PepperGram, not a hologram…

You might be asking, “What in the heck is a PepperGram, Sam?” Well, let me tell you. A PepperGram is a tool that creates an illusion technique that is used in cinema, video games, magic shows, etc. and it is known as the Pepper’s Ghost technique.

You might have seen the technique being pulled off as a “hologram” that you can make for your phone on social media. It is, in fact, not a hologram but it is pretty cool to make and enjoy. It’s like you are bringing a piece of Star Trek into 2023 finally. Before I share instructions on how to make one, let’s first try to understand what the science behind this wicked effect.

Pepper’s Ghost technique uses the laws of reflection. Mirror, mirror on the wall... whom amongst the laws must we manipulate to create an eerily image of something floating in free falling air? Answer is: the law of reflection.

“When light falls upon a plane surface it is so reflected that the angle of reflection is equal to the angle of incidence and that the incident ray, reflected ray, and normal ray all lie in the plane of incidence” - Merriam-Webster dictionary definition. I have tried re-reading that over and over again to somehow make sense of all the different rays but without going a little deeper in I would still be like a Minion, “whaaaa??” So, let me try to explain it so you aren’t like me at first.

The law of reflection states that the angle of incidence equals the angle of reflection. Two different angles, same distance. Measuring both angles (45 degrees) from an imaginary “normal” line that is a perfect 90 degree angle from the reflective surface, i.e. smartphone, mirror. For reference I kindly added a visual aid to cast your eyes upon.

So, if you would like to make one you can grab an older CD case that isn’t too scratched up, or any other clear harder plastic or glass (use safety precautions please) and cut four individual rhombus shapes that are all the same (you can find a template online). After you have all of those pieces, use some type of adhesive to meld them together on the angle sides, making a pyramid shape with a small hole on top and a bigger hole on the bottom. Grab your smart phone and search for ‘Pepper’s Ghost videos’. Place the smaller hole in the center of your screen, like an upside down pyramid. Get down to eye level with the angle and you will see a very cool, ghost-like effect.

Why do you have to be at eye level with the angle of the PepperGram in order to see the effect? The video that you have playing is being reflected against the side of the PepperGram and then directly outwards, or towards the middle of your phone. The reason you can see it in 360 degrees is because we have four different sides, all with the same angles, hence in whatever way you move side to side you will see it. Our eyes expect light to always travel in a straight line, however with the clear plastic, or glass, on a 45 degree, the light ray is diverted creating the effect.

Go try it out. It is very fun to look at when you are all done.

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