Video Essentials

The Basics of Green Screening


Call it green screen, blue screen, or chroma key, but it means the same thing: shooting against an even-colored background so that you can swap in your own more interesting background later.

While it was once the stuff of Hollywood movie magic, even home editing tools such as Adobe Premiere Elements and Pinnacle Studio now include a green screen feature (Pinnacle Studio Ultimate Collection even includes a green screen in the box). All you need to do is shoot against the right background and follow these tips to get the best possible results. (By the way, if you’re wondering where to get the fake background that you add during post-production, don’t worry: you can use any picture or clip you have on your hard drive.)

Paint if You Can
You’ve probably seen green screen fabric or paper backdrops, like the one in this picture, but painting the wall is an even better idea. You don’t need to worry about folds or wrinkles in the fabric with a painted wall, and setup is faster. Also, your scenes will be better lit, since a painted wall won’t absorb light like fabric. Look to a video store for chroma key paint. If that’s too expensive, you can go with a paint shop color that’s close. You video editing software can likely key into any color, so having the exact SMPTE (Society of Motion Picture and Television Engineers) color isn’t that crucial.

Take Time with Lighting
Lighting takes on new importance when green screening. You want to position your lights so you have even lighting throughout, with no light or dark spots. Use soft lights, so there’s less chance of shadows. Light both your subject and the screen separately, so your subject doesn’t cast a shadow on the screen. Be careful not to overlight the screen, or you’ll bounce the color back at your subject and get a little green or blue on their shoulders.

Place Your Subject
Your subject should stand six to eight feet in front of the screen, enough that they don’t cast a shadow and the screen looks even-colored behind them. Make sure they don’t wear green or blue, whichever color you’re using, or those body parts will disappear in editing.

Shoot it Blank
Record a little video of your green screen background by itself, before adding a subject. This will help you key in on the correct color when you’re editing the scene: You’ll be able to identify the exact shade that the software needs to remove more easily if you don’t have a person in the shot.

Blur Your Background
How convincing your green screening is will be revealed in editing. If the lighting on your subject is different from the lighting on the background you’re adding in, the effect won’t be convincing. You’ll also want to make sure that the camera height is the same for both. Here’s a tip for making the added background more convincing: Add a bit of blur to it. Having the background just slightly blurry creates an illusion of depth and adds to the realism of the shot.




Discussion

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  1. THanks for the blur tip, it makes a lot of sense. I do strugle with the edges. Overhead light helps with shadows as well.

    Posted by Becky Kirstein | August 24, 2010, 9:00 am