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• 1 2022-05-19T21:53:33+00:00 Further Insights: The Interior of Our Eye 1 plain 2022-05-19T21:53:33+00:00

  Further Insights

  The Interior of Our Eye

  The Camera Obscura represents the Inside of our Eye.

  — Francesco Algarotti17

  Having established that Selva’s casotto is a kind of elaborate camera obscura (and a peep show), let’s examine the mechanism behind it—its backstage, so to speak. From Selva’s description, the optical theater of the casotto is clearly based on a system of multiple projections that, together from different angles, create the immersive effect of a panoramic view of San Marco and the basin. In its theatrical display, the scenography of Venice comes alive as in a multidimensional living painting. These projections follow the principle of the camera obscura, described by Venetian aristocrat Daniele Barbaro nearly two centuries before Selva, in 1569. Barbaro writes:

  Make a hole in the blind of the room through which you want to see, as large as the lens of eyeglasses. Then take an old man’s glass, thick in the middle [convex on both sides] or similar to the spectacles of youths who are short-sighted, and fix this glass in the whole, shut[ting] all windows and rooms into the room so that no light enters except through the glass. Then take a piece of paper and place it in front of the glass so you see in detail on the paper everything that is outside the house, which can be seen at a specific distance more clearly such as you can find by moving the paper back and forth, closer to or more distant from the glass. Here you will see the forms on the paper as they are in reality, and the gradations, colors, shadows, movements, clouds, the ripples of the water, the flight of birds, and everything else that can be seen.18

  Farai uno bucco nello scuro d'una finestra della stanza di dove vuoi vedere, tanto grande quanto è il vetro d'un occhiale. Et piglia un'ochiale da vecchio, cioè che habbia alquanto di corpo nel mezzo, non sia cosa o come gli occhiali da giovani, che hanno la vista curta e incassa questo vetro nel bucco assaggiato; serra poi tutte le finestre o le porte della stanza finché non vi sia luce alcuna se non quella, che viene dal vetro; piglia poi un foglio di carta, et ponlo incontra il vetro tanto discosto, che tu veda minutamente sopra il foglio tutto quello che è fuori di casa, il che si fa in una determinata distanza più distintamente. Il che troverai accostando, overo discostando il foglio al vetro, finche ritrovi il sito conveniente. Qui vederai le forme nella carta come sono, con le digradationi, coi colori, o le ombre, coi movimenti, le nubi, il tremolar delle acque, il volare degli uccelli, e tutto quello, che si può vedere.

  See Original Language

  According to the most famous Italian science writer of his age, the aforementioned Francesco Algarotti, the uncle of the count in Selva’s dialogue, the camera obscura works precisely like one’s own eye.19 This analogy was well established: Leonardo da Vinci had suggested it in his Notebooks, and Giambattista Della Porta elaborated the idea in the first edition of his Magia Naturalis (1558), further expanding on it in a second 1589 edition in which he “hypothesizes a story-telling system” complete with “scenery, actors, and even a sound accompaniment.”20 Writing in 1604, Johannes Kepler provided an explanation of a “magic” experiment by Della Porta in which the latter employed a crystal sphere to produce a “floating image” of objects seen through it. This explanation amounts to Kepler’s demonstration of retinal imaging: “The pupil plays the role of a window, and the crystalline behind plays the role of a screen.”21 As Olivier Darrigol comments: “The essential point as Kepler himself saw it was that the eye acted as an optical instrument that produced an accurate painting (pictura) of distant objects on the retina.”22 Kepler in fact used the term pictura to indicate the real image impressed on the retina, like a painting of the object would be on paper or a canvas, distinguishing it from its virtual projection that he called the imago: in short, an image that cannot be projected onto a canvas or a screen, but one that appears to float in space as a “shadow” of the real image, like in Della Porta’s mise-en-scène.23

