and awkward.
At the end of the day it was a nice little callout that brought a little joy to a couple of us to see.
@@Alskaskan yea, it would have been weird if he just mentioned it in the middle of the video.
he also did it like, "i am mentioned about this because i showed his reaction to the glass i am talking about" kinda nice and casual way.
"im not promoting, im proud about him" kinda way.
The one simple trick the Gloam-Eyed Queen DOESN'T want you to know about!
10/10
I was expecting a lot of er references but found this only, good one
I can feel the %hp damage
Thank goodness I found this
True Elden Ring fans!
i have struggled with "Spin" of subatomic particles for years. The "it tells us which way the moving electric charge points its magnetic field" line felt like an epiphany i have waited decades for
Nice, and the reason the property is called "spin" is simply because the magnetic field of the electrons looks as if it was produced by the electrons spinning. Even though they're not, since they're wave functions at quantum level
I recommend PBS Spacetime for in depth content on electron spin and physics in general.
@@alexeifando747 I've seen their spin episode. While sure it does explain what spin does, even they couldn't make it intuitive. Ultimately the idea of something having angular momentum but also being a point particle that can't actually spin just breaks our imagination. There's a reason even physicists (or even more so physics students) joke about spin.
Congratulations, I still don't understand anything. 😅😅😅
it's kind of a mislabeling, since the fundamental particles don't have any size, they are points, any "wavelength" is just about probabilities So, they can't "spin" since they don't have any part that could face in different directions.
I see this flame and the first thing that comes to mind is the Godskin Cult.
the god-slaying flame...
AND NOT GIANTDAD‽
@@eyeballpapercut4400 The future is now, old man. (i say this as a dark souls veteran...)
came here to say this
I’m glad i didn’t have to scroll far to find the Elden Ring players on the video about black flames.
2:30 I like how your camera can't even remotely pick up on the actual rainbow in that diffraction grating, and just gives you three bands of RGB.
I find it fascinating and deeply troubling. If there is not a probabilistic fall off between colors of pure wavelengths, what does that say about their ability to capture color in a way that matches our eyes.
Nothing actually as you can produce any color of light with those 3 :D
I don't like
There must be something else going on because I can definitely capture say, yellow, with my digital camera
@@mynameisben123 No, you cannot. Your digital camera just captures a combination of red, green and blue that looks yellow to our human eyes.
6:10 So are you effectively saying that the "black" is acting more like a shadow from a translucent material? Shadow flames?
It's literally The Darksoul from Darksouls and if you think about it this is really what everything would look like if you were looking from the perspective of the brightest object in existence
The CRI of low-pressure sodium lamps is not just low, not just 0, it is actually Negative.
It is so wonderfully efficient at both illuminating as well as destroying any colour recognition.
Interesting, I did not know CRI could be negative. P.S. Plenty of sodium vapour lamps in my street.
@@gordonrichardson2972 Yeah, a nice quirk of how that number is calculated.
Granted - CRI was never designed for light that does not at least Appear to be white-ish, but still strange.
As I understand it 0 is as bad as it can get while technically being white. For example, a trichromatic light-source with narrow (or single wavelength) red, green and blue peaks would approximate white but it would also make things look as weird as low-pressure sodium lighting.
Because sodium street lights are effectively monochromatic yellow this makes them even worse than that. I believe that's why it has a CRI of -44
@@johnydl I was looking for some more information on low-CRI sources buuut seems like nobody wants to create such a useless product.
A lightsource having near monochromatic peaks that manage to hit the cones just right to appear white to us. Theoretically just 2 emission-lines should be enough, but i'd guess we can do with 3 :P
Brainiac75 did a video about this 2 days ago (watch?v=l9Gv5FVE-0c), he said the CRI was -44
About a decade ago, my wife and I were visiting Killarney, Ireland. While we were walking back from the town center to our B&B after sunset one night, we noticed that her bright red raincoat appeared a very dark gray under the streetlights. Turns out, this was the first time we had encountered sodium streetlights in person.
PRACTICAL APPLICATION:
I design optics for street lights. With respect to high pressure sodium lamps, we had to make sure our optics did not reflect light back into the arc tube because the sodium would absorb its own light and cause the arc tube to overheat. This would shorten the life of the lamp.
Practical application was Mary Poppins
Better than Green Screen
@@ChibiHoshiDragon Have you seen the Corridor Digital video?
@@llamallama2000 yup
Elden Ring Black Flame builds finally getting the love they deserve.
Elden Ring? You mean Dark Souls?
@@benjiusofficial No you're thinking of King's Field.
I have the immense joy of being incredibly colorblind. The enChroma glasses did not work for me. However, for $30, I found a particular shade of polarized dark brown cataract sunglasses at CVS (a large chain pharmacy/chemist in the US, for those unfamiliar), which allow me to interpret reds far more easily than I otherwise can. It makes being outside very pleasant, and it's honestly really cool to be able to see the things people have been pointing out all my life that I never understood the interest over.
It's a very noticeably subtractive experience, but I find my brain can easily ignore that aspect of it, especially after a few minutes of adaptation, and I get to experience the world slightly darker, and can notice red and red-adjacent things.
What’s the name of these glasses?
Can you now also see all the red herrings?
I'm not colorblind, but there's a pair of brown polarized glasses I get from Walgreens that makes greens really pop, especially in the sun. I find the shade of green really beautiful, so I just keep buying the same pair when they get worn out.
Best line: "Its a weirdly polarized topic now and I don't like being shouted at."
