[HN Gopher] Air Accident Investigation Branch: film lights cause...
       ___________________________________________________________________
        
       Air Accident Investigation Branch: film lights caused window damage
       on A321neo
        
       Author : camtarn
       Score  : 260 points
       Date   : 2023-11-16 18:54 UTC (1 days ago)
        
 (HTM) web link (www.flightradar24.com)
 (TXT) w3m dump (www.flightradar24.com)
        
       | photoGrant wrote:
       | Duh. These lights are frightening to work around sometimes. The
       | UV alone you'll get a sunburn working inside a studio lit by
       | them.
       | 
       | The black-body radiation is the true heat coming from them
        
         | theyinwhy wrote:
         | Of course no idea what you are using, but the industry's leader
         | seems to have it figured out:
         | https://www.arri.com/en/lighting/professional-lighting-acces...
        
           | photoGrant wrote:
           | Us industry professionals that use these tools beg to differ
           | 
           | https://cml.news/g/cml-general/topic/89024886#10533
        
             | theyinwhy wrote:
             | Thank you for the link. I am pretty sure following comment
             | is more on the side of reality: https://cml.news/g/cml-
             | general/message/10540
             | 
             | But good there is awareness about using equipment with old,
             | faulty hardware and the need for measuring uv levels as
             | part of technical checks.
        
               | photoGrant wrote:
               | Think of production and rental companies like airlines.
               | Some are the safest and well respected, some are a death
               | trap. Most operate middle to right. A lot of salt has to
               | be taken with a comment like that as it's more a legal
               | response than a valid one. i.e. he worked for ARRI.
               | 
               | To clarify, ARRI can only speak on behalf of what they
               | legally aim to sell. Not what the factory reality lets
               | out the door, or what any production does with their
               | equipment. They aren't evil, just a company.
        
               | theyinwhy wrote:
               | I deem the chances Arri tinkering with their equipment to
               | circumvent legal requirements to be zero. This "every
               | company is having a big, mischievous plan" theme is very
               | boring.
        
               | jacquesm wrote:
               | That's true, but there is such a thing as component
               | variation and there is also aging. It may well be that
               | the specified product is well within the safety limits
               | but the aging border case is no longer and if there isn't
               | enough margin that may well lead to trouble.
               | 
               | Depending on the amount of variation that trouble may
               | arrive sooner rather than later.
        
               | theyinwhy wrote:
               | I totally agree uv filter fitness should be part of the
               | equipment checks happening before an extensive filming.
        
               | jacquesm wrote:
               | I wonder to what degree the UV filter coating wears
               | _because of the UV_. After all it is made to absorb
               | precisely the most energetic component, that can 't be
               | without consequences over the longer term.
        
         | atoav wrote:
         | I have worked as a light guy on well above 20 film sets, this
         | is wrong.
         | 
         | All lamps that have a fixture which would be capable of
         | emitting UV lights (mostly HMI lamps) must have UV filters in
         | front of them. Typically they are part of the fresnel lense.
         | For LED this is a non-issue.
         | 
         | If you got a sunburn in a studio, that means they either used
         | shit lamps (non-industry standard), or the filters have been
         | removed. Either way this is a work safety violation and any
         | study worth their salt wouldn't stand for it.
         | 
         | The lamps are of course still something that you need to treat
         | carefully. First because it is a ton of power and heat, but
         | also because they are heavy. But if you use them in the way
         | intended by the manufacturer they are not more dangerous than
         | anything else.
         | 
         | A typical Arri HMI will even have a diagram with safe distances
         | for heat radiation engraved somewhere on the body of the lamp.
         | So you don't even need a manual to know you are doing it wrong.
         | 
         | I once had a HMI with a broken lense through which UV radiation
         | would leak on a outdoor set. We noticed this because a fist-
         | sized pile of insects started to accumulate right at the spot
         | where the leak was. The smoke from that was quickly noticed.
        
           | photoGrant wrote:
           | https://cml.news/g/cml-general/topic/89024886#10533
           | 
           | You'd be surprised what shortcuts budgets end up creating...
           | 
           | Source: A decade+ on film/photography sets as DIT.
           | 
           | p.s. Work on macro phantom stuff. You'll see.
        
             | nashashmi wrote:
             | Both of your posts are informative. I think we go back to
             | the parent comment that implies UV radiation is a general
             | affect, versus a result of shoddy manufacturing, near these
             | lamps.
             | 
             | Is UV a standard thing to avoid at every case, or just in
             | exceptional cases?
        
               | photoGrant wrote:
               | In every case bar working with infra sensors/aesthetics.
        
             | qingcharles wrote:
             | "Sunburn": http://news.bbc.co.uk/2/hi/europe/1983679.stm
        
               | pimlottc wrote:
               | Note in this case the sunburn was caused by natural light
               | as the interview was conducted during the day outdoors.
        
         | petee wrote:
         | They aren't (edit)carbon* arc lights, they are regular 1000w
         | par bulbs, which should all have UV filtering unless its a
         | knockoff.
         | 
         | If you're too close you may get burned from the heat, but
         | actors spend hours under them and don't get tanned.
         | 
         | But yeah, 72000 watts is alot of heat to pump at an object for
         | 9 hours
        
           | photoGrant wrote:
           | Carry a UV meter and tell me they do their job!
        
             | petee wrote:
             | Sure, when I'm back to work I'll definitely try carrying
             | one. I'm not opposed to knowing for sure, though personal
             | experience has shown it never to be an issue. I've never
             | gotten burned, nor heard of anyone burned; and with the
             | intensities we run you would at minimum expect eye burns,
             | but doesn't happen even on 14hr days.
        
           | loansindi wrote:
           | "Film lights" are pretty likely to be 5kW+ arc lamps.
           | Lighting fixtures definitely include filters to keep the UV
           | out of the beam, but film still loves giant HMI fresnels.
        
             | petee wrote:
             | I should have been more specific, i had mean to say carbon
             | arc, as those were alot different that todays technology,
             | though I'm not sure about the level of UV protection
             | offered back in the 70-80s
        
               | loansindi wrote:
               | Carbon arc was definitely a whole different ball game.
               | I'd think the fixtures were filtering at least most of
               | it, or else everyone on set would have pretty much the
               | same problems as someone doing arc welding without a mask
               | and sleeves in short order.
        
       | juanse wrote:
       | I would expect that those windows be more resistant to heat
       | considering the distance they have from the engines, in case
       | something went wrong.
        
         | SketchySeaBeast wrote:
         | I imagine if the engine bursts into flames they are probably
         | going to want to land the plane anyways.
        
           | jacquesm wrote:
           | Assuming you're over land, which definitely isn't always the
           | case. You better hope the integral fire suppression system
           | works. If it doesn't you're about to have your day - and
           | possibly much more - ruined solidly.
        
             | whalesalad wrote:
             | the A350 can fly with one engine, not sure about the
             | 321neo.
        
