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Fake ceiling as a giant soft source

ceiling overhead soft diffusion set

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#1 Tom Yanowitz

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Posted 22 March 2015 - 06:03 PM

Hello everyone,

I need your help.

 

I'm currently a film school student.

I will direct a very short film/exercise (one day of prep one day of shooting) in 40 days.

So the mood and the set design will be a weird mix between Kubrick films (2001, Clockwork..) and THX 1138, kinda.

 

Anyway we have this 4 by 10 meters set at school, that has no ceiling.

But I have one obligation for this exercice/short : only use a 16mm lens (on the Alexa).

10 meter long room, 16mm.. I'd better need something as a ceiling.

 

I'd want something white I could use as a diffusion so that the ceiling would be a giant soft source.

So I have two questions for you experienced people :

What would you consider for the ceiling (doesn't have to be realistic at all) given a very limited budget.

What kind of light could be use above that fake ceiling, to create a high-key look overall (the set will be mostly pure light with some black lines to give some perspective, the costumes black and white as well)

(we have tungstenes up to 4K, hmis up to 2.5k I think and kinos)

 

I'll also have some diffused light coming from the walls (I'll remove the windows of the set and place 216 frames instead)

 

Thanks everyone !


Edited by Tom Yanowitz, 22 March 2015 - 06:06 PM.

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#2 Satsuki Murashige

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Posted 23 March 2015 - 02:35 AM

How many footcandles do you need? Color temp? Does the whole ceiling need to be lit evenly? Assuming you have a grid above the set and enough space, maybe 2x 5Ks would give you enough spread at full flood.

If you don't need as much output, then maybe a series of Source4 Lekos with zoom lenses are the answer. Ideally you would have a really broad source like an Arri X Light or a Skypan but those are speciality lights, so I'm assuming your school wouldn't have them.

For ceiling material, I would go to the fabric store and pickup some bleached muslin. Stretch it over the top of he flats and secure it.
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#3 aapo lettinen

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Posted 23 March 2015 - 05:48 AM

the muslin sounds good  :)

 

For a shoot two years ago I used paper tablecloth for building a large bounce surface (about 7 x 9 meters hanging under a truss system). The seams may look very harsh but if you can even them out then you could benefit from the texture the paper may have. At least it is very affordable although very brittle and as said the seams don't look very good unless carefully evened out


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#4 Tom Yanowitz

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Posted 23 March 2015 - 01:47 PM

How many footcandles do you need? Color temp? Does the whole ceiling need to be lit evenly? Assuming you have a grid above the set and enough space, maybe 2x 5Ks would give you enough spread at full flood.

If you don't need as much output, then maybe a series of Source4 Lekos with zoom lenses are the answer. Ideally you would have a really broad source like an Arri X Light or a Skypan but those are speciality lights, so I'm assuming your school wouldn't have them.

For ceiling material, I would go to the fabric store and pickup some bleached muslin. Stretch it over the top of he flats and secure it.

 

Footcandles ? No idea I must say, I'd like to achieve a high key look at T4 or 5.6 (2.8 if I really dont have enough light) with an evenly lit 40m² set..

Color temp well it doesn't really matter I think. I'll choose the color temp that makes my white walls as neutral as possible.

Yes I'd like the ceiling to be evenly lit and do have a grid above the set, and we can adjust its height.

The flooded 5Ks seems like a good idea, although i'm not sure at what angle I would place them.

Maybe some smaller fresnels for some spots that the 5Ks would'nt cover.

 

And the bleached muslin seems is a good idea too, I'll just have to see how expensive 40m² is..

 

Thanks !

 

the muslin sounds good  :)

 

For a shoot two years ago I used paper tablecloth for building a large bounce surface (about 7 x 9 meters hanging under a truss system). The seams may look very harsh but if you can even them out then you could benefit from the texture the paper may have. At least it is very affordable although very brittle and as said the seams don't look very good unless carefully evened out

 

Yes but you're talking about bouncing light right ?

I have some wide shots where we see close to all the set so I need to diffuse from above rather than bounce for the ceiling.


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#5 Albion Hockney

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Posted 23 March 2015 - 02:20 PM

are you going to see the ceiling in frame?


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#6 David Mullen ASC

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Posted 23 March 2015 - 02:23 PM

You're better off with a grid of a lot of lights spaced evenly to fill the muslin ceiling from above evenly rather than a couple of big lights, unless you want to double-diffuse by hanging another large white bounce, like two 20x20 white muslins or UltraBounces and hitting it from the sides all around up into the bounce and then down into the muslin ceiling, but you may not get enough light level after all of that.

A grid of 1K pars (not parcans) pointed down through the muslin ceiling would work, for example, but you need enough to space them apart evenly, like every three feet / one meter.
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#7 aapo lettinen

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Posted 23 March 2015 - 02:28 PM

 

Yes but you're talking about bouncing light right ?

I have some wide shots where we see close to all the set so I need to diffuse from above rather than bounce for the ceiling.

oh I misread the original post. Yes, I was talking about bouncing from the paper surface. 

