The green color is also not unique to the Tech print, and seems to have been in all 1977 prints. I matched the Vader arrival scene of the raw LPP scan used for the SSE to the Vader arrival scene of the Tech scan (which is a neutral scene), and the Leia/R2-D2 shot that follows looks like this (don’t mind the artifacts, the video I have is very compressed, especially in the dark areas):
This is definitely not green or even cyan light. Light does not act like this especially Green light. It’s not lit with a green filter I can tell you that much.