               | jacquesm wrote:
               | Anything over water can fly with one engine out.
               | 
               | https://www.caa.co.uk/commercial-
               | industry/aircraft/operation...
               | 
               | A321 Neo LR is approved for that.
               | 
               | https://simpleflying.com/a321neo-long-range-approval/
        
               | HPsquared wrote:
               | Any twin engine can fly with one engine out. The over-
               | water part is that it can fly on one engine for a long
               | distance to get back to an airport - which tends to be
               | further away if you're flying over the ocean. Basically
               | having a bit more margin in the design for extended
               | endurance with an engine out.
        
               | jacquesm wrote:
               | > Any twin engine can fly with one engine out.
               | 
               | That generalizes to 'any plane with more than one engine
               | can fly with one engine out'.
               | 
               | > The over-water part is that it can fly on one engine
               | for a long distance to get back to an airport - which
               | tends to be further away if you're flying over the ocean.
               | 
               | That's where certification comes in: not all twin engine
               | planes are ETOPS certified.
               | 
               | > Basically having a bit more margin in the design for
               | extended endurance with an engine out.
               | 
               | Yes, and that translates into much more work than just 'a
               | bit more margin' under the hood, to get that margin you
               | also will need to take this into account during the
               | design phase of the aircraft, crew training, maintenance
               | schedule etc. Incidents under ETOPS conditions are rated
               | more severely than those in other situations.
        
               | leoedin wrote:
               | While I appreciate that modern aircraft are incredibly
               | safe, I don't think many people really appreciate what it
               | means for a flight and aircraft to be ETOPS 240 or ETOPS
               | 330 certified. That means if something happens in the
               | air, you have _4 - 5.5 hours of flying_ before you reach
               | an acceptable runway. You really are on your own.
               | 
               | Something to think about next time you're over the
               | pacific.
        
         | JumpCrisscross wrote:
         | > _more resistant to heat considering the distance they have
         | from the engines, in case something went wrong_
         | 
         | For the engine to melt a window, something has gone wrong
         | enough that this tolerance isn't material. (You'd need a lot of
         | heat. Plus enough turbulence to blow it laterally inward, but
         | not so much that it's allowed to cool. That combination
         | suggests a loss of power and a low-speed, _i.e._ low-altitude,
         | stall.)
        
           | trelane wrote:
           | Even more than that.
           | 
           | From the article: "They located the source of the noise as a
           | dislodged window pane aft of the over wing exit."
           | 
           | The engines are under the wing; the affected seals were over
           | it.
           | 
           | If you're melting the window panes in this scenario from the
           | engines, you're having a really, _really_ bad day. Plus, the
           | noise increase from a missing window pant would likely be the
           | smallest of the warning signs.
        
         | MadnessASAP wrote:
         | Failures, particularly fires, around the engines and wings are
         | either dealt with in minutes[1] or the state of the window
         | becomes no longer relevant.
         | 
         | [1] The complete list of options are typically starvation,
         | suppression, evacuation. Apply in that order and do so quickly.
        
           | jacquesm wrote:
           | Shouldn't there be an emergency landing somewhere in the
           | middle there?
        
             | ceejayoz wrote:
             | Landing is just a necessary part of the evacuation step.
        
               | mulmen wrote:
               | It's definitely not necessary. Parachutes exist.
        
               | ceejayoz wrote:
               | I think it's pretty clear the context is commercial air
               | travel here.
               | 
               | "Starvation, suppression, and evacuation" needs neither
               | "emergency landing" nor "don a parachute" to be added to
               | it to be understandable. Both are just prerequisite steps
               | to the "evacuation" mitigation.
        
               | jacquesm wrote:
               | Well, in a military context 'evacuation' might be 'pull
               | the eject lever', but in a commercial aircraft the
               | landing bit isn't optional because there are no ejection
               | seats and there isn't a way to exit the plane other than
               | after getting it on the ground (or the water) in one way
               | or another.
               | 
               | That prerequisite step may never be completed, due to the
               | aircraft being destroyed before it can be evacuated.
        
             | MadnessASAP wrote:
             | There are incredibly rare exceptions but almost universally
             | a uncontrolled fire on a aircraft in flight is not a
             | survivable experience. I had a tremendous fear of flying in
             | my younger years. I dealt with it through exposure and
             | becoming a technician in the air force. Fire is the only
             | thing that brings that fear back. Aircraft commonly survive
             | (land) incredibly violent stresses, partial structural
             | failures, widespread system failures, and explosions. They
             | do not survive persistent fires.
             | 
             | So no, if there is a fire, those 3 steps are your options
             | regardless of the aircraft's location or altitude.
        
               | jacquesm wrote:
               | To quote George Carlin: "The safety lecture continues...
               | "In the unlikely event of a water landing..." ... ...
               | well what exactly is... a water landing? Am I mistaken or
               | does this sound somewhat similar to CRASHING INTO THE
               | OCEAN?!!! "...your seat cushion can be used as a
               | floatation device." Well imagine that: my seat cushion...
               | just what I need... to float around the North Atlantic
               | for several days, clinging to a pillow full of beer
               | farts!"
               | 
               | Interesting reversal: in my younger years I flew all over
               | the planet, I can't even begin to estimate on how many
               | flights I've been. And then, a couple of really bad
               | flights in succession and I actually find it very
               | difficult to contemplate flying again even if I know that
               | statistically it's pretty safe and I'm exaggerating.
               | Rationality only goes so far, apparently if you scare the
               | lizard good a couple of times he remembers.
        
               | marcosdumay wrote:
               | I wonder how many terrestrial planes ever landed on water
               | leaving at least one survivor.
               | 
               | There is that one case that made the news worldwide for
               | months because of how hard it is... and I never heard
               | about any other one.
        
               | jacquesm wrote:
               | Many, actually:
               | 
               | https://en.wikipedia.org/wiki/Water_landing
        
               | marcosdumay wrote:
               | Oh, cool. If I counted that right, there has been 4
               | unplanned landings by large planes, and a bit more than
               | that of planed landings. But smaller (and slower) planes
               | do that all the time.
               | 
               | The part about smaller planes makes a lot of sense.
        
               | MadnessASAP wrote:
               | For me the cure came from the sense of control provided
               | by knowing everything that was going on the plane. All
               | the sounds, sensations, and movements I put a what and
               | why too. That and the literal control I get from being
               | one of the people responsible for keeping that pile of
               | parts in the air. It's some small comfort to think that
               | if I'm ever in an crash, I could've done something about
               | it rather then having died through no fault or inaction
               | of my own.
               | 
               | Also it gives me something to do other then sitting in an
               | airport terminal because the plane is delayed due to
               | maintenance issues.
        
               | jacquesm wrote:
               | Yes, I can see how that would give you a better feeling.
               | But I don't have your expertise so for me it feels like
               | I'm giving over control over my life to people who
               | presumably know what they are doing. Which is fine as
               | long as that picture gets reinforced but it breaks when
               | you get evidence to the contrary.
        
               | MadnessASAP wrote:
               | I don't know if this will make you feel better or worse,
               | but it's come rather apparent these days that the person
               | in row 0,regardless of their skill, is pretty much the
               | least reliable part of the system.
               | 
               | Except for the toaster, the bloody toaster is always
               | acting up.
        