Sad but true
At least hes honest about it instead of dancing around the topic without being blunt like most people these days (talking about any uncomfortable topic in general). It's refreshing to see
@@SangheiliSpecOp I love the shade (embrace the pun) Steve's throwing at EnChroma here....
"If they pass the happiness versus money test,
and you don't care about their dubious marketing practices,
and you don't care whether they make you happier than a placebo pair of shades under clinical testing conditions,
then maybe EnChroma glasses are for you."
I feel like an opportunity to make a polarization pun was missed.
I'd prefer it if he straight up voiced his opinion on EnChroma glasses. Most TH-camrs love controversy in their comments. Was Steve more worried about being shouted at, or litigation?
As a colourblind person, EnChroma makes me angry. Basically a scam.
imagine getting your youtube channel advertised by your uncle Steve Mould, what a move!
0:12 I mean we did that in chemistry class as a matter of fact, everyone should have since your chemistry teacher should warn you not to do that, as an invisible flame is very dangerous because, well you know you don't see it.
Chemistry like drivers Ed is not only optional but not the main core of education in America. I only took chemistry because I wanted to. Most people didn’t. Most of the kids who were interested watched a lil too much Breaking Bad and that was the only thing that got them interested.
@@dannyhothrikker4783 Crazy here it's 100% mandatory for all 3 main levels of high school education. You'll have it for at least 4-6 years.
@@dannyhothrikker4783 that's crazy, it's defenitly mandatory in high school over here you have to follow it for like at least 3 years I think with a maximum of 4~6 years depending on the level of education.
homeschooled kids:
@@elliot_rat actually homeschooling is illegal here.
Wow, came here for a black flame (which I knew would be about sodium absorption lines) and learned about glass blowing, colour blindness and - finally - a good explanation of an electron spin.
Was gonna say the same. So much packed in here. Like 5 years of secondary school. Come to think of it, how old am I? What year am I in?! 😅
Steve is slowly turning into Michael from Vsauce XD
You might not like being shouted at, but how about some praise? I highly appreciate you doing resarch into the glasses before shouting them out in any way, even more so that you actually share the controversy, instead of just saying it's bs or 100% fact. That's exactly what I want out of a science channel!
One guy did a series of videos on these glasses, claiming that because they are purely subtractive, they cannot enhance colour perception. I don't think that's actually true, but it takes rather a lot of reasoning/explanation. Ultimately I think it comes down to the fact that colours are determined by the _ratios_ of the components, and a subtractive filter can indeed change the observed ratios in real world scenes, leaving open the possibility of perceiving a wider range of colours.
I don't know whether or not they help people, I think that would need to be determined empirically using real-world scenes and some kind of blind glasses, but it was what I considered an overly-simplistic statement I objected to, so I'm glad Steve takes a more measured approach.
The difficulty is having to account for how the brain processes that information, which is something I rarely ever see discussed. @@SloverOfTeuth
No, if the glasses are strictly subtractive (which they are), then it would be impossible for a person using them to see new colors. The explanation is quite simple and logical, too: when you’re subtracting colors on the visible spectrum and are left with a new, altered spectrum, it’s the same as looking at something *without* that filter that already omits that particular spectrum. In other words, since every post-filter spectrum can also be created without the filter, then obviously adding the filter cannot create a “new” spectrum.
Put in mathematical terms, if we say that A is a set containing all possible spectrums that can be found naturally, and B is a set containing all possible resulting spectrums after applying the filter, B is a subset of A, which means that by definition it’s impossible for B to contain a value outside of A.
That’s not to say that Enchroma glasses don’t do anything. In fact, I think it’s pretty obvious (and not really at all disputed) that they help colorblind individuals distinguish reds and greens better, specifically by blocking out the confusing color, so something might look more green or more red. But the idea that they allow you to see “new colors” is ridiculous and as of yet has no logical or scientific evidence to support it.
@@openfire2691 There's a fault in your logic, which is easy to demonstrate by counterexample. If A is the set of all greys in a colour space, subtractive filtering can produce non-greys in B. Non-greys are not a subset of greys.
This is why I specifically limited my comments to real world scenes. If they occupy a limited part of the colour space, we can always generate additional colours by subtractive filtering.
HI STEVE I ENJOYED YOUR VIDEO
So, this is the secret behind Itachi's Amaterasu.
what
Litwrally my first thought was "I can be an Uchiha now"
@@xavierpadilla4113 yea me too haha
Interesting. It’s all Hocus Pocus to me….
😂
No that's based Emo-ness.
I'm diagnosed with deuteroanomaly, and I've had opticians really push the enchroma lenses. "You'll see what everyone else can see!" they cry. But what will I lose? I seem to see things in nature they don't. I'm not convinced. Thanks for the very balanced perspective on a somewhat contentious issue. Well Done!
EnChroma is a scam. "But what will I lose?" Your money.
You can find TH-cam videos exposing lies of enchroma and similar glasses.
Also you should probably change your optician if they push this crap
My brother was convinced to get those glasses by some TH-camr when he was young. My dad saved up for it and they eventually arrived. No different. Broke my brother’s heart. He moped for weeks, the TH-camr had really convinced him he could see like other people.
Sodium light again huh..? first the disney 'greenscreening' prism, now black flames! Sodium light is very useful for color spectrum science it seems.
It souldn't seem, it IS because of it's property of pure single color emmision
a fellow corridor crew fan
@@lux_fero Indeed, it was used over here because of the nearby observatory, as it's easy to filter since guide stars (ie. "their laser pointer") use the same wavelength (or very similar)
Corridor Digital, Brainiac75 and now Steve Mould. Us 589nm fans are on a roll this year
The sodium D line is a simple way of creating bright monochromatic light. These days, lasers are a thing, but it still has its uses.
