Holograms are — or at least, when done in their coolest, best way, can be — three-dimensional images trapped in a two-dimensional space. The whole idea that we can represent a tangible, three-dimensional object in a holographic form is a staple of both science fiction and fantasy alike. They seem magical, as if created using legerdemain and fairy dust.
And if you cut them up, they’re even more magical. Cut a regular photograph up and you’ll get a piece of the picture — but certainly not the whole image. That’s not true for holograms; if you cut them into pieces, each piece retains the entire image — as seen above.
Kind of. Let’s use a picture of a person’s face as an example. If you cut out where the person’s left ear is, the resulting piece will be the ear — and nothing else. But when you cut a hologram, the resulting pieces contain enough information about an image to display the whole thing. Cut where the ear is and you’ll get the whole person’s face in the resulting piece. You do lose something, however — what you lose from this edit is a bit of perceptive value.
Imagine that the whole, intact hologram is a window, looking at the face. When you cut out a small area of the hologram, it is the equivalent of covering up all of a window except for the cut out part. While you can still see the whole face, you can only see it from one vantage point, in the same way a door’s peephole allows you to see whatever is outside your door — but only at a very limited angle.
Because holograms are three dimensional renderings, each piece of a cut hologram gives you a bit of the information — but not quite enough to show you the full depth of the object displayed. But in most cases (unless your vantage point is of an obscured angle), you’ll see the full object in every piece. A neat parlor trick, if nothing else.
Bonus fact: Holograms record whatever the naked eye would see. So if you make a hologram which looks at — and through — a telescope or magnifying glass, whatever the telescope/magnifying glass is focused on will appear magnified in the hologram, as seen in this video.
From the Archives: Shadow Boxing: An elegant optical illusion. Two, if you include the bonus fact.
Related: “The Complete Book of Holograms: How They Work and How to Make Them” by Joseph Emil Kasper.