Most of us understand the basics of shooting a chroma key scene: set up a green or blue screen behind the subject, light it brightly and evenly, move the subject far enough in front of the screen so that the subject’s lighting won’t throw shadows on the background, light the subject, and away you go. Oh yeah, and make sure the subject isn’t wearing the color of the background!
But there’s something else that we should all be paying attention to that is often ignored - or simply not known. What will the scene that you are keying the subject into look like, and how can you light the subject to best match the lighting of that scene?
For example, if you know you want your subject to appear at a beach during sunset, light your subject as if he or she is standing on a beach during sunset! Simply bringing in a warm backlight from the direction of the sun setting helps sell the scene.
If it’s a bright, high-contrasty scene behind the subject, make your keylight a little harder, and minimize the fill. Pay attention to the shadows of the background, and try to match those angles. On the other hand, if it’s a cloudy day, light the subject with a big, soft, even source - like that provided by a cloudy sky.
This of course requires that the production team know before the shoot what the scene will look like behind the subject. It’s great if the director can provide the DP with a shot of the intended background. It's even better if this shot includes a close-up of a person standing in that background - so that we can see the way the light falls on his or her face.
However, many times the team decides the background long after the shoot is over. In this case, great 3-point lighting of the subject usually works fine.
But the more information we get ahead of time, the better we can make it look!
At Big Pictures we have extensive experience lighting for chroma keying, using backgrounds of all sizes - from huge green screens large enough to drop a car in front of, to small and portable enough to set-up anywhere.
Small and portable is definitely more commonly called for by our client base. In fact, our Wescott 6’x7’ collapsible Green/Blue screen gets the most chroma-keying work of all. It’s fast to set-up, and can be used virtually anywhere. It’s perfect for shooting a single subject, like we did for the Autonation shoot pictured here.
Written by Tom Miller This Article first appeared in the March 2008 issue of Big Pictures News. Copyright 2008, Big Pictures Media, Inc. All Rights Reserved.