The Pepper’s Ghost illusion has served as a unique way to conjure up posthumous spirits, entertainers and politicians for over 100 years. Whether it be dancing ghosts in the Grand Hall of the Haunted Mansion at Disneyland, Tupac Shakur on center stage at Coachella 2012, people reliving their memories in the retro future world of Reminiscence (2021) or candidates interacting with millions of voters in multiple locations at the same time, Pepper's Ghost is one of the most long-standing optical tricks ever invented. The gag is produced when a real or recorded image is reflected on a transparent screen at a 45-degree angle to create an apparition or human likeness.
The general idea was first associated with the Victorian era theatrical performances. The concept for the illusion was initially mentioned in a work of popular science by Italian playwright Giambattista della Porta called Magia Naturalis (1584) in the title “How we may see in a Chamber thing that are not.” della Porta wrote, “The variety of the images that appear, proceed either from the matter or form of the glass. Crystal must be clear, transparent, and exactly made plain on both sides. And if one or both of these be wanting, they will represent diverse and deformed apparitions to our sight.”
Fast forward to 1858 when English engineer Henry Dircks found himself surrounded by charlatans who claimed to audience members to have the ability to communicate with the dead and sought to dispel their methods by developing one of his own. He devised the concept of a hidden room located under the seating area with the actor situated inside, illuminated by oxyhydrogen-driven light which would then be reflected off a large pane of glass onstage, creating the illusion of a ghostly apparition brought to life. The trouble was that the approach required theaters to be completely rebuilt, which brought it to an early demise.
However, popular science lecturer John Henry Pepper resurrected the idea and took out a joint patent with Dircks; the former was able to execute the illusion without theatrical reconstruction during a performance of Charles Dickens’ The Haunted Man. Pepper’s version had the actor situated in the orchestra pit, and tilting a plane of glass 45 degrees while matching the actor’s angle on a board so as to make him easily obscured. Initially the illusion was marketed as Dircksian phantasmagoria, but the popularity of Pepper meant it soon became known as Pepper’s Ghost.
A spectator wrote in the July 17, 1863 edition of The Nottinghamshire Guardian, “The appearance of the Ghost, as an optical illusion, is one of the most remarkable discoveries of modern science. The apparent reality of the spectre puts into dim shade the living individual, who performs his part in the haunted chamber, rendering him more like the dark shadowy representative of a ghost, than the ghost itself ...[Pepper’s] observations on the laws of light were also very interesting, and his experiments in illustration of some of those laws, were highly instructive and amusing.”
The growing popularity of the illusion captured the imagination of prolific French author Jules Verne who laid the foundation for modern science fiction by writing Twenty Thousand Leagues Under the Sea and Journey to the Center of the Earth; Pepper’s Ghost was central in understanding the mystery at the heart of his Gothic novel, The Castle of the Carpathians, which was published in 1892. Verne wrote, “By means of glasses inclined at a certain angle calculated by Orfanik, when a light was thrown on the portrait placed in front of a glass, La Stilla appeared by reflection as real as if she were alive, and in all the splendor of her beauty.”
With the patent long since expired, Pepper’s Ghost has been globally adopted not only for theatrical performances but also theme parks such as the ballroom scene at the Haunted Mansion at Disneyland. Imagineers Rolly Crump and Yale Gracey were given responsibility for creating the illusions for the attraction and stored their developments in a warehouse. “Once, we got a call from personnel saying that the janitors requested that we leave the lights on in there due to the creepiness of all the audio-animatronic ghosts and such,” explained Crump. “We complied but put motion sensors in the room that would extinguish the lights and turn on all the ghost effects when triggered. The next morning, we came in and found all the ghost effects still running and a broom lying in the center of the floor. Personnel called and said that the janitors would not be back."
More recent examples make use of projectors rather than live actors. One of the most famous is Snoop Dogg performing next to the deceased Tupac Shakur at Coachella 2012. The virtual resurrection came at the cost of $500,000 and was created by Oscar-winning visual effects company Digital Domain which produced a believable computer-generated likeness of Tupac. “There's an overhead projector that sort of reflects down onto basically a tilted piece of glass that's sort of on the stage floor," stated journalist James Montgomery while being interviewed by NPR's Audie Cornish. "That then reflects the, well, reflection onto a mylar sort of screen, and it projects in this sort of 3D kind of thing where it allows the other performers to walk in front of Tupac and basically interact [with] him."
Using a similar approach was cinematographer Paul Cameron when shooting Reminiscence as the decision was made to have memory projections captured in camera and enhanced later in post-production. “What I had to do was, once we had the set designed, and knew where the machine and tank would go, I had to go through and figure out roughly where Hugh Jackman or Thandiwe Newton would be on any given scene and what their relationship would be to the projection during principal photography,” explains Cameron. “Not only did I have to shoot the scenes on location, but I also had to shoot the projection angles for projection in Nick Bannister’s office. There is a material called Hologauze which is like a shark skin material that you project onto that is used for rock concerts, theatrical events, and industrial presentations. One of the most politically savvy uses of Pepper’s Ghost was by Shri Narendra Modi who saw it as the means to address hundreds of campaign rallies at the same time during the Indian election of 2014. "A projector is placed high above the stage to stream visuals to the stage floor, which is then reflected on the stage background," reported the Times of India.
"This background is made of a special, almost transparent material that provides a 3D illusion." The next step in blurring the line between the illusion and reality are holographic displays created by companies such as Light Field Lab, which can produce a 3D rather than 2D image that mimics real lighting conditions from different perspectives. This technological innovation will certainly go way beyond what Giambattista della Porta ever imagined and will redefine how people interact with their imagination.