Pictured above is our own friendly ghost-host, as she floats in the hallway of the 'Hotel Lugosi'. I lived an apartment in those days - the mid 1990's - and ddn't have room for a big display, so I built a miniature Pepper's Ghost effect into our small living room window. It was completely automated, and when a visitor stepped up to the window, an infrared motion detector triggered the soundtrack, the animation system, and the lighting sequence. The show lasted about one minute, during which the ghost appeared in the hall, spoke to the viewer as its eyes flashed with the words on the soundtrack, while it hovered, gesturing and floating up and down, as you can see from the animation.
The ghost is a miniature FCG (described in detail elsewhere on this site - see the index page) and is lit by blacklight, which was faded up and down using a motorized shutter system. The display and the equipment required to run it took up the space required by a large kitchen freezer. The project cost back then was about $450, but with some cleverness on your part, it can be done for a lot less.
The Making of the Hotel Lugosi:
A Miniature Example of the Pepper's Ghost Illusion
The genesis of this project was my long-time participation in the construction of charity fund-raising haunted houses for Halloween, and the beginning of a series of Halloween windows last year with a miniature haunted house exterior. I should also mention my lasting affection for the Haunted Mansion at Walt Disney World, which contains a spectacular example (probably the worlds largest) of the effect which is usually known as 'Pepper's Ghost.'
The direct inspiration for this version of the illusion, however, lies in the hotel corridor scene found in the Disney/MGM Studios Theme Park attraction, The Twilight Zone Tower Of Terror. "What if," I thought while on one of several trips through the attraction, "one were floating outside the window at the far end of this hall, looking back toward the elevator doors?" If you've been there, you have the appropriate mental picture.
About Pepper's Ghost
A brief history follows, very loosely extracted from James Randi's book, Conjuring:
In 1862, a Liverpool civil engineer named Henry Dircks constructed a miniature working model of the effect, probably similar in arrangement to the one in Disney's Haunted Mansion attraction. But it was John Henry Pepper, a chemistry professor at London Polytechnic Institute, who, having seen Dircks' model, built the first practical full-size version and exhibited it on stage.
In the 1860s, magic lantern shows (the ancestors of the 1970's slide projector based 'multimedia' presentations) were all the rage in England. Sensation-hungry Londoners, who tended to forget the last big fad or craze as soon as a newer, fresher novelty arrived on the scene, beheld the startling effect of a transparent, three-dimensional ghost interacting freely with a live actor on a seemingly ordinary stage. Pepper's Ghost had materialized, and everyone forgot about magic lantern shows. The illusion appeared in public demonstrations far and wide, as similar entertainments had before it.
Eventually, the effect was incorporated into dramatic productions such as Hamlet, Macbeth, and Dickens' Christmas Carol. This progression seems natural, as special effects usually fare better in supporting roles than as stars in their own right.
It should be noted that earlier records of a similar effect exist. A document from 1588 entitled Magica Naturalis mentions a Jean Baptiste Giambittista Della Porta, who apparently constructed one. It is my guess that the public just wasn't ready for it at the time.
One discovers, when reading about the many optical illusions presented to the public in the 18th and 19th centuries, that the main working principles of most all of them have wound up finding a permanent home with modern conjurers (magicians.) They also reside comfortably in the special effects departments of the stage and motion picture industries, as well as amusement parks. Good, uncomplicated, and inexpensive effects never vanish entirely. You'll find Disney's Haunted Mansion employing simple motorized magic lantern slides in company with a Pepper's Ghost apparatus - in perfect harmony, and in full service to entertainment.
Deciding On Materials
The budget for this project was rather limited (about $400), and dictated my choice of materials. As I lack access to a table saw, drill press, or metal lathe, I had to use more primitive methods for construction than I would have liked. Since this work was done under pressure of time, I took whatever shortcuts I could without compromising the integrity of the apparatus.
I cut metal parts from old aluminum and steel stock from a previous project, and one of the effect motors (discussed below) is also recycled. The fit of the pieces is not perfect by any means, but is of close enough tolerance for the device to work reliably.
I used 1x1 stock, 3/4 plywood, and some decorative molding to construct the frame. Cardboard (purchased in 4 x8 sheets from a local box company) forms the hall walls and ceilings, as well as the cover for the machinery above the Effects hall. The halls attach to the combiner using hinges with removable pins, a technique which allows the device to be disassembled easily for repairs or adjustments.