 

I have used large translucent tarps for diffusing light every now and then on low budget shoots, they are actually quite good for this, even the cheap ones. They will of course not look like ceiling at all on the wide shots   ;)


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#8 aapo lettinen

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Posted 23 March 2015 - 02:32 PM

if the shoot is only one day then it might be cheaper to rent proper diffusion than to try replace it with cheap alternative. you will usually need more light when using improvised diffusion


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#9 Satsuki Murashige

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Posted 23 March 2015 - 07:43 PM

 
Footcandles ? No idea I must say, I'd like to achieve a high key look at T4 or 5.6 (2.8 if I really dont have enough light) with an evenly lit 40m² set..
Color temp well it doesn't really matter I think. I'll choose the color temp that makes my white walls as neutral as possible.
Yes I'd like the ceiling to be evenly lit and do have a grid above the set, and we can adjust its height.
The flooded 5Ks seems like a good idea, although i'm not sure at what angle I would place them.
Maybe some smaller fresnels for some spots that the 5Ks would'nt cover.

I was thinking that the 5Ks would be hung on the grid and pointed straight down at the muslin ceiling. It doesn't really matter if they spill over the sides unless you have backings
outside a window that you want to flag off. If it's an irregularly shaped set then I'd go with David's method of lots of smaller units spread out. That's a lot more work though. Or possibly even Space Lights above the muslin.

If you had enough space between the grid and the muslin, you could also rig a large frame of Ultrabounce and pound the 5Ks into it from the floor, which would essentially be a huge book light. You'd probably need 4x at that point.

This is where footcandles matter. 100 ISO, 1/50, f/4 = 100fc. Assuming you are shooting at 800 ISO, you could shoot at an f/4 with 12fc, or 1/8 the amount of light. That's probably doable with the book light - Bleached muslin loses 2 stops of light, so you'd have to be already getting 50fc from the Ultrabounce by itself.

Do you have any other practical light sources or props like visible LCD monitors in the frame? If so, then color temp and relative light levels are concerns.
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#10 David Mullen ASC

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Posted 23 March 2015 - 09:29 PM

You'd have to have quite a high grid for 5K's pointed down into the muslin to light a large area evenly, unless you could rig a 4x4 frame of diffusion in front of each 5K to soften them further, but then you'd still want a small grid pattern of 5K's to make everything even.


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#11 Stuart Allman

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Posted 24 March 2015 - 01:53 PM

Tom,

 

Perhaps you can use an approach I hear about quite a bit over on Roger Deakins' site.  He uses a rig of 60-200W tungsten bulbs in a circle and hangs that overhead as a soft space light.  If you have the time to build rigs like this, then it might be an option.  You can always double diffuse, using bleached muslin from the fabric store.  None of these things should be very expensive to buy.  As far as the diffuser that's seen in the picture...well, you might have to rent a large fabric if you want it to be continuous across the expanse of the set.

 

Stuart

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#12 Albion Hockney

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Posted 24 March 2015 - 10:40 PM

^ Stuart, can you link to where Roger talks about that? curious what scene that might have been used in?


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#13 David Mullen ASC

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Posted 25 March 2015 - 12:28 AM

We're talking about evenly lighting a 12' x 30' muslin ceiling piece. Sure you can use light bulbs, it would just be rather a lot of them -- if they are spaced every two feet in a grid, that's 6 x 15 bulbs, 90 bulbs to wire up. If every three feet, that's 4 x 10, 40 bulbs. Probably you'd have to use 250w bulbs.

Or maybe do a grid of 1K par bulbs, maybe roughly four feet apart, so maybe 3 x 7, 21 pars.

Many ways to keep dividing this grid... Maybe just a grid of two rows of 6K space lights, 2 x 4, so eight.

Deakins uses small and large rings of light bulbs -- that larger unit was used to light the dance floor in a bar scene in "Revolutionary Road".
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#14 Stuart Allman

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Posted 25 March 2015 - 09:42 AM

Sorry Albion,

 

I don't have a direct link.  I've been haunting the posts on his lighting forum for years, but unfortunately I lost my password and their admin has been unresponsive in restoring my account.  You should be able to do a search on his forums to find some examples.  I think some of the older information was lost when his site went down a while back.  I know he used this setup multiple times in the Jesse James film and others (I don't remember specifically).

 

I guess it just really depends on how comfortable Tom feels with such a large wiring job and whether of not he has the budget.  As we all confer, lighting a large area evenly isn't a task for a meager DP or one man band.

 

If this was my DP job I might look at renting a series of Kino image 87 lights and hang them overhead like shop lights.  With double diffusion they would probably be nice and even.  I just have no clue how much those cost to rent.  My experience is limited to using the gaffer kit.

 

S.


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#15 Tom Yanowitz

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Posted 17 April 2015 - 01:54 PM

Thanks a lot everyone for your great advices! (I was convinced I had replied earlier but apparently not, so sorry for that).

I'm currently looking at the prices for renting or buying bleached muslin for the two days, even that is hard on a low budget !

 

And as for the ISO setting of the Alexa, I was thinking it would be interesting to set it higher than 800 because :

- less light needed

- most of my set/costumes is high key/white, and I have shots with both the big source/ceiling and actors in the frame. So I might be able to get more "details" in the celing at a higher ISO, with actors at keylight, given the Alexa gives more highlight range the higher the ISO.


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