2. The orientation of the camera image
One question which has provoked comments from several readers is the effect that the camera has, depending on its design, on the orientation of the projected image. A simple booth-type camera of the kind just described produces an image that is upside-down. If the image is viewed from inside the booth it is also mirror-reversed (Figure 2). This is the likely arrangement for Vermeer's camera, as I argue, if it is assumed that he was using the solid back wall of the room as a projection screen. There is however another option: that the back wall contained an opening of some kind - a doorway or an internal window perhaps - in which Vermeer placed a translucent screen, perhaps made of oiled paper or ground glass. He could then have viewed the image on the far side of this screen, from a second space beyond the camera itself (Figure 3). This second configuration is equivalent to the modern photographic plate camera, with its ground glass viewing screen attached at the back. The projected image is still upside-down, but is not now mirror- reversed.8
Figure 2: A simple booth-type camera obscura at the back of Vermeer's room. The optical image is projected onto the back wall. Viewed from inside the booth, the image is upside down and mirror-reversed - as shown in the version of 'The Music Lesson' at lower left. Figure 3: A simple booth-type camera obscura, as in Figure 2, with the difference that here the optical image is projected onto a translucent screen set in an opening in the back wall. This image, viewed now from an adjacent space outside the room, is still upside down, but it is not mirror-reversed - as shown in the version of 'The Music Lesson' at lower right.
Using a camera with a translucent screen, as in Figure 3, Vermeer would have had to trace the image onto some semi-transparent medium, such as thin paper, and then transfer it to the canvas. In a camera with the solid wall as a screen, as in Figure 2, he could - in principle - have hung his canvas on the wall and projected the image directly onto it; but that image would have been mirror-reversed.
It is worth mentioning in passing one objection, made by several sceptics, that no camera is listed among the inventory of Vermeer's possessions made after his death.9 This is indeed the case, as noted in the book.10 It would naturally have been more convenient for the book's argument if the inventory had mentioned some form of optical apparatus. But absence of evidence is not evidence of absence. And in any case, had Vermeer's camera been of the booth or cubicle type, what might the inventory-maker have found? Those who raise this objection are perhaps imagining cameras in the form of rigid wooden boxes, like the portable instruments which were mass-produced in the 18th and 19th centuries. But a cubicle camera, once dismantled, would have consisted just of the members of a wooden framework, some curtains, little more. The key component is the lens. But this would have been small, and valuable. One can dream up all kinds of scenarios. Vermeer's widow Catherina might have hidden the lens away, or sold it discreetly, or returned it to Antony van Leeuwenhoek from whom it was borrowed...
I propose in the book that it is just possible to see Vermeer's cubicle, if very indistinctly, in the panorama of the back of the room reflected in the mirrored ball in 'Allegory of the Faith'. 11 David Bomford has questioned whether this small black rectangle is tall enough for a booth accommodating the painter. Maybe, he says, it is some lower piece of furniture, such as a table or chest. 12 I would not want to claim that the height is easy to measure with any precision in such a tiny detail. But the top of the booth does seem to be only just a little below the tops of the window casements, in which case it would indeed be sufficiently tall to stand in. It should be remembered what is more that Vermeer always sat to paint, as shown by the heights of the paintings' viewpoints.
I suggest in the book that, among various options, the room appearing in the ten paintings might possibly have been on the first floor at the front of the house of Maria Thins, Vermeer's mother-in-law, where we know he had a studio at the end of his life.13 This house, according to John Michael Montias, was on the corner of two streets, the Oude Langendijk and the Molenpoort.14 (It no longer stands.) Jørgen Wadum argues, as a reason why Vermeer could not have worked with a camera in this room, that there would then have been no space from which he could have viewed the projected optical image.15 The studio and cubicle would have occupied the full width of the house. In order to study the screen, as Wadum argues, Vermeer would have had to be outside the house, hovering one floor up above the Molenpoort. Figure 4 reproduces an enlarged detail from an 1830 map of Delft showing the putative location of Maria Thins's house. The possible position of Vermeer's studio is at the top (north) of the shaded rectangle. Wadum's logic is certainly correct, but only if the camera was of the type with a translucent screen, viewed from behind the cubicle (as in Figure 3). Indeed I raise this very objection myself in the book.16
Figure 5: Vermeer's room, mirrored in its entirety in relation to what we see in the paintings. The geometry of the room itself remains unchanged (since it is symmetrical): the effect is of seeing the same room from the other end. The optical image projected on to the back wall, as seen from inside the booth-type camera, is still upside down, but it is not mirror-reversed - as shown in the version of 'The Music Lesson' at lower right. In this situation, Vermeer could have projected an image of the scene directly onto his canvas and traced it. A camera with the back wall acting as an opaque projection screen, with Vermeer working inside the cubicle, could on the other hand have fitted nicely and completely within a space occupying the whole width either of Vermeer' s family home 'Mechelen' or of Maria Thins's house. In the book I make the suggestion that, had Vermeer' s camera been of this design, he could have traced the mirrored image of the scene onto a sheet of paper, and then rectified the image during the process of transferring it to his canvas. If for example he used the standard studio method of pricking through the design with a pin and pouncing, he could have simply turned the paper over before applying the pounce.17
There is one further theoretical possibility for the relationship of camera image to room, which I rejected in the book but which James Elkins has urged me to reconsider.18 This is that Vermeer's entire room was not oriented as we see it in the paintings, but was mirrored in relation to the paintings, like the room Alice stepped into through the looking glass (Figure 5). Because of the symmetrical design and arrangement of windows and floor tiles, this looking-glass room would have been exactly the same in its geometry as the room we see in Vermeer's paintings - as Figure 5 illustrates - but viewed from the other end, with the windows to the painter's and the viewers' right.19 I had two reasons for abandoning, with some regret, this initially attractive idea. The first was that Vermeer's models hold wineglasses, pour from jugs and play musical instruments always with their right hands. The second and more important reason was that there are real objects depicted by Vermeer which are asymmetrical, notably the maps and paintings by other artists, but which are obviously not reversed in Vermeer's painted versions.
Elkins makes the suggestion that the models could easily have been asked to hold objects in their left hands. He points out furthermore that the great majority of the asymmetrical items are seen frontally, not at oblique angles. This is true of all the 'painted paintings', the great majority of the maps, and the decorated case and lid of the virginals in 'The Music Lesson'.20 We assume a camera with the solid back wall used as a projection screen, as in Figure 2. The projected image is therefore mirrored; but because the room itself is also mirrored, the end-result is an image whose orientation matches Vermeer's final painting (see Figure 5). Elkins agrees that Vermeer could have worked as follows. First he would have traced the complete scene, leaving blank outlines in place of the images of the maps or 'painted paintings'. He would then have made a separate tracing on paper of the image of each map or painting, reversed this tracing, and reintroduced it in the appropriate position in the image of the whole scene. Because all of these items are seen frontally, and their images are therefore simple rectangles, this would have been a perfectly feasible and straightforward procedure. It has the great merit that the image in the camera can now be projected onto the canvas, and the greater part of it can be traced directly onto the canvas (with the exception of the asymmetrical objects) without any need for intermediate drawings.
