Advances in computer graphics and video projection allowed Sunday night's illusion to be far more lifelike than other recent efforts.
For the projection aspect, a San Diego company called AV Concepts used a variation of a visual effect that was discovered in the 19th century, known as Pepper's Ghost.
Though the projected image has been widely described as a "hologram," it is a 2-D image and not a hologram, which is 3-D.
The effect was first used in an 1862 dramatization of Charles Dickens' novella "The Haunted Man and the Ghost's Bargain," staged at the Royal Polytechnic Institute in London, according to Jim Steinmeyer, an illusion designer who has written extensively about the history of his craft, including Pepper's Ghost.
The effect relies on an angled piece of glass in which a "ghostly" image is reflected. "A piece of glass can be both transparent and reflective at the same time, depending on how it's situated relative to the audience," said Mr. Steinmeyer, pointing out the secret.
In the Victorian version of the trick, the glass reflected an actual actor, situated out of sight in near the orchestra. On Sunday night, the image was projected on a piece of Mylar—a highly reflective, lightweight plastic—stretched on a clear frame.
"What's happening in Coachella is virtually the same thing that was happening in 1862," Mr. Steinmeyer said. One difference: In the Victorian era, Pepper's Ghost was normally used to reflect actual, physical objects or actors, making them appear "dimensional" in ways that the projected or computer-generated imagery typically used today do not.
Mr. Steinmeyer used similar technology to create an illusion in which Frank Sinatra appeared at a 2003 concert.
A London-based company called Musion Systems Ltd. owns the patent for using a Mylar screen in the illusion. Musion said it licenses its technology to around 30 companies around the world, including AV Concepts. Its technology was also used for the 2006 Grammy Awards, when an animated rock band called the Gorillaz appeared to perform live on stage with Madonna.
AV Concepts President Nick Smith says that his company typically uses the technology for corporate events.
Tupac Shakur is the first dead entertainer the company has presented "live."
But Mr. Smith said the company has used the same technology to resurrect several late executives.
"We've brought past CEOs and things that like that back to life," Mr. Smith said, without getting more specific, citing non-disclosure agreements.
A tour with the virtual Tupac is likely but not guaranteed, said the person familiar with the situation. The nascent plans could fall apart for any number of reasons.
If the tour were to proceed, it would take many months of creative and technical planning, this person added.
A version of this article appeared April 17, 2012, on page B1 in some U.S. editions of The Wall Street Journal, with the headline: Rapper's De-Light: Tupac 'Hologram' May Go on Tour.
Go to bed, then wake up and do it all over again. I think that about cover's it 