It is essential that all areas except the Scene be non-reflective (unless scenic elements are to change as part of the illusion), and this usually requires painting them flat black. In this version, the entire frame, as well as the outside of the backstage area, is black. I haven't made an accurate count yet, but I estimate that 17 cans of black spray paint alone were used on the project.
The Scene Corridor
The Scene area is decorated as a hall in an Art Deco Noir hotel, and the scrims in front of the device carry out the theme of a lobby. It is constructed in a modified forced perspective; in other words, the hall gets narrower as it goes away from the viewer. This allows the hall to appear longer than it is, while saving space in the window area allotted for the apparatus.
The hall is wainscotted in black, separated by metallic silver trim (wood coated with Krylon aluminum particle spray paint) from the upper walls and ceiling, which are pale teal. The scrims on either side of the combiners viewer opening carry out the hall scheme to provide visual continuity.
The floor (including the combiner floor around the glass) is tiled in a pattern (shown at right) which forms diagonal Xs in a series of squares. The individual, triangular tiles are ornamented with a design combining Tim Burton-esque dark spirals with Anasazi Indian pottery designs. These tiles are used for more than decoration - they help to camouflage the slot occupied by the bottom of the glass in the combiner. This technique is often used in the construction of this effect, and works so well that I have almost put my hand through the combiner glass accidentally on several occasions.
How Does Pepper's Ghost Work?
It's the essence of simplicity, and with careful control of lighting, the effect can be truly startling. The only gimmick in Pepper's Ghost is a single piece of glass, and that doesn't even move.
The 'Dircks version' (it was actually invented by Henry Dircks, who then sold it to Pepper) is best demonstrated by looking out the window of a dimly-lit room during late dusk. With properly balanced lighting, you see a ghostly image of yourself, superimposed over the landscape outside. It's utterly simple, but with proper staging, the effect is mystifying.
In John Henry Pepper's version, the glass is usually set into a box, a four-legged frame, or similar structure, and is turned at a 45 degree angle to the viewer. You can visualize the piece of glass as a half-open door, or imagine it as one of the mirrors set into a periscope. This simple device forms an optical combiner. You can see straight through the glass, of course, but you can also see a semi-transparent image of any well-lit object placed directly to the right of the glass as if it were also in the space of the directly viewed scene. The two areas should be enclosed (save for the open end facing the glass), built to the same dimensions, and have independently controlled lighting. The area which is to be reflected in the glass should be blocked from the view of the audience by scrims or other covering.
There are any number of variations of this general effect, and they consist mainly of attempts to find novel ways to position the glass in relation to the viewer in order to make the gimmick less obvious. These include the use of half-silvered glass ('two-way mirrors') as in the Disney illusion which places a ghost next to the riders' reflection in a large mirror in the Haunted Mansion. Here, the ghostly figure is behind the half-mirror, surrounded by a black background, and is lit by a shuttered spotlight. The viewers see themselves reflected in the half-mirror along with the ghost, which fades into the scene by virtue of being the only lit object behind the translucent mirror.
One well known serious use of Pepper's Ghost is in the heads-up display in a fighter plane, where a ghostly image of graphic flight and radar data floats before the pilot. This is the version used in the plan for my project, and is probably the most common one.
Hotel Lugosi is a miniature version of Pepper, sized to fit into a residential window. Its combiner sits on a 14.5 inch square base, with the height of the glass being about 32 inches (of which only about 24 inches are used for the illusion, the rest being masked off by an opaque scrim.) The Scene and Effects areas are 24 deep, and taper down to about 9 inches wide at the far ends to achieve forced perspective (again, see the plan view, right.)
The Effects Corridor
The Effects area contains two mechanical animation devices which will ultimately be automated by a computerized program timer. Please note that the following devices do not come under the umbrella of Peppers Ghost, but are my particular augmentation to it.
The first device is a boom arm which lowers in an arc from the back of the hall near the ceiling (up) to the front of the hall near the glass, about 1/3 of the way to the floor (down). The boom can be instructed by a relay closure to step to the opposite position and stop. A figure can thus be flown in using this device, and flown out at the end of the program cycle. This arm also works a spring-loaded trapdoor over a blacklight tube, which serves as a mechanical dimmer. Nowadays, you can easily substitute a LED blacklight and a dimming controller. You will find more details of this mechanism and the corridor itself in the illustrations at right and the schematic below them.
The Flying Crank
Note: This material redundantly covers the basic Flying Crank Ghost, instructions for which are linked above this item on the index page. You should read this material for more information, if you plan to build the Hotel Lugosi.