"because id be dead" got me spitting out water lmao
Where? 12:30. You’re welcome.
Why couldn't the T. Rex eat pizza?
Because it was dead.
@@dibenp Thank you kind person
That line, the way it was delivered, gave me Jeremy Clarkson vibes. Probably just me though...
I forced my beloved to watch this section and they laughed harder than I did, which was wonderful
As someone with mild red-green colorblindness and a pair of Enchromas, I feel like I should say that they do work, but not to allow me to "see colors I couldn't see before"
Mostly what they do is allow me to distinguish shades of green and red that my eyes have trouble picking apart from the background by cutting out the duller shades of those colors and making them more vibrant.
Like, say, a green bush full of red flowers. Without Enchromas I might be able to tell that there are red flowers, but unless I got up close to the bush and searched for them, I wouldn't be able to just distinguish the red flowers at a glance.
My Enchromas allow me to do just that. And the same goes for different shades of green.
I could physically see those colors already, my eyes just sucked at picking them out from each other when they're all mixed up. Kinda like the colorblindness tests with the different colored dots.
They do make blues a bit purpley, though.
Thank you for this comment! I think I have nearly the same amount of red-green deficiency and I wondered if they would do anything at all. Distinguishing a red berry in a bush is trivial if I'm looking at it, but from a small distance away or at a quick glace it's nearly impossible. I'll have to try and find a pair just to try it out.
I have pretty bad red green colour blindness and the Enchroma glasses did absolutely nothing for me!
I have some Enchromas and mild colour blindness. Whilst wearing them, everything looks a bit weird and fake, BUT I am able to distinguish between colours that I otherwise wouldn't be able to. My main for use for this at work when reading things that have legends with colour categories - I can actually distinguish between things when using the Enchromas.
Please stop perpetuating the lie that is enchroma glasses. It's been proven that they are a complete and utter hoax... Look up MegaLag's video about them.
So it would be more correct to say the glasses are not about fixing the color blindness, but about fixing the uneven color distribution it brings? Because I can see how it would help the dynamic range of your vision.
i have to hand it to you, its great to make a video that is clickbaity like 99% of videos on here, but then actually gives incredibly detailed, interesting and educational information that could genuinely spark someones interest in science. Fair play.
Was that a hidden richard butt in the colorblind test? lol
HAHA! YES! I didn't notice it the first time .. (15:23)
Not just that, but it's a full dickbutt
It's an old meme, but it checks out 😂
I came here to see if anyone else noticed it too 😂
TH-cam ate my first comment lol, but I was identifying it specifically as a dickbutt.
Here in Sweden, I miss the highway sodium lights upon startup (I remember them shifting from purple/blue/yellow/deep red/orange to the final yellow light).
A late summer evening with a clear, rather dark sky, seeing the sodiums start up into the distance... awesome.
You just unlocked a childhood memory for me! Completely forgot this is how things used to look when I was a child ☺️
@@TeddieBean Colors are the keys. When I was 7 my parents shipped me off from Seattle to visit relatives on the east coast. Over 3+ weeks of constant entertainment, I remember exactly three things. The birds Connecticut (the only bright red, yellow, or blue birds in the northwest are found in zoos), a blue lobster in Maine, but mostly I remember flying into Chicago at night. My parents had no idea what the hell I was talking about, so I didn't find out until years later that Chicago was the first city in the country to switch every street light over to sodium vapor. I just happened to pass through shortly after, and it looked absolutely amazing.
I'm from USA, but I vividly remember light being different as a child. The sun was less white, more yellow. And the street lights were a hazy sunset color, amazing memories. Those industrial white buzzing lights were way too sharp. Nowadays either my senses have changed or light is different.
@@litttoe Most likely your memories are faulty. The sun is often portrayed as yellow because we know it's made of something like fire and the only time of day you can safely look at it for a second or two the light that gets through is either yellow or red, but the actual light emission from the sun is white. So unless you grew up in LA when there was visibly yellow smog, you're just remembering things wrong.
They were awful and they turned the sky a horrible murky orange colour.
I'm colorblind and have a pair of Enchromas. They do make it much easier to distinguish reds and greens, but they're not magic and I certainly don't see "new colors" I couldn't see before, although my colorblindness is not that severe either so I won't discount other people's experiences.
But the best demonstration I've been able to find of their effectiveness is rose bushes. For the most common types of red-green colorblindness, the red polka dots on a green background look that rose bushes have is especially problematic. From any sort of distance away, the roses lose their definition and start to just look like darker parts of the bush. But with the Enchromas, they pop out really strongly from the bush, even from quite a distance. So it's not so much that they help you to see new colors, as much as they improve your ability to distinguish and apreciate colors you could always see. It's not like (most) colorblind people can't see red or green at all, it's just a lot harder to distinguish them from each other in most situations.
Additionally, for all people (including normal-sighted people) they generally improve contrast and make all colors seem a bit more vibrant. I'm almost surprised that they haven't caught on as a luxury glasses brand just for the way they make everything look "more vibrant than real life". Although, that effect is really only true in especially good lighting.
I saw a review from a person who described them as making it easier to identify colors he normally had trouble with.
The reason that non-colorblind people aren't buying these glasses is that they make certain colors harder to see and comes with severe color shift
Regarding how Enchromas work. Given that computer and phone screens use RGB leds, i.e. they are specific colors that "trick" our brain into thinking we're actually seeing all the colors, do colorblind people have an easier time discerning colors in a screen vs. real life? If all Enchromas do is to supress the overlapping, then there shouldn't be any overlapping in screen leds.
