Mono iBroadcast » Ideas for Green Screen Video Producers

seo on July 29th, 2010

Utilizing green or blue screen (chroma key) in your video projects is a great way to introduce a professional and stylish look to your video productions. Since you will have the ability to alter the background of your production at any time in post production, there are no limits to the creative direction of your final composition. There are a wide variety of chroma key backgrounds to choose from that will give your video production a polished look similar to larger video productions.

Using a green (or blue) screen in your production pipeline is simple: get a solid green or blue background, film your subject in front of the background, then remove the chroma key in the background using your video editing software and replace it with something else. However, getting a clean key from your video can be a trial and error process that could cause frustration if the original videois not shot correctly.

Here are some techniques that you can use to make your green screen background production as seamless as possible:

Choosing your backdrop
a. A chroma key background can be any color as long as it is not contained within the foreground elements you would like to keep in the scene. Most video productions utilize either a green or blue screen. A clean key can be achieved with either color, but you will want to take into account the color of clothing your talent will be wearing and also make sure nothing in your scene closely matches the color of the background color you are trying to remove.

b. The more consistent and true your color is, the better you will be able to key the color out of your background footage. If you are using a linen or fabric backdrop, try to minimize the wrinkles and shadows in the cloth.

Illumination
a. The most important element of a good green screen video production is the lighting. A well lit scene will allow you to easily tell the software what color to knockout and what elements to keep in the scene.

b. Setup a series of lights that illuminate your backdrop consistently and try to reduce the number of hotspots on the backdrop. Outdoor or fluorescent lighting is a good option because it is a diffused light that spreads evenly across your backdrop.

c. Illuminate your subject fully with soft lighting. You may also want to try to add a spotlight pointing at the back of your subject. This will help to cleanly “cut” your subject from the background and will result in a cleaner key.
Setting up Your Scene
a. Place your subject a minimum of 4 steps from your backdrop. This will eliminate shadows from falling onto the green screen and will also help to minimize color spill. Color spill occurs when the reflected green from your backdrop “spills” onto your subject and causes the color of clothing or skin to change hue to match the backdrop . This can cause issues when the video software tries to remove the green from the backdrop and registers the green reflection on your subject.

Video Camera Settings
a. Try to shoot your video with the best HD camera you have available. If possible, use a camera that allows you to make manual adjustments to the ISO/Gain, shutter speed and white balance. The ISO/Gain controls should be set to a low setting. This will require more light, but will give you cleaner video with less noise and artifacts.

By following these simple rules and techniques, you should be able to create a clean shot that will allow you to easily remove the chroma key from your background. Now you can replace the green screen with a virtual background or other video background. Have fun!