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Best Green Screen Fabric Options

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Ken S.
Best Green Screen Fabric Options
on May 24, 2016 at 7:33:56 pm

I am wondering if any of you have used this green screen fabric and what do you think of it. I am doing a setup in a small studio with a low 9 foot ceiling and need something that is least reflective to control spill. I called them and they said it's made from commando cotton fabric. Would this be the best non reflective option.

http://www.chicagocanvas.com/product/chroma-key/


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Mark Suszko
Re: Best Green Screen Fabric Options
on May 24, 2016 at 8:41:00 pm

A felt-like texture will be rough and random on the surface and thus less reflective, so the stuff you showed might work. Spill mostly comes from two things: talent/subject too close to the screen in the first place, and over-lighting the screen. You don't need it bright, so much as you need it *even* and *saturated*

You can help kill green spill with gelled magenta back-lighting on the talent. Against bluescreen, you counter with bastard amber.

My rule of thumb on screen distance is the talent's height, plus a foot or two. Keeps the shadows off the screen and spill off the talent.

My first recommendation for cloth is always RoseBrand out of NewYork. They still offer swatch books with actual samples you can try in the studio.


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Ken S.
Re: Best Green Screen Fabric Options
on May 25, 2016 at 3:05:12 pm

Thanks Mark for the input. The room is rather small at 17 feet wide x 20 long and that's why I need the least reflective material. My subject will be about 9 feet from the screen and planned on covering the whole back wall and a portion of one side. Right now I have a cheaper muslin green screen from Ebay, it's 10x24 feet and paid $50 box for it, I would like to have the option of doing full body and some tracking shots. I figured covering three walls would create a problem with spill at 17 width. So my plan is to cover the full back at 17 feet with 7 feet on one side. I have already installed a wall track system for the backdrop and covered the windows. I need to take the backdrop to an alteration place to place grommets on the 24ft side. But then ran into the material above and was willing to pay the extra if it was going to help a bunch. I have used a smaller piece of the ebay green screen in the past and done fine with bust and up to the knee shots. But spill was an issue, but was able to get a decent key. Again, not sure how much better is the above material going to be, but if it is better then to me it's worth the extra.


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Mark Suszko
Re: Best Green Screen Fabric Options
on May 25, 2016 at 3:33:22 pm

I don't know the details of the shot you need, and you probably already knew this, but I'll note here for beginners that you don't necessarily need the entire room shrouded in cloth to get a wide or full-body chromakey shot. You only need enough cloth to get a few "clean" inches all around the subject; so-called "garbage mattes" and cropping tools will take out the rest of the room.

Unless there's a compelling need for more cloth, like a physical prop or needed object in the frame with the actor. If you mean to shoot 2- camera with angles, Roberto Rodriguez has shown that you can fake it with just one, by simply leaving the camera in place and having the actors rotate on their spot. To the camera, the effect is the same as moving the camera to a new side, but without any more cloth or work. Rodriguez uses turntables to help with this, but they're not strictly necessary. (Note: that trick will sometimes require re-lighting to set the key, unless you light it flat.)


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Todd Terry
Re: Best Green Screen Fabric Options
on May 25, 2016 at 3:44:16 pm

I'm not sure if the extra expense of that fabric will solve the issues that you have, you might be fine with what you've got.

The "nappy" surface of that fabric does make for good greenscreening... because it helps it light evenly and reduces shadows from wrinkles and folds, helping you get a good key. You don't sound like you are having an issue with that, though.

It doesn't, though, do much to cut reflectivity, which you say is your problem.

All fabrics are going to be reflective (although yes, some more than others... black velvet, for example, will have little reflectivity). Think about it this way, if you can see the green fabric, it is by very definition reflective... it is reflecting light back to your eyeballs allowing you to see it. I don't think the nappy fabric is going to be any less "reflective," and even if it was, would that be what you'd want? You'd just have to pour more light on it to get a decent level, which is just increasing what is being reflected anyway.

The issues that you are having, which I'm guessing is getting a green glow or cast to your talent would, I doubt, not be lessened by changing to this fabric. And things like actual reflections in eyeglasses, reflective jewelry, etc., wouldn't be changed at all.

The keys here are, as Mark said, to keep good distance between your subject and the backdrop... and, more importantly, not to "over green." If you have nothing but a talking head, there's no reason for them to be in a head-to-toe wraparound green room. You need no more green than will cover the frame. Actually, you need no more green than will cover the subject's edges, as anything else can be garbage-matted out. It's that "extra green" that is giving you trouble.

If this is a continuing problem, I'd suggest a system (roller system, or other), that will allow you to "fully green" the space only when needed, and let you use much smaller greenscreens when you can get away with it. Or alternately, black curtains or flags that will let you block all of the greenscreen that isn't needed for a particular shot.

Our most difficult key in a situation like this was a corporate shoot with an executive a couple of years ago. He wore eyeglasses with shiny tortoise-shell Rayban-style frames. We often seen reflective problems with glasses with the lenses, but in this case the arms of the glasses were so reflective that we knew would wouldn't be able to pull good keys... they would key right out. we had to put two black flags on C-stands right slightly behind and right adjacent to the guy's head. It worked, though, because we still had a good clean line of green around all the guy's edges.

And by the way, if you are handy at all don't bother with going to an alteration shop to grommets. If you can work a hammer you can do it yourself in five minutes with a five-buck grommet kit from the hardware store.

T2

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



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Ken S.
Re: Best Green Screen Fabric Options
on May 29, 2016 at 5:08:03 am

Thanks again guys, one question concerning lighting the subject, my kino flo light setup uses 4100k tubes to light the screen. Is it best to light the subject with a similar light and color temperature? When you setup white balance do you balance it to the subject and try to keep color temperature on subject close to 4100k. For example if I was to light subject with tungsten at 3100k and add a CTB full is that just as good as using CFL fixtures?


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Alan Lloyd
Re: Best Green Screen Fabric Options
on Jun 25, 2016 at 2:42:52 pm

Full CTB is far higher than 4100K - think 5600.

I would just leave it as you described, minus the CTB.

I see this is nearly a month old, how did it go?


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Ken S.
Re: Best Green Screen Fabric Options
on Jun 25, 2016 at 6:11:16 pm

Hi Alan, I just finished construction on installing kino lights in the ceiling and 44 foot wall backdrop track on the back wall and two sides. I only shot footage against the black backdrop so far. I will install green screen next week and have my first shoot. Concerning color temperature I should have said half CTB. I am trying to see if it's best to keep the lights on the subject close to the same kino temperature because the studio is small and any spill on the screen would be the same color. Or if it's best to keep my tungsten at 3200k and do I white balance based on the 3200k and ignore the 4100k kinos?


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Alan Lloyd
Re: Best Green Screen Fabric Options
on Jun 25, 2016 at 7:59:46 pm

Keep your tungsten as it is. There's really nothing to gain from wedging it.


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