Lighting Green Screen

[Ryan Handley]

Hello All,

 

I have a few questions hopefully someone can answer for me. I'm going to attempt green screening here in a few weeks. We are in a small room so there is not alot of space to work with here I'm talking about a room the size of 15x15.

 

We have painted a wall with several coats of green paint and have set up the lights. We are having problems getting the lighting even, we seems to have alot of light in the middle of the wall. We have tried moving the lights back and adding gels but we still get the same effect. This is a pain when it comes to keying the green out b/c around the edges all the green will not come out. We can get all the green out but the person on camera losses parts of their body.

 

As of right now we have 2 650 watt lights lighting the green wall and 2 150 watt lights lighting the person. We have the person on camera standing about 6 feet from the wall. Is there anything that anyone can suggest to help me out.

 

Thanks,

Ryan

[David Mullen ASC]

Two lights for the screen may not be enough to fill it evenly if you can't back them up enough. You could try adding some green-gelled fluorescents. You could try diffusing your lights a little.

 

I'm afraid one of the most important things is to use the biggest screen you can as far away as you can. Nothing is harder than dealing with a screen in too small of a space for anything other than a close-up in the foreground.

[Alvin Pingol]

Because you're in a small room, you will have trouble evenly lighting the wall with just two lights since you would be forced to place them so close to the screen, and like Mr. Mullen said, you will also be forced to place your subject close to the screen.

 

Having done some extremely limited greenscreen work (and incorrectly, mind you), I have now learned that the two things that must be true for any greenscreen work (whether you have two lights, or twenty) - a) the subject must be as far as you can place it from the screen, and b) the lighting ratios must be correct.

 

Deviating from these creates one of the most difficult problems to fix: Green Spill. As you can see from this thread, even with some of the best chromakey software, one is not able to pull a perfect matte with sub-par input material.

[Rob van Gelder]

Yes, de small room is basically the problem.

When your object is that close to the wall, the green spill light can "envelop" your subject and make it partly green too.

 

Another thing is that often the background is lit with too much light.

Try to have the background when green at minus 1 stop compared to the object.

When shooting bluescreen make this minus 1/2 stop.

 

You will be surprised how much you can key out with the background slightly under exposed.

That will also keep the spill on the model in control.

 

Can you open a door, photograph through the door an put the model further from the green?

 

 

Rob van Gelder