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Safe materials for creating light shafts

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#1 Kim Bolan

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Posted 12 January 2018 - 01:47 AM

In the film "Double Indemnity" Fed MacMurray is standing in the home of Barbara Stanwyck. Strong shafts of light are beautifully streaming down. I was told that John Seitz used metal filings (Possibly aluminum) to create that effect. This would not appear to be safe for anyone to inhale. I am thinking that Rosco fluid may be a safe alternative but may be a little difficult to obtain the correct diffusion. Might someone have another suggestion for a safe material which might remain airborne?

 
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#2 Phil Connolly

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Posted 12 January 2018 - 06:14 AM

You don't really want to use any powder materials to make haze, since you risk respiratory issues or risk explosion with flammable materials like flour.

 

Really your option is to use a smoke machine/hazer - either water based or cracked oil.

 

Cracked oil can cause breathing problems as well - its ok outdoors, but problematic on interiors and banned in some venues since it can leave a residue. But it does last longer in the air then water based systems, the machines tend to make more smoke quicker. Also you can get gas powered handheld units that don't need powering (again good for exteriors)

 

Water Based (rosco etc) - its the safest option - its vary rare that it can trigger any respiratory distress.

It should still be flagged on the call sheet and risk assessment because there is a still slight risk of increased attack for some asthma sufferers(but less then oil based). It does not last that long in the air so you have to keep topping it up - although different fluid mixes have different hand times and some are better then others. Work hard to eliminate drafts etc.. Disco party foggers are harder to work with then hazers because the smoke is more lumpy and uneven and even with a hazer you usually have to do a bit of work to waft the smoke about to make sure its even.  Higher end hazers can monitor smoke levels and top up.

 

A hazer is a smoke machine with some fans in it to chop up the smoke and mix it with air more - so it looks less like smoke and more like haze.  

 

Generally the challenges of working with smoke is keeping is even so it looks like a smooth haze rather then lumps of smoke wafting about. And keeping it constant shot to shot. It possible to get great results even with a basic disco style smoke machine - but its time consuming. For every 5 minute take you might have 5 minutes of smoke wrangling - so schedule accordingly. 

 

I directed this music video  (dop Leigh Alner) and we used a domestic smoke machine brought for £20: 

It worked but it slowed us down because the heating element was very small and would take a few minutes to heat up between blasts - so we'd have to wait for it to warm up between takes. The dust is mostly fullers earth but the beams mainly came from the party fogger and 2 x 2.5K hmi's backlighting. It was a small room so we got away with the smaller machine - as you can see  from the behind the scenes the smoke hangs ok:

 

 

So its a trade off really - shafts of light look awesome but you need to budget for the time and probably hire a couple of extra runners to with sheets of poly board to even the haze out.  This is easier to do on smaller locations where you can close doors/windows. Big drafty interiors (and exteriors) much more difficult. If you don't get the haze even it stops looking like haze and starts looking like smoke and draws attention to itself. 

 

Other tip would don't use too much haze - you want just enough to make the shafts of light visible. To much and it risks being noticed and messing with your contrast too much. 


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#3 Vladimir Cazacu

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Posted 12 January 2018 - 06:18 AM

Can you please post a photo of what you want to achieve?

 

It sounds to me like haze + a Source 4 Leko or Joker Bug would do the trick.

 

Here are a few stills that showcase this technique (not my work):

 

https://imgur.com/a/cpYKV


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#4 aapo lettinen

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Posted 12 January 2018 - 07:52 AM

I think clear water would be the only really safe particle to breath... 

but haze/smoke is probably the look the OP wants to create. normal hazers/smoke machines use ethylene/propylene glycol +water which does not cause too much breathing problems for most people.

 

 

salt crystals (pure NaCl dust) could also be quite OK to use for shimmering effect I think though could still cause breathing problems and is not good to inhale in large amounts. 

 

Any fine flammable powder in air = explosion hazard. Metal particles are additionally very unhealthy to breath as well as fine mineral particles (stone dust, fine sand, etc.) . 

IF the whole cast and crew would use good quality P3 respirators ("gas masks") then it might be ok to do a particle scene with powders, otherwise not


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#5 Kim Bolan

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Posted 12 January 2018 - 12:27 PM

Thank you all for the very rapid response to my question.

