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:
“The moment a man begins to talk about technique that’s proof that he is fresh out of ideas.”
—Raymond Chandler (1888–1959)
“In love as in art, good technique helps.”
—Mason Cooley (b. 1927)
“Every notable advance in technique or organization has to be paid for, and in most cases the debit is more or less equivalent to the credit. Except of course when it’s more than equivalent, as it has been with universal education, for example, or wireless, or these damned aeroplanes. In which case, of course, your progress is a step backwards and downwards.”
—Aldous Huxley (1894–1963)