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.
Only with a very dim sodium doped methanol (or other similarly colorless flame) saber, while battling under an EXTREMELY brightly streetlit night scene
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
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.
@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.
@ColdSnapHalo 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 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.
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.
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 RUclipsrs 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.
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 😄
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 RUclips 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.
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.
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?
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.
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.
@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)
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
I love this style of video. Rabbit holes! Tangents! Exploring further!! it’s really fun and I got so much more out of it than I was bargaining for. I teach physics and optics and spectroscopy are some of my favorite topics to geek out about, so this was a real treat. Nice work on this one.
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.
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.
1:00 well that explains why they're so much better than a green screen for chroma key work, assuming you have an appropriate optical system to make use of them
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.
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 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.
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
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.
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!
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!
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.
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.
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.
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.
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.
Steve said "You might be wondering..." EXACTLY as I was thinking just that. Somehow you knew. At 4:45 where other explanations stop...you take a 'boggled-mind' to 'ah ha'. On the way to the camera lens, the returning orange photons strike sodium atoms in the flame but scatter in random directions, leaving a net dark effect. It makes sense now!' Thanks for the thoughtful and engaging way you explain science.
@15:10 Red-Green colorblind person here if anyone’s interested. The image without encroma is normal (unsurprisingly). With encroma, it’s completely orange tinted to the point I can hardly pick out colors at all. I can see that the covers have yellow, blue and orange on them, but other than that it’s basically impossible for me to see what shades of color I’m looking at. So at least in this demonstration, encroma is making me go from mildly colorblind to pretty much completely colorblind.
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.
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.
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.
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.
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.
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.
5:12 "But the more important question is-" and I was expecting you to say "-why would you want a flame that doesn't make light?" The answer: to make a RUclips video.
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.
Some of us liked the old orange lights, the primal sense of fire beating back the night, where it's not about color but shape and location... friend or foe.
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
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.
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.
"There is no trick involved." **gets excited for cool black flames** "Actually, I lied there *is* a trick." My disappointment is immeasurable and my day is ruined. LAME.
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 RUclips 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
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.
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 RUclipsr 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.
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
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 RUclips. 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.
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
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?
I see this flame and the first thing that comes to mind is the Godskin Cult.
the god-slaying flame...
AND NOT GIANTDAD‽
@siletsocha444 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.
imagine getting your youtube channel advertised by your uncle Steve Mould, what a move!
Instructions unclear; summoned demon.
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.
"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
16:12 From one uncle to another, this is top notch uncling giving your nephew's RUclips 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.
@ColdSnapHalo 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.
it seems like there's no videos anymore tho
light sucking flames...
sounds like something that could go dark, darker yet darker.
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.
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.
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.
The Sanderson sisters are coming back with this one 🕯🔥
THEN WE NEED MORE!
Unless… 💀
I’m guessing he’s not a virgin.
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 RUclipsrs 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.
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 ruclips.net/video/UQuIVsNzqDk/video.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!
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 😂
RUclips ate my first comment lol, but I was identifying it specifically as a dickbutt.
He made Blackflame Sorceries from Dark Souls and acted like nobody would notice
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
15:07 "It's a weirdly **polarized** topic now..." * puts the sunglasses on as a the Who song starts blasting *
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 RUclips 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.
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
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
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. @LokiCentral
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
One step closer to being able to beam people with darkness.
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.
That's really cool
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.
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
I love this style of video. Rabbit holes! Tangents! Exploring further!! it’s really fun and I got so much more out of it than I was bargaining for. I teach physics and optics and spectroscopy are some of my favorite topics to geek out about, so this was a real treat. Nice work on this one.
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
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
"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 😂
bro said Chat GTP 8:56
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.
2:14 ..... your what? haha
Tiny Tesla coil 😅😂
I thought the same thing 😂
So no trick photography, just trick lighting. Got it.
1:00 well that explains why they're so much better than a green screen for chroma key work, assuming you have an appropriate optical system to make use of them
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...
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.
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.
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
@ImNova_96it was dickbutt
@ImNova_96 It's Dickbutt. A pretty old meme, but a classic.
Steve: "There's no trick"
Also Steve: Immediately show that it is a trick.
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.
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
8:57 "Chat-GTP" 😭
We got godskin duo's Black Flame Ritual IRL before GTA 6 💀💀💀
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.
12:43 made me cackle
"...there's no trick... now here's now I did the trick..."
0:40 yes BUT you gotta admit it looks pretty cool
Yoooo jajaja
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
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
12:48 That was completely unexpected, but totally welcome, lol
Bro is casting godskin incantations
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.
Your dry humour never ceases to make me laugh, loved the clever joke at 12:31
Also, he made a dickbutt colour blind test
16:20 super cool lad for playing gorilla tag 😎👊
-godskin noble has entered the chat
Maliketh walks in
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!
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!
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.
"There are no tricks"
Rest of video proceeds to explain how this is a trick.
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.
Orange is the new black, lol
When all R,G,B values are (0, 0, 0) = 🖤🖤🖤🖤
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
So it is how amaterasu look like irl
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
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.
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.
Steve said "You might be wondering..." EXACTLY as I was thinking just that. Somehow you knew. At 4:45 where other explanations stop...you take a 'boggled-mind' to 'ah ha'. On the way to the camera lens, the returning orange photons strike sodium atoms in the flame but scatter in random directions, leaving a net dark effect. It makes sense now!' Thanks for the thoughtful and engaging way you explain science.
Friede likes that.
@15:10 Red-Green colorblind person here if anyone’s interested. The image without encroma is normal (unsurprisingly). With encroma, it’s completely orange tinted to the point I can hardly pick out colors at all. I can see that the covers have yellow, blue and orange on them, but other than that it’s basically impossible for me to see what shades of color I’m looking at. So at least in this demonstration, encroma is making me go from mildly colorblind to pretty much completely colorblind.
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.
In the middle of every difficulty lies opportunity.
Great. You freed the Sanderson Sisters.
Unless…
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.
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?
"But what if it could get... darker than dark?"
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.
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.
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.
“There’s no trick here, just a filter that changes everything about the clip”
5:12 "But the more important question is-" and I was expecting you to say "-why would you want a flame that doesn't make light?" The answer: to make a RUclips video.
15:22 absolutely amazing!
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)
Some of us liked the old orange lights, the primal sense of fire beating back the night, where it's not about color but shape and location... friend or foe.
I just saw Brainiac75's video about the sodium lamp and the CRI bit lol
The science youtubers syncing up once more.
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!
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
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.
15:24. That got me laughing very hard, it's magnificent
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.
"There is no trick involved."
**gets excited for cool black flames**
"Actually, I lied there *is* a trick."
My disappointment is immeasurable and my day is ruined. LAME.
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 RUclips 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
For those non-native English speakers: it is about Natrium.
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.
2:20 Great Pink Floyd reference /s
Blackflame Friede is real.
Finally a DS3 comment after all the Elden Ring comments
A man of ability and the desire to accomplish something can do anything.