Green Screen Tips

Posted on by Oriana Chacon

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.

Lighting is especially important! Key Light, Fill Light and Back Light help separate the subject from the background. An even background fill helps too, especially Kino Flos from Moving Picture!
Lighting is especially important! Key Light, Fill Light and Back Light help separate the subject from the background. An even background fill helps too, especially Kino Flos from Moving Picture!

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.

If your subject is too close to the green screen, you will encounter reflected green light, ruining the effect in post.
If your subject is too close to the green screen, you will encounter reflected green light, ruining the effect in post.
Keeping your subject away from the background will minimize the amount of green light that spills onto your subject.
Keeping your subject away from the background will minimize the amount of green light that spills onto your subject.

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.

When the subject is too close to the background, not only is there a risk of reflecting green light onto the subject, but shadows created on the screen can be difficult to key out in post.
When the subject is too close to the background, not only is there a risk of reflecting green light onto the subject, but shadows created on the screen can be difficult to key out in post.
With more separation, a better backlight can be utilized to outline the subject, shadows disappear, and imperfections in the screen become out of focus.
With more separation, a better backlight can be utilized to outline the subject, shadows disappear, and imperfections in the screen become out of focus.

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.

A properly shot green screen shot will reproduce the color and edges of the subject realistically and sharp. None of the green from the screen should be visible in the final product.
A properly shot green screen shot will reproduce the color and edges of the subject realistically and sharp. None of the green from the screen should be visible in the final product.
Spilled green light can cause loss of color in the keyed subject and hard to remove green edge artifacts.
Spilled green light can cause loss of color in the keyed subject and hard to remove green edge artifacts.

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.