The second device lacked a name, so I dubbed it the Flying Crank. How does it work? Imagine a crank which is turned by a motor. Tie three or more strings to the handle end of the crank (the one rotating in a wide circle.) Fix three (or more) pulleys in your choice of locations on a plane parallel to (and almost level with) the circle described by the handle end of the crank, and put the strings through them. Hang the whole assembly from the ceiling, with the motor on top, and the circle of the crank below. The strings should now be weighted, and when the motor is run, the weights on the strings will move up and down somewhat like merry-go-round horses, but they won't move around in a circle. There is a very useful feature of this setup: the phase relationship of the up-down cycles of the objects on the strings may be varied infinitely by re-positioning individual pulleys to different locations around the crank circle. In the Hotel Lugosi illusion, this device may be switched on and off under program control, and could be arranged with position sensors like the ones on the boom arm described above, so as to allow movements timed to a soundtrack. In the Hotel Lugosi effects wing, the apparatus straddles over the pivot arm of the Boom Arm system, and shares space with it.
About The Mini FCG
The original ghost I used in the project was a square of cloth formed into a hood around the L.E.D. eyes. It worked well, but for 1996, I actually built a miniature FCG armature (as described in the plans) and painted it with an airbrush. The armature was made from paper clips, instead of coathanger wire, and I used very tiny L.E.D.'s for the eyes. The fabric I used is not extremely fluorescent. It is the combination of the transparency and low fluorescence that give the ethereal look to the trailing shroud. Too much fluorescence, or too great a variety of colors, will kill the subtlety, so as I mention in the FCG plans, be sparing in your use of paint.
As mentioned above, the Effects corridor contains a blacklight. This is mounted at the top front of the wing near the glass; the light spillage is blocked by opaque scrims which direct it back into the wing. When all is adjusted properly, only the figure can be seen glowing. This wing will also contain two low-wattage, program-controlled spotlights for use with other effects beside the ghost mentioned above.
The Scene corridor has two low-voltage (12v.) floodlights for accent lighting in addition to the wall lights. The small wall fixtures only light what is above them, so additional light will be needed to show off the hall properly. All lights in the hall are able dim and fade to black under program control.
The scrims on the front - facing the audience - are of translucent, almost transparent sheer black cloth with painting and trim added to match the Scene hall. These walls will be lit as necessary to provide consistency with the Scene halls internal lighting, and this lighting will also be under program control. These walls also house another effect. Behind the scrim cloth, on the back side of the wall frames, are panels painted black. Attached to the backing are scattered pairs of L.E.D.s, which can be lit by program. When lit, they appear as pairs of eyes. If the walls are darkened, the eyes appear to hover in space before the audience - and if other eye units are mounted in the Effects wing, the hall will seem to fill with eyes as well. Darkening the entire set with only the eyes lit makes quite a dramatic presentation.
What we originally had in mind was a series of spectral guests, one per week, each with their own little comments to make to the audience. In reality, this will have to wait for next year's version of the device. Each presentation would last less than two minutes, and be on the light or humorous side. The audio (voice, music, and effects) was originally triggered from a digital sampler, the kind used by keyboard players (a Roland S550). This soundtrack reached the viewer via an outdoor speaker (using the 70v. transformer system from the FCG plans) just above the window. The outside-of-a-window audience location provides complete isolation from motor noise, and makes the illusion that much more effective. We added an awning around the window (which had side wings extending two and a half feet out from the outside wall) to keep viewers from getting too close, and being able to see the Effects corridor's contents. This method was quite successful, and our neighbors are still mystified by the display.
The effects delivery systems (Boon Arm and Flying Crank) were altered in the last few years. A track was added to fly the FCG down the hall toward the viewers on an overhead crane. We have used this timer, based upon the ubiquitous 555 timer I.C. available at Radio Shack, to control the show. This simple circuit fires relays that turn off the brighter lights, and lower the boom arm, as well as trigger the audio. The timer is triggered by an infrared motion-detector - the kind used in home alarm systems, masked down to be less sensitive. When someone approaches the window, the show begins.
In 1996, the ghost recited a simple verse I cooked up two days before the opening (there were four other spiels played in rotation):
Good evening, and welcome to the Hotel Lugosi!
My favorite season is here again,
with tricks and treats for one and all.
Soon may the heat of summer pass,
and usher in the chill of fall!
So when you hear the lone wolves howl
and ghoulish voices' eerie calls,
you'll know where I'll be surely found,
a-haunting these familiar halls.
And if 'tis frightful fun you seek,
be you small or be you tall,
your spirits will rise with ghostly glee,
come join us at our Halloween Ball!