How Do Green Screens Work?
Green Screens work by combining images/video from two sources into a single image. The two sources are layered on top of each other, with parts of the top layer being filtered out to allow the bottom layer to show through. The green screen/chroma key filter that looks for and then renders transparent a particular colour (in this case, green). Green is often chosen because it is not a colour found in any human skin tones, thus preventing the people being filmed from being filtered out.
How Do You Use It?
Depending on the program you use, the process may look a little different. It can be broken down into 2 main categories:
- Filming in front of a green screen with the desired image being superimposed simultaneously
- Filming in front of a green screen with the desired image being superimposed later during editing
If you want to create your own green screen space in your school here is a Green Screen Handout to assist you.