Whether holograms of Tupac and Michael Jackson give you the heebie-jeebies or a dose of nostalgia, you’ve got to admit the technology is impressive. But how does it work? And are these really holograms or just projections?
Of course, not all onstage holograms are posthumous ethical conundrums. The technology has been used to simulcast performances by Janelle Monae and MIA, to throw the Gorillaz avatars on stage with Madonna, and to bring fictional stars, like Hatsune Miku, to life.
Sorry, They Aren’t Holograms
Let’s clear the air real quick. There’s a lot of debate on what is or isn’t a hologram. So, for argument’s sake, we’re going to stick with a very simple definition for the word hologram.
Holograms are freestanding 3D light structures. They aren’t projected onto a surface (that would make them 2D), but they can be diffused by glass, sci-fi moon crystals, or whatever object gets the job done.
So, Princess Leia’s secret message in Star Wars? That’s a hologram. The ghost of Michael Jackson? That isn’t a hologram—it’s projected on a flat surface and exists in 2D (but we’re still going to refer to these as holograms to keep things simple).
Either way, these holographic concerts are a step in the right direction. But they aren’t exactly a new idea. The holographic performances by Tupac, Janelle Monae, MIA, and others are based on an 1860s parlor trick called Pepper’s Ghost. It’s a simple trick that was used extensively at Victorian fairs, plays, and parties. You’ve seen it in action at Disney’s Haunted Mansion if you’ve ever been to Disneyland.
The Pepper’s Ghost trick is literal smoke and mirrors (well, minus the smoke). A reflective pane of glass is set on a stage and angled down toward a hidden booth. When the hidden booth is illuminated, it reflects an image onto the pane of glass, which then reflects the image toward the audience. At eye level, this image would look squished (remember, the glass is angled). But because the audience looks up at the stage, the image looks “correct,” with a ghostly, translucent quality.
Of course, your garden-variety Pepper’s Ghost trick requires an actor. Last time we checked, Michael Jackson was dead, so we can assume the technology has changed a bit, right?
Musion Eyeliner Projections
Musion Eyeliner sounds like a crappy local band, but it’s actually a patented, modernized version of the Pepper’s Ghost trick. And, in a way, it’s even simpler than Pepper’s Ghost.
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Source : How Do Holograms Work on Stage?
