by Jeff Allen


The first holograms I saw were at the Haunted House in Disneyland.” This quote has been heard many times at theme and amusement parks. However, none of the impressive illusions at Haunted House were actually holograms; they were created using some of the many methods of producing dynamic, three-dimensional, ghost-like images. Today, this “magical” technology — including holography — is more accessible and cost-effective than ever.

Three-dimensional images and effects suspend viewers in a state of astonished participation as they try, generally unsuccessfully, to figure them out. One of the illusions at the Haunted House at Disneyland is a ghost-like image sometimes referred to as Pepper’s Ghost. These types of images are produced in one location, and then reflected off a pane of glass or other transparent material, so that they can disappear and reappear in other locations.

This technology would allow park-goers to look out of a window and see articles in the room they are in. Disneyland did this successfully in the Haunted House by creating moving dancers in a room beneath the viewing area. These images were then reflected off an invisible pane of glass between park-goers and the room they were observing, and appeared to combine ghost-like images with the tables and chairs in the room. The intensity of light from the reflected image and the real image determines how solid or ghost-like the reflected image looks.

Turning the light off makes the image disappear. Another image may appear in its place by illuminating it at the same time the light is turned off. Knott’s Berry Farm uses a variation of this concept at its newest attraction, Mystery Lodge. A process described as a shallow-field aerial image effect is used to produce floating spirits that appear three dimensional (page 13).

The adage: “it’s done with mirrors” is also true. Solid, video, or projected images can be reflected with mirrors to other locations. In many arcade games, the image source is usually upside down below the viewing area. Then, with two mirrors almost at right angles to each other, the image is reflected in front of the player. This system also offers the ability to tilt the original image so the bottom of the scene seems close and the top of it, usually background objects, seems to be in the distance.

Optical projection systems utilizing Fresnel lenses can produce images without the use of screens. The images are optically focused by the Fresnel lens system to float in front of the viewer. Current Fresnel lenses are more than one foot in diameter, but lenses many times that size are being developed. Not only does this system offer the possibilities of suspended images, but it can also offer the sensation of passing one’s hand through the image, crating a truly magical interactive experience.

Parabolic mirrors can be used to actually focus the image’s light in a space. Most of us have seen this effect in table-top toys where a coin or other object seems to float within our reach. However, parabolic mirrors are expensive formats. At a past World’s Fair in Japan, a suspended gigantic parabolic mirror allowed visitors to enter a room and shake hands with upside-down, floating images of themselves.

Lasers can project moving three-dimensions onto water screens. A few examples of this effect include the Fantasmic show at Disneyland and Disney World and an outside display at the Luxor in Las Vegas. Using the aerated spray of the fountain as a screen, spectacular visual effects, messages, or stories can be choreographed, and then displayed in mid-air. A similar effect can be produced by projecting onto a scrim or multiple scrims.

Holographic optical elements (HOEs) are also used to create an “invisible” scene. HOEs offer, in most cases, a more precise method of displaying projected images than panes of glass or other transparent material. Since HOEs have optical properties, the visual result can be programmed for multiple purposes. HOEs are used for heads-up displays of airplane cockpits and some automobiles, enabling the pilot or driver to see important or desired operational data in front of them. This effect also, of course, can be used to created images in the viewer’s line of sight for ride purposes.

Many methods used to produce three-dimensional effects have surfaced or re-surfaced lately. The creation of three dimensions in multiple media is causing large lines as audiences wait to be immersed in an experience.

The use of polarized glasses, though a relatively old effect, has been improved. Also, filmmakers have learned how to compose scenes to get the most out of the three-dimensional effect. The use of computer animation, where the optimum geometric configuration of the scene can be programmed into the experience with the use of highly imaginative, if not photographically impossible, images has created amazing journeys for audiences, such as at the Luxor Live attraction at Luxor.

With glasses augmenting the viewers’ experiences, a 360-degree immersive experience is currently being developed. An area with rear projections on each of the walls surrounding the audience, who are equipped with either polarized or infrared liquid crystal glasses, creates a total three-dimensional experience without a helmet.

Liquid crystals in electronically controlled glasses where each eye sees different images have been used to create a dynamic stereoscopic effect using video. Imax as well as several home-office kits have successfully demonstrated this method, which includes a infrared system that eliminates the need for cables. The price and effort of handling these glasses are opposed to polarized glasses is more, but they require only on video projector.

