Warning: This article contains spoilers about “Rogue One: A Star Wars Story.”

Making a new “Star Wars” movie can be like gaining access to a toy collection that has been amassed over four decades. For the creators of “Rogue One,” a film designed as a narrative lead-in to the original “Star Wars,” it was a chance to play with characters, vehicles and locations sacred to this series.

But as they revisited the 1977 George Lucas movie that started the “Star Wars” franchise, and gave fresh screen time to some lesser-known heroes and villains, the staffs of Lucasfilm and Industrial Light & Magic faced artistic and technological hurdles: most prominently, using a combination of live action and digital effects to bring back the character Grand Moff Tarkin. This nefarious ally of Darth Vader and commander of the Death Star was played by Peter Cushing, the horror-film actor, who died in 1994.

In doing so, they also waded into a postmodern debate about the ethics of prolonging the life span of a character and his likeness beyond that of the actor who originated the role.

The effects experts and storytellers behind “Rogue One” (which was directed by Gareth Edwards and written by Chris Weitz and Tony Gilroy) say they have given careful thought to these issues and were guided by their reverence for this interstellar epic.