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Foam-backed Green Material with SEAMS.... Problems?

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Ralph Chaney
Foam-backed Green Material with SEAMS.... Problems?
on Dec 3, 2009 at 11:38:40 pm

Foam backed material handles wrinkles very well.

Problem is it only comes in 5' widths so anything over that requires a seam.

Manufacturers claim a properly made "over-lock" stitched seam will not present a problem for keying.
(at least not a problem for THEM...)

Any experience out there pulling keys off of SEAMED backdrops?


Thanks!

-> Ralph


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Todd Terry
Re: Foam-backed Green Material with SEAMS.... Problems?
on Dec 4, 2009 at 5:34:30 am

[Ralph Chaney] "Any experience out there pulling keys off of SEAMED backdrops?"

A bit...

Right now we have a 10'x20' greenscreen drop which is, fortunately, seamless. However, the one that it replaced a couple of years ago was seamed.... it had a big 'ol seam running right down the middle.

We never had any problem pulling keys, or troubles caused by the seam.

I think success is going to primarily rely on the quality of the seam, the skill of the DP in lighting it evenly, and the quality of your keying method. Better and higher-end key methods or plug-ins (Ultimatte, Ultra2, etc.), are probably not going to have much trouble with it. The native comes-with-it keyer in your NLE's software might not have as much success.

Those foam backed key drops don't really wrinkle, you're right. But... they do crease very easily, so you have to be extremely careful with folding and storing them. Rolling them up not too tightly is usually the best best. We used to have a foam-backed bluescreen that constantly fought that battle. And, unlike a wrinkle in a cloth drop, once you get a crease or a hard fold in the foam drop... it's there. You can iron or stretch out a wrinkle in a cloth drop, but creases in the foam are pretty much there to stay.

As far as cloth drops go, we've had really good success with that spray-on wrinkle remover that you get in the laundry detergent aisle. Few months ago we put up our greenscreen, and it was a total mess (we don't key much, so the wrinkles were really embedded). Hoping for the best, we put it up as usual, stretched it fairly well, and sprayed it down with the wrinkle remover (not soaking wet, but pretty darn damp all over). In an hour or so it was dry, and perfectly flat and wrinkle free. The stuff works.


T2

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






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Mark Suszko
Re: Foam-backed Green Material with SEAMS.... Problems?
on Dec 4, 2009 at 8:29:34 pm

One of the reasons I recommend RoseBrand in NYC tofolks is that I found they have an extra-wide seamless spandex-based cloth that's reasonably priced, and even available flameproofed... and I thought their prices were good.


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Ralph Chaney
Re: Foam-backed Green Material with SEAMS.... Problems?
on Dec 4, 2009 at 8:34:00 pm

Yes, I'll check out both spandex and RoseBrand in particular. I guess if I keep it on a roll, 8ft., it will stay mostly wrinkle free... and only fold it if transport doesn't allow an 8ft. length.

That crease problem with foam-backed can be a deal-breaker. Too bad.

Thanks.

-> Ralph


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Mark D'Agostino
Re: Foam-backed Green Material with SEAMS.... Problems?
on Dec 4, 2009 at 9:00:37 pm

We have two 22 x 14' canvas painted, (warm textured), drops. One is kept rolled on a carpet tube and the other is suspended on chain/rollers on the cyc track in our studio. The rolled up one is used to add more floor coverage to the hanging drop. To get rid of wrinkles we have one of those hand pump chemical sprayers that I fill with warm water. I hold the canvas taught with sand bags and spray a fine mist on the back of the canvas and once it's dry the wrinkles are gone. The canvases are seamed and were sewn professionally and they are nearly invisible. For our Wescott portable green screen we simply use a small clothes steamer to get rid of the wrinkles.I will check out that wrinkle remover spray you mentioned for when it's not practical to work with a steamer.

Mark D'Agostino
http://www.synergeticproductions.com


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Bill Davis
Re: Foam-backed Green Material with SEAMS.... Problems?
on Dec 11, 2009 at 12:12:28 am

I have a 12x12 foam GS that gets folded between uses.

Yes, it wrinkles a bit, but with proper lighting it NEVER has presented me a problem keying.

