Take 5: Five Tips for Better Bluescreens

Ever wanted to scarf down a baguette at the Eiffel Tower, walk your dog on the moon and add your own five-day forecast to the 10 o'clock news - all in the same day? In the video world, you can do it, no sweat, without leaving your back-bedroom studio. The key is chromakey.
The process is pretty easy, really. Shoot your talent in front of a bright blue or green backdrop, then use your editing software to replace the "key color" with another image, like the picture on a Parisian postcard, some vintage video of a moon-landing or a TV-style weather-graphic tooled in your titling program.
A lot of color-keys look crummy because of a few common mistakes. Here are five rules the pros use to prevent poor-quality keys.

1. Light it Right or it's Good-night
The first secret for obtaining killer keys is to sufficiently light your backdrop. If you light your green wall with a single lamp you may get a bright green hotspot in one corner and a dark green shadow in the opposite. Put simply: you can't key out a gradient background. The first secret to good keys is to achieve flat, even lighting so your key color is uniform and consistent. Fluorescent tube lights or large, soft lights positioned at the sides of your weather wall will work well to evenly light your set.

2. Keep Your Distance, Dude
Secret No. 2 is distance. Move your actors as far away from the background as possible and light them independently of the wall. This distance will allow you to position your key and fill lights so that no shadows are cast on the chromakey wall (shadows will not key out) and prevent wall-colored reflections from reaching your subject (colored halo reflections will key out, causing portions of your talent to disappear into oblivion). A strong back-light on the hair and shoulder will help outline the subject for a clean cutout.