From left: “Brooklyn” novelist Colm Tóibín, screenwriter Nick Hornby, actress Saoirse Ronan and director John Crowley at the London Film Festival on Oct. 12. (Photo by Joel Ryan/Invision/AP)

Days before Wednesday’s U.S. release of the movie “Brooklyn,” starring Saoirse Ronan, Colm Tóibín spoke about seeing his novel transformed for the screen. From his home town of Enniscorthy, Ireland, where much of the film was shot, he admitted shedding a few tears at the ending during two sold-out showings the night before.

Q: What’s been your favorite aspect of having “Brooklyn” made into a film?

A: I suppose what comes back to me when I see it is the emotion I had before I wrote the book. It’s quite sharp. There’s also an authenticity about it. Often an Irish film is just made for the global market, and the only place it cannot be shown is Ireland, because we just go, “It’s not like that here.” This film was shown in my home town, where I am right now, Enniscorthy, last night. It was shown to two audiences of 200, and not one person said that. I think we were lucky. Finola Dwyer was the producer, from New Zealand, and her mother was Irish and left Ireland for New Zealand the very year that Eilis leaves Enniscorthy for Brooklyn. So, from the very beginning there was somebody who understood what that was like. We had John Crowley, an Irish director who lives in London. And then we were lucky with Saoirse because she’s a star, but this is her first Irish part. She was able to play things that are very real to her: the whole idea of going away and being away, what home means. In a way this has been the center of experience, or maybe the secret history, of Ireland over the last 150 years: people leaving and coming back for a short time and leaving again.

Is the character of Eilis played by Saoirse Ronan in the way you envisioned her?

It’s hard to envision Eilis, in that she’s somebody who people like automatically, but she doesn’t cause this in any conscious or obvious way. Everywhere she goes, people help her and indeed fall in love with her, and she herself preserves a sort of innocence. Saoirse was able to do all that. And she was able to do something else, something amazing: She was able to move from looking satisfied or in control, to suddenly seeming to be about to lose control, or feeling very sad. She could let a cloud cross her face very, very quickly and easily and convincingly in a few seconds. The camera’s on her face quite a lot, and you see everything she’s feeling about leaving home, going away. She doesn’t have to speak; it’s there. If you’re a novelist, you can feel only jealousy toward it. It was brave of John not to let a line of dialogue in, just to leave the camera on her face.

Is seems to me that as a writer, you’re at the top of your game and continuing to get better. Does it feel like that to you?

No, it doesn’t feel like that at all. So you can say that, but I’ll have to say to you: Those sentences are written one by one. With each one, I was worried. I was never sure. The only way I was sure was when I would read a chapter over. I was able to do that, but as a reader. So it’s not as if I’m working blindly either. Right now, I’m working on a novel set in ancient Greece, and I’m really pushing myself as hard as I can go. And what I think every day is, “If you don’t work hard on this, if you don’t concentrate, this book will be no good at all.”

I sometimes refuse to see an adaptation of a book I love. Are there any books like that for you?

I never saw that adaptation of “Portrait of a Lady.” I read the book, and I teach the book, and I would just like to keep Isabel Archer for myself in my own imagination, in a sort of secret place. And I probably feel the same about “The Ambassadors,” “The Golden Bowl” and “The Wings of the Dove.” I’d like to keep those four Henry James books to myself.

Is there anything the novel “Brooklyn” does that the film, maybe any film, can’t do?

I think it’s almost the opposite — that there are things you cannot do in a novel. There’s a moment toward the end of the movie in which much more emotion is released than I will ever allow occur because I work with a sort of restraint, and I like endings where the reader just doesn’t know exactly what happens. In a movie, you make a different pact with the audience. You can’t just end a page before the real ending, which I think in a novel you can always do, and you almost must always do.

So does “Brooklyn,” the film, end after the book ends?

Yes, it brings it one step further. And it’s fun to see the difference. I saw it last night in Enniscorthy — I’ve seen the film I think four times now — tears coming. I’m a sucker for that ending.

Burns regularly writes for Book World. Her new book is “The Missing Woman and Other Stories.”