24 October 2026

^{A Victorian haunting explained: an illuminated performer below the stage supplies the ghost seen by the audience. Engraving from Le Monde Illustré, 21 January 1865.}

 

A ghost appears beside a living actor. It seems to occupy the same stage, yet the scenery remains visible through its body. In Victorian London, such apparitions became an attraction through an ingenious arrangement of glass, lighting and a concealed performer. Today, you can recreate a miniature version on your kitchen table.

Pepper’s Ghost is an optical illusion that uses an angled transparent surface to make a reflected figure appear within a scene. Its history begins with a familiar problem: a clever invention that needed someone to make it practical.

 

The Victorian origins of Pepper’s Ghost

 

Engineer Henry Dircks developed a theatrical ghost illusion, but his proposed arrangement required substantial changes to existing theatres. Owners were reluctant to rebuild their premises for a phantom.

John Henry Pepper recognised its potential. A chemist and science lecturer at London’s Royal Polytechnic Institution, he worked in a venue devoted to bringing science before the public. Spectacle helped attract an audience.

Pepper adapted the arrangement for more practical use. He demonstrated the illusion at the Polytechnic around Christmas 1862. The pair’s patent was dated 5 February 1863.

Their names shared the patent, but not the lasting fame. Dircks’s contribution became overshadowed by Pepper’s, a source of resentment. The ghost had acquired a name that proved difficult to change.

Pepper’s own account adds a revealing detail. Writing in 1890, he recalled intending to explain the mechanism at an early demonstration. The audience’s reaction was so enthusiastic that he postponed revealing it. Even a science lecturer could appreciate the value of suspense.

 

How the Pepper’s Ghost illusion works

 

To understand the performance, look at the engraving at the top of this page. An actor confronts a ghost above, while below stage level another performer supplies the apparition’s image.

A large, angled sheet of glass stands between the audience and the main stage. Spectators look through it to see the actors and scenery. At the same time, the glass reflects the brightly illuminated, concealed performer towards them.

Think of looking through a window at night. You can see outside, but you may also notice the reflection of someone in the illuminated room behind you. The glass combines the view through it with a reflected image. Pepper’s Ghost brings that effect under theatrical control. Illuminate the hidden performer and the apparition appears; darken their space and it vanishes. Your phone can take over the hidden performer’s role. 

 

How to make Pepper’s Ghost with your phone

 

Gather a smartphone, scissors, transparent tape and clean, flat, clear plastic. Thin packaging plastic or overhead transparency film can work. Avoid cloudy or scratched material: even ghosts deserve decent visibility.

You are making something resembling a miniature lampshade with four flat sides, narrow underneath and wide at the top. Both ends remain open. Each sloping face will act like a faint mirror.

The University of Arizona provides a pattern and assembly guide. Ontario Science Centre links to a compatible animation.

1. Cut four matching sides. Follow the pattern to make four trapezoids: four-sided shapes with a short edge opposite a longer, parallel edge. They resemble triangles with their tips chopped off. Use plastic that cuts safely with scissors; an adult should handle cutting when children join in.

2. Assemble your little lampshade. Tape the slanting edges together, leaving both openings uncovered. Keep tape away from the middle of the clear faces.

3. Prepare the performer. Open a compatible four-sided video full-screen. Its pictures are arranged around a central space, rather like four people sitting around a square table. Each supplies the image for one face of the viewer.

4. Set the stage. Lay the phone flat, screen upwards. Centre the viewer over the video with its small opening down and wide opening up.

5. Join the audience. Increase screen brightness, dim the room and lower your head to look through a sloping face. Look across the phone rather than directly down at it. Adjust your position until the figure appears inside.

If your ghost refuses to perform, check the alignment and turn off nearby lamps.

 

Why the phone ghost seems to float

 

Once the figure appears, the natural temptation is to look for something inside the viewer. Its apparent location is part of the trick.

A bathroom mirror offers a clue. Your reflection seems to stand behind the surface, although there is no second you brushing your teeth inside the wall.

Physicists call this a virtual image. Reflected light reaches your eyes from directions that make it appear to originate behind the reflecting surface.

With your viewer’s faces at roughly 45 degrees to the display, some light travelling upwards from the phone is redirected towards your eyes. Other light passes through the plastic, letting you see the background as well.

The bright figure appears superimposed on that background. Black areas in the video contribute relatively little reflected light, helping the apparition stand out.

Each face provides a separate reflected view of a flat image. Walking around the viewer will not reveal the back of a solid creature.

 

Is Pepper’s Ghost a hologram?

 

Those limitations have not stopped the technique enjoying a long career. Ontario Science Centre identifies Disneyland’s Haunted Mansion and Tupac Shakur’s 2012 Coachella appearance as examples of Pepper’s Ghost.

Phone viewers are also frequently called “hologram projectors”, a generous promotion for a reflection. True holography uses light-wave interference to record or reconstruct a light field; this experiment uses ordinary reflection.

For Halloween, the staging is yours. Begin with a black screen, gather your audience at the right viewing height, then start the animation.

Afterwards, switch on a lamp or change your viewpoint to see how the illusion weakens. You can explain the optics then. First, let your ghost enjoy its moment.