The political topicality of my October paintings means almost nothing to me, but in many reviews it is the first or only thing that arouses interest, and the response to the pictures varies according to current political circumstance. I find this rather a distraction.

There is sorrow, but I hope one can see that it is sorrow for the people who died so young and so crazy, for nothing. I have respect for them, but also for their wishes, or for the power of their wishes. Because they tried to change the stupid things in the world.

I was a student, and as such you generally rely on prior models of how to make art, but these were not satisfying. Then I discovered in photos what had been missing in paintings; namely that they make a terrific variety of statements and have great substance. That is what I wanted to convey to paintings and apply to it.

The first colour charts were unsystematic. They were based directly on commercial colour samples. They were still related to Pop Art. In the canvases that followed, the colours were chosen arbitrarily and drawn by chance. Then, 180 tones were mixed according to a given system and drawn by chance to make four variations of 180 tones. But after that the number 180 seemed too arbitrary to me, so I developed a system based on a number of rigorously defined tones and proportions.

Suddenly, I saw it in a new way, as a picture that offered me a new view, free of all the conventional criteria I had always associated with art. It had no style, no composition, no judgment. It freed me from personal experience. For the first time, there was nothing to it: it was pure picture. That's why I wanted to have it, to show it - not use it as a means to painting but use painting as a means to photography.

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.

To talk about paintings is not only difficult but perhaps pointless too. You can only express in words what words are capable of expressing-- what language can communicate. Painting has nothing to do with that.