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Old September 29th, 2006, 09:08 AM   #1
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green screen construction

I need a green screen on a 12'x10' wall, and I would like approximately six feet of screen on the floor. Does anyone know where I can find sections of quarter pipe designed for this? I think it would need a radius of one foot or so. Alternately, I could mount a rod on the wall and hang a long canvas that trailed out onto the floor. If this is a better option, does anyone know where I can find a mounting rod and a green canvas designed for this?

I would appreciate any advice. The screen doesn't have to cover the entire wall; really it only needs to be 8'x8' on the y-axis, but I do need it to extend onto the floor, and people will need to walk on it.

Thanks very much.
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Old September 29th, 2006, 01:26 PM   #2
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Use green Savage Seamless paper, on a stand. You can find it at B&H under "Lighting & Studio>>Background materials".

They have stands and everything, and you can get it in green for chroma-keying. Haven't used this method myself, but was shopping for something similar recently.

This is an inexpensive, temporary solution, among the many options you have. I believe there is a whole thread here on this kind of keying work.

If you need a permanent cyc-wall for your studio look at www.procyc.com

Good luck.
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Old September 29th, 2006, 07:17 PM   #3
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Harris...

If you're looking for green screen fabric, check out eefx.com.

I just started using their fabric and it's very nice. Wrinkles flatten out nicely. It lights very evenly. And the green color keys exceptionally well.

We used it in a recent commercial shoot and Keylight in After Effects created a nice key on the first click. Didn't take much adjustment to nail it.
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Old September 29th, 2006, 09:31 PM   #4
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I bought a canvas drop cloth at Home Depot and painted it green. - that may be a cheaper/faster solution for you.

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Old October 2nd, 2006, 11:45 AM   #5
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Thanks! I think I'm going with the eefx foam fabric, though I'm still not sure how I'll mount it.

By the way, how should I best light a green screen? I already have two 300 watts and umbrellas and a back light for the subject, but I have little experience with lighting a screen evenly. Do I need two or more? How close should they be to the screen? Should I use diffusion? My budget is flexible, but I'd like to keep the cost of the lights less than $600 or $700. Is this possible?

Also, if there is another thread on this topic, could someone direct me there?

Thanks again!
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Old October 2nd, 2006, 12:14 PM   #6
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Quote:
Originally Posted by Harris Porter
By the way, how should I best light a green screen? I already have two 300 watts and umbrellas and a back light for the subject, but I have little experience with lighting a screen evenly. Do I need two or more? How close should they be to the screen? Should I use diffusion? My budget is flexible, but I'd like to keep the cost of the lights less than $600 or $700. Is this possible?
i was able to light up a green screen 10 feet wide with just two Lowel Tota lights placed just off to each side of the screen. Each was aimed at the far end of the screen at a 45-degree angle. Illumination was very even.

Mounting it is simple. I used an aluminum pole suspended across two light stands and clamped the fabric to them with simple spring clamps.
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Old October 3rd, 2006, 10:03 PM   #7
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I just wrapped up my last job that required about three days of green screen. A week of solid rain, limited access to our actors (very busy sales reps) and a tight deadline forced a green-screen shoot indoors. The script called for a corporate look of black and white images with red composited elements to match the theme for the show.

This question about green screens comes up all the time, and the answer usually is “light evenly.” Since I’m finally taking a breather, I’ll elaborate and hope to save others some time.

Go here for picts: http://www.dvinfo.net/gallery/browseimages.php?c=48

1. Use a bright green material that is even colored, flat and smooth (without texture).
2. Mount the material so that it’s without creases. For paper, a tapered roll off will do. That is, hang it from the top and allow it to gentle curve outwards to the bottom. Otherwise, for fabric, stretch it taunt on a rigid frame.
3. Use even, soft, diffuse lighting that will “illuminate” the material without producing shadows. If you cannot avoid shadows, then make sure they are far enough away from the area of action and use garbage mattes in post.
4. Space your subjects far enough away to avoid green spill and avoid creating shadows onto the screen (unless that’s what you want, and/or it’s hard to avoid if using a green floor, etc.). You’ll have to light your subjects separately, but use lighting of the same color temperature.
5. Deal with green spill on shiny surfaces that have reflective/spherical properties (including sweaty skin, and light colored clothing). Also watch the hair, eye glasses, etc. Use of black gaffers tape, photographers dulling spray can fix some surfaces like dashboards and chrome.
6. If you can’t place the subjects far enough away to avoid spill, or have surfaces that reflect the green, then compensate by adding lights that overpower the spill and correct it back to white.
7. Use a large monitor while making adjustments, and perform a test shoot, taking the sample into post and checking to see how clean the key is.

If done correctly, even 8 bit 4:1:1 video will key well. I never once cracked open After Effects. Everything was done within Premiere Pro using the basic keying tools.

Here we cleared an area in one of our warehouses. I used a roll of flat green paper from an art store. Something bright but not glowing. I taped the paper to two telescoping stands, using a third to stretch out and put a sloping curve on the material, removing creases that cause self-shadowing. I used the house floods overhead, placing the paper directly underneath two them for even lighting.

I then placed tungsten flood lamps to deal with green spill, using a monitor to check. I also mounted a spot on the pole coming from the direction of the screen to light the edges of the subject and provide some separation.

My friend, Mike, assisted as gaffer and held up black canvas and/or black foam board to deal with reflections on the glass and nasty green spill too hot to flood out. Everything else was handled in post with garbage and track mattes.


I then white balanced the cameras to the lighting on the subject and ran some test in post before the talent arrived.

For the phone, I picked up a can of green fluoresant asphalt marking paint. It’s flat, bright, but neutral, sticks to anything, and keys well. (I wiped the buttons with oil before applying).

Additional work could have been done on some edges, but they liked the look and for a one time show opener, it was good enough, and I was happy to render the final.
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