One day in 1999, as he admired a small pencil portrait by the exquisitely precise hand of Jean-Dominique Ingres, artist David Hockney was suddenly possessed by an idea: that the almost photographic clarity of Ingres’s draftsmanship might in fact have derived, like a photograph, from the projection of the sitter’s image through a lens. Perhaps, in other words, Ingres may have used a small tool called a camera lucida, basically what Hockney describes as “a prism on a stick,” to project the figure before him onto paper, allowing him to sketch out his composition’s basic lines with nearly photographic precision. Hockney soon found definite confirmation of his eyes’ intuition; Ingres, as it turned out, often did carry a camera lucida with him when he drew his little portraits as a useful supplement to his income.

This information in turn drove Hockney to ask another question: How long had artists been working with lenses as Ingres had done? Again he turned first to the evidence of his own eyes. He covered a wall of his studio with reproductions of European paintings displayed in chronological order and began to study them carefully. Tentatively he identified a perceptible change in European drawing and painting that spread in the early fifteenth century from the Low Countries south to Renaissance Italy, soon coming to dominate the aesthetics of European art. This change, as Hockney describes it in Secret Knowledge, had to do with what he calls “optical characteristics,” essentially involving the plausible representation of figures in space.

He singles out, for example, “confidence of drawn lines,” the representation of complex fabrics in three dimensions, “the lighting we associate with photography,” and “an advance in naturalism.” With increasing conviction, he began to think that this change in the manner of artistic representation came about when fifteenth-century artists began to experiment with projection through lenses, and, together with their public, fell in love with the crystalline precision and spatial depth of the results. This predilection lasted, so far as Hockney could see, until the later nineteenth century, precisely the era, he notes, when photography itself began to come into its own as a medium.

To bolster his own observations, Hockney also began to appeal to various kinds of professionals for expert opinions on the place of lenses in the European artist’s tool kit: to art historians, and to a writer, Lawrence Weschler, whose account of Hockney’s thesis in The New Yorker in January 2000 sparked a good deal of interest, including that of a scientist, Charles Falco, who visited Hockney’s studio in March of 2000 and emerged a fervent, and vocal, believer in Hockney’s thesis. Eventually Falco used mathematical techniques to specify the kinds of distortions that might identify lens-projected images in art, and has become, for all practical purposes, Hockney’s fellow traveler. Hockney, mean- while, had become all but obsessed with the subject of lenses in European art, a condition he attributes in part to his growing deafness. With continuing contributions from Falco, Weschler, and such art historians as Martin Kemp, his obsession has generated a large, colorful book and a large, colorful discussion, although both have often revealed more about contemporary modes of thinking than they have about the artistry of the past.

Hockney’s quest began, as he says, with an ocular intuition: with a contemporary artist’s visual response to the art of the past. To prove that intuition, however, he sought corroborating evidence. As his own first line of argument, his book presents a series of detailed photographs of paintings and drawings, in effect inviting his readers to see through his eyes. From Hockney’s own work we know that these eyes are supremely attuned to color as well as line and space; this initial photographic essay, simply for its careful scrutiny of some beautiful drawings and paintings, will surely stand as the most lasting, and ultimately the most original, section of the book.

Part of Hockney’s analysis, however, begins from the awareness that some of these artists could do things of which he himself is incapable; as he admits, Ingres had to be an exceptional draftsman to produce what he did—but Ingres was an exceptional draftsman, exceptional in a way that Hockney, however talented in other ways, is not, any more than most composers can achieve the seemingly effortless melody of Mozart or Verdi. Hockney’s ego looms as large in his book as that of another artist, Benvenuto Cellini, in his egregious Autobiography; both are men of considerable charm, but for both ego acts as its own kind of lens, filtering, projecting, and distorting all that they see. Cellini dabbled in necromancy. Hockney contents himself with being an oracle. Of the display of reproductions tacked on his studio wall (eventually to be called “The Wall”), he writes:


It allowed me to see the whole sweep of it all…. I’m sure these things could have only been seen by an artist, a mark-maker, who is not as far from practice, or from science, as an art historian.

