The History of the Pepper’s Ghost Illusion
Just a three minute walk away from Twist Museum is 309 Regent Street. It’s now the home of the University of Westminster. Back in the 19th Century it was the Royal Polytechnic Institution; a place of teaching and enchanting the public with the latest scientific marvels. It was an inspiration for many modern-day museums like Twist. The Polytechnic’s Great Hall was always bustling with the latest technology being playfully demonstrated. For example, the public could go underwater in a diving bell, witness model warships being blown up with explosive charges triggered by the newly discovered electricity, and taste meat that was cooked using giant parabolic mirrors that focused light to become a heat ray. Above the hall, the roof contained Europe’s first photographic studio and next door to the hall, lecturers like John Henry Pepper would perform their science magic.
Today, Prof. Pepper is best known for a curious optical trick called Pepper’s Ghost (although his design was based on a less practical invention by Henry Dircks). The illusion was first demonstrated on Christmas Eve in 1862. The public had never seen anything like it, a translucent ghostlike skeleton magically appeared on stage and interacted with actors. Nowadays, many theme parks use similar techniques within their ride experiences, large concerts have hologram musical artists appear amongst the live action, and augmented reality is used in ‘heads up displays’ in cars and planes.
The illusion Prof. Pepper presented involved a huge transparent piece of glass across the darkened stage that reflected bright objects hidden from the audience’s view. The combination of seeing both through the glass and an additional reflection created the effect. The key is to balance the light levels of the two scenes. You will no doubt have experienced similar phenomenon when you have been inside a building and looked out of a window. During the day, the glass seems transparent, but at night, with the lights on inside, it’s difficult to look out the window without the scene being dominated by the reflections from inside the room.
How to Create Your Own Pepper’s Ghost Illusion 👻
Here is a simple way to create your own handheld version of the Pepper’s Ghost illusion to blow your kids minds this Halloween. When you look through the cardboard tube, you will see ghostly objects floating in front of what you’re viewing.
The diagram figures below show how the cardboard tube is designed. The dimensions above are a guide based on the size of an average smart phone. From a large sheet of sturdy cardboard cut out the shape that will form the tube. Cut 45-degree slots on both sides and a sheet of transparent plastic cut to size to fit through these slots. You can just use a piece of thin plastic, for example from some old toy packaging.
Just use some tape to hold the scope together and the plastic sheet can be pushed through the two side slots. You should have a hole cut in the top surface directly above the 45-degree angled plastic sheet. The hole should be smaller than the size of your phone’s screen. Secure two elastic bands either side of the hole to hold your phone in place.
Before attaching your phone, you need to take a photograph or a video of a suitable ghost. It needs to be bright but against a black background. If you’re adept at using the photo editing controls on your phone, you may wish to adjust the brightness, contrast and shadow settings to achieve the best photo. Also, turn your orientation lock on so that your phone screen won’t flip from portrait to landscape as you move the scope about. Carefully attach your phone to the top of the ghost scope without touching the screen or any of the buttons. When you look through the viewing window at a dark background, you should find a ghostly image superimposed on top of it.
Get creative and share your illusions with us on social media!
