CONDUCTOR and composer Timothy Brock was 10 years old when he saw his first silent film, accompanied by a live organ player.

It was the most incredible thing he had ever seen, he remembers, of that childhood day in Seattle. He was so taken by the experience, Timothy quickly hatched an idea.

"The next week I rented a bunch of films, Laurel and Hardy and lots of other stuff, from the library and asked a local church if they wouldn't mind letting me play the piano and I would run the films," he retells.

"I turned on the projector, ran to the piano and started playing for half an hour."

He laughs: "From that point my mother has been worried about my career ever since."

She needn't have been so concerned, the American went on to compose his first silent-film score for an orchestra at the age of 23 and in the following years has written nearly 30 silent-film scores and been commissioned by some of the most prestigious orchestras and film institutions around the globe.

Later this month he arrives in Glasgow to conduct the BBC Scottish Symphony Orchestra in a rare screening of Alfred Hitchcock's Blackmail.

Part of the Merchant City Festival, on the same day Timothy will also conduct the orchestra in an hour-long special edition of BBC Radio 3's Sound of Cinema devoted to music by some of Alfred Hitchcock's most celebrated composers.

For those who have never watched a silent film to the accompaniment of a full orchestra, it is an experience not to be missed, according to Timothy.

"It's very rare, it is not a common everyday thing. It is an event like no other, it's not like going to the cinema and it's not like going to a concert," he says.

"Suddenly 75 minutes seems like 10 minutes, it just goes by so quickly and you get sucked into the image. It is such an intense feeling to be part of cinema-making at the moment, because you're right there. There is nothing like it."

On the phone from Bologna in northern Italy, where he has just given the Italian premiere of his reworked version of opera composer Pietro Mascagni's score for 1917 film Rapsodia Satanica, Timothy talks about the challenges of performing live with a film.

"It is a very unique form of conducting because I come from the concert hall; I was trained as a symphonic conductor and have done opera and a little bit of ballet," he says.

"The big difference with silent film is that unlike dancers, singers and soloists, a projectionist doesn't wait for a cue, or come in at just the right moment depending on the pace that you feel like taking that day.

"If a film runs at 24 frames per second, which is typical silent film speed, I have to be within six frames per second accurate all the time.

"That gives me about a quarter of a second leeway. It depends on the film, of course, sometimes you can be more freer. Certainly not with Hitchcock.

"It's pretty tricky because you have to communicate with the players and make sure that your music is in complete sync and you have to make sure everybody is ready."

Usually at a performance Timothy prefers to see the film on screen, rather than on a monitor. In the case of Blackmail he is on intimate terms with the movie as he orchestrated the piece of music.

Watching the film time after time to learn its patterns and rhythms is an essential part of his work and he now conducts about 45 films from memory.

"You still need to have a score in front of you but you're not really reading the music any more," he adds.

Of Hitchcock's 13 silent films, Blackmail is undoubtedly one of Timothy's favourites.

"It is a great film, very beautiful and very intense. Between it and The Lodger, they are among the first true Hitchcockian films where he honed in on his style. From that point on you could really see a pattern developing in his work," he says.

It is a wonderful anomaly in today's digital age that silent films are back in vogue, thanks in many ways to the success of Michel Hazanavicius's The Artist.

The artform that had all but died out has been given a new lease of life.

" I tell an orchestra, we're not playing like our teacher or our parents. We have to play like our grandparents," he says.

" It's another world. It's not musty and dusty any more."

The Chaplin family's music director, Timothy has restored 12 scores from Charlie Chaplin films and oversees the music archive housed in Switzerland.

His next challenge is working with the Buster Keaton Foundation.

Bringing those silent movie heroes back to life is a full-time job. His mother needn't have worried ...

The Sound of Hitchcock, 5pm, City Halls, Glasgow and Alfred Hitchcock's Blackmail with live orchestra, 8pm, City Halls, both on July 25. Visit www.bbc.co.uk/bbcsso