10 ms·
Re-creating Disney's sodium vapor process [video]
- esafak 2y agotl,dr: Narrow-band lighting and optical filtering.
- footlose_3815 2y ago[flagged]
- astrodust 2y agoWhile I normally agree, that they went through the trouble to create an actual demonstration is worth the video click.
- CitrusFruits 2y agoThe Corridor Crew have been talking about this and trying to find a modern example for years. From what I understand, this is actually a pretty big deal to be able to re-create a technique that was lost to time. On a related note, I think this is the sort of channel that we should be encouraging and rewarding more. They do their best to make original and original content, while fairly regularly experimenting with and even pioneering new film making techniques (e.g. Anime Rock Paper Scissors). Sure they play the algorithm game, but they're not the worst offenders by any means.
- ChrisClark 2y agoHe's been trying to recreate this for years, I can understand why he's so excited to do it and that it works so perfectly.
- kibibu 2y agoThe actual cleverness was from Paul Debevec, who has done incredible things for the Vfx industry over his career.
- krasin 2y agoNormally, I would also prefer reading, but for special effects, I would rather see them on video.
- wincy 2y agoI don't know, when Nico gets excited about a project, I suspect it's genuine. It's part of why I watch the channel. His employees, (Wren especially), give off a silly fake enthusiasm vibe (or maybe he's just like that, and that's why he got hired, I don't know) but Nico only really shows up in the videos he wants to make. Guy seems like he's getting to live out his dream. The videos he spearheads are both technically impressive and time-consuming, such as Anime Rock Paper Scissors, which was a groundbreaking use of AI diffusion models a year ago, or this one.
- coayer 2y agoI've been watching these guys for so long — when Wren's speaking to camera in his solo videos he overdoes it but I think he's naturally pretty excitable. Niko is my favorite though.
- kidintech 2y agoAlthough I hold a similar view about "youtubers", please give these guys a chance; it's at best ignorant to type that instead of supporting one of the few teams/channels that are visibly passionate, hard working, and constantly putting out fantastic content.
- kadoban 2y agoVery interesting stuff. I'm curious if this means anything in terms of good vs perfect technology or what tech wins out in practice. This process seems just plain better than green-screen, so why did it lose out? Is is just that green screen is good enough? Was it too hard to do this sodium vapor process with random cameras back in the day? Are sodium vapor lights bad enough in some way that practically it lost out?
- buck746 2y agoIt lost because there were only 3 prisms made. It also required a lot more lot as running thru an optical splitter means at least half of your light was lost, it's not a big issue today. Modern cameras are insanely more sensitive than film was at the time. Alfred Hitchcock used this on "The Birds". In the YouTube video they got a great result even with a smaller studio than would have been used on Mary Poppins. The trick needed the screen as far back as you could get it to minimize the chance of spill, that used to be normal on blue screen before the software improved.
- kadoban 2y ago> It lost because there were only 3 prisms made. But it seems so much better that that shouldn't have been a blocker. Like optics isn't magic, and knowing that someone did it before should be enough incentive? Not like movies are a small or poor industry.
- cooper_ganglia 2y agoI wonder if it’s just more cost effective to use a well-established tool like green screen, and then contract out all the rotoscoping clean-up to other countries for less than minimum wage?
- kadoban 2y agoYeah maybe it's something like the person choosing the camera process doesn't directly have to deal with 12 hours of roto per day, so practically it's just not something they think about.
- pushedx 2y agoVery very cool, mindblowing actually, seems legitimately useful. There have been a few art installations over the years that use these lights: https://www.youtube.com/watch?v=hd077pa-5CI https://www.youtube.com/watch?v=hd077pa-5CI For a second I thought that the video was from this channel, which also does experimental cinematography stuff: https://www.youtube.com/watch?v=-4uzyhbDFas https://www.youtube.com/watch?v=-4uzyhbDFas
- bcraven 2y agoAfter seeing the Olafur Eliasson retrospective at the Tate Modern a few years ago I tracked down the components to build my own low pressure sodium vapour light. It's so weird, as those people say, so see things coloured... yet monochrome.
- jlarcombe 2y agoI rather miss them in the streets. It's only been, what, ten years or so since they've been replacing most of them with white LEDs round my way, but it's almost hard to remember that everything was yellow whenever you went out in the dark! Especially amazing atmosphere when it snowed...
