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What gels to use for green screen work?


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#1 Jim Feldspar

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Posted 20 August 2006 - 02:15 PM

I'm going to be doing some green screen shots so I searched on this site and found a lot
of information, including that people like to use green lights for green screen but green Kino
tubes were all that was mentioned. I'm using tungsten lights. Can anybody recommend specific
gels? Also, do people use blue lights for blue screen? Are HMIs good for this sort of thing?

I'm shooting Mini-DV which isn't the best format for green screen because it "loses" too much
color information according to what I've read. Any tips?
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#2 Michael Morlan

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Posted 24 August 2006 - 10:50 AM

Non-gelled tungsten lights can effectively light a chroma backdrop. While the idea is to create as saturated a green as possible on the backdrop, you can still pull an effective key without special coloring of the light. Coloring backdrop lights also reduces their potential bounce around the set thus falling on the foreground subject - especially with bluescreen.

Yes, Mini-DV is the worst possible choice for shooting a chroma keyed subject. It has only 1/4 the chroma data since it only samples chroma in one pixel for every square of four luminance pixels. However, contemporary keying software (like Ultimatte Advantage) have some compensatory algorithms to recreate that lost detail.
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#3 Chad Stockfleth

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Posted 24 August 2006 - 11:02 AM

sometimes a little minus green on the backlight can reduce spill. if your talent wears dark colors and non-reflective objects it will help too. (i'm talking shiny shoes, earings etc.) khaki can be a reflective b*tch.
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#4 Sander van de kerkhof

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Posted 25 August 2006 - 02:04 AM

i'm doing a chromakey project at this moment for a national TV show, i'm using 2 (500Watt) tungsten lights for the screen using a spot meter to make sure the light levels are the same on the whole screen.

be sure to use 2 lights coming from the screen as backlight this will help allot with your key.

greetz,

Sander
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