Television meteorologists use a green screen daily.
Removing a green-screen from a film frame is called "chroma keying" in the film world. This process removes a single color from the background, usually green or blue, allowing you to replace the background with an artificial one. Television stations use green-screens to present weather forecasts. Many low-cost computer editing systems can effectively key out a green or blue screen, enabling filmmakers who are on a budget to use this highly useful tool.
Instructions
1. Iron the fabric until it is smooth. Hang it where it is needed for the shot. Check it to make sure it has no tears or discolorations that might make editing out the green difficult.
2. Light the green-screen evenly and brightly. Be sure that it is lit from at least two sides and that no shadows or bright spots appear on it.
3. Light your foreground subjects with a kicker light -- a light from above. This will help the editing system distinguish the foreground from the background.
4. Film the scene using a progressive field, which records a full frame, instead of an interlaced field, which records half a frame and interlaces it with the next frame. Interlaced footage is prone to unwanted digital artifacts. Also, turn off any auto-sharpening features in your camera.
5. Log and capture your footage to your editing system. Open your chroma key tool and select the color and intensity that matches the actual color and brightness of your green-screen. Often, the first attempt may not remove all of the green. Fine-tuning the color and intensity to be removed is accomplished by trial and error, as no two situations are ever alike.
Tags: color intensity, editing system, field which, field which records, from background, green blue, which records