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 footage is not shot correctly.
Here are some techniques that you can use to make your green screen background production as troublefree 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.
- Lighting
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. Having multiple lights will help to even out the lighting in your scene. Fluorescent lighting and outdoor/sunlight provide good consistent and smooth indirect lighting to your chroma key background.
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.
- Subject Placement
a. Make sure your talent is at least 4 steps in front of your chroma key backdrop. This will help minimize shadows falling onto the green screen and will 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.
- Camera Setup
a. If you have access, try to shoot with the best HD camera possible. A camera that has manual controls for shutter speed, ISO and aperture are best. Set the ISO on your camera to 100 or 200 which should help to reduce signal noise and will smooth out the backdrop in your video.
If you follow these few simple rules, you can create high quality green screen footage that will allow you to easily remove the background in your video editing software.Now you can replace the green screen with a virtual background or other video background. Have fun!