Well, I don't believe there are subjects that can't be painted, but there are a lot of things that I personally can't paint.

Photography has almost no reality; it is almost a hundred per cent picture. And painting always has reality: you can touch the paint; it has presence; but it always yields a picture - no matter whether good or bad. That's all the theory. It's no good. I once took some small photographs and then smeared them with paint. That partly resolved the problem, and it's really good - better than anything I could ever say on the subject.

I find the Romantic period extraordinarily interesting. My landscapes have connections with Romanticism: at times I feel a real desire for, an attraction to, this period, and some of my pictures are a homage to Caspar David Friedrich.

But my motivation was more a matter of wanting to create order - to keep track of things. All those boxes full of photographs and sketches weigh you down, because they have something unfinished, incomplete, about them. So it's better to present the usable material in an orderly fashion and throw the other stuff away. That's how the Atlas came to be, and I exhibited it a few times.

Composition is a side issue. Its role in my selection of photographs is a negative one at best. By which I mean that the fascination of a photograph is not in its eccentric composition but in what it has to say: its information content. And, on the other hand, composition always also has its own fortuitous rightness.

It can be a work by Mondrian, a piece of music by Schönberg or Mozart, a painting by Leonardo, Barnett Newman or also Jackson Pollock. That's beautiful to me. But also nature. A person can be beautiful as well. And beauty is also defined as 'untouched'. Indeed, that's an ideal: that we humans are untouched and therefore beautiful.

Of course, pictures of objects also have this transcendental side to them. Every object, being part of an ultimately incomprehensible world, also embodies that world; when represented in a picture, the object conveys this mystery all the more powerfully, the less of a 'function' the picture has. Hence, for instance, the growing fascination of many beautiful old portraits.