What if your location is an exotic interior? You were able to get the rights to footage shot in an elaborate and ancient cathedral, and you want to show your talent having a hushed conversation in the massive space. To be believable, good lighting is the key.

For this shot, you will need a larger chromakey green background. Light it as evenly as possible. Then begin your lighting setup for the talent.

Carefully look at the footage you will use in the background. Where do the shadows fall? What kind of light is prevalent in the scene?

For the purposes of this setup, let's assume the lighting is diffused from a number of different sources, very warm and not really bright.

Set up a soft light as your key at the 4 o'clock position, so that it fills your talent's face. If you are working with two people having a conversation, decide which is the more important, and put that person on the side where more light will fall. The key light for one then becomes the fill for the other and vice versa. Set your fill so it is less intense than the key and doesn't give much direction. It should look like ambient spill light and match that in the cathedral. Finally, add a backlight at the 12 o'clock position, hanging above the actors if at all possible. Make sure you flag the backlight from your camera lens to eliminate lens flare.

When you have all of the lights set, white balance against a pale blue cloth. This will tell your camera that light blue is white, and the result will be a very warm-toned image. The result should be very believable (see Figure 2).

To make your chromakey experience successful, remember that you must light the background greenscreen as evenly as possible, and you should place the talent as far from the greenscreen as the scene will allow. You need to carefully study the background footage to determine the type of lighting needed and then work hard to duplicate its intensity and type. From outer space to the dark ages, the sky's the limit. With good planning and careful placement of lights and talent, your scene should be quite believable.

Contributing editor Robert G. Nulph, Ph.D., is an independent video/film producer/director and teaches video production courses at the college level.

With today's editing software, you have the ability to place any color behind your talent to use for a chromakey. All you have to do is make sure there is absolutely nothing close to that color in the clothing or eyes of your talent. The industry uses chromakey green because you so rarely see it in nature and fashion. You can buy chromakey paint or chromakey drops at your video supply store or big box retailer.