               | krisoft wrote:
               | > what exactly is... a water landing? Am I mistaken or
               | does this sound somewhat similar to CRASHING INTO THE
               | OCEAN
               | 
               | What a silly thing to say. First of all not all water is
               | ocean. Second the speeds and forces involved in a landing
               | and in a crashing are very different.
               | 
               | Here is how an aftermath of a water landing looks like:
               | https://youtu.be/x02cA6eamq0?si=-dQsJm353WySpv0Z
               | 
               | As you can see the airplane is designed to float.
        
             | ssnistfajen wrote:
             | If an emergency landing was achieved it would imply the
             | engine/wing fire was in a containable state.
        
           | Terr_ wrote:
           | > or else the state of the window becomes no longer relevant.
           | 
           | I appreciate this, er, implicit understatement.
        
             | qeternity wrote:
             | Rapid unscheduled disassembly.
        
         | whalesalad wrote:
         | the engines don't put out a lot of radiant heat, especially at
         | altitude where it is -50 outside. the lights on the other hand
         | are putting out a metric fuck ton of heat directly at the
         | illuminated area.
         | 
         | heat from an engine is directed straight out the back by nature
         | of the turbines.
         | 
         | modern engines are also what are called "high bypass ratio"
         | engines, where the outer ring of the engine (closest to the
         | cladding) is really just air flowing by. the combustion area is
         | smaller, in the center.
        
         | strangattractor wrote:
         | I as thinking how hot it gets sitting on a tarmac in Saudi
         | Arabia or Tucson in the summer. A nice BLACK painted fuselage
         | seems like a really bad idea. Just a thought.
        
         | kayfox wrote:
         | > considering the distance they have from the engines
         | 
         | The engines are under the wing, the windows are above the wing,
         | they are not very close to the windows at all.
        
         | chankstein38 wrote:
         | I was thinking this too... What if something caught fire in the
         | aircraft during flight? I assume they land regardless but it
         | goes from "Get the fire extinguisher and put it out" to "DO IT
         | BEFORE THE WINDOWS MELT OFF!"
        
         | ssnistfajen wrote:
         | The primary objective would be to prevent engines from creating
         | those unexpected excessive heat events in the first place.
        
         | nomel wrote:
         | With an engine fire, at speed, the vast majority of the heat
         | will be from the flame, in the air, traveling backwards at
         | hundreds of miles per hour. This leaves the radiant heat. At
         | speed, the radiant heat, from a fuel fire, has no hope of
         | overcoming the many hundred mph wind that is scrubbing along
         | the window, cooling it off.
        
       | GlenTheMachine wrote:
       | My research group used to use a Hollywood spotlight to simulate
       | the lighting in orbit. These lights take a long time to power
       | cycle, so once they're on you kind of want to keep them on,
       | otherwise it's 15-30 minutes once you turn them off before they
       | fully power up again.
       | 
       | So we left it on. After one test we left it pointed at our test
       | article, which was made of styrofoam. After a couple of minutes
       | it started smoking and melting. If we hadn't smelled the smoke
       | I'm certain it would have caught on fire.
       | 
       | We made very sure we never left it pointed at a fire sprinkler
       | after that.
        
         | cge wrote:
         | >We made very sure we never left it pointed at a fire sprinkler
         | after that.
         | 
         | The one time we had an inadvertent discharge of a fire
         | sprinkler in the historic building we're in was when a film
         | crew had a light positioned too close to one. It was not close
         | enough that someone without specific experience looking at it
         | would have thought it was too close. The light wasn't even a
         | high-powered outdoor film spotlight; it was for an indoor
         | shoot. Film lights can just be _very_ bright, and _very_ hot.
        
           | LeifCarrotson wrote:
           | Since it's that time of year again for my fellow northerners
           | with SAD, film lights can be wonderfully bright, and the heat
           | is a welcome side benefit!
           | 
           | Screw Verilux with their overpriced "10,000 lux" 10W panel
           | (only at less than 6 inches from your face), instead get a
           | high-CRI studio light over my reading chair and I'll be happy
           | all winter.
        
             | tjoff wrote:
             | I'm intrigued, any recommendations?
        
               | LeifCarrotson wrote:
               | I am currently using a Fovitec Bicolor 650 LED panel - it
               | was cheap and I am cheap. I replaced the power supply
               | with a higher-wattage unit because it flickered at max
               | power, that might be enough to make me not recommend it
               | but it works for me.
               | 
               | I previously used some adhesive LED strip lights on a
               | 24x24 plate of aluminum. If DIY electronics are your
               | aesthetic, go for it!
               | 
               | See also these posts:
               | 
               | https://meaningness.com/sad-light-led-lux
               | 
               | https://meaningness.com/sad-light-lumens
               | 
               | for a much more detailed writeup (no affiliation).
        
               | alright2565 wrote:
               | I personally use a 28600lm, 2ft, 220W linear bay light
               | from superbrightleds.com for $130. The CRI is only 80+,
               | but I personally don't think I can tell the difference.
               | Like the other poster, I am cheap, but like actually
               | cheap in that I made a spreadsheet to get the greatest
               | lumens/$.
               | 
               | I wouldn't suggest going brighter though, 30klm is
               | already bright enough I can't look at the light directly
               | and need to bounce it off the walls for comfort. The cat
               | doesn't seem to mind though:
               | https://i.imgur.com/aTegmqR.mp4
        
               | Scene_Cast2 wrote:
               | I use a 600W Godox M600BI, it's great.
               | 
               | I found that 200-300W is about the optimum from a dollars
               | per high quality lumen perspective. The SmallRig COB
               | lights are great if you can get them at a discount.
        
             | phyzome wrote:
             | Sounds more like a "you'll be warm for the rest of your
             | life" situation. :-P
        
               | ReactiveJelly wrote:
               | Just copy whatever train operators use as a deadman's
               | switch, so the light turns off if you don't squeeze a
               | handle very minute or something lol
        
             | conradev wrote:
             | Film lights are fantastic for emulating daylight.
             | 
             | I got two of these, $350, but they're fantastic and I use
             | them in place of my crappy ceiling lights:
             | 
             | https://www.bhphotovideo.com/c/product/1753990-REG/amaran_a
             | p...
        
               | KennyBlanken wrote:
               | Or you can just buy 490nm LED bulbs, which is the
               | wavelength the photoreceptors in the eye related to
               | circadian rhythms are most sensitive to. Just be aware
               | that they should be off to the sides and ideally
               | indirect, because concentrated blue light is actually
               | hazardous to the eye.
               | 
               | One can also buy a couple of bright, high-CRI LED bulbs
               | for one's existing lights and save themselves about $650,
               | because the difference between those and the studio
               | lights is typically red spectrum coverage, which is not
               | relevant for circadian rhythm / SAD treatment. The
               | film/TV LED lights are also designed to have a really
               | smooth spectrum, minimizing gaps. If you want to do
               | that...fine, but please don't advise people to waste lots
               | of money on something completely unnecessary.
               | 
               | I assure you, a double-height high-CRI LED strip running
               | along the edges of the room will throw a _fuckton_ of
               | light without the issues caused by having two very
               | intense point sources, namely shadows and glare.
               | 
               | There's almost never a problem with too much blue light
               | in the high CRI bulbs (in fact, the people doing the
               | spectrograms are usually looking for bulbs _without_ the
               | high blue spectrum spikes, and many people are looking
               | for bulbs without the blue spikes (and they 're hard to
               | find!)
        