Despite his professed skepticism about their competence, Hockney turned to professional art historians for confirmation of his ideas, and prints his correspondence with them in exhaustive detail as the third section of his book. As in his dealings with the Old Masters, his bravado sounds rather like the bravado of insecurity, and it is a pity that he could not have put it aside. In fact, however, the Old Masters of earlier times barely mention the use of lenses in their work. Hockney concluded, therefore, that their use of optical devices must have constituted some kind of secret tradition. Secrets are always attractive, of course; the very title of Hockney’s book exploits that attraction to the fullest, promising not only secret knowledge, but also rediscovery and lost techniques and Old Masters, all in one irresistible package. No reader who loves a secret will be happy to hear that this secret knowledge has probably been accessible all along. It is a matter of looking for it in the right places.

Artists, in the great course of history, have not necessarily been the most likely people to write about artistic technique; they are usually putting it into practice instead. Europe’s Old Masters, with a handful of exceptions, Rubens notable among them, were no different; they were trained in a craft rather than in the liberal arts. They passed their techniques down from master to apprentice, and in the busy environment of the workshop no one needed to write down instructions—furthermore, the best among them experimented constantly with new media and new methods. Successful artists seldom wrote much about their craft; they were too busy filling orders. When they did write, it was as likely to be about some other interest aside from their day-to-day work. In sixteenth-century Italy, for example, Michelangelo wrote vernacular poetry, Giorgio Vasari, biography, Benvenuto Cellini, fiction passed off as autobiography; Donato Bramante improvised short, pithy songs on the lute; Raphael studied the ancient Roman architectural writer Vitruvius and touted a new instrument for mapping—far from hoarding secret knowledge, he apparently intended to trumpet his invention to a reading public newly broadened by the introduction of movable type.

As Hockney himself concedes, his own questions about what he terms “optical characteristics” in European art virtually coincide with another set of questions that are as old as the Old Masters themselves. For the distinctive spatial sense that Hockney attributes to working with lenses also defined one of the salient qualities of Renaissance art—not only as we see it in our own age, but as it was seen in the fifteenth and sixteenth centuries, at the time when the artists who produced this art were living and working. They called their distinctive point of view “perspective,” “seeing through.” Hockney carefully distinguishes the development of linear perspective from what he calls optics and declares that the former is irrelevant to his own investigation.

And yet the age of perspective was an age that delighted in the invention of a variety of instruments designed to “see through” the workings of art and nature at every level of detail. All of these instruments used lenses and mirrors as the windows through which the world’s wonders were revealed, or, for that matter, counterfeited: telescopes, microscopes, eyeglasses, spyglasses, camerae obscurae, magic lanterns. Perspective and experimentation with optics went hand in hand. The connection has been put brilliantly on view in a recent show at the J. Paul Getty Museum called “Devices of Wonder,” curated by Barbara Stafford of the University of Chicago and Frances Terpak of the Getty Research Institute. In room after room of phantasmagoric displays, lenses and perspectives were shown to have been inseparable from the beginning and remain inseparable to this day; Filippo Brunelleschi, who first demonstrated linear perspective from the steps of Florence’s cathedral, did so by using a device with a mirror.

The connection between perspective and optical devices also appeared in literature from the period with which Hockney is most concerned; not necessarily in the writings of artists, but in those of writers with other kinds of expertise. Thus a figure whom Hockney briefly mentions and who looms large in the catalog for “Devices of Wonder,” the seventeenth-century Jesuit Athanasius Kircher, matter-of-factly confirms Hockney’s surmise that the Old Masters may have worked with lenses in a book called The Great Art of Light and Shadow (Ars Magna Lucis et Umbrae), first published in 1646, one of more than forty that Kircher wrote in his lifetime on a vast array of subjects. In a picture book as big, expansive, and visually persuasive in its own day as Secret Knowledge is in ours, Kircher notes that perspectival painting, what he terms “scenographic projection,” can either be done with lenses, “catoptrically” (literally, “by doing it with mirrors”), or with the unaided eye, “optically.”1 Each method, he reports, has its advantages and its drawbacks:


Depending on circumstance, these methods for scenographic projection…do not please the eyes equally. For if a great light appears from the same place where shadows are depicted, the image offends the eyes, as shadows necessarily exist in opposition to light. Again, if an image is made catoptrically, and set up to be seen from below, it will not exhibit the same charm as when it is observed from above, and likewise what is done optically, if seen from above, will seem less perfect.2

