I’ve been thinking a lot about time, recently. More specifically, about how we perceive it, and relate to it, and talk about it, and I’ve been wondering if we wouldn’t benefit from having more ways of making it visible. I don’t mean just ways of representing it passing: clocks are good at that, and there are plenty of ways the passage of time reveals itself that are transparent. Rather, I’ve been thinking about how to make the implicit passage of time explicit, to break something that seems temporally static into pieces that make it clear to us that time was passing when it happened, whether that stasis in time appears to us because something is instantaneous or because it seems to persist as part of our surroundings, the context in which temporally more active things happen.

From one of our meeting rooms you can see some trees standing in the flagstones outside the old IMAX building. The trees are young, with a slim trunk and a clear head of leaves on top, like a child’s drawing: the leaves are large and well defined, and if the sun shines brightly enough the trees cast clear shadows. I was struck, recently, by the indissoluble link between the tree and the shadow, and thought how satisfying it would be to be hold the shadow in place as the sun moved slowly round, breaking that link. As the shadows of the other trees crept across the flagstones, the discrepancy between them and the one shackled in place would become more visible: the angle between them would tell you how long it had been held in place.

Not literally possible, of course, and probably for the best. But I thought perhaps there might be a way to mimic this, to fix the shadow on the ground somehow so that it would be clear that wherever the shadow might be at present, at some point in history it had been elsewhere. You can get hold of photosensitive paper fairly easily, I think, but I wanted something that would act faster than paper. At the moment, I’m thinking about evaporation. I want to find some kind of mixture that would stain the ground at about the same rate that it evaporates, so that all you have to do to fix a shadow would be to spill this fluid over it and wait. If the sun was particularly strong that day, the shadow would be sharp and defined: if it was cloudy, or windy perhaps, it would be blurry and indistinct. The shadow would tell you not just that time had passed but also something about the weather: from a shape on the ground you could read the history of the sky.

The thing I like most about this idea is that you could make pictures by fixing overlapping shadows, if you had an object with the right shape in the way of the sun. I’d love to hand out vials of this shadow fixing elixir with a picture and GPS co-ordinates: from the angle of the shadows in the picture you’d have to work out when to pour the liquid on the ground in order to reproduce it. Or perhaps you’d just have a set of times and a location, and when you stepped back from the shadows you’d fixed over the course of the morning, a message would reveal itself. Lots of games. But in all of them, you’d have to think about the relationship between time and the world, and when you see it and when you don’t, and that would be, I think, a good thing.