               | conradev wrote:
               | Yeah - to be clear, I am not doing it for any particular
               | element of physical health or circadian rhythm, I am just
               | trying to emulate sunlight for aesthetic reasons (yum,
               | red spectrum coverage)
               | 
               | Smart bulbs sacrifice on light quality for color and dumb
               | bulbs can't adjust color temperature (even dumbly!).
               | Studio lighting is expensive but has both.
               | 
               | I love the idea of a high-CRI LED strip, because, yeah,
               | an intense point source is really not ideal to light a
               | room. But the strip would need to be bi-color, but such a
               | thing probably exists. I just moved and I have zero
               | ceiling sockets, so A19 is dead to me :(
        
             | jvm___ wrote:
             | I have two of the crappy 10,000 lux ones that I potato chip
             | chip to stay on top of my monitors in my home office.
        
               | yjftsjthsd-h wrote:
               | > that I potato chip chip to stay on top of my monitors
               | 
               | What does that mean?
        
               | potatochipclip wrote:
               | Presumably they mean a potato chip clip. The kind of V
               | shaped clip that one uses to close a bag of potato chips.
               | A fancy clothespin.
        
               | 6LLvveMx2koXfwn wrote:
               | A Bulldog Clip[1]?
               | 
               | 1. https://en.wikipedia.org/wiki/Bulldog_clip
        
             | brnt wrote:
             | Dont forget the small power plant you will now neef!
        
           | quickthrowman wrote:
           | > The one time we had an inadvertent discharge of a fire
           | sprinkler in the historic building we're in
           | 
           | Ouch, hopefully the film production company had liability
           | insurance! It's easy to rack up six figures of damage by
           | setting off fire sprinkler.
        
             | wkat4242 wrote:
             | It's usually not like in the movies that when one sprinkler
             | goes off, the entire building is getting a shower. That's
             | only for high risk installations.
             | 
             | Usually it's just one in the fire area, they trigger with a
             | heat sensitive capsule that breaks.
        
               | burnished wrote:
               | Do apartment buildings count as high risk? Genuine
               | question
               | 
               | Anyway if I remember my highrise fire safety training
               | right there is at least one building where on sprinkler
               | going off sets the others off. IIRC the pressure drop
               | from one unit activating triggered a pump and the
               | subsequent increase in pressure popped the other.
        
               | wkat4242 wrote:
               | No they don't. Only industrial places like storage of
               | flammables or high-dust that can cause explosions.
               | 
               | Of course it would be quite annoying to have your
               | apartment flooded because one of the neighbours let their
               | pizza burn :P
        
               | burnished wrote:
               | Cool, thank you for clarifying!
               | 
               | A burning pizza just kicks off the fire alarm, not the
               | sprinklers. Frankly I don't remember much past the the
               | whole drop in pressure detection leading to kickoff of
               | other sprinklers thing to suggest what level of
               | partitioning occurred .
        
           | burnished wrote:
           | How close/far we talking? Could you have touched the
           | sprinkler and the light at the same time (if you ignore
           | height difference related difficulties)?
        
             | KennyBlanken wrote:
             | Sprinkler vials are designed to break at temperatures as
             | low as 135 degrees. Air temperature plus radiated heat
             | could easily hit that even if the light is fairly far below
             | the head.
        
               | GlenTheMachine wrote:
               | There is no doubt in my mind that the light we used could
               | have set off the sprinklers from at least fifty feet.
               | 
               | I don't know off the top of my head the amp rating, but I
               | know we had to have the room electric supply upgraded
               | (and this was already a well equipped robotics lab - it
               | isn't like the electric supply was bad to begin with).
               | 
               | The light itself was about three feet in diameter, four
               | feet long, and, like, 200 pounds. It was a big old hunk
               | of photon-generating madness.
        
               | burnished wrote:
               | Yeah, I have a physical sense for how hot lights are, but
               | I don't have a physical sense for what 'surprising
               | proximity to a sprinkler' is and I'm trying to borrow
               | theirs to sate my curiosity.
        
         | nashashmi wrote:
         | What do you think about this? Is this what may have happened?
         | 
         | >I'm really surprised lights used to simulate sunrise placed
         | 20-30ft away could completely melt the foam holding the
         | exterior windows in place.
         | 
         | https://news.ycombinator.com/item?id=38221699
        
           | GlenTheMachine wrote:
           | I am absolutely not surprised, this should be a completely
           | expected outcome if you've ever worked with film lights. For
           | reference our light was probably more like 40-50 feet away
           | from our test article.
           | 
           | We loaned it to some NASA colleagues once, but their safety
           | manager refused to allow it in the building. At all.
        
         | CodeWriter23 wrote:
         | A school I was working out rented out as a location. The
         | lighting crew followed their standard protocols, power all
         | lights with the generator so when the Location Manager orders
         | the power down they know the lights are off. The wardrobe crew
         | on the other hand decided to move one of the lights for their
         | convenience and plugged it into the building power supply.
         | Someone else had moved a garment rack into range of the light.
         | 
         | About 3am the fire alarm went off. One of the elderly nuns was
         | sleeping in her room on the top level of the building, was
         | carried out by a firefighter.
         | 
         | The school was a converted English Tutor Mansion, had a grand
         | entrance with hand carved mahogany everywhere. The film company
         | hired a crew of like 30 cleaners that were scrubbing the smoke
         | out of the carvings with toothbrushes.
        
           | lobf wrote:
           | This is why film electricians are very strict about nobody
           | besides them plugging / unplugging anything. The best boy or
           | genny operator is always balancing loads and tracking power
           | usage, especially when house power is in play.
        
           | seabass-labrax wrote:
           | Would you mind specifying which school this was? I'm curious
           | because of your description (presumably that is English
           | _Tudor_ Mansion) of the architecture.
        
             | pcthrowaway wrote:
             | > presumably that is English Tudor Mansion
             | 
             | Although it's fairly common for schools to have tutors as
             | well
        
               | foobar1962 wrote:
               | But not common for english tutors to have mansions.
        
             | CodeWriter23 wrote:
             | Yeah, no.
        
               | seabass-labrax wrote:
               | Right'o! A relative of mine whose school was formerly an
               | English Tudor mansion related to me a fire he witnessed,
               | and it occurred to me that it would not be impossible for
               | this to be the same event.
        
