LONDON — Simon Boswell, who takes part in Raindance Film Festival’s In Conversation event on Friday Oct. 2, has been composing for film since 1985. Although his early work mainly comprised international horror and fantasy projects (notably Chilean director Alejandro Jodorowsky’s 1989 cult classic “Santa Sangre”), Boswell wasted no time in diversifying, branching out in the early 1990s with Danny Boyle’s home-grown black comedy “Shallow Grave.” Since then, the London-based composer, now 58, has worked in romcoms, comedies and serial TV drama, learning, perhaps more than anything else, that the old maxim “less mean more” is definitely true of film scoring. “You have to understand that the director, the producer, the actors, me and everyone else, we’re all making a delicate sandwich,” he laughs. “And sometimes music may just be a leaf of lettuce rather than a big chunk of meat.”

You’re very prolific. When you started, did you realize that film composing would become a career?
I had absolutely no idea at all. Obviously I was aware of music in film, but I had no interest in being a film composer. It all came as a bit of a shock. I’d been in bands and I was working as a record producer in Italy, in Rome, where I was introduced to film director Dario Argento, who’d seen my band play. It was his idea. He just said, ‘Look, I’m doing this film, “Phenomena,” with the two guys from my band Goblin. It’s too much for them — would you work with them?’ I said, ‘Yeah, sure.’ I had absolutely no idea what to do or how to do it.

So you were thrown in at the deep end?
I was indeed. Fortunately, the first directors I worked with were very open to doing things in a new way, or in a less conventional way. I mean, Argento was completely into heavy metal music, which I never really liked. I tried to persuade him to use more British Goth music! But as for my stuff, it was a weird hybrid of early synthesizers and guitars. I’m very embarrassed by some of it when I listen to it now, but I’m also proud of it, because it does sound fresh.

How did it become a career?
It was definitely through word of mouth in Italy. There was a very thriving Italian film industry in the 80s, which there wasn’t in the UK. So I did a film for Dario Argento, then Dario was producing a movie for Lamberto Bava — son of Mario Bava, the famous horror director — and I worked on that. Then I did a film with Dario’s assistant director, Michele Soavi [1987’s “Stage Fright: Aquarius”], and it just went on like that. But what was strange was, “Phenomena” was the only movie I actually did in Rome. Early on, I’d fly out, meet the director in the cutting room — “Santa Sangre,” Alejandro Jodorowsky’s film, was a good example of this — and talk through the film, and they’d give me a VHS. I’d take it back to London, then bring it back and show them where the music went. Or just post it back.

How did it go from there?
Well, then I began to get phone calls from people I’d never met. People who hadn’t even sent me a movie! They would say, “We’re doing a thriller, we need a tension theme. Make it five minutes long.” [Laughs] There are movies I’ve scored that I’ve not even seen. Or met the people involved.

How did you get involved with Jodorowsky?
That came about because “Santa Sangre” was produced by Dario Argento’s brother, Claudio. He was very polite and nice to me, and he gave me some really important pointers about what music can do for images.

What do you mean by that?
A lot of producers, especially in America, are terrified of the audience not getting the point, or not understanding it. So they tend to get the music to give people the same information they’ve already got. It’s a waste of resources. Whereas Jodorowsky had other ideas.

For example?
In the famous scene where the knife-thrower’s wife has her arms cut off by the knife-thrower, I said, “Do you want something really unpleasant and nasty for this?” And he said, “No, no, no — it must be uplifting, it must be joyous.” Because he was not giving you the same information twice — he was drawing you into the film’s surreal atmosphere. Because from the character’s perspective, she was becoming saintly — the fact that all this blood was spurting out was neither here nor there. So I’ve kept that as a key lesson: if you don’t give them the obvious thing, people become more involved. They’re more curious. But it doesn’t apply across the board, of course. If you’re watching “Die Hard,” you’re going to have to have “Die Hard” music — it’s popcorn duty for the music to do that.

