Technique
In order for the illusion to work, the viewer must be able to see into the main room, but not into the hidden or "Blue Room." The edge of the glass is sometimes hidden by a cleverly designed pattern in the floor.
The hidden room may be an identical mirror-image of the main room, so that its reflected image matches the main room's; this approach is useful in making objects seem to appear or disappear. This illusion can also be used to make one object or person reflected in the mirror appear to morph into another behind the glass (or vice versa). This is the principle behind the Girl-to-Gorilla trick found in old carnival sideshows and in the James Bond movie Diamonds Are Forever.
The hidden room may instead be painted black, with only light-coloured objects in it. In this case when light is cast on the room, only the light objects reflect the light and appear as ghostly translucent images superimposed in the visible room.
In the Haunted Mansion at Disneyland/Disney World, the glass is vertical rather than angled, reflecting animated props below and above the viewer that create the appearance of three-dimensional, translucent "ghosts" which appear to be dancing through the ballroom and interacting with props in the physical ballroom. The apparitions appear and disappear when the lights on the animatronics are dimmed on and then off.
Read more about this topic: Pepper's Ghost
Famous quotes containing the word technique:
“In love as in art, good technique helps.”
—Mason Cooley (b. 1927)
“The more technique you have, the less you have to worry about it. The more technique there is, the less there is.”
—Pablo Picasso (1881–1973)
“I cannot think that espionage can be recommended as a technique for building an impressive civilisation. It’s a lout’s game.”
—Rebecca West (1892–1983)