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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]

#11

Post by kadoban »

cooper_ganglia wrote: post #7
kadoban wrote: post #5

Earlier quoted context omitted.

> 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.

I 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?

Yeah 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.

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

#12

Post by cladopa »

kadoban wrote: post #3

Very 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?

>so why did it lose out? Is is just that green screen is good enough?

It looks that the problem was manufacturing the prism, as simple as that.

Today you can use unusual wavelength LEDs without phosphorous to do the same thing probably way cheaper.

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

#13

Post by 486sx33 »

cooper_ganglia wrote: post #7
kadoban wrote: post #5

Earlier quoted context omitted.

> 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.

I 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?

I think part of the deal is that, no amount of manual intervention will allow translucent objects (like the veil) as nicely as sodium vapor lighting , also motion blur

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

#14

Post by xemoka »

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;

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

#15

Post by largbae »

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"

Does the magic color need to be within the frequency range that the camera and video format can record?

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

#16

Post by modeless »

largbae wrote: post #15
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"

Does the magic color need to be within the frequency range that the camera and video format can record?

Most 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.

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

#17

Post by Animats »

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.

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

#19

Post by ikiris »

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"

Because you want color bands that you control, not that are naturally emitted.
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