When I first painted a number of canvases grey all over (about eight years ago), I did so because I did not know what to paint, or what there might be to paint: so wretched a start could lead to nothing meaningful. As time went on, however, I observed differences of quality among the grey surfaces - and also that these betrayed nothing of the destructive motivation that lay behind them. The pictures began to teach me. By generalizing a personal dilemma, they resolved it.

All photographs are far more important than any painting.

Turning to the colour-classification methodology: The starting point are the four pure colours red, yellow, green and blue; their in-between shades and scales of brightness result in colour schemes containing 16, 64, 256 and 1,024 shades. More colours would be pointless because it wouldn't be possible to distinguish between them clearly.

I've never found anything to be lacking in a blurry canvas. Quite the contrary: you can see many more things in it than in a sharply focused image. A landscape painted with exactness forces you to see a determined number of clearly differentiated trees, while in a blurry canvas you can perceive as many trees as you want. The painting is more open.

I wanted to say something different: the pictures are also a leave-taking, in several respects. Factually: these specific persons are dead; as a general statement, death is leave-taking. And then ideologically: a leave-taking from a specific doctrine of salvation and, beyond that, from the illusion that unacceptable circumstances of life can be changed by this conventional expedient of violent struggle.

A student researching into my work has actually traced the newspapers and magazines where I found theses images and has found out that many of them illustrate a collection of gruesome stories, murders and suicides which contrast with the images used. There is a contrast between the message carried by the text and that suppressed by the illustration.

Yes, we were amazed when that happened. It was a real joke to us. Konrad Lueg and I did a Happening, and we used the phrase just for the Happening, to have a catchy name for it; and then it immediately got taken up and brought into use. There's no defence against that - and really it's no bad thing.