"The Perfect Medium: Photography and the Occult", Metropolitan Museum of Art, New York.

On first and second sight, "The Perfect Medium: Photography and the Occult," at the Metropolitan Museum of Art, is a very weird show. I wouldn't call it fabulous--too many of the photographs in it are revolting little things--but it is fascinating. And it is puzzling on a number of fronts. How were these things made? The wall texts and catalogue do not always tell us, unless we are meant to suspend disbelief and give some credit to occult concepts like "vital fluid" and ectoplasm. The caption for one plate in the catalogue matter-of-factly claims that photographer Frederick Hudson "probably incorrectly" identified the spirit of the daughter of a seventeenth-century buccaneer. Indeed, (But who knows?)

Did their makers and consumers believe in these "documents," even when they were in on the artifices involved in their production, even when they were intelligent, modern people like Sir Arthur Conan Doyle (who was a proponent of such pictures and whose spirit was supposedly captured in a few)? Not clear. How are we to distinguish between hoaxes and serious investigations? Not clear either: Both partake of gimmickry and experimentalism. And yet it's too easy just to say that it all comes down to photographic deception. Not least of the show's puzzles is what to make of the curators' intentions: Were they entirely serious? Or are they putting us on just a little? The "just the facts, ma'am" presentation of this odd material is a bit too solemn and scrupulously objective to be believed, quite. And so one wonders if there isn't something tongue-in-cheek about this caricature of scholarly neutrality. Finally, what, if any, is the larger point of this show? Does it offer a different way of understanding the "perfect medium" of photography? Or is it just a side trip to the lunatic fringes of photography's history?

I'll choose the first road, though I see no reason why a little play can't be added to the equation. We are told at the outset of the catalogue that there are three different ways of taking the occult photographs in it: from the believer's point of view; as aesthetic objects; or with the detachment of an historian (the view the exhibition purports to take). I propose a fourth option, and that is to take a speculative path and to think a little about what all this might do for our understanding of what a photograph is and what its history tells us. After all, photography and speculation--thought experiments as well as other kinds of trial-and-error--have gone together from the beginning.

[ILLUSTRATION OMITTED]

"The Perfect Medium" is full of neologisms, the most wonderful of which is the "skotograph," a spirit photograph taken without a camera or light but by pressing a phorographic plate against the face. To the "radiograph," the "electrograph," and the "thoughtograph," we could add some of our own inventions: the "indexograph" (or "digitograph"), the "somogram," the "chemograph" or "obscurograph," and perhaps even the "occultograph." The word "photography" is just such a neologism itself, and its history is rife with further neologisms. This tells us that photography has always been a science-fiction concoction whose experimenters constantly speculated about what kind of medium it was, and what defined it.

"Drawing-by-light" is the definition that was settled on. (Contrary to what is commonly thought, the photograph was never considered simply a camera-made image. It still isn't, according to the Oxford English Dictionary, which includes no mention of the camera in its definition of the word "photography.") But light is only half the story, for darkness--the obscurity in the camera obscura--is also needed to make a photograph: both the darkness of darkrooms and camera interiors, and the occlusion of light that is necessarily part of any photographic inscription. And this brings me to another point: The obscure and the occult are almost synonymous with one another, sharing a sense of the dark, of the secret and mysterious, the hidden and imperceptible. What the occult adds to the mix of obscurity is the experimental and the magical, as well as forms of "science" that belong either to the past (alchemy, for example) or to the future (much of modern physics, say, from Einstein on).

So, "The Perfect Medium" is not as much a side trip as it might first appear; rather, it taps deep into photography's dark heart. Any photograph is a trick, after all--a conjury of optics and a chemical reaction, which happens below the threshold of sight. In it, magic and science are not far apart: Indeed, what is the difference between the two, if not that magic is a science uncoded, outmoded, and not subject to proof, and science, by contrast, is a magical art proven, systematized, and entered into the book of accepted up-to-date knowledge? "The Perfect Medium" speaks directly to the way photography is situated at the shifting borderline between the two. Its double-exposure ghosts, its seance documents, its records of the flow of ectoplasmic material from mouths, noses, and navels, and its experiments with "vital fluid" impressions made with the dark--rather than light--side of the photographic equation are all located at that borderline.

The "photographs" of hands and fingers made with electricity, heat, sweat, and other invisible energies, but without light or the camera, are both the most arresting and the most serious of the various sorties into the occult presented here. They are also the most interesting, because they are the most truly speculative in their quest into the invisible end of the photographic spectrum, that place where alchemy and chemistry, physics and metaphysics meet. It is in them that the "surrealist conditions of photography," to invert Rosalind Krauss's famous formulation, deserve the most respect. And it is in these "occultographs," more than in all those camera-made pictures of mostly female mediums, that another, possibly gendered, meaning of the "perfect medium" comes to light. It allows us to consider photography a "feminine" medium, more fundamentally a matter of volatile internal processes hidden from the eye than of technological mastery and scopophilic command.

"The Perfect Medium" is on view at the Metropolitan Museum of Art, New York, through Dec. 31.

Carol Armstrong is a professor of art and archaeology and Doris Stevens Professor of Women and Gender at Princeton University.