Pepper's Ghost is a special effects technique for creating transparent ghostly images. It works by reflecting the image of a ghost off of a sheet of plexiglass. IThis effect has been a staple of theaters and haunted houses since John Pepper popularized it in the 1800s. In this project, I am going to show you how you can incorporate this technique into your Halloween setup.
Step 1: How the Illusion Works
Step 2: Create a Ghost in Your Pictures and Video
Set up your camera in front of the desired background. Position your ghost to one side of the camera. The ghost can be a person in a costume, an image on a computer monitor, or just a picture. Hold up the plexiglass in front of the lens at a 45 degree angle to both the camera and the ghost. The camera will see a faint reflection of the ghost.
You may also get reflections of other objects around your ghost. To avoid this, you can either set up your ghost in front black backdrop or you can put the ghost in a dark room and use a flashlight or lamp to light up just the ghost.
Step 3: Create a Ghost in a Window
Creating a ghost in a window is a good way to restrict the field of view and give you a little more control. First you need a large sheet of plexiglass (preferably at least half the size of your window). Next you need to set up a table underneath the window. Then use books or cardboard to make a surface that is level to the window sill. Prop up your sheet of plexiglass in the corner of the window at a 45 degree angle. You may wish to also use a clamp of some kind to help secure it in place. Then position your ghost figure to the side of the window just out of view.
You need the room to be dark so that the edges of the plexiglass won't be visible. As a result, you will need to illuminate the ghost with a lamp or flashlight. Because the room is dark, you probably won't need a black backdrop for the ghost as long as you are careful to illuminate only the ghost.
The result is a transparent ghostly figure in the window that stares at people as they walk by your house.
Step 4: Create a Ghost in a Doorway
Position the ghost next to the door. Then prop up the plexiglass in the door frame at a 45 degree angle to both the doorway and the ghost. Make the room dark and illuminate the ghost with a flashlight or lamp. This setup is the most impressive because you can display a full sized ghost. Unfortunately, it is also the most expensive. A 4x8 sheet of plexiglass can cost several hundred dollars.
Step 5: Other Applications of the Pepper's Ghost Illusion
The pepper's ghost technique is also how "holographic" stage performances are made. A projector above the stage projects the image onto a reflective panel on the stage floor. A sheet of clear plastic angled over the stage partially reflects the image to the audience. This gives the appearance of a "hologram" on stage. Examples of this are the Tupac "Hologram", as well as several performances by the Gorillaz and Miku Hatsune