I consider "proper" green screen lighting to be at least two matched 4 tube fluorescent sources (standard tubes at either 3200 or 5600k) rigged at the sides or top and bottom. Kino Flo Divas are idea. Or Cool-lights 4 bank fixtures if you want to save money. I've used both and both make for Excellent keys. Long tube fluorescents like full sized Kino-flos are even more forgiving - but the 4' models work fine with slightly more careful setup and aiming.

With that kind of lighting setup, minor wrinkles AND all seam issues disappear.

If you try to use point sources, - and particularly if you can't get them at the proper angle to the fabric (short studio syndrome) then the seams might present a problem.

In green screen work - lighting is always more than half the battle.

Good luck.



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Ralph Chaney
Re: Foam-backed Green Material with SEAMS.... Problems?
on Dec 11, 2009 at 1:19:54 am

Bill, good news about your experience with foam-backed material. Todd warned to be "extremely" careful with folding to prevent a crease (vs just a wrinkle).

Have you ever creased yours? How do you fold yours?

I would normally store it on a roll yet have to fold it from time to time for transport... probably fold the roll over.

Todd and Bill, if I ever folded it for travel by plane, put uncompressed, yet still folded, into a large suitcase, do you think it would crease?

I suppose with enough space and light power, even a crease could be overcome... yet I'm often faced with less that ideal space.

Q: What size screen would be large enough for interviewing 1-2 people, waist up and not much movement?

Q: Would 4' shop-style fluorescents, each with TWO bulbs be adequate to light behind two people?

I'm trying to develop a system that can be as portable as possible...

One more Q: I read to avoid hard-light backlights, be they magenta gelled or not. Strong soft was recommended. Have you had experience with hard backlight creating a key problem?


Thanks much!!! I'll put together whatever system seems best for best results, be it with 8 bulbs or 4, or spandex or foam-backed... even if transport becomes more cumbersome.

This thread is invaluable...



-> Ralph


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Bill Davis
Re: Foam-backed Green Material with SEAMS.... Problems?
on Dec 19, 2009 at 8:10:58 am

Yes, I've "creased mine. As I indicated, with proper lighitng it just doesn't matter. With im-propper lighting it probably will matter. So there you go.

You say "interviewing 1-2 people. Those are two TOTALLY different things.

IMO Lighting a single person is at least 4 to 6 times easier than lighting two people. For a single person, a soft key, a bounce fill and a back light will nearly always do the job.

For two-shot, you're talking 2 keys, two fills and two rim lights. A MUCH more complex lighting plot with much more opportunity to control individual elements.

(There is a technique of lighting where one can set up crossing keys such that you can used half-scrimmed spill from the key to provide fill for the second person - but that's pretty sophisticated and not much done in my experience.)

If you just want a boring flat single camera shot from the front, than I suppose you could say that you don't need much more greenscreen to do a 2-shot than a single. But that's an awful way to shoot dynamic interviews.

Much more typical is to use two or even 3 cameras - one with the wide establishing shot, then two cameras crossing to shoot the individuals reasonably head on when they are speaking. It's nice in a setup like this to use OTS (over the shoulder) angles to include a bit of the head and shoulders of the second party when the first party is talking. Rigged like this, the field of view for a two person interview greenscreen either needs wings or needs to be REALLY wide to accommodate the two crossing wide angles.

To do both good subject lighting AND good greenscreen lighting for something like this you'll need a pretty LARGE open space, and you really can't scrimp on the lighting kit.

Finally, hard lights work the same on a green screen that they do on a human face. Which is to say that as a light approaches a point source, that light's cast shadow from anything, a fold, a stray thread, a facial blemish, or a human wrinkle will be EXAGERATED.

Conversely, soft light hitting any green screen surface from MANY angles - (precisely what large soft sources do) will FILL IN any stray bumps or imperfections and leave you with a smooth appearance.

Good for your greenscreen. Good for your actors. Good for your video.

End or story.



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Ralph Chaney
Re: Foam-backed Green Material with SEAMS.... Problems?
on Dec 20, 2009 at 5:15:05 am

Thanks Bill,

Looks like I'll experiment with various sizes of backdrops (the other-than-green ones I own) to see what sizes of screens will work best for 1 and 2 people. And thanks for the reminder about the second camera position, something I use often in interviews, even with one person. If I'm greening them, I'll need that wing screen in addition to the back.

Thanks again,
Ralph

-> Ralph


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