system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why do we use a Green Screen to make special effects? Why not purple, or blue, or any other color?
gpt
You don't have to!  Any single color screen could function as a "green screen".

But green is a popular color to use because it is very uncommon in the human body so you lower the risk of having random pieces of your people disappearing.