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Green Screen Lighting Issues - Dark area noise and harsh feet shadows

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Calvin Gaunce
Green Screen Lighting Issues - Dark area noise and harsh feet shadows
on Jan 20, 2015 at 3:30:08 pm

We have a recurring shoot where we continue to run into the same two issues. Our set consists of a medical exam table sitting on top of a green screen. The talent sits on the exam table and we record 'Doctor/Patient interviews'.

ISSUE 1: When the talent is on the taller side, their feet hang down past the bottom of the exam table and create really harsh shadows on the green screen, making the footage very difficult to key.

ISSUE 2: The dark area on the front of the exam table, behind the talent's legs, is very noisy.

I believe these two issues are linked and both have to do with lighting. However, I have yet to find a permanent solution to either one of them. I am currently setting a small LED light in front of the camera that helps with the shadows, but it still isn't solving the problem.

Our camera is a Panasonic HMC150 and I use the 'Keylight' effect in After Effects to key the footage. Keying is very difficult around the feet shadows and some of the green reflection shows on the exam table, which in turn, ends up being keyed slightly creating a lot of noise. I use the 'Remove Grain' effect to help remove the noise.

Any advice on a solution is greatly appreciated. I've attached screenshots of the issues. Thanks!




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Mark Suszko
Re: Green Screen Lighting Issues - Dark area noise and harsh feet shadows
on Jan 20, 2015 at 3:54:33 pm

Just hitting it with more hard light will also increase green spill reflections. What about adding soft light to just the green area? You can also invoke more than one instance of a key, and use masks to define where it is applied.


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Todd Terry
Re: Green Screen Lighting Issues - Dark area noise and harsh feet shadows
on Jan 20, 2015 at 4:04:26 pm
Last Edited By Todd Terry on Jan 20, 2015 at 4:06:43 pm

I would think that could be easily fixed by adding another lighting instrument.... but not something on or at the camera as you tried...

Just a little special of some kind down near the problem area....



It doesn't even have to be a "real" instrument... could be anything... a clamp light from the hardware store, an LED shop light from Harbor Freight, someone's desk lamp that you borrowed when they weren't looking... anything to kill the shadows and brighten up that area. I wouldn't worry much about color temp in this instance.

You'd probably have to put it fairly close and garbage matte it out of the scene, but that's easy breezy.

All that being said though, I'm a bit surprised that KeyLight wasn't able to pull you a clean key with that scene.

T2

P.S. My sticking-my-nose-in-it addendum from the "we didn't ask directorial advice" department would be, "Why would anyone ever want a head-to-floor shot of this scene anyway? I suppose there is a reason....

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Calvin Gaunce
Re: Green Screen Lighting Issues - Dark area noise and harsh feet shadows
on Jan 20, 2015 at 4:35:07 pm

Thanks, Todd. A simple light like you have demonstrated does seem to be the best solution. I've stayed away from that in the past because the talent tends to move their feet back and forth and I didn't want them to cross in front of the light. However, I don't think that will be in an issue if I monitor their feet and the light placement. I appreciate it!

Calvin


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Calvin Gaunce
Re: Green Screen Lighting Issues - Dark area noise and harsh feet shadows
on Jan 20, 2015 at 4:17:17 pm

I will try the soft light. I usually use masks and multiple instances of keying, but it seems like unnecessary extra work. Thanks for your comment!


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