Green screen lightning, "rooflights picked up in refection of subject"

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Eljoninjo

Well-known member
Hi, im building a new green screen and the light is going to be fluorescent based in the roof. The problem this gives, is for the lamps targeting the floor is going to be picked up in my subjects reflections. How do you tackle this, I se that big studios like to use "spacelamps" but they must give the same problems I guess. Chimera, has F2 lihgtbanks that is large but so is the price:cry:

Im thinking if its possible to buy a large transparent cloth (like the one in softboxes) and make all the roof lights to a big softbox? or more if somebody have a good tip of were to buy this type of material cheap?
 
Simply Light your back wall and use [SIZE=-1]Rosco 3931 Rigid Silver for flooring. No need lighting your floor, you should have Green reflection from the wall.
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Thanxx, I will look for a peace of cheap diffuser in the "greenhouse" and try hitting it with some light and se how its acts.

Heres a little mockup of what im thinking:
http://www.joelarvidsson.com/mockup.jpg

This is just a mockup and dont show how much lights it would need. The ones above is from a calculation.
 
Sorry for posting this 3 links again...
just to make it clear, this is calculated with the lights pointing down normal, spreading a even light on walls and floor:
http://www.joelarvidsson.com/Videostudio01.jpg
http://www.joelarvidsson.com/Videostudio03.jpg
http://www.joelarvidsson.com/Videostudio02.jpg

But it does not give me any control of just lighting the walls and will give me problems in the subjects reflections. So the dummy, mockup i was thinking on lights that target the walls instead as the example picture + make the rest of the roof to a bigg softbox that i can turn on seperatly...
 
I been looking around and found that alot of people use translucent rip-stop nylon to build softboxes. Anybody here that have worked with it? and does anybody know what
drafting velum is???
 
I'd be careful about lighting a green floor from above. You'll be getting huge amounts of bounce light onto your subjects from beneath- making keys very difficult to pull. In general floors should be something from your set not green. Subject and screen should always be lit separately and kept as far apart as possible. The ideal setup is actors far in foreground with zero spill lighting coming from the screen. Here's some details:

http://www.film-and-video.com/broadcastvideoexamples-greenscreen.html

Noah
 
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rip stop nylon or grid cloth - comes in different strengths and is an excellent diffusion material - but isn't really made for attaching to lights. So just attach it to a frame away from the light.

Drafting vellum is what I think we call 'tracing paper'. It is a also great at diffusing - but will really suck up a lot of the light you are trying to pump through it. It also is extremely fragile and easy to rip = kind of a pain to work with. But -if its in the ceiling away from things that can tear it -you could give it a go.

Overall - I don't know if your overall idea is a good one because - as was stated by another poster - you want to keep your GS lighting separate from your subject lighting -if possible. A giant soft box is almost impossible to control.

I am adding this - I would choose gridcloth in almost any off-camera diffusion situation over tracing paper. I carry 4x pieces of full and light gridcloth with me to EVERY job I go on.
 
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But how would you light the floor with out hitting the subject??
The plan was to have seperate controlls, one for the walls and one for the "roof softbox" that i can dimm to control the spill abit.
 
Eljoninjo said:
But how would you light the floor with out hitting the subject??
Click to expand...

I have only done 2 greenscreen projects, and it this has been impossible.
Just try lighting the walls and the floor separately and try to light your subject enough to keep the green cast out as much as you can. To separate your subject I would use some sort of backlight wiht a minus green gel, so make sure you leave room to hang a backlight or just leave enough room to set a stand for the lamp.

Don't try to make the shot's color perfect becouse with this setup its really difficult, Just try to get as good image as you can and then color correct in post.

my two cents
 
Have you consulted with an experienced Gaffer about this. That's where you'll get the best advice about how to do it.
My advice would be to remain very flexible. Must be able to liught the back wall separately and only use the floor lighting when you need it. You should be able to turn off and preferably dim or somehow adjust every lamps output. Every shot will be different.
 
Or light the floor from below. I have only backlit screens, but I suppose it could be done for floors.

Your floor layers would be:
Glass
Diffusion
Full Green Gel
Fluo lights

This is something you'd probably have to engineer to withstand weight... which is probably why I've never seen it done for floors.
 
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