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First Time Green Screen


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#1 Anthony Caffaro

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Posted 03 October 2007 - 11:23 PM

Hey, I'm shooting for the first time on green screen on Friday. Just doing some basic test to then play with in post with effects etc. Basically its my first time with green screen. I've done some reading on the topic.

I understand the screen should be lit to about the same F-stop and be about 1/2-full stop under the key light of the actors to prevent green spill. When lighting my actors I need to make sure those lights don't hit the screen correct? What are some helpful tips? Of course have them about 10 feet away from the screen, use of barn doors, flags, etc. Though does anyone have some other useful trick?

Also what about the floor? The screen doesn't fall onto the floor so its just a big green backdrop in a sense with a black floor. I assume I can just leave it as it is.

THANKS
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#2 Michael Nash

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Posted 04 October 2007 - 02:43 AM

The whole idea is to have a evenly lit green background wherever your subject overlaps it. So if shadows or a black floor are out of frame, or far enough away from your subject where they don't touch the subject, you're fine.

Here's an example from a two-camera greenscreen shoot I did last weekend. In an extreme wide shot where we needed to cover the person head-to-toe the 2K fresnel (on the roll of paper, lower right) was in frame. But it was far enough away from our talent that in post they can simply cover it up with a "garbage matte."

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#3 Spencer Stewart

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Posted 05 October 2007 - 06:07 PM

Make sure to have a rim light (of course) to help separate your talents from the background. Some people like to gel it amber too. It should help a lot in post, especially with the hair.

Good luck!

Edited by Spencer Stewart, 05 October 2007 - 06:08 PM.

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#4 Michael Nash

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Posted 05 October 2007 - 10:57 PM

Make sure to have a rim light (of course) to help separate your talents from the background. Some people like to gel it amber too. It should help a lot in post, especially with the hair.


This is a myth -- you don't necessarily need a backlight to pull a clean matte. The only thing that matters in pulling a clean matte is the difference in chroma between the subject and the green screen. For example an actor in a black suit and with black hair presents a clean black line against the green background with no backlight.

Sometimes a backlight (especially colored the complement of the screen -- magenta in this case) can help fill in or neutralize green spill from the greenscreen. But in general if you're having to pump light onto your subject to wash out green spill, your greenscreen is lit to brightly to begin with.

Light your subject in the way you want it to appear in the composite. If you want a backlight on your subject in the final comp, light it that way. If you don't, don't.
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#5 Spencer Stewart

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Posted 08 October 2007 - 08:44 PM

This is a myth -- you don't necessarily need a backlight to pull a clean matte. The only thing that matters in pulling a clean matte is the difference in chroma between the subject and the green screen. For example an actor in a black suit and with black hair presents a clean black line against the green background with no backlight.

Sometimes a backlight (especially colored the complement of the screen -- magenta in this case) can help fill in or neutralize green spill from the greenscreen. But in general if you're having to pump light onto your subject to wash out green spill, your greenscreen is lit to brightly to begin with.

Light your subject in the way you want it to appear in the composite. If you want a backlight on your subject in the final comp, light it that way. If you don't, don't.


Thanks for the correction.
Spencer Stewart
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Rig Wheels Passport

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Broadcast Solutions Inc

Aerial Filmworks

The Slider

Technodolly

Tai Audio

Abel Cine

Wooden Camera

CineTape

Visual Products

FJS International, LLC

Metropolis Post

Paralinx LLC

Opal

Willys Widgets

Glidecam