ART / Self-Portrait: Bridget Riley talks about Fall, one of six early works on show at the Tate, London

SEURAT, Paul Klee and the Futurists were my roots. Particularly Klee. In the 1960s I had the opportunity to explore what those forms and lines and colours could do when they no longer had to describe anything. I wanted to discover their own character.

Fall was hung in my second one-man show at Gallery One in 1963. What I was doing here was taking a single form and examining its characteristics. Think about what a curve actually is: it either rises or falls about a straight line. I wanted to put that curve under as much pressure as I could without losing its character.

The painting is about something under extreme pressure which still retains its essence, but only just. The curve moves from side to side - always to the same precise measurement and that constant acts as a kind of stability. It 're- curves' when people are looking at the painting because the movement taking place through the pressure is counterbalanced. At first the painting is stable then it gets going and builds up a vivid energy and eventually it dislocates. But then the painting returns to stability. It's a cyclical experience - a movement of repose, disturbance and repose.

The dislocation doesn't actually break the unity completely, but it's taken to the point where it threatens it. In different ways that idea has informed all my work.

Five recent paintings by Bridget Riley, Castlefield Gallery, Manchester (061-832 8034), to 9 Oct. Six paintings, including 'Fall', the Tate, London (071-887 8000), to 9 Oct.

(Photograph omitted)