           | rkangel wrote:
           | Why is it always the wardrobe department? Years ago I worked
           | as local crew at The Mayflower in Southampton (UK). We had to
           | evacuate during the show one night because wardrobe had a
           | toaster they weren't meant to have, and managed to set fire
           | to some costumes.
           | 
           | I was quite impressed the with the evacuation procedures -
           | almost 3000 people outside in under 3 minutes!
        
         | ekianjo wrote:
         | > which was made of styrofoam.
         | 
         | styrofoam melts super easily so not sure that says much
        
         | ibejoeb wrote:
         | Was it an old arc lamp?
        
           | pbjtime wrote:
           | NO!
           | 
           | It was a brand new arc lamp.
        
       | ironmagma wrote:
       | Did they at least get some good footage out of it?
        
       | codedokode wrote:
       | I don't understand, if those lights are so powerful then how do
       | actors survive under their light?
        
         | buildbot wrote:
         | Humans are actively cooled, and I think these lights were much
         | higher power and much closer than typical film lights are to
         | actors.
        
         | dmitrygr wrote:
         | Your cells will multiply to heal damage. Most polymers will
         | just crumble.
        
         | tjohns wrote:
         | First, stage lighting is already uncomfortably hot for anyone
         | working under them for any length of time.
         | 
         | Second, these weren't ordinary stage lights. These were lights
         | for use outdoors to simulate natural sunlight, which is much
         | brighter (and hotter) than what you'd normally use indoors.
         | 
         | Third, they were probably positioned too close, and left on for
         | too long. Just a guess on this one.
        
           | wkat4242 wrote:
           | Still, if they are sunlight stimulators, wouldn't that mean
           | that the heat from real sunlight could cause this also? These
           | lights were too far for air heating to be an issue. So it
           | must have been all IR.
           | 
           | Maybe this kind of foam isn't entirely up to the spec either.
        
             | WalterBright wrote:
             | When I lived in Arizona, one quickly learned not to leave
             | vinyl records near the car windows! Or crayons.
        
               | wkat4242 wrote:
               | Yes my ex' glasses broke on their own while lying on the
               | dash in Australian summer. I still have them lol
        
         | hengheng wrote:
         | There's a minimum distance of like 10-30ft with these lights.
         | They're also uncomfortably warm, prompting humans to leave
         | after a while but not airplanes.
        
           | rosywoozlechan wrote:
           | Can LEDs be used to create the same brightness without the
           | heat?
        
             | ceejayoz wrote:
             | If you're filming at high frame rates the flickering might
             | become apparent.
        
               | gpm wrote:
               | So feed them with DC current? It's not like we're talking
               | consumer lightbulbs that need to convert AC to DC as
               | cheaply as possible to stay competitive.
        
               | Scoundreller wrote:
               | It's possible, but I'm thinking a lot of constant-current
               | devices will have some ripple in their output, even if
               | smoothened. Human eye won't see it, but high frame rate
               | camera might capture at just the wrong rate to see it.
               | 
               | It's an surmountable problem, but can be expensive if it
               | doesn't need to be overcome often.
               | 
               | (All speculation on my part)
        
               | mrob wrote:
               | Follow your switching regulator or rectifier with some
               | analog filtering, then a linear regulator to convert the
               | remaining ripple to heat. It doesn't have to be very
               | expensive, and only loses a little efficiency. I have LED
               | light bulbs that work like this.
        
               | mlyle wrote:
               | > then a linear regulator to convert the remaining ripple
               | to heat.
               | 
               | I've become much less of a fan of the "switchilinear"
               | approach. The control loop of a linear regulator isn't
               | fast enough to respond to fast switching frequencies; the
               | regulator is effectively just a resistor in a filter
               | network at that point.
               | 
               | Even if your switching frequency is in the regulator's
               | loop bandwidth, the loop's gain at that frequency is
               | almost certainly very low.
        
               | codedokode wrote:
               | Ususally they use PWM for controlling the brightness
               | because LEDs change their spectrum with voltage change
               | and this is undesirable. That's why PWM is used in laptop
               | and smartphone screens.
        
               | mlyle wrote:
               | You can filter that to be as small as you'd like. Also,
               | it can intrinsically matter much less; if you're
               | switching at, say, 1MHz (which can be desirable for
               | smaller inductors), you're talking about thousands of
               | cycles of ripple in each frame.
               | 
               | Assuming you're using a global shutter camera: even if
               | the ripple is completely unfiltered, the only remaining
               | intensity effect would be that some frames get 8000
               | "blinks" in a frame and some get 8001.
               | 
               | Already, stage and film lighting is a relatively small
               | market compared to the entire lighting market, but it's
               | not so small that NRE can't be spread across a lot of
               | units.
        
               | itishappy wrote:
               | Incandescent suffers the same issues if run off mains. I
               | think the filament itself has a bit of a filtering effect
               | (it takes time to heat and cool), but for sensitive film
               | work I assume you'll need power conditioning either way.
        
               | mlyle wrote:
               | > I think the filament itself has a bit of a filtering
               | effect (it takes time to heat and cool),
               | 
               | I believe the time constant for most small lamps is 30ms
               | and longer for bigger lamps. 1 / (2 * pi * 30ms) is 5Hz,
               | so 120 Hz will be about 30 dB down. This is probably just
               | barely big enough to matter.
        
               | Filligree wrote:
               | These ones, apparently, take fifteen minutes.
               | 
               | I wonder what the filament looks like.
        
               | mlyle wrote:
               | Lights that take a long time to warm up are more about
               | establishing an arc or gas temperature for full
               | operation. They still respond to power fluctuations more
               | quickly than the time it takes them to warm up.
               | 
               | E.g. I have both fluorescent and HID lamps with this
               | characteristic; they take a couple minutes to reach full
               | brightness, but still will dim when a big load kicks on
               | and turn off immediately when I flip the switch.
        
               | saalweachter wrote:
               | I feel like the film industry is big enough you should be
               | able to engineer and market a special, non-flickering,
               | tuned spectrum LED light that produces 80-90% less heat,
               | and as long as the TCO isn't like an order of magnitude
               | higher, you'd have a gangbuster success.
        
               | KennyBlanken wrote:
               | High CRI, tunable color balance and temperature LED
               | lights are very widespread in tv/movie/commercial shoots
               | and have been for years...
        
               | codedokode wrote:
               | LED lights can be made small, flat and portable which is
               | good for TV (e.g. for news reporting).
        
               | saalweachter wrote:
               | Do you happen to know if the lights everyone tells
               | stories about -- both this news article, and other
               | anecdotes -- are already LEDs, and still absurdly hot,
               | because more light is better?
        
               | kuschku wrote:
               | The LEDs only reach up to 800W in the case of the
               | SkyPanelX, while regular halogen lamps are still needed
               | for more focused, higher brightness lights (which go up
               | to 18kW per lamp(!))
        
               | saalweachter wrote:
               | Yeah, even with the 4:1 lumen:watt advantage for LED
               | bulbs, that's still a nearly 6x brightness advantage for
               | halogen.
               | 
               | Is the limiting factor the technology to make a 4500W LED
               | bulb in the same form-factor/focus as the 18kW halogen,
               | or does it just become prohibitively expensive to do so?
        
