One would, of course, expect mirrors to be of interest to Magritte – these fragile reflections of reality which turn it round and render it intangible. And there are many moments when, viewing one of his pictures, one has the sense that one might be looking into a mirror. A fragment of the world placed within a frame or apparently seen through a window might, by a twist of perception, be seen as a reflection in a mirror, a perception that suddenly turns the space of the picture inside-out.

But there is one painting where Magritte very directly addresses what he might have called ‘the problem of the mirror’. ‘Not to be Reproduced’ is one of the paintings commissioned from Magritte by Edward James in 1937 and it’s usually taken to be a portrait of James. He stands with his back to us facing into a mirror but instead of seeing his face in the mirror, we see once more the back of his head.

Perhaps, then, this is not truly a mirror but a cunningly painted trompe l‘oeil. But, as he does with his window paintings, Magritte includes one small element which blocks our attempt to explain this image within the image as anything other than what it seems to be: a mirror. At bottom right, a book rests on the ledge in front of the mirror and it is reflected correctly – that is reversed. It is a French edition of Edgar Allan Poe’s Aventures d’Arthur Gordon Pym, a fact which may or may not be useful in explicating the painting but can’t deflect the proposition of the image that this is indeed a mirror that, when you look into it, shows you a view of yourself that you yourself can never actually have.

I first saw Not to be Reproduced (the actual painting as opposed to a reproduction) on the same trip in 1978 when I visited the Belgian surrealists in Brussels. Before that, I spent some time in Rotterdam, where, one day, I visited the Boijmans von Beuningen Museum. Not to be Reproduced was there, having been purchased the year before.

I spent a while in front of the painting, moving in towards it, until my eyes suddenly refocused and I found myself looking not at the surface of the painting itself but at the reflection in its protective glass. I was then in a conceptual phase with my own photography, so I stood squarely in front of the painting and took two sets of eight photos. With one set, I focused on the painting and, with the other, on the reflection in the glass, with the other paintings in the gallery reversed and shimmering. And my own image, vague and insubstantial, hovered somewhere inbetween what was front of me and what was behind me.

L Mirror photo