Dark Arts
It’s well known that we see differently in the day and at night. Most of the time, art is experienced in quite bright conditions. Rarely do we see exhibits in genuine darkness, conditions under which our eyes are given time to adapt to their night vision mode, known as scotopic vision. This is especially true of the kind of art viewed in galleries, but it’s also true of movies, theatre and dance venues. While we might experience darkness in the theatre or in a cinema, it is rarely dark enough for long enough for our eyes to be operating scotopically. And this is likely to have been the case throughout the entire history of art.
Well, at least the history of art for the last few thousand years. Art had, of course, being going on for a long time before that. Cave painting dates back at least 50,000 years, and the world’s first hashtag was carved into a stone by a human over 70,000 years ago. And some extraordinary recent discoveries suggest that our ancient non-human relatives, homo naledi, may have made similar abstract carvings over 240,000 years ago, deep in a South African cave system.
An abstract carving made over 240,000 years ago
It seems that we have always been into art. But we might wonder how different was the experience, sitting in a dark cave lit only by a faltering flame, taking in a carved hashtag dusted with glowing ochre, as opposed to wandering through the latest Monet exhibition at the Royal Academy, huge canvasses lit uniformly to perfection.
We can imagine that it would have been very different indeed. Here, let us just focus on one specific aspect, namely the response of our eyes. While this might seem an odd place to start, given the great psychological and emotional states likely to be induced by these highly contrasting environments, it is nonetheless true that some great art owes its greatness almost entirely to the way in which it interacts with our visual system.
Jackson Pollock’s One: Number 31, 1950
This work, viewed here, is not uninteresting, but has almost no impact. Viewed up close at MOMA, where it is hung and properly illuminated, the painting literally comes alive before the eyes. The fractal nature of the pattern is certainly partly responsible. But it is also due to a kind of tension produced by what’s known as transaccadic integration, by which the visual cortex combines signals from the central foveal region of the eye, as it darts around the picture, and the peripheral region, which has quite different temporal and spatial responses. Because it’s impossible to separate any object from its surroundings, the visual system is constantly being challenged. A fascinating subject which deserves more study, but here only relevant to support our assertion that some great artistic experiences rely on the artifacts of human vision.
It’s often said that at night we don’t see colours, this being due to vision being dominated by the response of cells called rods, which are very sensitive to light but are monochome, while colour vision is due to another kind of cell called a cone, which only activates at much higher levels of light. Of course this isn’t quite true: we can fortunately easily distinguish a red stop light from a green go light when we drive at night. Both types of receptor are active under these conditions, responding simultaneously to bright and dark regions of the scene.
Aside from their ability to distinguish colour, another important difference between rods and cones is their response times. Cones have a temporal response of around 15ms (around the duration of a 60fps movie frame), while rods respond about 10 times more slowly —they integrate over a longer time and are therefore able to capture much lower levels of illumination.
This difference in response times between rods and cones leads to observable visual artifacts at night. An easy way to experience this is to hold out a lit cigarette in near darkness. (We speculate that the paucity of scientific research into scotopic vision may be linked to the decline in smoking in much of the world) If you wave the lit cigarette, you will see that the lit tip moves out of phase with the main body: it appears to be floating in space unconnected with the rest of the object.
The same phenomenon can be observed, for example, with brightly illuminated instruments when driving a car a night. Sometimes the dashboard appears to float independent of the housing which contains it.
To summarize, when we see observe moving objects in dark conditions, and when those objects contain both illuminated and non-illuminated regions, we perceive those regions as moving with respect to each other. This effect also occurs when the object is static, but relatively close up, due to changes in perspective arising from the natural movement of our heads.
Let’s return in our imagination to that deep cave, sitting in near darkness, looking at a stone carving whose features have been enhanced by a pigment which shines a little in the firelight. Perhaps we see it float around against the immovable stone background. Or, more accurately, we see the immovable stone background float around it. Perhaps this expands our minds a little, in the same way that a hallucinogen might, by revealing the world to be not exactly what we perceive it to be.
Who knows. But it’s tantalizing to speculate that, by exploring this kind of art, we might recapture the experience of the first art goers at an exhibition staged before humans walked on the earth.