I have to wonder why they don't just take advantage of stereoscopy, like there's this meme of "impossible colors" created by seeing one color in one eye and one in the other. You'd think technically it'd be possible to give difficult colors a stereo difference (maybe that's uncomfortable though)
@@Nico_M. I've never actually thought about this before. It kind of makes sense, but I definitely still have trouble with colors on screens sometimes. I don't think it's any less, but I couldn't tell you why.
My physics professor once bemoaned sodium street lamps getting phased out. Apparently, it's extremely useful in astronomy, as you can't normally see the stars because of light pollution. Yet with sodium street lamps, all you needed to do to make your telescope work was to put on a filter, blocking sodium's emission.
15:22 is something that I didn't expect to see, but I was glad it was there.
how do you mean? db isn't more than a couple years old... right? oh god
i had to scroll more than i expected to see someone talking about this
i am glad we all were here to see it
What a throwback. I miss /b/
I feel strangely violated, and yet still glad
ah, yes, one of the old runes
Back in my physics days, you could look up all of these lines and transitions in textbooks. Or on NIST, but that page seems to be strugging. I did the looking up for you:
The 819nm transition is a 3d-3p transition. The other ones are from higher orbitals, 5s-3p for 616nm and 4d-3p for 569nm.
That peak in the IR is actually another doublet at 818.3 nm (3d2D3/2 → 3p2Po1/2) and 819.5 nm (3d2D5/2 → 3p2Po3/2). See "Surrogate measurement of chlorine concentration on steel surfaces by alkali element detection via laser-induced breakdown spectroscopy" in Spectrochimica Acta B by Xiao et al.
Thank you!
I love the NIST page for this. It has exactly what you need and no more: physics.nist.gov/PhysRefData/Handbook/Tables/sodiumtable3_a.htm
15:22 Dammit, Steve. I can't believe you've done this.
By the way, your description of spin & quantized angular momentum was one of the most interesting one's I've encountered. I'm definitely going to have to keep coming back and rewatching that segment to wrap my head around it.
Damn, I'm glad you brought up that timestamp; I wasn't really paying much attention at that point and totally missed that detail.
shoutout dickbutt
😏
I didn't want to seem like a Dick, Butt I saw it too.
Surf Wisely.
0:40 yes BUT you gotta admit it looks pretty cool
Yoooo jajaja
15:07 "It's a weirdly **polarized** topic now..." * puts the sunglasses on as a the Who song starts blasting *
Those old street lights are nostalgic af...
All the memories of being driven back home from visiting family, late at night and falling asleep to the sound of the moving car and the atmosphere created by those old street lights. 🌃
And they didn't block out the night sky as much
Reminds me of coming late in the winter evening from the university, passing through a dim park with big yellow spheres as lanterns... A bit eerie, uncomfortable, but also dreamlike...
we are making a mistake by not keeping them
😢
@@SuperAWaCit's good that LEDS replaced sodium in some ways though, the monochromatic color completely removes your color vision, so it might be hard to identify some street signs.
How to make blackflame:
Step 1: Touch random paintings until one of them sucks you in
Step 2: Fight a nun dual-wielding scythes to the death
Step 3: Pledge yourself to he Gloam-Eyed Queen
Instructions unclear, i am now multiple parallel universes away
Show flame.
does it still count if I didn't beat phase 3 ? I mean, blackflame was created
is this an elden ring reference or a vampire survivors reference
"How can a point-like particle have angular momentum?" (at 11:35) I think is because it's a vector rather than a point. It has a a location and also a direction and rate conveyed into reality as a location over time with the rate being set to "infinity" which is not possible so it hits the universal speed limit instead. You can essentially think of it as a fundamental aspect of spacetime, not just space, and you can think of it as a particle that moves on the smallest possible scale every universal "frame" (in video game terms), meaning it is so fast it updates its location faster than everything else but no faster than the computer (the universe) can process its movement.
The reason it applies to very well to computer programmed hit scan lines is one of the many reasons very smart people think we may be living in a simulation. But this is only one interpretation and it's very possible that we're viewing it through the lens of the current information age which is programmed to simulate real world concepts and so of course the simulations work like the real world. But do our simulations work the same as the real world from an extradimensional creature gazing into our universe like a child with an ant colony? Probably not, and it's equally possible we are not living in a simulation at all. The result (virtualized digital simulations based on reality as we know it) cannot be used as data (scientific measurements of reality) to determine how reality works. Not without a control of course, among other things.
"I wouldn't see that dip if I was doing this experiment in the vacuum of space - because I'd be dead." That had me rolling
I loved that joke 😂
0:13 No, that's a terrible idea, I don't want to be burning without even knowing where the fire is.
Corridor Crew also did a video where they used a set of sodium lights to essentially re-create vfx similar to what was done on films like Marry Poppins. It involved an interesting camera set up, but resulted in a more defined chroma-keying to where you don't have to worry about other colors bleeding into the void.
That was a really interesting video.
Yeah, you need to split the incoming light so you can get the image without the sodium color, and the image with just the sodium color. Then you can invert the sodium-only image to use as a matte for the non-sodium image.
Since it’s all achieved optically, background replacement can be done entirely with film and an optical printer. And since sodium light is such a narrow wavelength, it doesn’t bleed into anything you want to keep and you get near-perfect transparency.
Love how you explained such complex topics in such an easy to hear way! Love from Brazil!
Moving from sodium lights was a real problem for astronomers as narrow band filters were common and cheap, the LED lights are much harder to filter out due to having multiple peaks and the phosphors not being to a standard chemistry resulting in different lights having different frequency outputs.
