90 minutes of Static

How did the idea originally come about, and why Silent Running?

Glasgow Film Festival approached us to see if we were interested in doing something. I had seen Silent Running for the first time at some point in 2009, so it was still in my head. Nobody has asked us to do [a soundtrack] for a new movie yet, but we got fed up of waiting so decided to do it to a movie that had already been made instead.

What are your thoughts on the original score, including the Joan Baez songs?

I like it, even if I'm not a huge Joan Baez fan. I like how at odds it is with the space setting. Basically it's strange, orchestral folk music throughout the whole thing. I suppose this is because the importance of the forests is the thrust of the whole film.

Do you think the film has stood the test of time well?

I do. I mean, there are parts where it looks like the spaceships are built of Lego and the robots aren't really very robotic, but this came before Star Wars and looks infinitely better than the slew of terrible sci-fi films that appeared in the 80s. As far as the narrative goes, it seems really prophetic. Humans are basically stupid and are destroying the planet – and themselves. It's kind of a timeless message.

What differences are there between this and writing a standard album?

When we're writing our albums we go to great lengths not to accidentally attach 'concepts' to them, or lean too heavily on well established generic hooks. But with a soundtrack, we get to do that. There are rules we get to follow without feeling like we're supposed to be breaking them. It's a whole new approach for us, and really interesting.

What are the main technical hitches in a project like this?

Well, as usual, we have taken on much more than we really needed to and are now drowning in a flood of technological syncing issues. The one main goal for us when we started this project was to make sure that the whole thing still worked as a movie – we didn't want to just jam or improvise for 90 minutes while the film played out. We wanted our score to breathe with it – to erupt when something explodes and switch things up precisely with the editing of the film. Doing this exactly as we have decided we want to do it has involved a lot of maths, midi, and headaches.

Have there been any problems with clearance rights?

We haven't been fully involved in this, fortunately – our wonderful booking agent and management have sorted most of that out, along with the people at Glasgow Film Festival. I know that we got an email from the director Douglas Trumbull, wishing us luck, which has made our year!

Seventies sci-fi cinema is often held up as a golden period for the genre. What are your views on why this is?

I would cautiously suggest that sci-fi films of the 70s are revered because of their place in the context of the whole of modern cinema more than anything else. They were being made at a time when studios were only really beginning to understand the possibilities of new technology, and hadn't quite grasped the fact that sci-fi movies didn't have to be restricted to cult movies or B-movie nonsense. There's a sense of something fresh and new, like listening to a Buddy Holly record.

By the time you reach the 21st Century, for every Moon, you had to stomach an entire trilogy of Star Wars prequels. In contrast, the 1970s looks pure and real in a way that green screen never can. I once read an article that argued you can tell how good a sci-fi movie is by the quality of the spaceship's 'corridor set'. Try it out. It's foolproof. And the corridors in Silent Running look pretty cool.