  Freely adapting Kepler’s terminology, I suggest that Selva’s optical theater is based on the same principle: it also contains picturae (the “animated paintings” on the wall) and imagines or “imagoes” (the virtual projections floating on the floor). In other words, the casotto is also a complex optical experiment and demonstration: both an immersive simulation of Venice and a walk-in model of our optical apparatus. This principle is consistent with the way Algarotti had described the camera obscura in his best-selling Newtonianism for the Ladies, a dialogue between the author and the Marquise E.: “But what will you imagine if I say to you when we are in it [the camera obscura], suppose yourself to be placed in one of your Eyes, and to see everything that passes there?”24 A camera obscura, Algarotti adds, tongue in cheek, “is not the worst place in the world to entertain a lady (fig. 3).”25 Moreover, the camera obscura is a tool used by artists to produce picturae of the world. Indeed, Algarotti devotes an entire section of his Essay on Painting to praising it as a wonderful device for apprentice painters, because in it one can see and admire picturae painted by the hand of nature herself:

  We may well imagine that, could a young painter but view picture by the hand of Nature herself and study at his leisure, he would profit more than the most excellent performances by the hand of man. Now, nature is continually forming such pictures in our eye. The rays of light coming from exterior objects, after entering the pupil, pass through the crystalline humor and being there refracted, in consequence of the lenticular form of that part, proceed to the retina, which lies at the bottom of the eye, and stamp upon it by their union, the image of the object, towards which the pupil is directed. The consequence of which is that the soul, by means as yet unknown to us, receives immediate intelligence of these rays and comes to see the objects that sent them. But this grand operation of Nature, the discovery of which was reserved for our times, might have remained an idle amusement of physical curiosity, without being of the least service to the painter, had not means been happily found of imitating it. The machine contrived for this purpose consists of lens and mirror so situated that the second throws the picture of anything properly exposed to the first and that too of a competent largeness on a clean sheet of paper, where it may be seen and contemplated at leisure.26

  This lengthy passage well illustrates Algarotti’s point of view, the feedback loop of science and art in his writings. His explanation involves two fundamental aspects: the camera obscura is a demonstration of how our vision works because its mechanism makes nature’s operation visible and understandable for us; and the camera obscura is a tool that enables the painter to produce “better,” that is, more “realistic” pictures, closer to nature’s own “painting.” Just as nature “paints” (the image of) things on our retina, the camera obscura projects them onto a canvas or a wall. In the Essay on Painting, which is also a kind of painter’s manual, Algarotti writes in the tradition inaugurated by Renaissance perspectivism, a tradition resting on “the ultimate visual paradox: complete deception in the service of utter veracity.”27 Yet, Algarotti is also a representative of his time. As Massimo Mazzotti writes, his “celebration of Newtonian experimentalism is subtly but constantly associated with the adoption of a sensationalist perspective”; as a matter of fact, “Voltaire remarked that Algarotti knew ‘his Locke’ as well as ‘his Newton’; Newtonianism for Ladies was indeed a celebration of both as the fathers of modern philosophy.”28 The “artificial eye” is an expression that perfectly sums up Algarotti’s “radical sensationalist epistemology,” also exemplified by his early experiments with prisms.29 Natural processes and the apparatuses designed to simulate them feed into each other, and this feedback loop is at the (proto-cybernetic) roots of both artistic practice and experimental knowledge as Algarotti conceives them. Both science and art experiment with, and depend on, the tools scientists and artists build to understand and imitate nature’s proceedings.

