green screen makes good sail

trwhisner

Active member
I just shot a clean plate outdoors on top of a building with an actor. We set up the green screen rig to about 8 feet by 14 feet and draped the green screen. There was not a lot of wind but suddenly that rig went on a trip. We had to chase it down and then it toppled over. Anyone know of a good way to anchor this thig down? sandbags?
 
Re: green screen makes good sail

Man, always sandbag your tripods left outside. Don't care if they are holding an elephant in plane, safety first! One time I saved an actor from a rigid reflector that just flew like it was paper. I still cary the marks...
 
Re: green screen makes good sail

if you use a complete frame (ie. four sided frame to stretch rag over) 8x8 or larger u should also tie four lines to the frame, two lines at each top corner. the front lines tie to something (sandbags, grates, anything solid or heavy) in front and the back lines tiee to something similar in the back. when done properly you can fly 20x20 in upto 15 mile per hour winds 12x12 to about 20mph winds and 8x8 about 25mph gusts. with winds over 30 even a 4x4 on a reflector and four bags may go over. these aren't set numbers and always ere to the side of safety. this is in addition to bagging the stands.

ps: hire grips
 
Re: green screen makes good sail

You know what's really fun? When your DP asks you to fly a butterfly outside a 2nd floor window 1 foot away from the house, and the location is one block away from the beach at high tide.

Now that's some wind.
 
Re: green screen makes good sail

I was using a frame with 1 tripod on the left, one on the right, one very long pole in the middle. I am wondering, even with sandbags on the bottom it will be quite leverlike. Maybe tie the tops to sandbags as well, front and back.

I think I will sandbag my dvx tripod as well now. Don't want to see that (with dvx) do a superman off the side of a building.
 
Re: green screen makes good sail

ah, that's what nygrip was suggesting. Damn that evelyn wood speed reading course, I get no comprehension.
 
Re: green screen makes good sail

how heavy should the sandbags be. lugging lots of 50 pounders in a car I think will tend to make the car a accidental low rider.
 
Re: green screen makes good sail

On top of a building, I would definately not rely on just shot bags. That thing should be tied down to something secure or else don't do it. Watching that rig fly off the side of the bldg will not be fun and you will get sued every which way.
On the ground, we tie to trees and cars.
Lead filled shot bags usually come in 25 lb size but there are larger & smaller sizes around
 
Re: green screen makes good sail

U r going to do compositing anyway.Then why dont u green screen the whole action in a safer place ;D
 
Re: green screen makes good sail

I have a shoot coming up next week where I wanted to shoot some of the interviews in front of a green screen (indoors of course). My question is, does it matter what kind of green it is? Could I go to the local fabric store and get a green sheet of fabric and use to light stands to hold it up? I'll get C stands later. Also how far in front of the screen should the talent be? Should there be some distance from them and the screen? Finally how many lights are needed for green screen shoots? Like I said this will only be a seated interview so I won't need to light a large screen. I do plan to use 3 point lighting on the talent.
 
Re: green screen makes good sail

does it matter what kind of green it is?
The actual color isn't vital, but the closer to pure green you can get the easier it'll be to pull a key. The more presence of other colors, the more it'll complicate the key.
Could I go to the local fabric store and get a green sheet of fabric and use to light stands to hold it up?
Yes you can get fabric-store green, just try to get a pure green.

Hanging it off light stands might be a little tough, you want to get it to drape with no folds or ripples, you want it as perfectly flat and shadow-free as you can get.

Also how far in front of the screen should the talent be?
As far as you can get 'em. At least 10' if possible. There are two reasons.
1) Avoiding shadows. You don't want your lights casting shadows onto the green fabric, it'll cause you headaches when trying to pull a key.

2) spill. If you blast lights at the greenscreen, it'll become a giant radiating green softlight. You don't want that light spilling on your talent, it'll make for terrible edges all around.

Finally how many lights are needed for green screen shoots?
They once asked Abraham Lincoln how long a man's legs should be, and he said "I reckon they should be long enough to reach the ground."

So, you need as many lights as you need. It depends on the screen size, mainly. Use at least two on the screen itself, use diffused soft lights as equidistant and even as you can get them, and you may find it easier to use three or four. Don't light the screen to be very bright, but get it evenly lit, with the same amount of lumens hitting every portion of it (which is impossible, but try your best anyway). You can use the DVX's Marker function to spot-check the evenness, scan the DVX around the screen and see if you can get the Marker % readout to be the same everywhere. If it varies by a few points that's probably not bad, but if you have hotspots that are 10 or 15 points hotter than the darker spots, you'll have trouble pulling a good key from that.

You don't need the screen to be bright, just even. The brighter you make it, the more it'll glow green and light up your foreground (which is bad!) If you make it too dark it'll probably start getting noisy, which is bad too. Aim to keep the screen 1 or 2 stops (or so) below your key light.
 
Re: green screen makes good sail

I forgot to ask when I do go to the Fabric Store how large a sheet am I going to need? I guess I can measure off the area I am going to be shooting in and decide from there. Also how do you suggest me hanging the sheet? I was thinking some sort of stands like a light stand but have a bar like a shower rod at the top to drape the sheet over. This is just till I can get some C-stands.
 
Re: green screen makes good sail

Steve Kaeser Backgrounds sells a background holding system that is pretty much exactly what you describe, two "light stands" and an extending rod in between. I think it's about $100. I don't think the stands are appropriate for use as real light stands because they don't have a 5/8" spud on top.

As for the size of the screen, it's difficult to get one that's too big. I've used one of those portable systems with a 12' screen and found it to still be too small to shoot 4 people against. I have a portable 5x7 FlexDrop which is big enough for one person shots but not much more than that. So get it as big as you can.
 
Re: green screen makes good sail

Ok thanks. I have a big B&H "bible" as I like to call it of all Lighting Equipment and they had some background stands in there.
 
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