Interesting! And a bit sad
@@SteveMould Might be sad from a normal colour vision person's perspective, but from someone (like me) with Protonomalous colour "blindness" the disappearance of Sodium street lights has made EVERYONE SAFER on the roads at night!
Why? Because if we don't see a traffic light change from orange to red on a street with Sodium lights then we can very easily completely miss the red traffic light, possibly causing an accident! Especially so if we aren't familiar with the area, or a new set of traffic lights have been installed - a situation which actually happened 30-odd years ago when my brother (also with similar vision to me) missed seeing a new set of lights in a very familiar area lined with Sodium street lights. Fortunately we had my older sister in the car who realised in time that neither of us had seen the red light. She got our attention in enough time for my brother to stop the car with the nose over the line. Fortunately it wouldn't have caused an accident on that occasion as there were no other cars nearby, but there easily could have been.
I for one do NOT miss Sodium street lights (despite also being interested in Astronomy). We are ALL safer from their disappearance.
Awful for bats too.
Your sodium lamp isn’t pure sodium. There is at least a hint of neon in there for arc initiation, and I wonder if that is part of your spectrum impurity. Take another spectrograph of it when first cold lit, and I’ll bet that highlights the non-sodium component.
Yes. But no. The sodium overpowers all other gases in the lamp by a LARGE margin. Brainiac75 just did another video on this. He does a good explanation and also a spectrograph so you can see where the lines are.
Yes the other lines are impurities. And the infrared line is probably just heat.
Nope. All the peaks he's seeing when the lamp is at full brightness are from sodium. The other prominent peak in the infrared at 10:00 is another Na doublet at 818.3 nm (3d2D3/2 → 3p2Po1/2) and 819.5 nm (3d2D5/2 → 3p2Po3/2).
@@dreamyrhodes Completely false. All the lines visible here are due to Na and a single sharp peak in the infrared is not "just heat". That's not how it works, that's not how any of this works.
@@dreamyrhodes Heat is chaos and chaos doesn't produce sharp emission peaks. Look-up 'black-body radiation' if you want to know, what kind of spectrum is produced by heat.
Please never stop doing these kinds of videos. You are literally broadening my horizont. There are many things that are far out of my reach, knowledge wise, and you tap into them, but you also make me understand enough. It really is fun and exciting to watch videos like this. Not necessarily because of the topic, but because of how you are driving us in your bus through knowledge town. Sightseeing with you is fun, not boring. It's pleasant and exciting to learn more and to see the world a little bit through your eyes. (Or rather mind really lol).
Thank you for putting this effort into your videos!
11:06- best explanation of electron spin I’ve heard yet. Thanks Steve!
Fun fact, Robert Bunsen had an assistant with a speech impediment called Beaker.
Meep.
Did he perhaps have a friend who was a Swedish chef?
Jim Henson based Bunsen & Beaker on them
I once gave blood at a Cambodian hospital, and I read that the name of the male phlebotomist was Bun Sen. It took me 5 minutes to stop giggling enough so he could get the needle in.
Disney used "amber screen" in Mary Poppins , that predated green/blue screen special effects, back in the 1950s . It used sodium lamps. And it is superior in many ways to green screen and blue screen. It's even possible to do transparent things like water and fine hair, which has proved very difficult to do in green screen.
Green screen, blue screen, black screen, and white screen all predate the sodium lamp amber screen technique by many decades. Mary Poppins is one of the only examples of amber screen because it's not nearly as reliable as the other chroma techniques
A modern way to do scary clean colour key composite is to have the background of retroreflective material (3M Scotchlite) and place a green non-diffuse ringlight on the lens. You also lose all colour key spill this way. If you're dealing with green items, you can also use RGB ringlight and switch to a different colour. But due to how saturated the colour is, you usually don't even need to, because real world pigment greens can't compete with the LED on saturation.
One could potentially enhance it by going complimentary, switching the ringlight frame synchronously between green and purple every frame. Of course only for cameras that record in non motion estimated CODECs. But this is also largely unexplored territory, because i guess standard colour key works well enough.
Still having a near-true moving matte from sodium light does have advantages!
This is the comment I was looking for. The TH-cam channel "Corridor Crew" did a video not long ago where they resurrected the technology, showing off just what it can do that a green screen can't.
@@SianaGearz with the advent of machine learning/AI , amazing things become possible. The ability of the AI to distinguish what is background to remove/replace is uncanny, and it's only getting better by the second! It's starting to make chroma key look like old hat.
@@MyProjectBoxChannelSure, but if you look at the demo on Corridor's channel using a modified version of the sodium lamp setup it's pretty much flawless, far outperforming any other process available today including current AI based systems. I'm sure future AI vision setups will eventually be able to just about match it, but doing it with a near perfect optical process is going to be very reliable and simple to implement, whereas AI systems are always going to have glitches and edge cases, not to mention being a lot more expensive to run for the foreseeable future
Wow, I can't believe that I've never put two and two together, but I honestly didn't realize until now that sodium street lamps render color useless. It's not that I'm color-blind or anything; it's just a sort of conceptual understanding I've not stopped to consider enough for it to sink in. Always just thought of it as 'weird orange.' Amazing what you can miss! Thanks.
Low pressure sodium lamps are really rare in my country (these days?). The first time I drove through an area that had them, it really threw me for a loop. I could not understand why all the normally red or blue signs were grey.
I’m a welder and always find it really fascinating when I’m looking at what I’m welding through my hood. Or when I’m cutting some steel with oxy/acetylene torch or using a plasma cutter.
