“Because the foreground is only recorded in blue and red, it leaves the actors looking magenta-tinted. To solve this, Netflix uses artificial intelligence to put the full range of color back into the foreground, using a photograph of the actors lit normally as a reference to create a realistic-looking green channel.”
Netflix lights actors red and blue against green LEDs so the camera’s green channel holds only the background. Hair and glass key out cleanly in real time. The price is that nobody on screen has a real green channel anymore. Every face in the shot is a guess an AI rebuilt from a reference photo.