5. Painting in the camera
In the book I emphasise two main uses to which Vermeer could have put his camera. The first was as an aid to composition.46 The camera is a device, of course, which collapses a scene into a picture. I argue that Vermeer would have set out his pieces of furniture and positioned his sitters in some provisional arrangement, chosen a viewpoint, set up his camera, and studied the resulting image on the camera's screen. He would have gone on to make adjustments to the positions of furniture and viewpoint, and alterations to the models' poses, always judging the consequences for his composition by reference to the optical image, until he was finally satisfied. He composed, that is to say, with the objects and human figures themselves - much like a studio photographer or a film-maker. His second use of the camera would have been to trace detail and obtain accurate perspective outlines.
I have plenty of practical experience myself of drawing with camera obscuras - something which is relatively straightforward and unproblematic. In those types of camera where the artist traces an image projected over his shoulder onto an opaque surface, there is always the difficulty that his hand and drawing implement create distracting shadows - but these are far from insuperable. I put less emphasis in the book on the idea that Vermeer might have painted inside the camera, largely because of the practical difficulties such a process seemed to present. Nor do 16th and 17th century writers on the camera say much about this possibility, with the exception of G B della Porta, who writes in Magia Naturalis that "one who is skill'd in painting, must lay on colours where they are in the Table [i.e. on the camera screen]."47 The problem here is that an artist is entirely enclosed within a cubicle-type camera, and sees the optical image in near-darkness. In these conditions one would imagine that he could not properly see the pigments on his palette. If the optical image was projected directly onto his canvas, and he tried to apply colours over the image, then the projected light would surely interfere with his perception and judgement of the appropriateness of those colours. And if he was working say with a canvas hung inside the cubicle alongside the projected image, then the canvas would be in darkness; and if he somehow illuminated the canvas, then this second source of light would make it difficult to see the camera image.
Despite all these easily-imagined difficulties, the idea is strongly implied by several writers on Vermeer and the camera obscura (and I am guilty here myself), that he somehow painted directly from or onto the camera screen: not least in the proposition that he reproduces artefacts of optical images - passages out of focus, 'circles of confusion' around highlights - in pigment.48 The implication is even stronger, and made in relation to the work of many painters, in David Hockney's recent Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters.49 In the BBC film shown to coincide with the publication of the book, Hockney demonstrated how optical devices of various kinds, including camera obscuras, might have been used for measuring and drawing - by van Eyck in the 'Arnolfini Wedding,' and by Caravaggio in several figure compositions. However Hockney did not attempt in the film to paint using optical aids; and when pressed on this question in discussion, he has responded with the proposition that, once artists had obtained drawn outlines using optical apparatus, they would have moved back and forth, now studying optical images in the darkness, now painting on the canvas in full light.50 They would have relied, that is to say, on their visual memories to carry information from optical image to canvas. Of course they would, at the same time, have been able to study their subjects directly. I made a similar suggestion about Vermeer in my book, in relation to the later stages of the painting process.
I did however propose, following Lawrence Gowing, that Vermeer might have put down a first layer of paint in monochrome, over a light ground, directly under the projected camera image.51 Gowing reproduces an x-ray of 'Girl with a Pearl Earring' to support this contention, which reveals a sharp differentiation of the lowest paint layer into distinct areas of uniform tonality, light or dark.52 Jørgen Wadum says that this high contrast is a photographic artefact, and that the x-radiography simply reveals areas where white lead has or has not been used.53 Such contrast he says is not found in Vermeer's paintwork itself. But he is contradicted here by the most recent scientific analysis of the painting in question, using both x-rays and examination with the naked eye.54 This study has confirmed the existence of a dark underlayer, whose purpose "must have been to brush in a monochrome image on the smooth, light-coloured ground." Melanie Gifford, in another study of Vermeer's technique, has found the same in other paintings, as for example in 'Woman Holding a Balance', where "broader areas of brown paint represent the masses of shadow, with the light buff colour of the ground serving as the lights."55 Whether it would be feasible to carry out such a process of painting in monochrome inside the camera remains however a matter for experiment.
James Elkins says, rightly, of the optical procedures posited in Hockney's book, that they are all 'radically undertested'; and the same applies to these ideas about the monochrome underpainting in Vermeer. "No one, including myself', he declares, "knows what it is really like to get inside a camera obscura and make a drawing, a grisaille, or a painting."56 I would demur about drawing, but otherwise Elkins certainly has a point. Several of my painter correspondents have declared their interest in making experiments, and at least one is building a suitable camera; but so far I have seen no results.57 Leo Stevenson, another painter, has however made some pertinent observations from his experience in copying pictures - including Vermeers - for which he uses projected slides.58
This method, involving as it does a process of precise transcription from a projected optical image, has obvious relevance to the practicalities of working in a camera obscura. Stevenson agrees that trying to paint in colour under projected light would be impractical, for the reasons I have outlined above; but he keeps an open mind on the question of whether Vermeer might have painted in monochrome inside the camera. What he does say is that painting directly in grisaille over a projected slide tends, in his experience, to exaggerate tonal contrasts, "For example, dabbing in an area of white onto the canvas will suddenly make that area gleam much brighter than the rest of the image. Conversely, painting in dark tones will suddenly make that area appear much murkier than it should be. Both these effects are because the tone of the reflected light from the image is suddenly exaggerated by the increased or decreased reflectivity of the area that the light falls on."59
On the other hand, one great merit of the camera for the painter, according to Stevenson, would be the way in which the tonal range in the image is radically reduced from the range of brightness that would be observed directly in the scene itself. This point is also made by David Marshall, a photographer and scanner operator.60 All naturalistic painters are faced with the task of creating an illusion of the great range of brightness seen in life, with the very limited tonal resources of pigments. The camera image offers an intermediate stage in this necessary process of restricting the tonal range - although since the light is projected rather than reflected, highlights will still be much brighter than the most brilliant white or yellow paints. Stevenson and Marshall describe how an artist like Vermeer works to stretch or compress the ranges of tonality in different parts of a picture in order to overcome these difficulties of matching pigment to light.