I wish we still used sodium streetlights, the modern streetlights are far too bright, it doesn't feel like night-time at all. I wondered why night-time actually felt like night time as a kid, it was because of the street lights.
Bright street light feel safer.
@@dickiewongtk I guess. I'd rather walk in the dark personally. But I think that's just me being an absolute goblin of a person.
It's really awful for nocturnal animals. Messes with bats, eels, turtles, birds, and all manner of animals. Plants too. It's really bad.
@@NFM1337 that is fair but why not then dim LED lights?
I can't believe Steve slipped Dickbutt into a colorblindness dot test 💀
I think it is the best
Bro I want but can't like you comment
Where was thet? I was wondering about top raw middle to the right image that I can not understand at 15:37. Is that it? Or do I have a color blindness?
@@akselor It´s the one at 15:21
Glad I wasn't the only one
I saw a misconception in this video which keeps getting spread, mainly because the actual explanation is a lot trickier and weirder to understand than the actual reasoning. In the video, Steve says that the reason there are two lines is because the electron spins are either in the same direction or different direction from the orbital angular momentum. But, this is not true. Rather, it is because of statistics and the Pauli exclusion principle.
The Pauli exclusion principle says that an electron cannot be in the same quantum state as other particles. As it turns out, there are 4 different options for spin orientation: both spinning in the same direction upwards, both spinning in the same direction downwards, one spin up and the other spin down, and then vice versa. We then write these as a math statement. The first one is written as ↑↑, the second is ↓↓, the third is ↑↓, and the last is ↓↑. HOWEVER, as it turns out, ↑↓ and ↓↑ are not actual "good" states. For those who this word means something to, they aren't eigenvectors of a 2x2 matrix -- which is necessary for a state to be physically possible. So the solution is to change the set of states we work with to: {↑↑, ↓↓, ↑↓+↓↑, ↑↓-↓↑}. This is the set of all possible spin states.
Now onto the Pauli exclusion principle. Because an electron is a "fermion," when you swap two electrons, all that should change is the overall quantum function -- the thing which describes the electron -- should have a negative sign. Let s be the spin state, and p be the rest of the function -- describing which orbital the electron is in. We write that the whole function P is a function of particle 1 and 2, written as P(1,2) and equaling s(1,2)*p(1,2). In other words, P(1,2)=s(1,2)*p(1,2), with * just meaning multiplication. The "fermion" statement I made means P(2,1) = -P(1,2). So, s(2,1)*p(2,1) = -s(1,2)*p(1,2).
Now, we will look at each of the spin states. Note that when you swap the order of the first three spin states, we get ↑↑, ↓↓, ↓↑+↑↓. The last is identical to ↑↓+↓↑ because you can swap the order of addition. HOWEVER, the last state becomes ↓↑-↑↓ = -(↑↓-↓↑). This means if the particle is in the first three states, then we have to say p(2,1) = -p(1,2), and if the particle is in the last state, p(2,1) = p(1,2). This property is what causes the electron to have different energy levels.
If the particle has the first property p(2,1) = -p(1,2), the particles tend to be repelled away from each other, and we say that the position function has a "fermionic" behavior. In fact, THIS is why solids are solid. It's not that there are electromagnetic forces repelling electrons from electrons. Rather, it's because of this fermionic behavior of matter. Neutrons do the SAME exact thing, which is why neutron stars are a thing. They are held together and kept from collapsing by this pressure called "degeneracy pressure," despite having a neutral charge.
If a particle has the second property, p(2,1) = p(1,2), the particles tend to be attracted towards each other, and we say that the position function has a "bosonic" behavior. Light is a boson. A bosonic particle tends to be attracted to other of the same type.
I will make an important distinction: the repulsion of fermions and the attraction of bosons ONLY happens because the particles are EXACTLY the same. All electrons are 100% completely indistinguishable, there is no way to know for 100% certain one electron is not another electron or one photon is not another photon. Fermions are ONLY repelled from other fermions for which they are 100% absolutely identical to, and bosons are ONLY repelled from other bosons they are 100% absolutely identical to. Protons, neutrons, and electrons, for example, are not repelled from each other by this degeneracy pressure.
FINALLY we can get into why the energy levels are different. If they are in the fermionic position state, we call this state the "triplet" state, and the position function needs to be of a higher energy because of the degeneracy pressure pushing the electron further away. And, if they are in the bosonic position function, we call this state the "singlet" state, and the position function needs to be of a lower energy level.
Now, I will admit, I feel like there is something slightly wrong here. I believe an important statement is I need to say magnetic fields show up someplace in here because iirc, splitting of the singlet and triplet state don't occur unless if there is a magnetic field. Iirc, this magnetic field is due to the nucleus's spin (?). I am willing to correct myself if I made any mistakes. At the very least, the misconception which keeps getting spread is that objects are solid because of electromagnetism, which isn't true; it's because of spin statistics.
The main point is that electromagnetism plays little to no role in this, and the role it plays is weirder than you think. It's not "spins in same or opposite direction" but much weirder.
As @yorickandeweg2134 pointed before, it's spin-orbit coupling, so speaking about 2-electron behavior (fermionic/bosonic states) is incorrect. However, (somewhat miraculously) it turns out that the addition of spins of 2 electrons obeys the exact same mathematical rules as addition of electron spin and its angular momentum! Thus your description is largely correct. The key difference is that angular momentum on P orbital is 1, so instead of 1/2+1/2 addition (described by your arrows) we get slightly more complicated 1+1/2.
i genuinely don’t get this but now i’m determined so im commenting so i can come back to it later. to be fair i just woke up and haven’t gotten to this part of the video yet
🤓
@@yorickandeweg2134 Ok, yes, I agree! I think I got excited because the hyperfine and spin-spin coupling tends to be rather misunderstood too often as being an EM effect and not just a pure quantum effect. But, I humbly admit I was wrong!
