The producer of Roman Polanski’s Berlin competition entry The Ghost Writer tells Patricia Dobson about the challenges during post production – and why financing the film wasn’t easy.

This is your fifth collaboration with Roman Polanski. What makes him a director you enjoy working with?

Roman co-writes the scripts he directs so he knows exactly what he is going to shoot before the film begins shooting. He shoots exactly what’s in the script – the script is the bible – which is great for me as his producer because it means I know exactly what I’m getting. But, you know, I have to read it very closely because sometimes a comma can mean much more than you think. I’m very proud of this film because Roman has done a fantastic job. It’s not an action movie but you won’t be bored for one second – as usual with Roman’s films, the audience follows the action from the point of view of the main character. It’s a Hitchcockian film, similar in style to Frantic but with a completely modern style.

You were faced with some unique challenges during post-production…

I don’t want to talk about the obvious [Polanski’s arrest in Switzerland in September 2009] but I will say that post-production was difficult on this film. It took a lot of energy and cost. Roman is very precise and doesn’t want to give anything up so that is a challenge. Particularly because the biggest challenge here was the weather. The setting was very important to Roman – the story is mostly set on the East Coast of America in winter and we used locations in northern Germany and Denmark. It had to be cloudy and rainy but during the shoot it was sunny all the time so we had to keep going back and forth from Berlin to the north coast to catch the rain. In the end, we had to create most of the weather in post-production.

You’ve got a great cast here – Ewan McGregor, Pierce Brosnan, Kim Cattrall, Olivia Williams.

Roman is an actor too so he always has a fantastic relationship with his cast. He doesn’t just give directions, he plays every part too, and the actors respond to that. And like in all his films, there are great actors in very small roles – James Belushi, Eli Wallach, Robert Pugh, Tom Wilkinson.

How did you get together with Polanski?

I first worked with Roman on the stage play Amadeus in 1981. Then we did Bitter Moon together in 1992 and it was Roman’s first outing as a producer on a film he was directing and he enjoyed being involved in the production very much; it gave him more artistic control and freedom. He’s been a co-producer ever since. I’m the kind of producer who is involved from the first to the last. That’s why I only work on one film at a time. I love being totally involved, sharing the risk and the commitment with the director. Roman, [producer] Alain Sarde and I work completely as a producing team and we deal with everything together. It makes for a very pleasant experience because we don’t have any executives sending us production notes, no emails in the middle of the night, and Roman can work in peace. We’re all friends so everything is out in the open and we have to agree. There is total freedom but lots of discussions.

Was it easier to finance this given the cast, Robert Harris’s source novel and Polanski’s reputation?

Every film is a new challenge. This is a totally independent film. Financing wasn’t easy because of the cost - this is a big budget film for a European film; the cost was $43.6m (€32m) - and because the book was only a best-seller in the UK. It was expensive because of the locations in north Germany and Denmark and the sets we built at Babelsberg including recreating the villa, which was the main set.