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Balancing mutiple sources


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#1 Miguel Bunster

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Posted 06 November 2005 - 11:25 PM

Hi,
I am in the following situation.
I am shooting at this big office area where I plan to use the fluorecents for lighting the office area (I will light the actors with other units). They barely give me a t:2.0-1.4 2/3 incident reading at 500 ASA. The walls are light colors which help. Now I color measured them and all of them go around 4800K to 5100K and most at 4950K. Now my biggest issue is that I have as well daylight coming in which in theory is around 5600K but if I get an overcast day it might go up to 11000K and I dont want to get the exteriors blue. I cant put 85 gels on all the windows because of budget. I can maybe switch the fluorecents to 5500 units but I dont know if its worth it. So my plan toward it is to shoot with the 5218 rated 500 uncorrected (to gain th extra stop) and time back in post. My worries are that the exteriors may look to blue anyway and I want to keep the interios as neutral as possible. Now if I dont b\swith the fluorecents I may be able to get 85 gels. I am as well complementing the scens with HMI thorugh diffusion and Kino units.
I have tested tungsten film shot uncorrected in exterios and timed back and I find the result pretty good. Never have done it under fluorecents and the green tinti worries me because if they time out the exterios may go a little magenta in theory and I really dont want that.
So in any ones opinion should I
1) Keep the 5000K fluorecents (no minus green added) and shoot 5218 uncorrected?
2)Switch to 5500K fluorecents, shoot 5218 uncorrected?
3)Keep the 5000K fluoreents, gel windows 85 and shoot uncorrected? When time back exteriors wuld go way warmer....

My worries about putting minus green to the fluorecents is that it takes away about 1/2 stop which under this circumnstances is a lot especially because I am doing steadycam.

I am finishing on print on vision stock whichi I like but I havent been able to test this thing yet.

Here are to images. The hallway and a door of the hallway where we see the view of the city. The windows will have detail outside.


[attachment=802:attachment][attachment=803:attachment]

Any help would be great! Thanks!
Miguel

Ps: i will be shooting with CS4 which open to a T:2.1 and ideally I want to shoot all at a t:2.8 and msot of it on a 24mm or 35mm. I still want to have ideally a 2.8 so I can give my 1Ac some play.
Best
Miguel

Edited by Miguel Teitelboim, 06 November 2005 - 11:28 PM.

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#2 Tim J Durham

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Posted 07 November 2005 - 12:19 AM

Hi,
I am in the following situation.
I am shooting at this big office area where I plan to use the fluorecents for lighting the office area (I will light the actors with other units). They barely give me a t:2.0-1.4 2/3 incident reading at 500 ASA. The walls are light colors which help. Now I color measured them and all of them go around 4800K to 5100K and most at 4950K. Now my biggest issue is that I have as well daylight coming in which in theory is around 5600K but if I get an overcast day it might go up to 11000K and I dont want to get the exteriors blue.

Best
Miguel

I don't know if this will help, but I find an overcast day to be in the 5300k to 5900k range (white clouds back-lit by sun- no blue sky). The only time I ever get a color temp of 10,000k or above is if I take a reading in the shade where the light source is the blue sky itself. So you are more likely to get fouled up on a sunny day where the sun has passed over your building (ie: not coming in the windows) and the daylight entering is that which is reflected off the blue sky.

An overcast day will be a good thing in your scenario.
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#3 David Mullen ASC

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Posted 07 November 2005 - 12:33 AM

Yes, overcast is not THAT blue. You're thinking of skylight.

If you can't swap all the tubes to something like Kino 55's (very expensive) or Chroma 50's, then you'll probably be OK with the coolness of 4900K tubes and daylight windows. You can either shoot 500T unfiltered, or you can use a Tiffen LLD filter, which you don't have to compensate for, exposure-wise. It helps somewhat to keep the negative from getting too blue. Either way, you still need to time it in post to look neutral.

Problem may be that the tubes in the office may be close to 4900K, but also have a significant green spike if they are Cool Whites. So if you correct for them in post to remove the green cast, the windows & daylight will go pinkish.

Now if you're willing to use a softer, grainier stock, Fuji F-500D Reala would be a good choice to handle this situation.

Edited by David Mullen, 07 November 2005 - 12:34 AM.

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#4 Miguel Bunster

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Posted 07 November 2005 - 01:05 AM

Thanks for the info!
Now I already have the film so I cant change it. So when I time out the green from the tubes will the skin look normal? and I should add the green to my units right. I will be using HMI all the time. If I dont switch the fluorecents I may be able to get some +Green to add to the windows. That should do the job?

I have one more question for the same project but different. I am shooting a big scene with windows in th BG, I am ND 1.2 the windows to bring them down to the exposure I want. Ideally I want them to go 2-3 stops over (5218) but my concer is reflections inside when I ND them. I will be Shooting most at a 2.8 as well. Is 2-3 stops over briht enough to kill internal reflections (Not counting any light heads)?
Thanks!
Miguel
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#5 David Mullen ASC

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Posted 07 November 2005 - 01:27 AM

Just depends. Make sure the ND gelling is tight and neat because any room lights will reflect in the gel and show that it is rippled. Be prepared to dress the camera and crew in black and put a large black cloth behind the camera to hide reflections of the crew, although you're probably right that a daylit background view will overpower any reflections in the room (except for lighting reflected.)

If your flos have green in them, you'll have to add matching green (often 1/2 PlusGreen) to both the windows and any HMI's you add, so you can then later remove all the green in timing. Faces should turn out OK.
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#6 Miguel Bunster

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Posted 07 November 2005 - 02:08 AM

Thats great help! Thanks once again David. That takes one issue out of my head.
Best
Miguel
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