               | kuschku wrote:
               | LEDs produce 80% less heat, but they also fail at much
               | lower temperatures. Which is the major limiting factor
               | for LED brightness today, as the cooling solutions get
               | larger and more esoteric the more power you concentrate
               | in an area.
        
               | zamadatix wrote:
               | Flicker isn't inherent to LED lights rather it's inherent
               | to being particularly cheap when making them. Even just
               | good consumer LED lights will have an extremely constant
               | output.
        
               | kube-system wrote:
               | I don't think it's that, I think the primary reason is
               | color:
               | 
               | https://en.wikipedia.org/wiki/Color_rendering_index#Film_
               | and...
        
             | filterfiber wrote:
             | The light spectrum from LEDs is undesirable.
             | 
             | But otherwise yes they would be less hot.
        
               | codedokode wrote:
               | LED lights (small, flat, square panels with LEDs) are
               | used in filming for TV.
        
             | itishappy wrote:
             | Without heat? No. With less heat? Yes.
             | 
             | Light is energy, and filming requires a lot of light, so
             | there's always going to be significant visible energy
             | available to heat things up. (Unless you're filming a
             | mirror, but in that case why are you illuminating it?)
             | 
             | Incandescent lights emit a lot of invisible energy in the
             | form of infrared radiation, while LEDs are designed to emit
             | most of their energy in the visible spectrum. This means
             | LEDs need less energy to produce the same visual effect,
             | and therefore impart less heat. Another option is to slap a
             | "hot mirror" or "cold mirror" (like the one from the
             | dentist's office) in front of your lights that separates
             | the visible from IR.
             | 
             | https://ogc-jp.com/en/wp-content/uploads/2017/08/cat12.jpg
             | 
             | https://www.edmundoptics.com/c/hot-cold-mirrors/989/
        
               | hex4def6 wrote:
               | I wonder why they don't use hot / cold mirrors to
               | separate the visible light from the IR. You could bounce
               | the IR energy (upwards(?) or into a heatsink) so that the
               | scene isn't as intensely heated.
        
               | KennyBlanken wrote:
               | There are in fact theater lights at least as early as the
               | 90's with cold mirrors to direct IR to a heatsink, to
               | extend the life of gobos and gels, and put less IR on
               | actors.
               | 
               | Cold mirrors that large are expensive and it's just
               | complexity/something to break or need servicing
               | (cleaning) so I doubt they were stocked much by rental
               | companies or saw much usage in tv/movie production.
        
               | jacquesm wrote:
               | It's hard to get the same effect with LED though due to
               | spectral differences.
        
           | TaylorAlexander wrote:
           | There's that old saying: place a fire under an airplane and
           | it will quickly move itself away. Slowly heat it with film
           | lights and it will stay there until its seals melt. I am
           | surprised the flight crew didn't remember this common saying!
        
             | scyzoryk_xyz wrote:
             | Give a flight crew film lights and they will scare the
             | plane away, but teach them how to light for film and they
             | will fly that plane for a lifetime.
        
         | reactordev wrote:
         | I've explained this before but I'll chime in here and explain
         | it again. Spotlights like these used for filming get hot
         | (temperature wise) as well as having the ability to focus the
         | beam. The lights heat will fall off but a focused beam will
         | retain more of its energy. Now, some movie makeup has built in
         | SPF. Stage makeup definitely has some. On stage, you'll often
         | see fans blowing to keep people cool or they will use
         | _diffused_ lighting and not spotlights which don't generate so
         | much heat.
         | 
         | Spotlights like these though, you might as well be holding a
         | giant magnifying glass. The beam is culminated and will cook
         | whatever it's pointing at. _Will it cook a human?_ Yes if you
         | stand there, still, for long enough. You will definitely get
         | sun burned. If you get within 10 feet it will feel like your
         | standing in an oven. Within 5 feet and your skin could boil.
        
           | LeifCarrotson wrote:
           | It culminates in cooking the human. A laser beam is
           | collimated, a spotlight only approximately so.
        
         | jacquesm wrote:
         | I've been on a couple of film sets and when those big lights
         | are on you better not be caught unprepared especially not when
         | they are focused. The lights are usually kept running between
         | takes (and during shorter breaks) and you will definitely
         | realize you are 'in the beam' when you walk across the set.
         | Another commenter here mentions UV protection built into make-
         | up, I wasn't aware of that but it makes good sense.
         | 
         | One thing I learned while webcasting Yves St. Laurent's fashion
         | show in the mid 90's is that the flowers wilt within minutes of
         | being placed due to all of the heat from the lights. So the way
         | they dealt with that is that backstage there is an absolutely
         | enormous amount of flowers ready to be deployed and they just
         | cycle through flower arrangements continuously for the duration
         | of the show so that the flowers are always fresh. It's tens of
         | people walking to and fro without pause.
        
           | js2 wrote:
           | > Loy wrote that the biggest problem during shooting was the
           | climactic dinner party scene in which Nick reveals the
           | killer. Powell complained that he had too many lines to learn
           | and could barely decipher the complicated plot he was
           | unraveling. It was the one scene when several retakes were
           | necessary, which brought up an entirely new problem. The
           | script called for oysters to be served to the dinner guests
           | and, in take after take, the same plate of oysters was
           | brought out under the hot lights. Loy recalled that "they
           | began to putrefy. By the time we finished that scene, nobody
           | ever wanted to see another oyster".
           | 
           | https://en.wikipedia.org/wiki/The_Thin_Man_(film)#Filming
           | 
           | (Great movie BTW!)
        
             | jacquesm wrote:
             | That's why food photography is an art form. Often the
             | actual food is substituted by something that is more
             | resistant to the thermal onslaught of the lighting but that
             | looks identical.
             | 
             | As to the number of takes and food: one particular set I
             | recall was for a cookie brand, they did endless re-takes
             | and the actress that had to eat the cookies started to get
             | sick enough to vomit. We were all pretty happy when the
             | director was finally satisfied with what must have been his
             | masterpiece.
        
               | codedokode wrote:
               | So the cookies were not as great as advertised?
        
               | pgeorgi wrote:
               | It is the dose that makes the poison...
        
       | gnabgib wrote:
       | Previously: "Missing windows discovered on U.S.-bound plane after
       | departing London" [0] (125 points, 91 comments, 6 days ago)
       | 
       | [0]: https://news.ycombinator.com/item?id=38221121
        
       | LASR wrote:
       | So basically, this could have been a serious incident if they
       | used a lower power light that did not cause the window to fail so
       | obviously. I bet with a full pressure differential at cruising
       | alt, this might have blown up catastrophically.
       | 
       | Quite scary what kinds of causes trigger such incidents. As a
       | frequent flier, I would have never imagined something like this.
       | 
       | How are there no regulations that should have prevented or caught
       | this? I bet there will be now.
        
         | jacquesm wrote:
         | Since it has happened before I don't think there will be any
         | such regulations.
        