  In his writings, Algarotti seems to push his praise of the camera obscura further than his most illustrious contemporaries, such as Joshua Reynolds who, in his Thirteenth Discourse on Art, delivered to the Royal Academy of Arts in 1786, warned artists that views of nature “represented with all the truth of the camera obscura” would appear deficient when compared with a painting of the same scene by a great artist.30 Reynolds expressed an opinion largely shared by his contemporaries. Algarotti’s argument seems more nuanced. Through the camera obscura, a model of our visual apparatus, things can be more clearly perceived than through our own eyes. As he writes:

  When we look at an object in order to take it into consideration, there are many others around it, which at the same time reach our eyes, preventing us from distinguishing its own modulations of color and light, or show it only faintly and lost, as though suspended between seeing and not seeing it. In an Optical Box, instead, our visual power is all focused on the single object in front of us, and every other light is silent.31

  With an elegant and eloquent synesthesia, Algarotti captures the virtue of the artificial eye: by focusing our “visual power” on a single object—or rather, its well-lit copy through an optical box—we can better grasp its contours, excluding all the fluctuating, evanescent shadows that surround every object in the crowded field of vision of our everyday experience of the world, constantly suspended “between seeing and not seeing.”32 Algarotti writes: “The best modern painters among the Italians have availed themselves greatly of this contrivance; nor is it possible they should have otherwise represented things so much to the life”—thus giving indirect credit to the controversial but suggestive Hockney-Falco thesis according to which the shadowy realism of modern painting, from Caravaggio on, is based on an extensive use of optical tools.33 The key expression here is “much to the life.” As Algarotti writes, in a camera obscura, objects appear even more vivid and more “delightful” than they appear to us in real life: “The shades are strong without harshness, and the contours precise without being sharp.”34 In the second dialogue of Newtonianism for the Ladies, Algarotti extols the virtues of the camera obscura even further. Echoing Barbaro’s description, he writes:

  If to a Hole made in the Window-shut of a darkned [sic] Room, you apply a Lens, and over-against this at a proper Distance there be placed a Sheet of white Paper, you will see all the Objects which are without the Window (especially those which are directly opposite to the Lens) inverted and painted upon the Paper with a Beauty, Vivacity and Softness of Colours that would make a Landskip [sic] drawn by Claude Lorrain, or a Visto [sic] by Canalleto [sic] appear faint and languid. You will perceive the Distance of the Objects exactly the same as you would do in a Picture that is the Smallness of those Objects which are far off from a little Confusion and Obscurity, from a certain Faintness of the Colours, and in short, from a most exact Perspective the grand Secret of that happy Art of Delusion, Painting, which accompanies and assists all I have been describing. It is impossible to express to you the Pleasure that results from the Motion and Life which animates [italics mine] this fine Piece: The Trees are really agitated by the Wind, and their Shadow follows the Motion [italics mine]. The Flocks bound upon the Lawns, the Shepherd really walks, and the Sun Beams [sic] play upon the Waters. Nature draws her own Picture inverted and in Miniature. 35

  Se ad un foro fatto nella finestra di una camera oscura si applicherà una lente, e dietro in faccia ad essa si porrà ad una certa distanza una carta bianca, voi vedrete sopra questa dipingersi al rovescio tutti gli oggetti, che son fuor della finestra, e massime quelli, che stanno dirimpetto alla lente con una vaghezza, vivacità, e mollezza di colori, che un paese di Claudio di Lorena, o una veduta del Canaletto, vi perderebbono molto al paragone...

  See Original Language

  In this crucial passage, Algarotti presents a paradox: the camera obscura possesses extraordinary aesthetic virtues that even surpass those of the views painted by modern masters like Claude Lorrain or Canaletto, possibly with the help of tracing or shading devices such as the Claude Glass (named after Lorrain), a kind of landscape mirror capable of representing “Nature with more force, purity and finish than the camera obscura, because the reflection in it is simple and the objects are painted there instantaneously” (fig. 4).36 Animated paintings, a self-portrait of nature, albeit “inverted and in Miniature”: this is what the camera obscura makes visible. The original Italian text literally says: “the life that animates everywhere this painting.” This is why the images projected by the camera are a better model for painters than nature—and arguably reality—seen with their own eyes. “The colors are of a vivacity and richness that nothing can excel,” and amongst all the parts thus lighted and shaded “prevails such a harmony… that scarce any one of them can be said to clash with another.”37 Algarotti’s emphasis is on lighting and shading rather than on geometrical projections. Showing “the objects, which lie near the eye, as it were, with a hard and sharp pencil, and those at a distance, with a soft and blunt one,” the camera allows the painter to produce images such as those produced by Canaletto, which appear not only more balanced but also “truer” than those that can be caught by an observer with the naked eye.38

