Luckily, this isn't for grain removal but to fix mistakes that still bugged Fincher.
Fincher got together with Collider’s Perri Nemiroff and told her how AI was used to achieve the restoration. Fincher mentions the scene in a bar where Detectives Somerset and Mills chat about the case. Turns out, the scene had a teeny tiny mistake in it, but Fincher is known as a bit of a perfectionist, so it probably bothered him.
“In this case, there was this unasked-for and unearned camera pan where a character moved, and then the camera panned over to follow them but followed them late and overshot them and ended up seeing more of the bar than was intended,” Fincher described. A character’s jacket proved to be a real problem in trying to fix the shot, but now, with the help of AI, Fincher was able to get the shot he wanted on the new version.
“So we took three or four different shots from earlier, which had a jacket in them that we liked, and then we input that, and then we had it spit back out AI, and then took the background from where the camera landed and just composited them together.”
Easy peasy! Fincher seems to have also found other uses for AI than just the one bar scene.
“There were shots that I didn’t even realize where I would consider today to be unusably out of focus, and some of those things we were able to go in, make mattes of the section that we wanted, and use AI to at least get the focus in the eyes to be on the soft side, but not completely useless,” the director told Collider.
Aliens can be quite divisive. Some people like the very clean digital look but I prefer the Blu-ray release which has quite a lot of natural grain too it. But if you compare editions, you'll see that over the years, with each release, Cameron has changed the look of the film in regards to colours.
In an ideal world, studios, with directors assistance and approval, would scan the camera negative and leave it at that with no tinkering afterwards. 😄
In regards to Cameron's other films, they've all had various use of AI but Titanic and The Abyss come out really well and I believe The Terminator hasn't done too badly either.