         | buildsjets wrote:
         | Aircraft fuselages are not balloons, and they do not
         | catastrophically pop if the fuselage is punctured in discrete
         | locations. Relevant recommended viewing is "operation
         | guillotine fuselage test" on YouTube, where large steel blades
         | are dropped through pressurized aircraft fuselage sections to
         | validate no explosive decompression. In the late 1950s, BTW.
         | 
         | Commercial aircraft are required to be designed to maintain
         | 15,000 foot equivalent cabin altitude after any probable
         | failure, which includes multiple missing windows, per the
         | requirements of 14 CFR 25.841 and it's EASA equivalent.
         | 
         | There is already regulation in place that should have caught
         | this but did not. The captain is required to perform an
         | external visual inspection of the aircraft before departure,
         | which follows a checklist that includes looking at the windows.
         | It appears that did not happen.
        
           | scarby2 wrote:
           | > There is already regulation in place that should have
           | caught this but did not. The captain is required to perform
           | an external visual inspection of the aircraft before
           | departure, which follows a checklist that includes looking at
           | the windows. It appears that did not happen.
           | 
           | We've no idea if the damage was visible prior to takeoff. It
           | may have easily passed a visual inspection on the ground
           | before moving at speed with a pressure differential. As per
           | the article at least one of them appears to have detached in
           | flight and struck the horizontal stabilizer.
        
           | wkipling wrote:
           | The walk around is not required to be done by the captain.
           | It's not a checklist but a visual inspection of the aircraft
           | as per the FCOM.
           | 
           | Also the engineer who signed off the aircraft will do a walk
           | around.
           | 
           | The location of these windows might have made it hard to spot
           | the damage.
        
         | nomel wrote:
         | > How are there no regulations that should have prevented or
         | caught this? I bet there will be now.
         | 
         | I would think a pressure check would be _trivial_. I would also
         | assume a visual inspection is part of takeoff (camera or
         | human). I assume this sort of thing is rare enough to not
         | warrant the extra time /cost of these trivialities.
        
       | closeparen wrote:
       | Is this significantly more heat than you would get from a tarmac
       | delay in Phoenix?
        
         | jacquesm wrote:
         | Overall less energy but locally much more due to the fact that
         | it is focused. By comparison: a lighter doesn't have a whole
         | lot of energy, but it outputs that energy in a tiny volume
         | resulting in combustion. The lights they used are not quite
         | lighters but they can cause fires if you concentrate their
         | output in a small enough area. A tarmac radiating heat is an
         | enormous amount of output but on a W/sqm basis for delivered
         | power it is a fraction of what those lights can do.
        
       | gomox wrote:
       | Can someone explain how:
       | 
       | * Damage to the left leading edge of the horizontal stabilizer
       | was noted as well. Investigators found acrylic in the puncture,
       | consistent with a window pane.
       | 
       | And:
       | 
       | * The aircraft remained properly pressurized throughout the
       | flight.
       | 
       | Are not mutually incompatible? (i.e. a window pane hit the tail
       | in flight and somehow the aircraft remained pressurized?)
        
         | reportingsjr wrote:
         | Aircraft windows have multiple, separate panes. Presumably only
         | the outer pane dislodged and the inner ones remained in place.
        
         | fsckboy wrote:
         | the cabins of airplanes are actively pressurized by pumping air
         | in, and constantly removing some air so carbon dioxide doesn't
         | build up. The pumping that feeds the replacement air could be
         | higher capacity than the flow through a missing window.
         | 
         | pressurization of aircraft is not required till 12,500 ft
         | (3810m) so the air pressure differential at 15000 is not likely
         | to be that great.
        
           | epcoa wrote:
           | > pressurization of aircraft is not required till 12,500 ft
           | 
           | Well, no. I don't think cabin altitude for passenger
           | airliners has ever been that high, so you need pressurization
           | much lower than that (typically starting around 6000 ft for
           | modern aircraft).
           | 
           | Edit: Even the Boeing 307 Stratoliner was pressurized to 8000
           | ft.
        
             | mwint wrote:
             | Pilot here - it's legal to fly at 12,500 in an
             | unpressurized aircraft indefinitely. See https://www.ecfr.g
             | ov/current/title-14/chapter-I/subchapter-F.... Cabin
             | pressurization is set to a lower altitude, but that's not
             | for a legal requirement. It's just nicer to be at higher
             | pressurization.
             | 
             | And, I mean, think about it - there are _towns_ at 9k+
             | feet.
        
               | epcoa wrote:
               | > but that's not for a legal requirement.
               | 
               | This one? https://www.law.cornell.edu/cfr/text/14/25.841
        
         | imadethis wrote:
         | There are three window panes on a commercial plane. The outside
         | pane maintains pressure, while the middle one is a failsafe in
         | the event the outside pane fails (the inner pane is cosmetic
         | and to prevent people from messing with the important panes).
         | 
         | Without reading the report, the outside pane could have failed
         | and hit the stabilizer while the middle pane continued to hold
         | pressure as expected, therefore no contradiction in the two
         | statements.
        
         | illwrks wrote:
         | As far as I understand it, there are several layers that make
         | up an airplane window, the one in the middle is the vital one
         | and the extra layers on either side have other purposes.
         | 
         | In this incident, the outer frame had melted and the outer pane
         | had separated from the rest but the central layer was OK at
         | that point in time.
         | 
         | https://thepointsguy.com/news/what-are-airplane-windows-made...
        
         | mjg59 wrote:
         | You need to pump air into a plane to provide oxygen. That
         | implies that you need to let air out. The pressurisation system
         | in planes is able to deal with a moderate amount of air exiting
         | the aircraft without losing pressure, and the lower the
         | altitude the easier that is.
        
           | WalterBright wrote:
           | You can have a hole the size of a quarter with no effect on
           | cabin pressure.
           | 
           | This is why the fear that a bullet fired in the airplane will
           | pop it like a balloon is unfounded. Poking a hole in the
           | fuselage won't do anything. A bullet would have to hit and
           | disable something critical (and there's always a backup for
           | critical parts).
        
           | wkipling wrote:
           | Not oxygen, air. The outflow valves on modern aeroplanes are
           | almost the size of the windows themselves. They would
           | progressively close to maintain cabin pressure.
        
       | OJFord wrote:
       | Discussed recently here:
       | https://news.ycombinator.com/item?id=38221121
       | 
       | That article isn't as good (less technical/more 'pop' audience)
       | but they both link the actual AAIB report which I found quite
       | interesting and surprisingly readable, and I don't think either
       | article has anything extra to offer. I'd suggest skipping
       | straight to it:
       | https://assets.publishing.service.gov.uk/media/6544b3089e05f...
        
       | foota wrote:
       | Sounds expensive.
        
       | userbinator wrote:
       | I'm a little surprised that the window panes aren't so much
       | physically bigger than the opening such that even if the seal
       | failed they'd still be held in place by cabin pressure.
        
         | wkipling wrote:
         | They are generally plug type
        
       | davidhyde wrote:
       | I just don't understand why all movie set lights haven't
       | instantly been replaced by their LED equivalent. Why do people
       | still use these things that are crazy expensive to run and can
       | set things on fire?
        