 

I reviewed the MSDS for Rosco Delta Haze Fluid and it appears to be the least invasive product for producing haze. The HMIS Rating is 1 – slight hazard so I would suspect that someone with respiratory issues or who are respiratory sensitive could be adversely effected. The more confined area would of course increase the sensitivity.

 

 

Thank you, Mr. Connolly, for the suggestion of flagging the use of haze producing materials on the call sheet. I would also have the MSDS available. Consistency of the haze is also an issue and a machine such as the Rosco V-Hazer Fog Machine might be the best solution. Also, the suggestion for using “sheets of poly board to even the haze out.” That is something I had not originally considered and appreciate the suggestion.

 

Thank you, Mr. Lettinen, for pointing out the use of “flammable powder in air = explosion hazard” and the use of “salt crystals (pure NaCl dust)”.  Salt crystals are a product I had not considered and will further research.

 

Thank you, Mr. Cazacu, for the suggestion of using “Leko or Joker Bug”. 


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#6 Samuel Berger

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Posted 12 January 2018 - 01:30 PM

In "Supernatural" they used walnut shell dust for this effect. It was spread with a sandblaster.


Edited by Samuel Berger, 12 January 2018 - 01:31 PM.

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#7 Kim Bolan

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Posted 12 January 2018 - 01:35 PM

Walnut shell dust is an interesting material. While this would not be toxic I would be concerned with the inhalation hazard. The need for a respirator or at least a dust mask might be required. 


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#8 Stuart Brereton

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Posted 12 January 2018 - 02:05 PM

Walnut shell dust is an interesting material. While this would not be toxic I would be concerned with the inhalation hazard. The need for a respirator or at least a dust mask might be required. 

 

If you need to use a respirator, it is by definition not safe.

 

Fog and haze fluid is used all over the industry without harmful effects. Don't try to reinvent the wheel here, just use what is safe.


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#9 Stuart Brereton

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Posted 12 January 2018 - 02:18 PM

In "Supernatural" they used walnut shell dust for this effect. It was spread with a sandblaster.

I doubt that they used walnut dust for aerial haze. It's harmful to breathe, and an irritant to eyes and skin. It's also potentially explosive when hanging in air.

 

It's mainly used to artificially age sets with surface dust. If they were blowing it in with a sandblaster, it was probably to ensure an even spread over the set, long before any actors or crew were present.


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#10 Samuel Berger

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Posted 12 January 2018 - 02:22 PM

I doubt that they used walnut dust for aerial haze. It's harmful to breathe, and an irritant to eyes and skin. It's also potentially explosive when hanging in air.

 

It's mainly used to artificially age sets with surface dust. If they were blowing it in with a sandblaster, it was probably to ensure an even spread over the set, long before any actors or crew were present.

 

Just repeating what they said on the actual DVD commentary about the haze in the air.


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#11 Stuart Brereton

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Posted 12 January 2018 - 02:26 PM

 

Just repeating what they said on the actual DVD commentary about the haze in the air.

Unless it was the actual Special Effects guys doing the commentary, I'd take that with a grain of salt.


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#12 aapo lettinen

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Posted 12 January 2018 - 02:28 PM

Yeah even the salt dust can be slightly harmful if inhaled in larger amounts. Drying of membranes etc.

I would not use wood dust, both more or less flammable and some wood species create potentially carcinogenic dust...

I think it is not recommended by physicians to use heavy respirators if one has asthma or lung problems, so asthma patients can stay away from the set and the rest use a respirator if using dust effects. Normal hazer smoke is safe to use though without protection, it only smells bad for normal people and most others only get slight symptoms from it
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#13 aapo lettinen

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Posted 12 January 2018 - 02:35 PM

Ps. Dyst masks are good for nothing, they are mainly a cosmetic fix and will still let harmful particles through. One really needs to use a respirator when working in dusty environment fir longer time. I personally use the same filters used by asbestos workers, they work better for fine dust than a cheap-o chinese paper mask...
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#14 Samuel Berger

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Posted 12 January 2018 - 02:37 PM

Unless it was the actual Special Effects guys doing the commentary, I'd take that with a grain of salt.

