TWO questions needed to be answered before I could review ``The Holographic Instant: Pulsed Laser Holograms'' on view at the Museum of Holography here: What is holography? And what is a hologram? The museum provided the answers. Holography is the method of making three-dimensional images with the aid of laser light. A hologram is an image produced by this method.
More specifically, a hologram is a piece of film or glass coated with a photographic emulsion that has been exposed to laser light reflected by an object. Instead of making a flat image on the surface of the emulsion in the manner of a photograph, a hologram has no image on it at all. When a light is played on it, however, a three-dimensional image appears to float behind, or in front of, the hologram. The latter can be so startlingly lifelike that one is tempted to reach out and touch it - only to discover that there is nothing there.
That temptation can be very strong, especially if the image extends forward and beyond what would normally be the flat picture surface. The nearer wing of a bird in flight, for instance, can appear to project a foot or so from the wall on which the hologram is placed. And a hand in a portrait can seem about to reach out to touch the viewer.
Such effects are the particular specialty of pulsed holography, a process utilizing short bursts of laser light (as opposed to the more frequently used continuous-wave laser) to freeze movement in whatever it portrays. This enables artists and scientists to produce astonishingly realistic holograms of otherwise difficult or inaccessible subjects: flying creatures and human portraits; instantaneous events, such as a bullet shattering a glass; and images impossible to view normally, such as subatomic particles or the core of a nuclear reactor.
These subjects and many others are depicted in all their colorful three-dimensionality in the museum's current exhibition. Its 45 holograms from nine countries explore the medium's various aspects, from the purely scientific to the artistic, and range from works that can be of interest only to specialists in the field to images that cannot fail to have the widest public appeal.
Who would not be fascinated, for instance, by Margaret Benyon's ``Cosmetic Series Self-Portrait #3''? Approaching it, one sees only a somewhat stylized painting of a young woman's head. Move an inch or so to the right or left, however, and one is suddenly face to face with an extraordinarily vivid ``portrait,'' complete down to every wisp of hair and facial texture.
The same is true of a study of Boy George made up as a clown. The illusion of volume and actuality is so remarkable here that one has to stop oneself from reaching out to touch the long, soft eyelashes curving upward, the white, creamy skin, and the tufts of hair growing out of the head. Everything is so lifelike and real that it takes a while to realize that one very important element is missing: movement - and with it, life itself.
Once one is aware, however, of how deathly still, how frozen in time, everything is, then that awareness itself begins to play an increasingly crucial role in one's reactions to these works.
I, for one, remembered the sight recently of a perfectly preserved fly embedded in amber, and the similarities between it and these portraits were vaguely disquieting. So much absolute stillness slowly casts a subtle pall over the viewing experience.
With that, unfortunately, the magical aspects of the illusions gradually began to diminish, leaving only the scientific and technical accomplishments - which are obviously remarkable - and whatever level of art was achieved by those who aspired to it.
But how does one approach these works as art? By what standards does one evaluate something so totally new and capable of such hitherto impossible feats?
Holography, after all, is neither photography nor sculpture, although it is related to both. And neither, in the hands of an artist, is it a gimmick or a purely scientific activity.
For a critic, the situation is similar to that confronting early 19th-century writers who first attempted to deal with photography as an art form. Most of them made the mistake of judging it by the values and ideals of painting - just as many of the early photographers committed the error of trying to make their photographs look like works on canvas.
Photography survived and gradually established its own identity. Holography, on the other hand - at least when it is perceived as an art form - is still somewhat unclear about its creative potentials, although it obviously already has a powerful and unique expressive voice.
But just what are its creative potentials? I doubt anyone really knows, although one can, on the basis of what's in this show and what can be found in books, periodicals, and other exhibitions, very cautiously project one or two possibilities.
Portraiture is obviously one, especially the kind that goes beyond precise physical appearance to reveal something of the depths and nuances of the human spirit. A touch of psychological or spiritual insight would go far toward neutralizing the ``fly in amber'' quality many portrait holograms have - particularly if it is presented unselfconsciously and in an informal manner.
Holographic films and holographic television are other distinct possibilities, although specialists agree that both would require huge sums of money and many years to develop. And there's no question that the medium has great potentials in the area of conceptual art. One glance through Holosphere, the museum's quarterly journal, should dispel any doubts one might have as to the type and quality of work being produced by innovative art holographers around the world.
The exhibition continues at the Museum of Holography, 11 Mercer Street in SoHo, through Sept. 20. For those interested in the history of holography, the museum also has an exhibit detailing its development from 1948 to 1978.