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First Green Screen Test (Actually Purple Screen)


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#1 Tanner Almon

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Posted 07 December 2008 - 02:37 AM

Hey everyone,

So here is a link to my first attempt at "green screen" (We actually used purple fabric because we wear green in the video).

Super Steve (Purple Screen Test)

Obviously it is far from perfect, especially in the shots where I am wearing blue (Had I not put a blue background behind that shot it really looked bad). This is a bit of a problem because my friends and I have a film we want to shoot this January where there are a lot of driving shots that we would like to do with green screen.

Listed below is the setup I used, and if anyone has any ideas on how to improve I'd definitely appreciate it.

1. I shot with a DVX100A in 24P Advanced. I shot in 4 X 3 to maximize resolution. The gamma I used was cinegamma.

2. We (my fiancee and I) were standing about four feet in front of the purple screen. The screen was lit with two tungsten balanced Kino Flo Diva Lights. We were lit by two diffused Arri 650 Fresnels. And we were backlit by an open Arri 300.

3. I edited in Final Cut Pro and used the chroma key tool to key out the purple.

4. The fabric was purple felt.

Anyway, I thought we were pretty well separated from the purple but obviously it did not key perfectly. I get that having a better camera would obviously help, but if you have any ideas on how I could have lit better please share.

Sorry for the long message. Any suggestions at all would be appreciated. Please, if I did a horrible job please let me know. I need to learn how to get looking seamless.

Best,
Tanner

Edited by Tanner Almon, 07 December 2008 - 02:41 AM.

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#2 Jonathan Bowerbank

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Posted 07 December 2008 - 05:04 AM

I suppose using purple is better than chroma-red since there's far less purple found in skintones ;)

Other than that, MiniDV is just always going to be bad for chromakey because of its limits in resolution and color sampling.
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#3 Frank Cook

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Posted 08 December 2008 - 02:59 AM

You might want to move the screen further away. It helps if it is out of focus, and you will get less reflected light from the screen on the talent. I like at least 8 feet between the subject and the screen - but it's not always possible.
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#4 Tanner Almon

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Posted 08 December 2008 - 08:48 PM

Thanks guys. Yeah, hopefully we'll be shooting our next project with the Panny HVX or Sony EX3. And hopefully we'll have more space than my apartment so that we can get that screen out of focus.

One thing that is certain is that we will have a green screen and not a purple screen. I never even realized there was a chroma red. I think the one advantage that the purple did have over the green is that it probably did not reflect near as much as green would. I think that's probably one negative thing about the color green, that it's hard to control the bounce .

Anyway, thanks for checking it out. If anyone has any thoughts as to which would key better (HVX or EX3) I'd be happy to hear.

Best,
Tanner
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#5 Adrian Sierkowski

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Posted 08 December 2008 - 09:00 PM

I keep my green screen 1/2 under key if i can to help control bounce.
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#6 Jim Keller

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Posted 17 December 2008 - 06:38 PM

You may want to try applying the appropriate color smoothing filter (for DV that's 4:1:1) before pulling the key (It's a video filter under the "keying" heading in the more recent versions). I've found it really does help smooth out the noise around the talent. Not 100%, of course, but it helps.

Edited by Jim Keller, 17 December 2008 - 06:40 PM.

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Aerial Filmworks

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Media Blackout - Custom Cables and AKS

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CineTape

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Technodolly

Abel Cine

Tai Audio

Gamma Ray Digital Inc

Visual Products

Metropolis Post

CineLab

Glidecam

Ritter Battery