Another section of Kircher’s Great Art of Light and Shadow touted his own version of a camera obscura under the tantalizing title “How Anyone Can Become a Painter.” There he insisted that with the help of his marvelous device, “anyone, however ignorant of the art of painting, will be able to create depictions of images that will be the envy of any painter”—without the hard years of apprenticeship, and in the full-blown Baroque era of Rubens and Bernini.3

Kircher, let it be clear, also boasted that he could teach anyone to compose beautiful music by using his Combinatory Art, or to survey like a professional with the help of the machine he called his “Pantometrum Kircherianum”; he was a huckster and a showman as well as a first-rate scientist, and a perceptive collector of art, ancient, modern, and exotic. Kircher was also an incurably terrible draftsman, whose charmingly crude renditions of Egyptian scarabs, dragon kites, subterranean lakes, and erupting volcanoes show that he, at least, never learned how to depict “images that will be the envy of any painter” with the help of his machines. Instead, professional engravers transformed his clumsy sketches into lavish illustrations for the dozens of books he published in his fifty-year career. This wily Jesuit, of all people, knew full well that it took an Old Master to paint like one, and that even then, the professionals of his own day could come up short:

Our Painters of the Roman Academy commit errors when they try to paint daytime scenes at night by candlelight, unless they know how to compensate with great and singular industry for the crudity of the shadows cast.4

Not a mark-maker in Hockney’s sense (although he may have marked as much paper in his lifetime as his sometime collaborator Bernini), Athan- asius Kircher probably knew as much as anyone in his day about the effects of light and lenses. He had been trained by a Venetian glazier to grind his own glass, and became an early user of the telescope (he called it the “Astronomical Tube”) and microscope (which he called “Smicroscopium”); he stocked his museum with magic lanterns, a camera obscura, and elaborate devices that used lenses and mirrors to project beams of light or whole images. He argued that smells, thoughts, and fertility itself could be projected just like light in a process he called actinobolismus (Greek for “ray-throwing”). And he knew artists; he certainly worked on two projects with the great Gian Lorenzo Bernini, the Fountain of the Four Rivers in Piazza Navona and the obelisk-bearing elephant who stands in front of the Roman church of Santa Maria Sopra Minerva. It seems more than likely that among the thousand books in the collection of his contemporary, the architect Francesco Borromini, Kircher’s popular accounts of ancient Egypt, light and shadow, magnetism, or cosmology might have figured prominently.

Clumsy draftsman but superb observer, Kircher insisted repeatedly (when not selling his machines) that the basic problems of artistry have more to do with the acuity of eye, mind, and hand than with tools, a basic point that Hockney also makes repeatedly in his own book. Kircher’s criticisms of contemporary art in The Great Art of Light and Shadow focus on the accurate observation of light, shade, and their effects when projected through every kind of instrument or seen by the unaided eye. This enthusiastic creator of truly marvelous machines knew perfectly well that every method brought its own problems along with its insights. Lenses project an image with great accuracy, to be sure, but the image is also diluted, distorted, evanescent, and often upside-down. Some artists surely used them, many did not. Hockney and Falco, in their enthusiasm, exaggerate their prevalence; Kircher, who was in a position to know, probably gets it right by stating that they are no more than an option.

Lenses or no lenses, neither David Hockney nor Athanasius Kircher could or will ever attain the artistic precision of Ingres or Raphael, who were both draftsmen of transcendent manual skill, trained from an early age in a long tradition, any more than either of them could ever carve stone as well as Bernini. (It is no accident that the hypermeticulous Raphael would be the artist with whom Ingres felt a special affinity.) Raphael’s contemporaries saw the hand of God in his work; despite its many protestations to the contrary, there is a part of David Hockney in Secret Knowledge that really does hope, deep down, that it was all done with mirrors rather than by genius married to incessant hard labor. It was a hope that Kircher’s marvelous painting machine also acknowledged, and aimed to exploit. But one man’s limitations do not necessarily provide a sure guide to the abilities of someone else.

