6 ms·

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

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 3y ago
>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.
- deleted 3y ago
  [deleted]
- LeifCarrotson 3y ago
  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 3y ago
    I'm intrigued, any recommendations?
    - LeifCarrotson 3y ago
      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-led-lux https://meaningness.com/sad-light-lumens https://meaningness.com/sad-light-lumens for a much more detailed writeup (no affiliation).
    - alright2565 3y ago
      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 https://i.imgur.com/aTegmqR.mp4
    - Scene_Cast2 3y ago
      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 3y ago
    Sounds more like a "you'll be warm for the rest of your life" situation. :-P
    - ReactiveJelly 3y ago
      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 3y ago
    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_apm022xa10_amaran_cob_200x_s.html https://www.bhphotovideo.com/c/product/1753990-REG/amaran_ap...
    - KennyBlanken 3y ago
      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 3y ago
        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___ 3y ago
    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 3y ago
      > that I potato chip chip to stay on top of my monitors What does that mean?
      - potatochipclip 3y ago
        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 3y ago
        A Bulldog Clip[1]? 1. https://en.wikipedia.org/wiki/Bulldog_clip https://en.wikipedia.org/wiki/Bulldog_clip
        jvm___ 3y ago
        Ya, that style. The ones from the dollar store for potato chip bags have that nice wide mouth, so it can grab the monitor and then the light rests on the monitor but is kept from falling by the clip. You can clip one vertical on the vertical edge and one on the horizontal edge of the monitor. Just don't party on your desk or move it too much.
  - brnt 3y ago
    Dont forget the small power plant you will now neef!
- deleted 3y ago
  [deleted]
- quickthrowman 3y ago
  > 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 3y ago
    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 3y ago
      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 3y ago
        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 3y ago
        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 .
      - quickthrowman 3y ago
        Perhaps you’re thinking of how the jockey pump and main pump work together in a sprinkler system. A jockey pump maintains pressure in the system and is sized at less than the flow rate of one sprinkler head. The main fire pump is activated when a pressure transmitter detects a drop in pressure. The jockey pump can’t maintain pressure when a sprinkler head opens, and the drop in pressure starts the main fire pump.
- burnished 3y ago
  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 3y ago
    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 3y ago
      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 3y ago
      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 3y ago
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 https://news.ycombinator.com/item?id=38221699
- GlenTheMachine 3y ago
  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 3y ago
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 3y ago
  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 3y ago
  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 3y ago
    > presumably that is English Tudor Mansion Although it's fairly common for schools to have tutors as well
    - foobar1962 3y ago
      But not common for english tutors to have mansions.
      - xp84 3y ago
        All the English Tutors chipped in to get one mansion between them.
ekianjo 3y ago
> which was made of styrofoam. styrofoam melts super easily so not sure that says much
ibejoeb 3y ago
Was it an old arc lamp?
- pbjtime 3y ago
  NO! It was a brand new arc lamp.
agent327 3y ago
I worked with a solar simulator that has 19 lamps, each using 35 kW of power. It has a heavy metal shutter that is used to quickly turn off the light. Once the shutter is closed, the operators have ~45 seconds to turn the lamp off, otherwise they risk damaging the shutter. Some other facts: * While handling lamps, you are not allowed to be in the lamp room without hearing protection, just in case one implodes. * A single lamp emits enough light that it can cause permanent blindness. * Lamps are water-cooled. Here's a picture of the back of the unit: https://www.esa.int/ESA_Multimedia/Images/2014/04/Sun_simulator https://www.esa.int/ESA_Multimedia/Images/2014/04/Sun_simula... (it still lists the old power rating, but it was increased to 35 kW a few years ago, when BepiColombo was tested. The lamps were also refocused at that time, to cover a smaller diameter circle. The sun emits a ridiculous amount of light...) Here's a picture of a spacecraft being lit up by the lamps (at a really low light level): https://www.esa.int/ESA_Multimedia/Images/2008/03/GOCE_ready_for_testing_in_the_Large_Space_Simulator https://www.esa.int/ESA_Multimedia/Images/2008/03/GOCE_ready... I wrote the software that monitors lamp output during use, and also the software used to calibrate the alignment of the lamps (they need to be properly centered).
- camtarn 3y ago
  That's incredible!