  What Algarotti describes here is more than just a physical phenomenon. Kepler’s distinction between pictura and imago helps us characterize the psychological dimension of Algarotti’s writings. As A. Mark Smith writes, this distinction transposes the focus of our vision “from the retina to that mysterious place where mind and brain supposedly meet,” thus striking “perspectivist visual theory…at its epistemological heart.”39 In the passage cited above, Algarotti uses the word “soul” to indicate the mysterious, virtual place where our vision takes shape. An ontological ambiguity comes to light that Newtonian science can only acknowledge: on the one hand, reason and the science of optics with its experiments and cleverly built devices, telescopes, microscopes, and camerae obscurae teach us that we cannot trust our own senses; on the other hand, experimental science is based on our senses, enhanced through a technical apparatus that “mirrors” our anatomy. An epistemic circle is inevitable. As the Marquise objects to her interlocutor in Algarotti’s Newtonianism, “Really, I cannot help thinking that we are in a very strange Condition . . . I have only the Mortification of seeing that we are under a perpetual Delusion, since, if what you say be true, Things appear to us very different from what they really are.” To which the author replies: “It is certainly very strange, answer’d I. Our Knowledge can make but very little Progress, unless it be conducted by the Senses. They continually make us believe Things which a more refined Sense, or our Reason, afterwards contradicts.”40

  This is also what Selva’s “installation” aptly illustrates combining within the same space picturae and imagines—“truer,” livelier copies of reality along with reality’s shadowy, evanescent reflections. In this curious experiment, an “artificial magic” designed to entertain its visitors on the public piazza, reason and senses are equally stimulated and caught in a double bind. Illusion demonstrates science and science feeds illusion. As Lorenzo makes clear in his Dialogues, this and similar “games” crafted by his father were aimed to elicit curiosity, trigger wonder, and demonstrate how our body and mind work in a cleverly pleasing and entertaining way. In other words, Selva’s amusing experiments share the popularizing spirit of Algarotti’s Newtonianism in which Newton’s and Locke’s teaching come together. After all, it was the latter who, in his Essay Concerning Human Understanding, compared understanding to a dark room:

  External and internal sensation are the only passages that I can find of knowledge to the understanding. These alone, as far as I can discover, are the windows by which light is let into this dark room: for methinks the understanding is not much unlike a closet wholly shut from light, with only some little opening left, to let in external visible resemblances, or ideas of things without: would the pictures coming into such a dark room but stay there, and lie so orderly as to be found upon occasion, it would very much resemble the understanding of a man, in reference to all objects of sight, and the ideas of them.41

  Arguably, Locke presents a description that matches the process of understanding with the aesthetic ideal of an illusionistic virtual realism: only through an “artificial eye” can reality be perceived, imitated, and understood properly. Selva’s optical theater thus synthesizes all the aspects we have highlighted in the theatrical construction of a Venetian virtual reality. Not only, in Kemp’s words, does the camera obscura provide “a guide for painters,” and “an analytical model for the optics of the human eye,” but it does so while “producing visions to delude the spectators,” albeit in a way more consistent with eighteenth-century experimentalism than seventeenth-century magic.42 Hence, the “animated paintings” displayed in the casotto are more than just copies, or reflections of the world: they are ideas of the world as we perceive it, through our “soul” or our transcendental faculties, as Immanuel Kant will suggest a few decades later.43 In Selva’s casotto it is an idea of Venice, indeed an ideal Venice, that comes to life.