When shooting on green screen, there is a common expression used on the set; “we’ll just fix it in post.” But, for the best results, and keeping your composite editor sane, it is a good practice to follow these simple tips:
1 : Light your screen evenly. Kino Flos are usually the best; offering a very even light and intensity. Shadows, wrinkles and gradients in intensity can make it more difficult for your compositor to control the colors in post.
2 : The greater the distance between the screen and your subject the better. If your subject is too close to the green background, the light being used to light the screen will begin to reflect onto your subject. When the time comes to key out the green, part of your subject will get keyed out with it. The edge pixels will also pick up the green interference, making the edge of your subject appear jagged with green artifacts.
Moving the subject away from the background also enables you to utilize a good back light to create a solid edge light, free of green artifacts. This separation also helps avoid shadows that can murk up the green screen. Keep in mind that as the subject moves away from the screen, you may need a bigger screen due to the perspective of your shot making the screen appear smaller.
3 : When possible, if the composited scene is supposed to appear to be outside, shoot it outside. The natural power of the sun is very hard to replicate indoors. If that is not possible, at least shoot the proper color temperature with properly balanced lights. But most importantly, make sure your lighting scheme for the green screen matches the lighting scheme for the plate background shot. The shadows need to fall the same way and the exposure should match. ALWAYS shoot your plate shot first.
4 : If you are shooting a subject that will end up being out of focus in the scene, do not shoot them out of focus. Shoot them in focus and then de-focus them later in the composite when doing the computer graphics work because pulling keys of defocused subjects is problematic.