For centuries performers have been using this famous method to scare and amuse the audience. Pepper’s ghost is the illusion for creating transparent ghostly images. This illusion method is used in theatre, museums, televisions, amusement parks, and concerts.
In 1862 John Henry Pepper an English scientist promoted the illusion in a demonstration. An example of this technique is seen at Haunted Mansions. At 2012 Coachella Music and Arts Festival, the Pepper’s ghost illusion was used by Digital Domain for the onstage appearance of Tupac Shakur with Dr.Dre and Snoop Dogg.
Another example is the Pepper’s ghost illusion of Michael Jackson at the Billboard Music Awards in 2014.
The tricks consist of a stage which is arranged into two rooms, one that the audience can see, and the other is hidden, also known as the “blue room”. Plexiglas, or a plate of glass, or plastic film is placed in the main room at an angle that reflects the outlook of the blue room in the direction of the audience. The glass has to be as invisible as possible and also making sure that no light is reflected off it.
When it is dark in the blue room and the lights are bright in the main room then the reflected image is not visible. To make the effect work the main room lights are dimmed and the blue room lights are brightened.