Similarly, the limits of Hockney’s “Wall” have set a boundary on his investigation that is entirely arbitrary. As Athanasius Kircher, at least, was well aware, neither lenses nor perspective made their first appearance in the fifteenth century. In Hellenistic Syracuse, nearly two thousand years earlier, Archimedes claimed to wield a concave mirror from the heights above the city that set ships afire in the bay below. Writing to the Christians of Corinth in the heyday of Imperial Rome, Saint Paul compared our perceptions in this life to seeing a mirror’s murky reflection “through a glass, darkly.” Ancient Greek and Alexandrian painting barely survives, but ancient Roman wall paintings played complex optical games with a freedom that admitted multiple, even reverse perspectives, houses growing wider as they recede back into the distance, distinct vanishing points and perspectival systems tailored to individual viewers in a room, or ranked in order of importance to the theme of the decorative scheme.

Some of the perspectival effects most characteristic of Renaissance art owe as much to scrutiny of ancient artworks as to contemporary advances in technology; this constant, paradoxical interplay between antiquarian curiosity and scientific curiosity is what make the period so extraordinarily fertile—Raphael’s brand-new mapping tool, a magnetic compass fixed to a revolving table, was invented to measure the ruins of ancient Rome. But if the peculiar qualities of Renaissance art cannot be “explained” by a mechanical device, then Secret Knowledge requires a much more complicated discussion, taking in philosophy and culture, as Athanasius Kircher felt compelled to do in The Great Art of Light and Shadow; he was also compelled, as a man of his time, to discuss religion.

A two-day symposium on Hockney’s thesis, held at the Humanities Institute of New York University in December 2001 under the aegis of its new director, Lawrence Weschler, emphatically, if unintentionally, revealed that what makes the art of the Old Masters so distinctive and powerful seems not to be the spatial placement of figures, not even their color, but rather their modeling, that interplay of darkness and luminosity that the Italians call chiaroscuro (bright-darkness), whether expressed in Caravaggio’s stark contrasts of light and shadow or Leonardo’s subtle “smudged” sfumato. Athanasius Kircher, for his part, called his book The Great Art of Light and Shadow, not The Great Art of Projection. For him, light was the essence of existence, and not only because, as a good Jesuit, he was captivated by the Gospel of John’s description of God as light. He also believed that sunlight carried what he called a universal spermatic power on its rays, eternally ready to fertilize the receptive earth.

At the same time, Kircher could also observe light and shadow with scientific detachment. Without naming particular artists, he notes how Caravaggio and his followers achieved their distinctive chiaroscuro and criticizes it as coarsely unrealistic. Caravaggio’s early paintings, in fact, showed a far broader range of colors and fewer contrasts than his brooding late works, all done in shades of lead white, black, brown, and red. Ironically, one of the inspirations for the Milanese artist’s change of hue in Rome may well have been that bright colorist Raphael, who experimented increasingly in his later years with night scenes and pale figures emerging from darkness. Among them are a self-portrait with his young fencing master, the rugged, contrasting faces of the Venetian scholars Andrea Navagero and Agostino Beazzano, the beautiful blond banker Bindo Altoviti casting a heart-stopping glance, blue eyes and bee-stung lips, over his pale, smooth shoulder.

Caravaggio, unlike Raphael, was not much of a draftsman. Despite Charles Falco’s efforts, in Secret Knowledge and in the NYU symposium, to ascribe the painter’s anatomical distortions to projection of his models’ figures through lenses, the oddities will not go away so easily or for Falco’s reasons—and in the end, the inaccuracies hardly matter when Caravaggio’s paintings have so much else to say. (Besides, a painter like Botticelli, who was a great draftsman, also created figures that defy every rule of human proportion for the sake of his sinuous line.) In telling his intense painted stories, Caravaggio’s dramatic lighting, suggestions of sound, smell, and touch, and searing force of character take precedence over anatomy. For Caravaggio, light, as in Kircher’s universe, gives life as well as form.