- BoxOfRain 2y agoI really prefer the old yellow sodium light to the harsher white LEDs, I get that the SOX bulbs weren't economical to make any more for various reasons but wish we could have migrated to monochromatic yellow LEDs instead of white ones. They're not just more pleasant aesthetically, they're also better for insects and animals than broad-spectrum white lights. I don't get the obsession with making lights as cold and harsh as possible, give me warm light that makes the night look like night rather than a bad approximation of day. At least by the time they got round to doing my street they used a lower temperature white than the ultra-harsh 'prison yard white' colour used in the earlier installations.
- djmips 2y ago
- modeless 2y agoHmm, why don't people do this with near infrared? It would allow using full spectrum lighting, and would be easier to selectively filter. I'm guessing the answer is "they do, it's just uncommon and you haven't heard about it"
- xemoka 2y agoNeat little rabbit hole, thanks. It lead to Netflix's "Magenta Green Screen: Spectrally Multiplexed Alpha Matting with Deep Colorization" by Dmitriy Smirnov, Chloe LeGendre, Xueming Yu, Paul Debevec: https://arxiv.org/abs/2306.13702 https://arxiv.org/abs/2306.13702 Not with a non-visible spectrum, but along the same lines. I can't seem to directly find anything with NIR though;
- djmips 2y agoThanks for digging that up!
- largbae 2y agoDoes the magic color need to be within the frequency range that the camera and video format can record?
- modeless 2y agoMost camera sensors need a filter to block infrared light because they are sensitive to it. Remove the filter and replace it with an infrared pass filter, and you've got an infrared camera. It may not be as sensitive as in visible wavelengths but you can use brighter infrared lights to compensate if necessary. This sodium vapor process already uses two cameras so it would work the same way. It seems possible to produce a four-channel camera sensor specifically for this use case, if it was popular enough. Given how common green screen is in Hollywood I'm surprised I haven't heard of anyone doing it. Maybe Hollywood just doesn't care because they can do regular green screen and just hire someone to fix it in post.
- hollerith 2y ago
- Animats 2y agoIt looks like Redwood City's old sodium-vapor streetlights, recently replaced with LEDs. The Golden Gate Bridge also used to use such lighting. That still looks yellow, but in 1972 the original sodium-vapor lamps were replaced with ones that required a yellow filter.
- jayknight 2y agoOn a trip to San Diego, I ran to a grocery store one night, and had a hard time finding my car because of light like that, and I couldn't tell what any of the colors were. It's that still common out west?
- dylukes 2y agoSan Diego is near the Palomar Observatory and Mount Laguna observatory (see map [1]). The observatory as well as environmental concerns of bright lighting at night messing with wildlife is why San Diego in most zones at night uses what appear to be Low Pressure Sodium (LPS) lighting. See also [2] for the current code. However, over time these LPS streetlights started to be replaced by Induction lighting. And as of 2016, the new standard is LED based, which is supposedly even better for light pollution [3]. In areas where sea turtles nest, LPS lighting is still preferred, as it is very different from the white light from the moon they use to navigate [4]. One nice consequence for residents: as a result of the strict light pollution regulation, and the consistently clear skies, most nights one can see a surprisingly large number of stars in the sky for an urban city environment. Nothing close to a clear night far north or out in the desert, but still more stars than you might expect. --- You can read more about it here: [1] https://www.sandiegocounty.gov/content/dam/sdc/pds/docs/pds211.pdf https://www.sandiegocounty.gov/content/dam/sdc/pds/docs/pds2... [2] https://www.sandiegocounty.gov/pds/docs/LightPollutionCode.pdf https://www.sandiegocounty.gov/pds/docs/LightPollutionCode.p... [3] https://www.sandiego.gov/sites/default/files/12-14-16-adoption-of-street-lighting-standards-and-drawings.pdf https://www.sandiego.gov/sites/default/files/12-14-16-adopti... [4] https://conserveturtles.org/information-sea-turtles-threats-artificial-lighting/ https://conserveturtles.org/information-sea-turtles-threats-...
- 2y ago
- jmpman 2y agoI’ve been doing something similar using “cheap” Chinese band notch filters. Had no idea about this Disney process. Also using this for AI training purposes. It’s amazing what you can buy on Alibaba, fully custom frequencies.
- krasin 2y agoI would be interested in some links!
- sixothree 2y agoAfter you using sodium vapor out a different light source?
- jmpman 2y agoDifferent frequency.
- p_noumenon 2y agoAny thoughts on whether some frequencies are superior to others for various reasons, or what strengths/weaknesses different frequencies have?
