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Re-creating Disney's sodium vapor process [video]

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Re: Re-creating Disney's sodium vapor process [video]

#101

Post by djmips »

hondo77 wrote: post #88
lqet wrote: post #62

Earlier quoted context omitted.

Yes, extremely impressive. "Mary Poppins" rightfully received an Oscar for best visual effects. I am continuously amazed at the level of innovation done at the Disney studios back when Walt Disney was still alive. Rewatching Snow White with my daughter a few months ago, I was flabbergasted by the animation quality, even when compared to animation movies made decades later. Just look at these water scenes: https://you…

It's not that they forgot how the multiplane worked. They understood it...in theory. However, they were quirky beasts and it was knowledge of those quirks that was lost. Like getting an old car to run--most people these days don't know about pumping the gas pedal to keep it running.

Pumping to start the car, to prime the carb but never heard of the keep it running part unless you been needing to keep the revs higher until it warms up? But then you don't need to pump, just hold it.

Re: Re-creating Disney's sodium vapor process [video]

#102

Post by djmips »

BoxOfRain wrote: post #75
jlarcombe wrote: post #58

Earlier quoted context omitted.

I 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...

I 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 har…

I don't have any solid evidence but I feel like the LED also disturbs sleep of people who live near street lamps. Also I found out recently that never putting an outdoor light shining upwards is somewhat less disruptive to moth navigation.

Re: Re-creating Disney's sodium vapor process [video]

#103

Post by djmips »

xemoka wrote: post #14
modeless wrote: post #10

Hmm, 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"

Neat 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 Not with a non-visible spectrum, but along the same lines. I can't seem to directly find anything with NIR though;

Thanks for digging that up!

Re: Re-creating Disney's sodium vapor process [video]

#104

Post by fnands »

speps wrote: post #98
fnands wrote: post #71

Earlier quoted context omitted.

> 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 ;-)

It's explained in the video. Keying algorithms are getting better thanks to AI image techniques. However the training data they use is based on green screen technique so has the same issues at times. Using the sodium vapor method to film training data that looks correct to start with would improve these AI algorithms.

Very cool!

Re: Re-creating Disney's sodium vapor process [video]

#105

Post by p_noumenon »

jmpman wrote: post #85
sixothree wrote: post #54

Earlier quoted context omitted.

After you using sodium vapor out a different light source?

Different frequency.

Any thoughts on whether some frequencies are superior to others for various reasons, or what strengths/weaknesses different frequencies have?

Re: Re-creating Disney's sodium vapor process [video]

#106

Post by p_noumenon »

modeless wrote: post #10

Hmm, 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"

The answer seems more to be, "people haven't really been using this magical technology in decades", so maybe they'll start coming up with innovations to it eventually, and find out whether or not near-infrared frequencies are superior or not or what the advantages/disadvantages are.

Re: Re-creating Disney's sodium vapor process [video]

#108

Post by kadoban »

astrodust wrote: post #96
kadoban wrote: post #33

Earlier quoted context omitted.

Fair. But looking at that story (very interesting btw, thanks), they did recreate it. So incentive does mean a lot when $$ is also available, which I'd suspect it is in movies.

I think the US nuclear program has a much bigger budget than Disney, and if they need something, they just get it. The movie industry had cheaper options, so they went with those.

I think you're underselling Disney's budget and reach. Yes, it's probably technically smaller than the US nuclear program, but even just Disney is worth $200 billion USD, ignoring all other studios and etc. Movies are big money.

Re: Re-creating Disney's sodium vapor process [video]

#109

Post by dylukes »

jayknight wrote: post #81
Animats wrote: post #17

It 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.

On 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?

San 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/pds2...

[2] https://www.sandiegocounty.gov/pds/docs/LightPollutionCode.p...

[3] https://www.sandiego.gov/sites/default/files/12-14-16-adopti...

[4] https://conserveturtles.org/information-sea-turtles-threats-...

Re: Re-creating Disney's sodium vapor process [video]

#110

Post by jmpman »

p_noumenon wrote: post #105
jmpman wrote: post #85

Earlier quoted context omitted.

Different frequency.

Any thoughts on whether some frequencies are superior to others for various reasons, or what strengths/weaknesses different frequencies have?

The 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.
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