The first thing you need to do when planning on using a green screen background is to understand the rules of shooting on green screen, or chroma key. The green screen needs to be as even as it can be and fit across the entire background in the camera’s frame. The actors need to be a distance from the green screen as well, possibly up to six feet.
The reasons for these rules are to make sure that the green screen is lit properly and no shadows interfere with the chroma removal effects. When a person or object is too close to the green screen, there is too much of a chance that the green will bleed onto the subject making the edges look pixilated and ruining your chroma effect. With enough space between the two objects, the chance of the light causing a green glow on the subject reduces, making the effect look cleaner.
Finally, it is important to make sure that nothing in the foreground, from clothing to props to even eye colors match the green that you use for the green screen background. The worst feeling in the world is to remove the green screen, making the entire background look perfect, and then realizing that your actor’s eyes are now black holes.
Supplies for Green Screen Backgrounds
There are many sites on the Internet promising chroma green screen and paint that can run hundreds of dollars. However, there is also a way to make your own green screen backgrounds for much cheaper and still achieve the same effect. There are some detractors who claim you need a specific shade of green or a specific material to achieve the best effect, but any color of green can pass the test as long as nothing in the foreground matches the color of the green you use.
One great thing to use, and you will need a lot of it, it green gift wrapping paper. On Amazon.com, the paper averages around $1.27 a role as of March 2011, or you can find it at your local hobby store. Buy a roll of green tape to attach the paper to each other to make the green screen background the right size. This tape on Amazon.com is $7.58 as of March 2011. It is better to tape it on the backside, so the front remains the same color.
Creating the Shots
Make sure that the actors and props are at least six feet from the green screen background and set up separate lights for the green screen itself. Work with these lights until there are no shadows on the green screen background.
Next, set up the lighting for the actors and foreground subjects. Play with all the lighting, tweaking them here and there until there are no shadows whatsoever on the green screen background regardless of where the actors move and no matter what they do. The lights on the actors and the lights on the green screen should work in collaboration to eliminate all shadows.
Once it is shot, import it into your editing software, use the chroma keying techniques in the software and add the new background. If you lit it right, the green screen background can be transformed into whatever your heart desires.
Article Reference: Author’s own experience.
Image References: Images of products acquired from Amazon.com, sample shot from author’s personal video.