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Color balance in the Great Outdoors


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#1 MICHAEL TAPP

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Posted 17 December 2007 - 01:45 AM

Hey Guys-

One afternoon this week I am shooting a scene with a couple stuck in traffic. We are going to have the car parked in a parking lot. There's going to be a bus parked behind the car and a car on the passenger's side and the driver side of the talent's car. We are going to shoot the master shot through the windshield and then a cross close up for the passenger and the driver.

Our lighting scheme is to fly in a 12 x silk overhead to diffuse the sun. We are going to have a 1200 HMI Par (1200 Arri Sun) off to one side shooting through some sort of diffusion. We are also going to have a flag on stand by for any stray reflections, and there will also be a polarizer in front of the lens.

My big question is about a gel for the 1200 HMI. I read that HMI color temperature ranges from 5600 Kelvin - 6500 Kelvin. We're going to be shooting about two hours before sundown and the light is going to be a little bit warm (guestimating around 4400 degrees Kelvin). Since I'm not positive what the exact color temp. of the 1200 HMI(no color temp. meter!), how am I supposed to know the specific gel I need to order? We probably only have enough cash for one gel instead of each level of C.T.O. . Thanks for taking the time out to read this and any input that you have will really be appreciated.

Edited by MICHAEL TAPP, 17 December 2007 - 01:45 AM.

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#2 David Mullen ASC

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Posted 17 December 2007 - 02:07 AM

I actually don't like to match the color of soft HMI fill to the sun -- it should be cooler than the sunlight anyway because it's the skylight in theory. That's also why using blue bounce material instead of white to reflect the sun is nice, because you keep some of that color temp difference.
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#3 Tim O'Connor

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Posted 17 December 2007 - 08:34 AM

I actually don't like to match the color of soft HMI fill to the sun -- it should be cooler than the sunlight anyway because it's the skylight in theory. That's also why using blue bounce material instead of white to reflect the sun is nice, because you keep some of that color temp difference.



Always learn something from you, David. Seriously, thanks. The blue bounce material never occurred to me
but it sounds great.


What do you use for blue bounce material? Is it something you make or is it an expendable available from
a rental house? I've certainly seen warm reflectors but never anything on the cool side. Sometimes I get
bead board from a building supply place and I've seen a lightweight cheap blue colored 8' x 4' board there.
Maybe that would work although it's a strong blue. I'm guessing maybe I could spray paint a lighter, softer
blue onto some Foam-Cor or use some kind of colored griffolyn?

Michael, if you're getting the HMI from a rental house and want to know just out of curiosity, you could ask them
if they could measure the color temp. for you. Somebody there should have a meter.
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#4 MICHAEL TAPP

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Posted 17 December 2007 - 12:03 PM

Really, thanks for the replies. This board is a great resource. I've never thought about how a shaft of direct sunlight will be cooler than the ambient light outside. You're the man David Mullen.
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#5 David Mullen ASC

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Posted 17 December 2007 - 12:07 PM

Really, thanks for the replies. This board is a great resource. I've never thought about how a shaft of direct sunlight will be cooler than the ambient light outside. You're the man David Mullen.


Warmer, not cooler.

I think the bounce material is called "Daylight Blue".
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#6 MICHAEL TAPP

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Posted 17 December 2007 - 01:03 PM

Originally I was thinking of the 1200 light as the source/key, and the the 12 x overhead as the fill/ambient. But anyways now I understand the reasoning for the difference in the color temp between the two. Thank for you for your time.

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#7 David Mullen ASC

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Posted 17 December 2007 - 01:12 PM

If you're using the HMI to create the effect of hard sunlight hitting their faces, then it does have to be gelled warmer, especially if there is any real sunlight in the background. Usually 1/4 CTO or 1/4 CTS works, until you start having to match sunset, then you need 1/2 CTO, then full, etc. But often, except at late afternoon, direct sunlight doesn't reach the faces in a car.

Also remember that your silked overhead sunlight will be warmer than real skylight. That's not necessarily a problem, but again, you don't want your HMI looking cooler than that if it is used hard and direct as sunlight, not softened as fill.
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#8 Mike Williamson

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Posted 17 December 2007 - 02:46 PM

I think the bounce material is called "Daylight Blue".


In the October AC article on "3:10 to Yuma", Phedon Papamichael talks about using Daylight Blue bounce material to keep the fill cooler. I actually wasn't crazy about the look, I guess I felt that bounce light in the desert should be warmer since it's reflected off of sand and redish rocks, etc. Anyhow, "3:10" is a good film to watch for mixed color temperatures during the day scenes.
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#9 Tim O'Connor

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Posted 17 December 2007 - 09:04 PM

In the October AC article on "3:10 to Yuma", Phedon Papamichael talks about using Daylight Blue bounce material to keep the fill cooler. I actually wasn't crazy about the look, I guess I felt that bounce light in the desert should be warmer since it's reflected off of sand and redish rocks, etc. Anyhow, "3:10" is a good film to watch for mixed color temperatures during the day scenes.



That'll be fun to look for. Sounds like a good tool, although maybe used differently according to taste.
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Metropolis Post

rebotnix Technologies

Gamma Ray Digital Inc

Broadcast Solutions Inc

Tai Audio