The combination of three-dimensional movie experience and movement offers a new world of simulation rides. One such ride is opening in the Forum at Caesar’s Palace in Las Vegas, showcasing several computer-generated adventures.

Using a three-dimensional bust or surface as a screen and then creating an animated sequence with projectors can produce a dynamic and believable illusion of ghost, spirit, or “talking head.” Disney has successfully used this effect in the Haunter House. It is also being used at many other locations, such as in the lobby of the MGM Grand hotel in Las Vegas.

In one respect, holography offers one of the most precise methods of creating three-dimensional reality, since it has the ability to literally reconstruct visual reality. Obviously, the Pepper’s Ghost effect also duplicates visual reality by reflecting the light of an object off of glass, but those objects will have to be somewhere in the area.

Whether the desired effect is a ghost-like illusion, solid object, moving scene, or objects appearing the same space, holography offers a large array of three-dimensional images or illusions. Holograms can be small to life-size, solid or transparent, static or kinetic, one color or multi-colored.

Holograms are being used often now in zoos (St. Louis Zoo, a T-rex skull) and natural history exhibits (San Francisco Natural History Museum). Generally, these holograms stand on their own since the illusion is so impressive and magical.

Incorporating holograms in mixed media opens up all sorts of possibilities. People are just starting to understand holography and how to use it in ride experiences. Disneyland first used one in its Pinocchio ride when Lampwick, the donkey, looks into the mirror and sees himself (the hologram) as a boy.

Besides the dynamic impression a hologram, it also offers the space-saving advantage of a complete volumetric scene existing in a two-dimensional plane. A diorama that originally occupied a four- by six-by nine-foot space can now be holographically contained in a two-dimensional four- by six foot flat surface.

By “stacking” several holograms, exposing different holograms from different reference angles on one hologram, multiple scenes or different objects I the same two-dimensional space can be created.

A laser-illuminated hologram could actually create a three-dimensional 10- by 20- by 10-foot room or larger with complete parallax on a two-sq-ft or smaller hologram with ten people in it and windows looking into other rooms.

By interfacing holography with other media (film, video, and computer animation), three-dimensional moving holographic images can be created without glasses or other visual aids. This is becoming one of holography’s most exciting applications, even though the basic technology was first developed by Lloyd Cross, one of holography’s pioneers, 20 years ago. Continually, more holographic laboratories are equipping themselves with this capability, even for formats larger than three by six feet.

Now in its forty-eighth year, holography continues to progress. Obtaining a holographic image to meet the needs of a ride or attraction has never been easier. Catalogs of existing holographic images offer hundreds of choices. In addition, many holographic laboratories offer customized image services.

Holographic material is often being used in packaging products or on magazine covers. Parks should consider packaging a ride or an attraction with similar kinetic effects. Though used sparingly today at some parks, the applications are endless for interior or exterior design. The look is exciting and futuristic, and there is a choice of hundreds of designs and patterns. In addition, holograms require virtually no upkeep and last indefinitely.

Holography is an emerging medium that will continue to grow, mature, and become increasingly accessible. Its most interesting application in attractions and rides is its ability to create windows into other dimensions. So much of perceived reality is the result of sight, and holography has the ability to record and display visual reality, or create a realistic “impossible” scenario.

Even at holography’s present state, there are many possibilities that have not yet been approached. With each new application, light is not only shed on its capabilities, but it helps define and mold its next level of development.

The desire of the public to have an experience that is immersive and interactive is growing every day. The concept of a “holo-deck,” where individuals enter a completely believable reality or adventure while having the ability to interact or somewhat control the experience, is becoming the goal of many in the entertainment industry.

Virtual reality has created a continuing path of different immersive virtual worlds. While the computer as a tool is becoming faster and less expensive, and thus more widely accessible, the virtual experience is becoming more complete. The eventual merging of virtual reality with holography will bring us closer to the “holo-deck” experience. The recent development of a “holographic window” could completely eliminate the need for helmets or glasses for an interactive three-dimensional experience.

To quote Lloyd Cross: “The synthesis of computer and holographic technologies will create new media, such as virtual realty using HOEs and interactive holographic display methods using integrated computers. And I think it’s still possible that we could have at least one holographic movie theater to celebrate the turn of the century.”

Not only are the rides and attractions today more technically advanced and immersive, we are fast approaching a time when we will be able to experience our wildest dreams — and interact with them

Jeff Allen, author of Magic Windows: Pocket Holography, is a consultant based in Sausalito, Calif.