Lucasfilm addresses Rogue One controversy

Gizmodo has an article by Germain Lussier about Rogue One:

It's been almost two weeks since the release of the latest Star Wars film, Rogue One, but much of the talk surrounding the movie is about characters from forty years ago. Now, in an interview with The New York Times, several of Rogue One’s most prominent contributors have given their accounts of the film’s controversial decisions.
Those decisions have to do with using digital effects to both bring back the late Peter Cushing (photo, above) as Grand Moff Tarkin and inserting Carrie Fisher’s young Princess Leia in the film, just as both of them appeared in 1977's A New Hope.
The first question is, why you need to see those characters at all. Kiri Hart, a producer on the film and head of Lucasfilm’s Story Group, explained that, in the case of Tarkin, he’s crucial to the story. “If he’s not in the movie, we’re going to have to explain why he’s not in the movie,” she said. “This is kind of his thing”—meaning, of course, the Death Star, which of course Tarkin ends up in charge of by the time A New Hope begins.
However, the filmmakers weren’t sure how the CG effect of Tarkin was going to look and, because of that, alternative solutions were planned. “We did talk about Tarkin participating in conversations via hologram, or transferring that dialogue to other characters,” said John Knoll, a producer on Rogue One who is also the CCO of Industrial Light and Magic.
To complete the effect, actor Guy Henry was on set, dressed as Tarkin, with full performance capture rigs on his head. “We’re transforming the actor’s appearance to look like another character, but just using digital technology,” Knoll explained. That data was sent to ILM, where they did their best to capture Cushing’s nuance. However, they quickly realized that was no simple task, especially after the realization that the lighting in A New Hope was different than Rogue One. Both things upped the challenge of recreating Cushing as Tarkin considerably, but the team eventually felt like they hit a strong balance. It’s “a super high-tech and labor-intensive version of doing make-up,” Knoll said.
As for Princess Leia, Hart believes she’s an essential part of the story, too. “To deliver on that moment of hopefulness, that is really underscored by the fact that you do get to see her face,” Hart said. “That’s the best possible use of effects, to enhance the meaning and the emotion of the experience for the viewer.” Like Tarkin, Leia was played by an actor on set (Ingvild Deila) and then digitally altered to look like a young Carrie Fisher.
Cushing’s estate approved the use of the actor’s likeness and, though it seemingly raises many questions about ethics, Knoll believes its a technique that can and should only be used sparingly. “It is extremely labor-intensive and expensive to do. I don’t imagine anybody engaging in this kind of thing in a casual manner,” Knoll said. “We’re not planning on doing this digital re-creation extensively from now on. It just made sense for this particular movie.”

You can read even more about this in the article by Dave Itzkoff in The New York Times (Warning: this article contains spoilers about Rogue One: A Star Wars Story:

Lucasfilm and Industrial Light & Magic said their re-creation of Cushing was done with the approval of the actor’s estate, but the technique has drawn criticism from viewers and writers. The Huffington Post called it “a giant breach of respect for the dead,” and The Guardian said it worked “remarkably well” but nonetheless described it as “a digital indignity.”
Knoll said he and his colleagues were aware of the “slippery slope argument”, that their simulated Cushing was opening the door to more and more movies using digital reproductions of dead actors.
“I don’t imagine that happening,” Knoll said. “This was done for very solid and defendable story reasons. This is a character that is very important to telling this kind of story.” He added: “It is extremely labor-intensive and expensive to do. I don’t imagine anybody engaging in this kind of thing in a casual manner.”
If Star Wars films are still being made in fifty or a hundred years, Knoll said audiences would probably not see likenesses of Mark Hamill or Harrison Ford playing Luke Skywalker or Han Solo. (He noted that Alden Ehrenreich had already been cast to play the young Han Solo in a coming film about that character.) “We’re not planning on doing this digital re-creation extensively from now on,” Knoll said. “It just made sense for this particular movie.”
The filmmakers also pointed to a scene at the end of Rogue One, when the intercepted Death Star plans are delivered to Princess Leia, who has ben digitally recreated to look like Carrie Fisher (photo, below) in the original Star Wars as an appropriate and effective use of the technology. (Fisher died on Tuesday.) 

In her first shot, when Leia is seen from behind (with her trademark hair buns), she is played by a flesh-and-blood actor, Ingvild Deila. Then, in the reverse angle, when Leia is seen from the front, her face, hair and costume are a digital re-creation of Fisher, based on footage from A New Hope. (The character’s extended hand is Deila’s.)
“To deliver on that moment of hopefulness, that is really underscored by the fact that you do get to see her face,” Hart said. “That’s the best possible use of effects, to enhance the meaning and the emotion of the experience for the viewer.”
The Rogue One filmmakers reviewed the dailies from Star Wars and turned up other 'Easter eggs' to add to their movie. They included unused footage of the X-Wing fighter pilots known as Red Leader (played by Drewe Henley) and Gold Leader (played by Angus MacInnes), who help wage the rebels’ attack on the Death Star.
(Some of that original film, Knoll said, was “somewhat underexposed”, requiring some digital repair work. The actors were then transferred by rotoscope from that footage and inserted into computer-generated cockpits for Rogue One.)
Knoll said he did not come across a “vast gold mine” of footage that Lucas did not use. “George was pretty economical in the way he shot the films,” Knoll said. “When he was happy with a performance, he’d go, ‘All right, I got it.’”

Rico says he looks forward to seeing it... (With Carrie Fisher dying, they'd've had to replicate her, anyway...)