2:09 could someone please tell me more about how this works? that looks very cool (exciting gas with tesla coil)
Posting for everyone else who doesn't have patience - he doesnt have the camera set to full color (natural color), he's disabled auto white balancing on the camera, and he's shining an incredibly bright sodium street light on the scene.
I'm pretty sure we used those same glasses in a class of mine for brazing copper pipe. Our teacher was very clear in stating these are NOT a pair of sunglasses and to use them on the road is VERY BAD. Those glasses are blocking the red/orange spectrum and apparently a couple students wore them out of class and rear ended a guy because they couldn't see their red brakelights.
Wow! Most science videos manage to teach you one amazing fact - this one just kept coming and coming with more and more answers to questions I've always wondered about. It's like a 6 month science course crammed into 20 minutes!
Someone I know recently combined Maple Syrup & buttered Popcorn thinking it would taste like caramel popcorn. It didn’t and they don’t recommend anyone else do it either.
About the enchroma glasses, a youtuber "megalag" made a few episodes exposing the whole color correction glasses industry, you might find it interesting
I think that's exactly his point when he refers to the topic being "weirdly polarised". Megalag presumed bad faith on some of the sponsored influencers and some of his viewers have become toxic and attacking the influencers.
@megalag enters the chat!
Yeah they are just a marketing scam that way too many people fall for.
@@Karavusk They do work though. Not nearly as well as they advertise, but they're still effective. I bought them as a gift to my father - and while they didn't provide immediate WOW effect, he would often write me something like: "Oh I didn't know those were actually red before"
@@MusaA1i I would recommend watching the megalag video series on this
Thanks for all the neat videos over the years Steve!
A man of ability and the desire to accomplish something can do anything.
Your dry humour never ceases to make me laugh, loved the clever joke at 12:31
Also, he made a dickbutt colour blind test
the way you explained how certain waves of light is produced was far more understandable than what my high school physics class taught me, it actually kinda annoyed me how well you explained it
I'm seriously impressed by how accurate, yet accessible, this video is. The relation between light spectrum and atomic orbitals is the heart of Quantum Mechanics; it's what drove its development historically and it's where the theory makes predictions that stumped the rest of physics. It's also the foundations of just about all of chemistry, material science, and the starting point of nuclear physics. I'd so far as to say that it's the most important development in the last 200 years of physics. And this madman casually explains it in 15min in a stunningly visual way.
username checks out
@@thenonsequiturusername also checks out
@@LIamaLlama554 you better provide some llamas pronto or you'll break the chain of usernames checking out
@@QuantumHistorian Either 554 or twice 554, ideally.
(technically this post has no name)
David subscribes to the "stuff your tent into the bag" strategy over nicely folding it.
Hey Guys. @15:31 There is a set of Color blind tests.
I'm not previously had issues with color blindness, But I cant tell if one of these tests are a control or not.
From the top left to the top right. The numbers are | 45 | 2 | [Squiggly lines] | 42|
For reference if anyone is curious the bottom row from left to right is | 74 | 97 | 6 | 3 |
Is the second from the right on the top just squiggly orange, brown, and green lines for you too?
Edit: Its apparently 15:31, I missed a 1
I too saw just those three colored squiggles in the third-from-left-on-top image. I paused and looked at it sfor a while.
I also have not had issues with colorblindness. Whatever the situation, you and I are both in it.
Colour blind tests frequently come with controls, number 3 is also gibberish for me so I wouldn’t be surprised if that was the control
Slight correction: It’s actually at 15:31 (took me a while to figure that out!). I also see a bunch of squiggly lines on the top line, second from the right. It is probably a control, as others have said. Otherwise, I see
45 / 2 / squiggle / 42
74 / 97 / 6 / 3
15:31
@@DawnDavidson yeah, i do think its for a control, so people cant fully guess their way through the test. for those with normal color vision its easy to tell its squiggles, but with slight color issues they would be able to tell there is something there but could have issues seeing the full squiggles.
Small correction about the streetlights. Most lights you'll find outside use high pressure sodium, which has a CRI of about 25. What you are using here is referred to as low pressure sodium, which has a monochromatic light with a CRI of about 5.
He's going to summon the 3 witches from Hocus Pocus like that 💀
Finally someone else makes a reference.
Heh
And yet not a single person has mentioned virginity
Uncle to uncle, shouting out your nephew's yt channel is a 10/10 best uncle move. Respect.
Incredible episode Steve, one of your best yet. I’ve seen a dozen efforts at explaining the black sulfur flame over the years and none have been as clear and complete as yours. Great job.
15:23 I see what you did there 😂
Is that a- 😱
I must say, it did catch me by surprise.
Me, a colourblind person: I did not in fact see what you did there
@@TheBrettMayesit was dickbutt
@@TheBrettMayes It's Dickbutt. A pretty old meme, but a classic.
Back in the early 1980s, after I acquired my driver's licence, I ran a red light on a section of roadway lit by sodium street-lighting because I happened to approach the lights after they'd turned to amber, perfectly camouflaged amongst the sodium lights. Fortunately there were no other vehicles around as it was very early in the morning!
