Help me understand greenscreen...

[camarade]

Hi,

While I've done simple greenscreen stuff before, one thing that keeps puzzling me is how they replace footage in "live" plates. For example, in Soul Surfer the actress had a green arm that they removed in post, and I assume they did something similar in Black Panther, screencap from the movie.

In a controlled studio environment one could just make 2 separate shots & compose them... but how does it work in scenes like this when there is "stuff missing" behind whatever is removed with chroma?

Been looking for articles that explains this but never found anything. Thanks,

 

[El Director]

It's essentially "rig removal". The tricky part is patching in stuff when there is an "organic" background behind what you want gone, such as other people. The most common technique is projection, here's a simple tutorial that will give you some insight into the process.