         | usefulcat wrote:
         | Color temperature, I would guess.
        
         | rtpg wrote:
         | Can an LES array nicely reproduce similar color spectrums? If I
         | had to guess I imagine the film lamps emit a pretty broad range
         | of color.
        
         | SkyPuncher wrote:
         | Light quality.
        
         | KennyBlanken wrote:
         | The cost of running them isn't relevant. What is relevant:
         | being able to get more light from a limited amount of
         | house/set/generator power, and the control over them. They
         | don't require a dimmer pack, just power and DMX (wired or
         | wireless) to control their brightness, color temperature,
         | activate special in-light effects like flickering/strobing,
         | etc.
         | 
         | Some directors prefer the spectrum completeness and profile
         | from tungsten (or the ultimate, carbon-arc, which is virtually
         | indistinguishable from the sun.)
         | 
         | I also think there are levels of light that aren't really
         | feasible except with carbon arc because LEDs don't like heat
         | and that limits power density.
         | 
         | I don't remember what movie it was, but there's a photo of an
         | enormous balloon light - larger than an entire house - over a
         | farmhouse somewhere in the midwest, at night. Pretty sure it
         | wasn't LEDs as the source, but I could be wrong.
        
           | _kb wrote:
           | Possibly the set of Nope: https://www.reddit.com/r/Damnthatsi
           | nteresting/comments/xmdx0....
           | 
           | Not a balloon, but a big diffuser with a whole bunch of Cineo
           | 410 LED sources.
        
         | ComputerGuru wrote:
         | Spectrum continuity and spikes, flicker, active cooling,
         | ridiculously short lifespans at ridiculously high levels of
         | brightness, and a sprinkling of "the old way is the only way"?
        
         | strogonoff wrote:
         | Ever heard how painters hunt for pigments? Sure, if you run out
         | of orange you can just mix red and yellow, but the end result
         | will reflect different frequencies than when you used a
         | dedicated orange pigment--meaning some oranges in your final
         | work would look ever so slightly different (and sometimes
         | _very_ different under some light conditions or angles) from
         | other oranges or from what you would like, especially over
         | time.
         | 
         | The situation can also be flipped and apply to light sources,
         | and those by definition are key in photography.
         | 
         | In case of LED light, its colour balance can be declared to
         | match some reference Kelvin number, but because it is "fake", a
         | mix of spikes in the spectrum (roughly at R, G, and B for RGB
         | LEDs, phosphorus-covered white LEDs have the spectrum more even
         | but its own gaps and bumps), and materials of various colours
         | can reflect inbetween those peaks, or right at those peaks,
         | those materials can look 1) different from scene to scene and
         | from light to light or 2) plain wrong in post production,
         | compounding variance between camera sensors or films (which
         | create colour from their own mix of R, G, and B), lenses, etc.
         | 
         | Added to other flaws of LEDs, such as longevity (of cheaper
         | units), issues with brightness and colour reproduction
         | consistency, PWM, etc., they make a poor choice for a variety
         | of situations[0], but in photography particularly so,
         | particularly where colour reproduction and continuity matter
         | (TV and film).
         | 
         | By contrast, black body radiation--hot and more energy
         | intensive--is a solid spectrum of even light, without spectral
         | discontinuities or flicker at any brightness.
         | 
         | [0] In some situations those flaws are considered acceptable.
         | You may have noticed how two identical OLED iPhones displayed
         | at an Apple Store, even fully reset to defaults, can have
         | obviously different white point when you look at them side by
         | side--that's colour reproduction/emission variance and/or
         | degradation over time. Similarly, you can often spot PWM
         | flicker if you reduce brightness and squint at an OLED phone
         | with your peripheral vision. These things don't matter much,
         | since 99.99% of the time we look only at our own device and our
         | colour perception and flicker tolerance is adjusted to it. Not
         | so with photography; you can't afford colour variance between
         | two different lights even in cases where it's not noticeable to
         | the naked eye in the moment, whereas PWM restricts your FPS and
         | shutter angle options.
        
           | HPsquared wrote:
           | White LEDs do not produce three narrow spectral peaks. That's
           | only RGB LEDs, which are a very specific thing and not the
           | norm. LED lighting uses phosphors and produces a broad
           | spectrum.
           | 
           | Take a CD / DVD (if you can find one in 2023) and look at the
           | spectrum from your phone flash, or any other LED lamp, and
           | observe the broad spectrum. They all have some sort of blue
           | peak, but it's very small in "warm white" lights.
        
             | strogonoff wrote:
             | That's true, I edited my comment to note phosphorus-coated
             | LEDs, but that coating still leaves spectrum with gaps and
             | bumps. Besides, the more coating you add, the less bright
             | or energy efficient your lights get, and sets can require
             | _very_ bright lights.
             | 
             | Other issues, such as PWM flicker coinciding with your FPS
             | and shutter angle or LED controller interference in audio
             | recording, remain.
             | 
             | From my understanding, today mature LED-based solutions can
             | only mitigate these issues with varying success, not
             | eliminate all of them entirely, all this mitigation adding
             | complexity and cost, while on the other hand one could just
             | use a black body emitter so that those issues are not
             | technically a thing, and try not to set things on fire.
        
               | kuschku wrote:
               | If you try out the newer ARRI LED based solutions such as
               | the new Skypanels, they've fixed that entirely. And even
               | low-budget lights such as the newer Aputure ones produce
               | an amazingly even spectrum (though their cheapest
               | products have a bimodal distribution)
        
               | strogonoff wrote:
               | Those that sell for $4k+ USD? Perhaps they mitigate these
               | issues (can't find any research that compares the
               | spectrum to black body and addresses the other issues),
               | though not sure if they are more budget effective if you
               | have a well fire hazard trained crew.
        
               | kuschku wrote:
               | They don't just mitigate them, they're entirely free of
               | them. There's a reason Skypanels are standard on every
               | single major hollywood production nowadays.
               | 
               | That said, if you need a _lot_ of light, halogen is
               | without alternative. There 's a reason the ArriMAX with
               | its 18kW halogen lamp is still popular.
        
         | Aardwolf wrote:
         | Bad color rendering index.
        
       | NKosmatos wrote:
       | I'm curious to see what kind of photos they took.
       | 
       | Having so many of these huge lights, blasting out 12KWs each, for
       | 4-5.5 hrs just to get a few photos of a plane sounds a little bit
       | too much, but hey who am I to judge :-)
        
       | alexpotato wrote:
       | I went to college in the late 1990s and I distinctly remember my
       | university had banned halogen lamps.
       | 
       | The reasoning was that:
       | 
       | - college students are busy/forgetful so will leave the light on
       | 
       | - there are times of day where no one would be in a dorm room
       | 
       | - BUT that dorm room is a bigger dorm with potentially lots of
       | other students
       | 
       | - an unattended halogen lamp could set fire to an object on a
       | desk etc
       | 
       | this post feels like a much bigger version of the above
        
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