Bingo! Exactly the same thing happened while my brother was driving in the late 80's/early 90's, but fortunately without actually running the red light (newly installed lights on a very familiar road lit by sodium lights) since we also had my older sister in the car who called out "red light" when she realised neither of use had seen it. Stopped with the nose over the line. No cars nearby (~9pm), but easily could have been. The traffic lights were visible from over 200 metres away, but like your experience had already changed to red before they were in our view, so were lost in the sodium lights. For that reason I do not miss the sodium street lights - we are all safer from their disappearance.
I've never seen this channel before, but I have to say I love your way of explaining it. Perfect tempo, to, at least for my "it's almost 2 AM" brain.
Oh, wow, you perfectly explained something that i totally flunked at/failed at explaining years ago to others.
At the time i had known most of this, but, really struggled in expanding on this explanation, because, i struggled with condensing this information down into something bite size like this.
Awesome video.
"I'm not using any camera trickery" ... "other then this trick" ... :|
To be fair he didn't mess with the camera
@@sg5sd furthermore it looks the same in person
It’s not camera trick, it’s lighting trick
It’s a lighting trick based off of the camera’s auto balancing, i.e., a camera trick. And no, it’s not what the eye sees. The opening frame at 1 second looks like a white room with white light, and an obsidian flame, all because of auto balance. With the auto balance turned off, it would look to the eye more like frame 31 seconds, which is a lot less impressive: a yellow washed room in mono light with a tuned-out flame.
@zedex1226
but the flame isn’t inherently black either
Wow! WOW! This is instantly one of my favourite videos online. So much good stuff - told without equivocating, yet just deep enough to get what you need and then move on. I'm going to suggest this to so many people. Thank you for an interesting, broad, focused (yes) and intellectually honest work of art and exposition.
Black flame gives me PTSD ever since those damn godskins
I just saw Brainiac75's video about the sodium lamp and the CRI bit lol
The science youtubers syncing up once more.
Wasn't his bulb -44 CRI?
@@Bluelightzero Yes it was!
I noticed this as well.
I literally scrolled the comments looking for a mention of @brainiac75 and hit the comment button a few milliseconds before I saw yours!
2:14 ..... your what? haha
Tiny Tesla coil 😅😂
I thought the same thing 😂
You can also get a "light pollution filter" from an amateur astronomy shop which also blocks the sodium lines. Unfortunately it doesn't work well for the intended purposes anymore because most sodium streetlights are being replaced by white LEDs.
LEDs are pretty bad for wildlife too, even insects. Very disruptive for them.
I really liked the glow of sodium streetlights, there's some nice sides to really white leds (they make plants look magical during nighttime), but otherwise it was nice for the night to look like the night.
@@unatwomey7112 Live near a corner and have 2 out from and one to side. Can basically read a book out back garden in the middle of the night with the amount of light pollution. Terrible for just looking at the stars.
When they used sodiums they designed the shroud to reflect as much light downwards as possible. With the Leds it's like they barely bother.
this is the closest thing to black light & black lightening that i wanted to see as a kid 🖤🖤🖤🖤🖤🖤
i had a dream about it that's why i always imagined black flames
Amaterasu just fueled that more😂
black lightning
& black light 🖤
So no trick photography, just trick lighting. Got it.
one of the most beautiful sights I have seen was after a night of LSD, the earliest morning twilight above, sodium lamps below, and pure darkness of city buildings between. the differences between that single wavelength light at the bottom and the glorious full spectrum yellow-blue sky was insane
Very nicely done, good explanation of subatomic photon production (and absorption). As a theoretical concept, I had thought about "dark light", but had never seen an example of such as being demonstrated via a black flame. Of course, there are well known examples of "invisible" flames (partially a function of the flame temp, and the relative energy levels of the electron orbits), a terrifying example of which is the methanol fuel used in race cars. It has happened when a driver is being burned with a flame no one can see, but the process of being burned becomes extremely apparent.
Really enjoyed the laid back delivery (and I have a degree in chemistry so I probably wasn't learning a huge amount but the presentation was great.).
12:48 That was completely unexpected, but totally welcome, lol
15:23 ... you mother f..... 😂 You friggen got me
I thought I was the only one 😂
omg it's a dickbutt D:
I never expected to see this hieroglyph in a steve mould video
I couldn't make out wth it was supposed to be until I read this comment.
Classic reference
This video is amazing. Your casual explanation of spin to get to the why of the double lines emmiting form sodium was marvelous, I love when I get answers to questions I didn't know I have.
And I'm totally using that orbit analogy to explain this.
Thx for your content, cheers Steve
Awesome science still after so many years of youtube. Thanks Steve. I've been watching only occasionally but for long enough to have noticed we both have gotten visibly older. You've built something great here in that time. Keep up the good work teaching us new amazing science things...well, at least new concepts to me, and probably most of the viewers. Cheers to many more years to come doing what you so pasionately love to do.
16:20 super cool lad for playing gorilla tag 😎👊
That third image on the color blind test at 15:35 better be a joke or I may need to see an eye doctor
Yes
73 but its very hard to see
@@dmytrog6127 The third image on that test only shows numbers for certain color blind people. If you can read numbers there, you might want to consider visiting an eye doctor!
If it serves as a clue, the larger one slightly previous to that timestamp was a dickbutt.
It might have something to do with the monitor, but I had to copy it into a editing software and turn the contrast up almost to the maximum to see it, but it is there.
Awesome video, wish I had the setup to do this sort of thing. I'd never get anything else done!
For the enchroma glasses, I'd refer you to "Megalag", he did/is doing a deep dive series into them. Very well reseached and definitely worth the watch.
I'll second that. Excellent deep dive into the company.
We got godskin duo's Black Flame Ritual IRL before GTA 6 💀💀💀