How did you get involved with British director Richard Stanley?
Funnily enough, Richard thought I was Italian, because he’d seen my name on all these Italian films — when he came to do “Hardware” he contacted Dario’s office in Rome, and they said, “Well, he lives in London.” [Laughs] We just got on very well. Richard is a very inspiring personality and is clearly cut from a different cloth from most people. It really chimed with me that this was my first British film. By 1990 I’d done 25 Italian movies, so it was important. But by the same token, it looked nothing like a British film, so there was a real opportunity to do something more organic and more challenging that fitted within the cyberpunk atmosphere of the film. Iggy Pop has a cameo as a DJ, Lemmy from Motorhead is in it — there was a crossover into the rock world that enabled me to do some quite out-there feedback guitar things. He just left me alone, really.

Four years later you did Shallow Grave. How did that come about?
Well, Danny is another Argento fan. At our first meeting he said, “I just love ‘Suspiria.'” So he was keen for me to inject some of that darkness into “Shallow Grave.” I mean, it’s quite funny, “Shallow Grave,” but very dark as well.

What was he like to work with?
Yet again, another director who just let me be. Directors often care more about the songs they’re going to put into films, actually, which rarely have anything to do with me. Danny’s very good at that. So when “Trainspotting” came along, I did start working on it, but he decided he wanted it to be all songs. And he did a great job. But “Shallow Grave” was a big leap up for me, because it was a big hit in the U.K. And it led to me being offered a lot of different stuff — movies like Tim Roth’s “The War Zone.”

How did you approach that? It’s a very grim film…
Very grim indeed. This is why I think directors and composers need to just be really smart with each other and with the audience. We realized that if you’re going to make a film in which children are being abused, you can’t expect the audience to put up with the usual music, music that either softens it up or turns it into entertainment. It’s too raw. So the more I wrote, the more we chucked out. We made it really sparse. I’d get a small string section and ask them to play with no vibrato, so there would be no expression. The main thing was that we did not want to write a theme that people would whistle!

Shortly after, you did “Born Romantic.” What were the challenges of scoring a romcom?
That came about through my association with Nick Willing — I did his film “Photographing Fairies.” Then his wife Michelle started producing light comedies, the first being “This Year’s Love.” “Born Romantic” was the second one, which is about salsa dancing. The thing that I’ve learned is that comedy music is really difficult. I personally think the funniest music in comedies sounds like the composer is really grumpy and doesn’t get the joke. If it’s all sliding trombones, then it’s a “Carry On” film. You need to present people with pastiches, in a way.

Is that what you did with “Churchill: The War Years”?
That was a very difficult one for me. I coped with that by doing pastiches of some very ’40s-sounding romantic music. Peter Richardson, the director, was asking me to do the most insane things… [Laughs] It got cut out in the end, but he phoned me one day and said, “Could you possibly write ‘Hitler Has Only Got One Ball’ in the style of James Brown?” Which I still have, actually! [Laughs] I’m quite up for doing comedy, I just find it difficult.

How does television work compare to film scoring?
It’s tricky, I think, because it’s a lot of music. If it’s an orchestral score — like “Tin Man” or the “Jason and the Argonauts” remake — there’s so much music, they have to give you a budget that’s enough to record four hours of music, which is quite a lot to ask. So you tend to turn into a team, with orchestrators and copyists managing what is quite a big project. I’ve done very little TV, which is not by choice. I’d like to do more, because at points in your life, it can be a much easier thing to do. You know what you’re doing for the next three or four months!

What are you doing at the moment?
I have three films coming out soon, and beyond that I’m touring my stuff live. I have a band called The And — very confusingly — and I’m playing wherever I can. Lots of festivals. I’m off to Romania, then Mexico. We play reinterpretations of a lot of my scores, especially the horror ones, with a huge video backdrop. It’s a bit like Velvet Underground meets Pink Floyd, really, in a very psychedelic way.

So you’re going back to your roots?
Yes, I am. It’s funny, that. Because if you’re in a band, and your band doesn’t make it, you have very few options. You can become a record producer, which I did. Then I went one stage further and was really very lucky to be asked to be a film composer. On my first movie with Argento, I remember thinking, “Fuck, I can do anything. I can have feedback guitars, I can have people scraping their fingernails down a violin.” It really blew my mind. It was a wonderful opportunity for me, and I’m very pleased that it happened to me. It keeps me very fresh.