The power of sound to put an audience in a certain psychological state is vastly undervalued. And the more you know about music and harmony, the more you can do with that.

I started using film as part of live theatre performance - what used to be called performance art - and I became intrigued by film.

In discussing the process with the actors, I made it clear to them that they could improvise but that the sum total of their improvisation needed to impart certain plot points, and schematic material.

I might have a guitar or a piano on set to play something for the actors.

I've held onto little musical sketches that I thought could be useful, and the more time that I spend doing them for each film, then the more I have to draw on.

I never had any urge or desire to do like a big spectacular movie with thousands and thousands of extras. I'd rather watch paint drying. But put me in a room with three people having a hard time, like a character situation, and then you're into a really intense portraiture kind of concept.

Each film is different. Time Code was very quick - a matter of months. Miss Julie has been on my shelf as a script for some seven or eight years. But then the shooting process was very quick - 16 days.