 

I'd have to look, it was in the first three seasons when they still shot on S35mm 3-perf film. Back then, the show looked a lot better. Now it's shot on digital and just looks like everything else on TV. I stopped buying the Blu-ray sets after season 7 I think. At one point they were using a Canon 5D Mark II as a B camera.


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#15 aapo lettinen

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Posted 12 January 2018 - 03:23 PM

most hard wood dust (oak, ash, etc.) is hazardous and may be potentially carcinogenic. carpenters are usually very careful about this.... not a good idea to blow hardwood dust all over the cast and crew unless wanting harm their healt :huh:  if that would be the whole point maybe adding a little bit of grinded asbestos on the top  :ph34r:


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#16 Phil Rhodes

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Posted 12 January 2018 - 03:28 PM

For pity's sake.

 

Use a hazer.

 

Nobody is using anything but a hazer.


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#17 Jaron Berman

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Posted 12 January 2018 - 03:41 PM

That shot was like 3 seconds long, any haze will work - plus the effect wasn't particularly strong so I think trying to find some alternative way of doing it would be counterproductive.  There are a lot of CRAZY things that were done for effect in that era on stage and screen, some are probably missed and some probably not so much.  Haze is such a common effect, you can choose from hundreds of variations in formulation in fog/haze/atmospheric effect, and nowadays safety is taken into consideration when mass marketing the fluids.  Broadway uses a LOT of atmosphere because it's part of the scenic design to have beam effects.  In a musical, those actors are doing 2x shows a day, 5-6 days a week SINGING in haze, so you'll find that actors equity has some of the strongest opinions of what constitutes "acceptable" haze/fog. 

 

Oil haze hangs longer and is usually quicker to saturate, but if you use a LOT day-in, day-out it will eventually make some residue.  Generally the only "oil slick" will be directly next to the machine.  Water-based isn't necessarily any less residual just because it's "water based," and you tend to go through quite a bit more fluid to create the same effect - so I find it leaves as much tackiness in the end.  Either way, test the hang time in the space you're using in "game conditions" because the spec sheet that says "7-15 min hang" isn't taking into account movement of people, air drafts, temperature, etc - which do change the time/saturation you get.


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#18 Tristan Noelle

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Posted 12 January 2018 - 04:22 PM

I key gripped a feature a few years ago where they used walnut shell dust in combination with a DF-50 hazer for one scene in a small room. Ill have to have to post some pictutes to link to but the particles looked cool catching a shaft of light from a 400 Jo-Leko.

As to its safety, I cant say. The prop person handled it and I think it was his first gig. I didnt notice any ill effects the one day. It was more hazardous to the Red as it clogged the heatsink and made it terminally overheat a few days later; had to replace a board.
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#19 Phil Connolly

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Posted 12 January 2018 - 04:24 PM

Generally you use things like fullers earth for dust effects, because you need it to be non flammable ideally, wood dust would be madness

 

http://www.tvandfilm...ust-and-debris/

 

Also it looks good and its not toxic but you still don't want to be wafting it about too much and getting people to breath it in even if it is non toxic. Inhaling  any particulate matter in any quantity is going to be asking for trouble.

 

As a filmmaker you have a duty of care for you crew and performers - so shouldn't be exposing them to anything that could affect their health. I think the situation in theatre is slightly different because the complaints i've seen about haze effects mostly  relates to long running musical theatre shows and long exposure to haze effects (8 shows a week) can dry the thought and make singing more difficult. Its not dangerous per se but if your doing a long run musical for months/years with lots of haze effects and breathing in deeply cos your singing maybe theatre actors have a point. Maybe something like "phantom of the opera" where your swimming in dry ice and haze effects that might build up


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#20 Stuart Brereton

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Posted 12 January 2018 - 04:48 PM

When you join the union here in the US, you have to complete a number of safety classes. One of these is specifically about respiratory hazards and the proper use of respirators. It's something that is taken very seriously. As a result, any potentially harmful substances, such as walnut dust, should only be used as intended, and by trained SFX crew.

 

There's any number of substances that you can blow into the air to create haze, and many of them are very bad for your health. Let's be responsible and not make wild suggestions when there is a readily available and safe product designed for exactly this purpose.


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