cge 3y ago

>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.

deleted 3y ago
[deleted]
LeifCarrotson 3y ago
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 3y ago
  I'm intrigued, any recommendations?
  - LeifCarrotson 3y ago
    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-led-lux https://meaningness.com/sad-light-lumens https://meaningness.com/sad-light-lumens for a much more detailed writeup (no affiliation).
  - alright2565 3y ago
    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 https://i.imgur.com/aTegmqR.mp4
  - Scene_Cast2 3y ago
    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 3y ago
  Sounds more like a "you'll be warm for the rest of your life" situation. :-P
  - ReactiveJelly 3y ago
    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 3y ago
  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_apm022xa10_amaran_cob_200x_s.html https://www.bhphotovideo.com/c/product/1753990-REG/amaran_ap...
  - KennyBlanken 3y ago
    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 3y ago
      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___ 3y ago
  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 3y ago
    > that I potato chip chip to stay on top of my monitors What does that mean?
    - potatochipclip 3y ago
      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 3y ago
        A Bulldog Clip[1]? 1. https://en.wikipedia.org/wiki/Bulldog_clip https://en.wikipedia.org/wiki/Bulldog_clip
        jvm___ 3y ago
        Ya, that style. The ones from the dollar store for potato chip bags have that nice wide mouth, so it can grab the monitor and then the light rests on the monitor but is kept from falling by the clip. You can clip one vertical on the vertical edge and one on the horizontal edge of the monitor. Just don't party on your desk or move it too much.
- brnt 3y ago
  Dont forget the small power plant you will now neef!
deleted 3y ago
[deleted]
quickthrowman 3y ago
> 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 3y ago
  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 3y ago
    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 3y ago
      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 3y ago
        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 .
    - quickthrowman 3y ago
      Perhaps you’re thinking of how the jockey pump and main pump work together in a sprinkler system. A jockey pump maintains pressure in the system and is sized at less than the flow rate of one sprinkler head. The main fire pump is activated when a pressure transmitter detects a drop in pressure. The jockey pump can’t maintain pressure when a sprinkler head opens, and the drop in pressure starts the main fire pump.
burnished 3y ago
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 3y ago
  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 3y ago
    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 3y ago
    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 3y ago

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 https://news.ycombinator.com/item?id=38221699

GlenTheMachine 3y ago
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 3y ago

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 3y ago
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 3y ago
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 3y ago
  > presumably that is English Tudor Mansion Although it's fairly common for schools to have tutors as well
  - foobar1962 3y ago
    But not common for english tutors to have mansions.
    - xp84 3y ago
      All the English Tutors chipped in to get one mansion between them.

ekianjo 3y ago

> which was made of styrofoam. styrofoam melts super easily so not sure that says much

ibejoeb 3y ago

Was it an old arc lamp?

pbjtime 3y ago
NO! It was a brand new arc lamp.

agent327 3y ago

I worked with a solar simulator that has 19 lamps, each using 35 kW of power. It has a heavy metal shutter that is used to quickly turn off the light. Once the shutter is closed, the operators have ~45 seconds to turn the lamp off, otherwise they risk damaging the shutter. Some other facts: * While handling lamps, you are not allowed to be in the lamp room without hearing protection, just in case one implodes. * A single lamp emits enough light that it can cause permanent blindness. * Lamps are water-cooled. Here's a picture of the back of the unit: https://www.esa.int/ESA_Multimedia/Images/2014/04/Sun_simulator https://www.esa.int/ESA_Multimedia/Images/2014/04/Sun_simula... (it still lists the old power rating, but it was increased to 35 kW a few years ago, when BepiColombo was tested. The lamps were also refocused at that time, to cover a smaller diameter circle. The sun emits a ridiculous amount of light...) Here's a picture of a spacecraft being lit up by the lamps (at a really low light level): https://www.esa.int/ESA_Multimedia/Images/2008/03/GOCE_ready_for_testing_in_the_Large_Space_Simulator https://www.esa.int/ESA_Multimedia/Images/2008/03/GOCE_ready... I wrote the software that monitors lamp output during use, and also the software used to calibrate the alignment of the lamps (they need to be properly centered).

camtarn 3y ago
That's incredible!