View Full Version : Greenscreen

03-23-2009, 09:35 PM
I'm going to be shooting a music video that requires a large outdoor background to be greenscreened. There will be a large group of people standing in front of the wall around 50 or so and the wall will be pretty large. This will be outside and too large to have a backdrop.

I am thinking of getting a lot of large green construction paper and covering the wall. I am editing with FCS2 and shooting with HMC150. Is FCP sufficient in doing chroma keying or would i be better off using another program? And will the construction paper work and what would be some technical things that would be a must to make this look as realistic as possible? I've seen some footage that looks pretty good.

Any advice about keying would be good as I have not done a whole lot. Thanks.

03-24-2009, 04:56 AM
I've used green construction paper before!!!

My only problem was getting the lighting even.
With uneven lighting the green will not be consistent so that will make you keying harder.
Also if you are using many different pieces of paper, they can vary in color but that might not be enough to cause any real problems.

03-24-2009, 10:57 AM
You could film them in small groups and composite together. Will there be alot of camera movement?

Green paper will work, but I prefer a specialized material like the stuff you get from EEFX. I have one of there screens and it helps make keying a dream.

As far as the camera goes. Shoot 720p60 to help minimize motion blur. Reduce sharpening. Use a specialized keyer like Keylight (in after effects). Light the green screen evenly. Have the actors stand as far from the greenscreen as possible to reduce greenspill.

03-24-2009, 11:17 AM
The shot will only be 10 seconds tops at the end of the video. I don't think I'll have to move the camera as I know that will be easier to key. I would love to get a screen from EEFX but cannot afford as I would need an extremely large one.

If I am shooting outside on a sunny day would that be sufficient to produce an evenly lit screen or should I bring in other lights to even out. I'm hoping the sun is enough to do the trick.

03-24-2009, 02:50 PM
It's going to be hard to rely on the sun when it moves every 15 minutes. I would bring enough light to light with out the sun and just think of the sun as an added bonus!

03-24-2009, 06:58 PM
Relying on sunlight can result in an hots spots and an uneven screen. It's best to get diffused sunlight if you can. A high cloudy day would be nice or a even diffusing the sunlight through a uber-large sheet.

Again, since it's going to be a short static shot, you could consider filming small clumps of people and compositing. (If you move the camera, then you need to worry about motion tracking and parallax.) Then you can get in closer and get better keys and when reduce the image size for the final comp some keying imperfections will be hidden.

03-25-2009, 08:59 PM
Here's some rough greenscreen tests I did. I bought a big role of green plastic/fabric from Party City and put it on the wall. Did the best I could to light it evenly. First clip is keyed in FCP and the second is keyed with Motion.