Furthermore, there were cheaper ways to produce optical effects than by using lenses, and most artists were living hand to mouth much of their lives. As many of the panelists in New York pointed out, artists like Hans Holbein the Younger used geometric projection—a grid—to produce foreshortenings, or those apparent distortions called anamorphic images: twisted, deformed figures that make sense only when viewed in a mirror. Holbein’s Ambassadors, a formal portrait sliced obliquely by the stretched figure of an anamorphic skull, seems, once again, to be making Saint Paul’s point about seeing “through a glass, darkly” until death shall bring us face to face with God. Holbein’s worldly diplomats exist on an entirely different plane from the memento mori that flits before them with the evanescence of a feather, or a chill breeze; only we see their mortality revealed along with the vanity of their own vanity—and ours as well. (See illustration on page 12.)

Indeed, the larger question raised by the conjunction of optical technology and art (and one that both Hockney and Falco should perhaps be addressing with more urgency) involves identifying what precisely it was that lenses enabled early modern eyes, and not only those of artists, to see, both physically and in the imagination. Galileo’s telescope famously turned him into a “Starry Messenger” who saw both new flaws in the universe and sublime visions: pockmarks on the face of the moon and new stars beyond number.

Athanasius Kircher’s smicroscopium led him to marvel, like van Leeuwenhoek before him, at the complexity of creation, at all the tiny things unseen by human eyes until the seventeenth century:

If you examine the powder of rotten wood under the Smicroscopium, an immense pullulation of little worms will be found, of which some are outfitted with little horns, some have wings of a sort, others are not unlike centipedes, and you will see eyes like little black dots along with noses; thus God, Greatest and Best, shows Himself as marvelous not only in the vast bodies of the world, but also in the tiniest little animals, imperceptible to every eye, when he gave them their individual parts, without which they could not move nor perform any of their other vital acts. Because they themselves have been placed in the world with bodies so tiny that they are beyond the reach of the senses, how tiny can their little hearts be? How tiny must their little livers be, or their little stomachs, their cartilage and little nerves, their means of locomotion?5

Initially, the sudden revelation of these things unseen lent strength to the Neoplatonic idea that our physical sense of sight penetrated no further than “through a glass, darkly.” Reality clearly lay somewhere else, far beyond the capacities of the naked eye. Art, that supreme figment of sight, drove the point home by creating layers of meaning: Holbein’s ambassadors and skull; Raphael’s simultaneous portrayal of God as a bearded man with a halo and as a shower of light in his Disputa of 1508; Caravaggio’s Calling of Saint Matthew, where a beam of light singles out the future martyr with far more authority than the languid gesture of Jesus (see illustration on page 10). And yet, both this layering of art and this Neoplatonic view of the world were legacies from the ancient past, compatible with, but not caused by, new technology.

Even when science became a viewpoint in itself in the eighteenth century, its insistence on elegance and order proclaimed—and still proclaims—its Neoplatonic heritage. We who are entirely at ease with the Hubble telescope’s revelation of stars being born deep inside baroque clouds of gas are equally comfortable with the Platonic conviction that the world is wrought with ineffable elegance. Perhaps this is one reason why Jan Vermeer’s lucid vision of seventeenth-century Delft, long thought to have been executed with the help of a camera obscura, could still bring solace to the present-day judges who are compelled to endure the tales of Bosnian war crimes while holding court in The Hague. The greatest art of light and shadow has always involved the spirit as much as the hand and eye, and in elucidating this truth a very good art historian can sometimes make an essay about art into a work of art in its own right, as Hockney implicitly acknowledges by citing the art historian Roberto Longhi at the beginning of his book.

In the debate engendered by Secret Knowledge David Hockney spoke of his own deafness, and it is hard to resist taking this condition metaphorically; it brings on inner visions at the price of stopping conversation. He and Charles Falco have become true believers in a world that is to a great extent of their own making. The Old Masters who inhabit this world are not always made more vivid by the authors’ excess of enthusiasm in the service of a grand theory. Instead, these real and talented people are more literally than ever seen through a glass darkly, objects of what Athanasius Kircher called “projection of the imagination,” actinobolismus imaginationis—fantasies of powerful suggestion, but fantasies none- theless. Hence, despite all its misinformation, superseded science, and tendentious opinion, Athanasius Kircher’s redoubtable Great Art of Light and Shadow, an Old Master in its own right, is still probably the most informative book to read on how Old Master artists used the technology of lenses in creating their art.

This Issue

February 28, 2002