Jason Korsner spoke to Amores Perros director Alejandro González Iñárritu in Los Angeles, where his film was nominated for the Best Foreign Language Oscar.

How did you get started as a film maker?

I started off writing TV adverts. I saw those as rehearsals for a feature film. I read lots of scripts and got myself introduced to Guillermo Arriaga. We originally planned to make 11 short films to show the contradictory nature of Mexico City, but we ended up settling on three and expanding them . We wrote 36 drafts, each one on a type-writer. It took three years. The writer has to be disciplined, so that the director can use his instinct and intuition.

It must be hard for a first-time director to work with such a large cast.

I used 52 actors from different backgrounds. I chose many first timers so that we could share the innocence of our first time together. I chose actors who shared elements of the characters. I made them live in their roles beforehand, to prepare. That meant one of them living in a slum, for example. We also used perfumes to help them get into character. I wanted to concentrate on the actors, as they are what you see on-screen. I treated the locations like a stage, to give the actors their space. The cameramen had to work around them.

From the soundtrack, you can tell music is very important to you.

I’m a frustrated musician, really. I think musically. I don’t like gratuitous music though. That’s used to make up for the failure of the film makers to create the right mood. The music has to add another dimension. To get some original sounds in the score, we used things like plastic gutters and a cake tray.

Previously published on bbc.co.uk/films