I recently visited the newly restored Ghent Altarpiece at St Bavo’s Cathedral, which is now accompanied by an augmented reality introduction in the crypt. This review-essay explores a sonoptical reading of the painting and considers affinities between the medium of oil as a technology of Early Netherlandish painting and the digital world-building of 3D design.

Central Panel of Mystic Lamb

Fig. 1: lower register, central (inner) panel from the Ghent Altarpiece.
Image: wikimedia/public domain

A Technology of Light

Oil binds pigment. It permits luminescent painting techniques like glazing. Jan van Eyck's facility with this image-making technology established a level of realism in Early Netherlandish painting that has since been the subject of much commentary.

For instance, the Flemish painter, poet and writer, Lucas de Heere (1534-1584) described the panels of Het Lam Gods as ‘mirrors and not painted tableaus’ (Depoorter and Van Dan Abeele, 15). De Heere’s comment speaks to more than the representation of detail. To describe the panels as ‘mirrors’ is to call attention to the way they delineate depth.

A mirror is a physical thing in front of and beyond a viewer. A mirror’s image appears in front of and beyond its glassy surface. This double case of the beyond-ness of a thing/image causes us to lean in for a better look.And as we do so our reflection moves towards us, unfolding the z-axis of Cartesian space.

So mirrors encourage play. They induce body gestures, forwards and backwards. But to make a painting that has the quality of a mirror an artist needs a way to represent depth. In the fifteenth century, oil’s capacity for the painting of light assumed this technological function. And under Van Eyck’s control, it dispensed a ravishing luminance.

Fountain from the Mystic Lamb

Fig. 2: 'The Fountain of Life' from the Ghent Altarpiece.
Image: wikimedia/public domain. Cropped original file.

The Sounds of Things

The union of means and skill in Ghent Altarpiece permits a vital sense of a thing’s material nature—how it might feel to touch; how it might move if subject to some force; how it might have some existence beyond our own.

Van Eyck inscribes the materiality of things by attending to their illumination. As viewers, we perceive the panel paintings and think about what their depicted objects do. We call upon our individual experiences as we imagine another world, replete with causes and effects.

The paintings induce our capacity for depth perception and our sense of potential motion through three-dimensional space. Motion is the fundamental condition of sound energy. And so the paintings let us imagine the sounds of things. They have a sonoptic quality.

Take the fountain in the foreground of the lower-register, central panel (fig. 2). The style of painting renders the physical properties of water, beyond its light-reflecting nature. As our eye moves away from the spout, we note a gradual increase in the spaces between individual spurts.

The rate of change in the size of this negative space suggests the gravity-induced trajectory of liquid. But the painting of water also inscribes another kind of movement. It show us the movements of artistic labour: the traces of prior acts of mark-marking.

The dashed discontinuities in the water-lines are signs that a pigment-laden applicator has been applied to, drawn across and removed from the surface of a Baltic oak panel. And so we attend not only to the painting of movement in an image, but also, to the movements necessary for painting an image.

Further, Van Eyck uses line in order to represent light, as well as water. The white-gold light rays that descend from the summit of the panel have a diagrammatic quality. We might imagine a small arrow appended to each ray to show the trajectory of something we do not actually see.

In contrast, there is nothing diagrammatic about the jets of water. We might well perceive something like these blanched trajectories in the corner of our eye on seeing a fountain. This use of line across diverse phenomena bridges their physical difference. I am reminded of the thirteenth-century English philosopher, Robert Grosseteste, who believed that light to be the first form of things.

At some point, the eye may stop following these lines of light before they exit the frame. It may trace instead the playful springs of water. The frequencies of light are far higher than those of sound. And so there is a strange transduction, a slowing down of things as we enter the audiogenic realm and attend to the sound of water with our ‘inner’ ear.

Annunciation scene from The Ghent Altarpiece

Fig. 3: The Annuciation (outer panels, upper register) from The Ghent Altarpiece.
Image: wikimedia/public domain
. Cropped original file.

Encounters Between Worlds

The catalogue for the exhibition, Van Eyck: An Optical Revolution (Museum of Fine Arts, Ghent, 2020), notes the innovative way in which Van Eyck paints cityscapes and ‘by doing so introduces parts of reality into his paintings’. (Depoorter and Van Dan Abeele, 46). It also notes that there has been some debate as to whether the houses depicted in the Annunciation panels (fig. 3) were painted after real buildings in the city of Ghent.

Regardless of the truth, Het Lamb Gods presents a trope of encounters between real and imaginary worlds. Metaphysical streaks of light share pictorial space with realistic jets of water. The panels of the Annunciation stage an amalgam of light sources that suggests the viewer’s position itself contributes to illumination, a matter clarified by the shadows in the lower-right corners of the frames (ibid., 54; see fig. 3).

So it is fitting that the new, augmented reality introduction to the altarpiece in the crypt of St Bavo’s Cathedral is characterised by encounters between the physical and the digital. The experience makes an apt prelude to viewing the work of a painter who ‘plays with various levels of reality in which the real world and the painted world become as one.’ (ibid., 54).

As a visitor-participant, you wear a headset and set out upon an individual journey, your pathway marked by virtual arrows that appear to hover just in front of you. You are immersed, through the headset, in audio––a soundtrack with spoken commentary. Your attention is directed, variously, to real-time renderings of 3D digital art and real artefacts in the crypt.

Some of the latter are in freestanding exhibition cases—a scroll manuscript, for instance. Some are at floor level, such as Hubert van Eyck’s grave. Others are above your head, like the paintings on the pillars of the crypt. And so you may find yourself inclining, slightly, towards the things you see through your visor—digital and real—to review their nature, your body movements in concert with your curiosity.

An Intervening Zone

In the digital arts, designers often source objects (sometimes known as ‘assets’) in some elementary state and import them into a virtual world. In the case of visual work, this may be in the form of geometric constructions; in the sonic arts, as real-world sound recordings. But in working with these objects in the digital domain, a hybridity develops that quickly obscures their origin and elemental nature. This process of defamiliarization is characteristic of digital arts practice.

The composition of elements (in the sense of developing them and putting them together) in the Ghent Altarpiece displays something of an analogous way of working. There is a borrowing of familiar forms, which calls upon the viewer’s experiential knowledge of physical places and things (the buildings of Ghent, the motion of water jets etc.). Yet there is also a sense in which a thing capacity is extended beyond its real nature (light qua water, for instance).

Still, the historical gap between digital art and fourteenth-century oil-painting is marked by a transitional journey that visitors must undertake before viewing Het Lamb Gods. Having finished the introductory tour, you return your headset to the attendant and ascend to the ambulatory, via several flights of stairs or elevator.

This ascending passage dims the memory of digital emanation. You emerge into a place where daylight is filtered by the tracery of stone windows and shadows are eased by electric light. You keep moving forward, curving gently to the right, following the walls of the choir, beyond the stillness of the side chapels.

Finally, you reach the Sacramental Chapel and the multi-million-euro encasing of the altarpiece. You have crossed an intervening zone and exchanged one technology of image-making for another. You see the most stolen painting in history, its reality revealed by the reflection of light on pigment bound in oil.


Depoorter, M. and Van den Abeele, L., Van Eyck: An Optical Revolution. Ghent: Museum voor Schone Kunsten, 2020.

text copyright © N.G.Brown, 2022.
Not to be reproduced without permission.