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Old February 21st, 2007, 07:05 PM   #1
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Green Screen Construction

I've read many threads in here but wanted to throw this out for input as my screen will be fairly large. The wall is 16ft high by 48ft wide. There are 6x4 vertical posts to attach to. I have spoken with Rosco and am looking at their chroma key paint. I'm considering 4x8 sheets of Luan because of it's smoother surface. Above I'll be adding light trusses and possibly some cable rigging gear. Fabric doesn't seem to make sense for such a large area but I have concern about joints. Maybe they can be taped off or caulked. There are three 12ft garage doors for load in and complete control of the lighting environment. Any input would be greatly appreciated. This is a permanent studio installation.
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Old February 22nd, 2007, 12:18 PM   #2
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Michael, why wouldn't you use fabric for this? You would end up with something relatively cheap which could be easily stored and transported for future use. Rosebrand will be happy to stitch any of their fabrics together to creat a screen of any size. If you're worried about wrinkles then you can use the Spandex product which can be tightly stretched.

http://www.rosebrand.com/A_Com/showp...ectGroup_ID=34

But it's probably better to just go with the 16'-5" wide Trevira which could be seamless. Depending on your budget and space, you could have it finished with a pipe pocket at the bottom to stretch the fabric, and/or grommets around the edges so it can be stretched in all directions.

Talk to Peter Monahan, he knows *everything* about soft goods and can explain all your options. His number is 800 223-1624 x246
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Old February 22nd, 2007, 12:29 PM   #3
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Thanks for the response Boyd, I don't know why either way, that's the input I'm looking for, at 16x5 sheets, considering my dimensions I'd likely have about 10 seams coming down the wall, not sure if that's a problem or not. This is a permanent studio installation. I wanted to explore this option so again I really appreciate the response and I will be contacting Rosebrand.
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Old February 22nd, 2007, 12:42 PM   #4
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dry wall would be even smoother than luan, and you would have nice smooth seams.
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Old February 22nd, 2007, 02:13 PM   #5
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That also sounds appealing as long as it's finished right, you have any experience with it in greenscreening? Any thoughts on limitations?

Thanks very much
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Old February 22nd, 2007, 04:49 PM   #6
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Boyd I spoke with Pete - great guy, very helpful. He did actually think that for a large permanent installation that drywall would indeed create a great flat surface. I think I might go that route, more finishing work but hopefully worthwhile. He appreciated your referral.
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Old February 23rd, 2007, 08:48 PM   #7
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Quote:
Originally Posted by Michael Best
I've read many threads in here but wanted to throw this out for input as my screen will be fairly large. The wall is 16ft high by 48ft wide. There are 6x4 vertical posts to attach to. I have spoken with Rosco and am looking at their chroma key paint. I'm considering 4x8 sheets of Luan because of it's smoother surface. Above I'll be adding light trusses and possibly some cable rigging gear. Fabric doesn't seem to make sense for such a large area but I have concern about joints. Maybe they can be taped off or caulked. There are three 12ft garage doors for load in and complete control of the lighting environment. Any input would be greatly appreciated. This is a permanent studio installation.

Michael, I have quite a bit of experience building chroma key walls. The
one we have in our studio is a 1300 sq ft green cove. It has no corners
or hard edges. The back wall is 12 x 30 and it slopes 14 ft forward to a
height of 16 ft. The floor and sides do much the same. When i built this
i had to construct each curve out of fiberglass, much the same way as
an auto body shop. All flat surfaces are 1/2" or 3/4" pressed board.
( HARD FLAT SMOOTH SURFACES )
When you build even a large flat wall i cannot over state how
important it is to use at least 1/2" material and to either liquid nail very
evenly or use dry wall screws spaced no less than 14 inches apart in
all directions. The reason this is so important is, over a large area, like
the one you are talking about, you will either develope stress cracks or
warping will occur. I would suggest using Rosco digi comp paint and their
hard coat primer. Rosco makes tape, spray paint and material that matches
their paint. One last thing, painting with any chroma key type of paint is
not like painting with any paint you have used before. You don't want the
last edge you painted to dry before you overlap to the next. This paint is
quite expensive and you will need at least two coats but in my estimation
it is worth it.
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Old February 23rd, 2007, 09:00 PM   #8
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Let me know what my bill is.....Thank you for that post....Chris, this forum is priceless..
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Old February 24th, 2007, 01:18 AM   #9
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Is chromakey paint really any different than regular paint? I would think that flat green paint should work assuming the surface was prepared properly. I would recommend priming everything white first so you don't eat up expensive chromakey paint. I suppose what I would do in this situation is get some quality regular paint tinted the chromakey color. After priming white and putting a base coat of green, I would use a gallon of the expensive stuff as the last coat. For a wall that big, you probably need right around two gallons per coat (assuming you primed and also aren't wasteful) since it is almost exactly twice the surface area of a 12x12 bedroom.