- jmpman 2y agoThe frequencies I’m using are very specific to the subject I’m filming. It’s closer to a machine vision problem, and it isolates the desired object almost perfectly from the background. I’ve considered filing for a patent, it works that well.
- fnands 2y ago> Also using this for AI training purposes. Cool! Training for what? You can't just drop a juicy comment like this and then leave us hanging ;-)
- 2y ago
- jiggawatts 2y agoThe original beamsplitter cube isn't some exotic custom device that would cost tens of thousands to make. It's just a dichroic beamsplitter, which is a standard optical element available from online sellers. Variants of these are commonly sued in scientific experiments, optical devices, etc... Here's one for under $300: https://www.meetoptics.com/beamsplitters/plate/longpass-dichroic-beamsplitter/s/alluxa/p/3037 https://www.meetoptics.com/beamsplitters/plate/longpass-dich... Just search for: "589 nm beamsplitter".
- laserbeam 2y agoI can't find any that are prism shaped (in the short time I spent on the website). I don't actually know what kind of manufacturing challenges you get if you want to place these splitters at the center of a prism. However, I'd guess these are the components the guys are using between the prism and the cameras.
- rerdavies 2y agoPresumably, the exotic part of the beamsplitter is that the dichroic filter must be a bandpass filter with a very narrow passband around 596nm. Yours is a high-pass filter, which wouldn't work for this application.
- eurekin 2y agoSo, a second beamsplitter with low-pass filter wouldn't cut it?
- lightedman 2y agoNope, you need a notch filter.
- Tally 2y agoI mean, a bit more searching did seem to turn up a few notch beamsplitters near the required frequency (not quite the same frequency though) I am wondering if part of the reason that finding these at the frequency of sodium vapour lamps is partly due to those lights no longer being common. Or perhaps that those just aren't frequencies common to laser optics, which seems like the biggest market for these kinds of devices anyway. Though, I see no reason why you couldn't use a laser for this process anyway, with matching notch filter.
- Arnavion 2y agoSomewhat related: My favorite video about green screens and chroma keying, from Captain Disillusion: https://www.youtube.com/watch?v=aO3JgPUJ6iQ https://www.youtube.com/watch?v=aO3JgPUJ6iQ
- deleted 2y ago[deleted]
- slacker_news 2y agoI saw this video come up on my Youtube multiple times, but never wanted to watch it because of the clickbait title and thumbnail. But I see the title on Hacker News and was right away interested so clicked on it. I wish the title could be straightforward on Youtube.
- spdif899 2y agoCheck out this extension: https://dearrow.ajay.app/ https://dearrow.ajay.app/ Same guy that made sponsorblock; crowdsourced titles and thumbnails. Tends to have good coverage on anything reasonably popular. Also has features to reduce the clickbaitiness of videos that haven't had someone submit better titles/thumbnails.
- slacker_news 2y agoThat looks perfect for me thank you!
- sschueller 2y agoWhat I find incredible is that this was done with film without modern tools such as those light meters and a preview mask on an LCD screen. They had to do a test and then process the film for each adjustment. A extremely tedious process and that doesn't include the work that was required to produce that prism.
- stolsvik 2y agoA bit light on the detail of how the standard green-screen process works in post: I'd prefer a bit deeper dive into the problems one encounter. And then compared harder to how this became easier with the sodium lights, compare and contrast. I think that was glossed over too fast. Otherwise really interesting!
- scotty79 2y agoNarrow band amber LED would probably not be terrible for this application. Or even magenta ones with different filters.
- garaetjjte 2y agoI wondered previously how feasible would it be to manufacture digital camera sensors with modified color filter mosaic, so instead of usual Bayer RGBG you would have RGB+589nm mosaic.
- rzimbauer 2y agoThe key element here that wasn't explicitly mentioned in the video is that this would likely requre genlock to sync both cameras facing the beam splitter for this to work decently well on any moving subject. I think this is the reason they're using the Z Cam (presumably E2) cameras visible at 2:48, 3:31, 4:05, & 11:05 because that's one of the most inexpensive genlockable cameras available. This would rule out most mirrorless and prosumer video cameras unless the subject isn't moving fast or a half-frame misalignment is acceptable. Heck, a non-genlocked version of this might be preferable to weird motion blur on existing chroma keyed backgrounds. Very exciting tech
- erincollective 2y agois this what they're doing here but with polarization instead of wavelength? https://patents.google.com/patent/US20070247553A1/en https://patents.google.com/patent/US20070247553A1/en
- delfinom 2y agoYes, thankfully the patent claims are specific with polarization so the method with sodium vapor here is safe.