Comment by danielvf | Hacker News Reader

Comment by danielvf | Hacker News Reader

Just to add some color on this from a lighting point of view. The film lights used look like Maxibrutes[1], which are 12,000 watts of old school, non-LED power per fixture. Looks like they used six lights, so 72,000 watts.

Now in a past life, I've stood a similar distance in front of a giant, super diffuse 72,000 watt light, while wearing full body welding protective gear/goggles, and it was cooking hot right through all the leather gear.

However, this looks even worse - it looks like they are using very tight beams on those fixtures. From the photos on the ground with the lights, it looks like only three and half windows are getting lit up. That's an insane amount of power being concentrated into a small space, and yeah, I'd believe it could wreck some damage.

(Hah, just read the AAIB report[2], yes, they are indeed Maxibrutes)

[1] https://www.filmgear.net/index.php?route=product/product&pro...

[2] https://assets.publishing.service.gov.uk/media/6544b3089e05f...

Thanks for the context, that's really interesting: big numbers, wow.

Question: why not LED? Is there some quality of incandescent (I assume) bulbs which LEDs can't duplicate more cheaply? I guess so, but what would you say it is?

These lights date from the 60's, and were, and continue to be, the cheapest and most reliable possible way to throw boatloads of light at something. They are also flexible in that you can load them up with very narrow bulbs, as used here, or wide, or many choices in between.

It's hard to overemphasize just how much the film industry values reliability over everything else. These things are stupidly reliable. There's probably a big case somewhere on a truck nearby with a bunch of replacement bulbs of different zooms, and that's about the only thing that can go wrong here.

I've written the software stack for two different high-performance theatrical LEDs, and the hardware side is near rocket science to be ultra reliable and ultra performant. It's possible to get the same qualities of light out of LED's as from a tungsten bulb, but it's expensive and difficult, so most LED's lights are ether noticeably different, stupidly expensive, or both.

On the other hand, the maxi brute here costs 1/10th as much, and has been battle tested by generations of roadies.

Plus, the warm glow is nice.

> Question: why not LED? Is there some quality of incandescent (I assume) bulbs which LEDs can't duplicate more cheaply? I guess so, but what would you say it is?

I'd suspect the coverage of the light spectrum (CRI or equivalent) also plays a role.

Spectrum/shape of the spectral efficiency curve. Sure, you can get a vague color temperature match out of LED, but it's HARD to get a curve out of LED that looks at all like sunlight or like tungsten incandescents. And even the really good ones are noticeably deficient in reds. I can totally believe that if they're attempting to simulate a sunrise there's nothing like massive incandescents.

Not to diminish your valuable insight, but if they were simulating a sunrise, I doubt they had these at full throttle. My guess is they used old school lightning panels because of the orangey filament glow at lower wattages. WDYT?

Oftentimes a simulation will involve "overpowering the sun". You're not doing the lighting in the dark, you're adding light to an existing scene to simulate the sun being where you want it to be.

Day for night shooting is a similar idea - by changing color balance and adding more light to emulate the moon - it's possible to give the impression of darkness.

Even with the lights operating at half throttle, there is also a significant amount of energy in the non-visible spectrum from 6 of them focused on a small area for 5 hours. It’s amazing the acrylic windows didn’t melt, only the foam seal around them.

The window panes did melt, or at least deformed and shrunk. That's how they departed the aircraft.

The mentioned foam is on the inside of the cabin liner. The interior walls that line the actual pressure hull. The foam seals role is probably noise and vibration reduction, not pressurization.

These are almost always run full power, and if you want less light, you just flip some of the bulbs off. (You can actually see two bulbs off in the far middle fixture in the photo)

An yes, they are probably going for an orange glow inside.

I mean insolation at sea level is on the order of several hundred watts/square meter depending on your latitude and the time of day. Sunlight is very bright compared to almost every artificial light source so I'm still surprised that a window designed to bake in direct sunlight for hours was damaged by these film lights.

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