I bet you can get a drywall contractor to do a fine finish if you tell them exactly what you want. They can also probably curve the bottom of the wall. I believe there are prefab products for making curved drywall.
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Old February 24th, 2007, 06:46 AM   #10
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Yeah the curved bottom gives me some concern, I'm not sure how that will be accomplished yet. I also think I need some kind of cover to keep the screen clean.
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Old February 24th, 2007, 09:16 AM   #11
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Marcus has the right idea when he says to get some flat green paint close to
the chroma color and use it as a base coat after primer. That color itself will
work as a chroma background but not as good as chroma key paint. most of
us, when we first plan to build these huge walls say, " hey, why go buy that
expensive paint Ill just go sown to the hardware store and do a color match."
Well you will find that there is no comercial tint base that will allow that
much color saturation. Having said that, you will still help your self by using
a close color as a base.
As far as building a radius along the bottom like a cyc wall. As I stated
before, fiberglass is the best way to do this but unless you have done this before I would not recomend. Another way to do this is to use shower board.
I believe it is 3/16" thick and quite bendable. It has a white shiny side and
a flat textured side. use the flat side as your surface. When you build your
wall leave a gap at the bottom less than two feet from the floor and run

a board that is 3/16 or 1/4 inch thinner than your wall across the whole length make sure this is
very stiff and secure because this is where you are going to fasten your
shower board and as i have said before you have no idea how much this can warp and kill your edges. Now if the floor is concrete or wood you can
run a furring strip or flat moulding app two feet or less away from the wall.
Run this the full length and either liquid nail or nail if you have a wood floor. once this is dry you can bend your shower board and pop it right into
your oppening and you will have a perfact radius. Practice bending a piece
of some elexible material before hand so you know exactly what radius you
want and how far away from the wall you want to place your furring strip.
Now as you keep adding one shower board to the next make a backing plate out of four to six inch strips of shower board. Run this backing strip
behind the the first board leaving half of it exposed. Liquid nail and use 1/8" pop rivits about 4 inches apart all along the edge. Now apply liquid nails to the exposed backing plate and pop the next shower boaet in. Keep
doing this on each new board as you go along. When you use pop rivits add
the backing washer so you don't just pull through the backing strip. If it seems like i am being anal about securing these edges I AM NOT. With the
slightest change in humidity each 4x8 board will flex in its own way. The
idea is to make this radius one long piece.

Sorry for the strange layout of this. I AM NO TYPIST FOR SURE
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Old February 24th, 2007, 09:18 PM   #12
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Forget the typing, very helpful post Michael. I'm not questiong the paint at all, I already made the decision to go with the chroma paint regardless of price. I like the green base coat also because I think I'm going to use green board instead of regular drywall, not because it's green but because of it's moisture resistant properties. The shower boards are an excellent idea, thanks so much for taking the time.
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Old February 26th, 2007, 02:57 AM   #13
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I've seen a simple construction method with skateboard ramps where they use a radius cut in plywood for the stringers/studs and fasten thin sheets of plywood down to make the surface. They double the layers of thin plywood for strength. Thin plywood will make quite a curve if given time to stretch. The good thing about using something like plywood is the ability to create a smooth finish with putty or joint compound. Plastic won't allow fillers to bond like they will to fiberglass or wood.

I still think there are specialized drywall products made for curved surfaces. The ability to smooth plaster/drywall is a big plus. Perhaps fabric could also be draped in the corner, but I doubt you could get the transition smooth enough.

I think it might be best to use a lighter shade of green for the first layer. Good reflectivity is going to be important under a saturated color. Perhaps chromakey paint has enough white solids to supply it's own reflectivity, but it couldn't hurt to go lighter on the base coat. Always keep a wet edge when painting. Don't paint over something that has been drying for a few minutes. Point the side of the roller that does not connect to the wire frame towards the area you have already painted. The frame side of the roller tends to get more pressure and can cause ridges. The non-frame side has flexibility and is better for smoothing the ridges. In this situation, it is probably a good idea to strain your paint before starting. Make sure to cross-mix gallons of the same color to make sure they are exactly the same. Use excellent quality brushes for the edges or you will cost yourself a hundred times the savings of cheap brushes with labor and poor results.
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Old February 26th, 2007, 02:07 PM   #14
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There are such products to achieve said curved bottom, a search for bendy plywood will more than likely find some reinforced products that will do the job you intend, there is a product called neatflex that would do this, there are others as well more along the lines of very flexible plywood yet of a thicker than normal (for it's bendyness) thickness, it's a case of seeing what is available near you.
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