Casting the right actor for the right part is some unspoken thing between the two of you to communicate.

Casting is always critical but in this case, 'The Way Back', I was looking internationally to a degree for an interesting mix of gentlemen, Irish, Polish, Russian and American. Not many people had the qualifications, people who would play the game, particular to this industry. So I had to research amongst the cast. They had to be very very prepared as we had to start shooting as soon as we could, there wasn't any time to talk, and there would only be three or four takes.

You get very little from the studios anymore, it's all independent. And I think the studio, with the exception of something like The Social Network, a fine film, very interesting, but as for studio pictures, that's it, what else? There was more only a few years ago. So it changes, and I'm trying as much as I can.

Various studios are still shooting on film with digital grain and the DI negatives, it's not ideal. We should really be all film or all digital. But that being said, the old way of graining in the camera, now you can make changes like a painter. It's dangerous because you can ruin the film, you can over-fiddle. We've all seen films and gone 'what the hell is that?'

Sixty-five days principle photography, five-day weeks, which is the only way I'll work. With my cinematographer Russell Boyd, we take as much time as possible before pre-production, looking at stills. The next most important thing: he will come to me and talk about lenses. And I'll see his plan, which is generally great, and I might talk about how the light will be, handheld or not? I talk very freely, and try not to talk specifically, just talk around it, because it can unlock all sorts of things.

In 'The Way Back' survivors were all ordinary people, and that's the whole point, that's who I felt these people should be, and they shouldn't be that hero that stands out.

It's spiritual, a man that has a past and regrets, but you can as a director take a shot, and there's something in the eyes and the face, you just can't fake it, you can't teach it, and I think Ed Harris has that quality.