If you have ever been to Disney’s Haunted Mansion in any of its global incarnations, you have traveled through the ballroom scene. Your “doombuggy” vehicle passes along a second floor overlook, where you can watch the ghosts gathering for a “swinging wake” below. A funeral car delivers ghostly party-goers to a banquet hall where they dine and dance. Two portraits come to ghostly life to finish their duel in midair.
This scene is a marvel of technology, but not modern technology. In fact, the illusion was based on a 150 year old stage magician’s trick. The effect is known as Pepper’s Ghost. If you do not want the illusion spoiled, you may want to quit reading here. For those of you who are curious, however, here is a brief explanation of this old yet powerful effect.
The effect was named for John Henry Pepper, a chemistry professor at the London Polytechnic Institute who explained the illusion in his 1862 book “Wonders of Optical Science.” It has been used over the years by everyone from stage magicians to phony mediums and spiritualists.
The illusion is based on the properties of light reflection through glass. Although you may not have realized it, a sheet of glass separates you from the room below. Directly above and below your ride vehicle are sets of animatronic figures. When the figures are illuminated, their reflection appears in the glass in front of you. You are simultaneously viewing the real props, such as the funeral car and banquet table, and the reflected “ghostly” images of the hidden animatronics.
Unfortunately, the Imagineers who designed the ride did not take into account that the apparitions are a mirror image of the animatronic figures. If you look closely at the dancers, you will see that ghostly women are actually leading the men.
This simple but effective illusion has truly stood the test of time. Next time you are in the Haunted Mansion, see if you can notice the effect for yourself!