Today, the majority of visual effects are achieved through the use of computer-generated imagery (CGI).

BBC: By James Christie

The set was rudimentary: the control room of the satellite-communication center would be completed with computer-generated imagery, imagined by the Wachowskis down to the minutest detail.

NEWYORKER: Beyond the Matrix

One difference: In the Victorian era, Pepper's Ghost was normally used to reflect actual, physical objects or actors, making them appear "dimensional" in ways that the projected or computer-generated imagery typically used today do not.

WSJ: Tupac Shakur 'Hologram,' Seen at Coachella, May Go on Tour

Walt Disney Pictures came to Comic-Con in 2008 with test footage from what was then referred to as "TR2N, " a sequel to the 1982 cult classic "Tron, " one of the first films to use computer-generated imagery.

CNN: The long rollout: Studios build early buzz at Comic-Con