Watching the films of Joanna Hogg, a late-blooming British master, is like watching a blank canvas become a work of art. There is no plot in the conventional sense, but character. Start with small details. Add in impressions and feelings. Build visual elements stroke by stroke, until near the end, the big picture emerges almost in real time, with full impact.

“The Souvenir” is another small, quietly devastating drama by Hogg, and perhaps the most ambitious and personal of her four films. It is about a love affair, both in front of and behind the camera. And her fourth film is the first to get a major American release — Martin Scorsese, a fan, signed on as executive producer to give the project a boost.

The love affair onscreen — between a film school student in 1980s England with big dreams and a sense of awakening, and an older, sophisticated writer who has a secret heroin addiction — is a fascinating train wreck. It’s kind of like “A Star Is Born,” with all the talent and self-destructiveness but none of the fame.

But the behind-the-scenes love affair — with film as an art form — is quite riveting. Hogg, 59, was inspired by her own destructive relationship during her film school years, when she took her eye temporarily off the ball. Her directorial career went through several detours, including years in British television, before she made her feature debut, “Unrelated,” an excellent film about a woman adrift among friends during a vacation in Italy, in 2007 at age 47.

But back when she was in film school, she made a promising 28-minute short film called “Caprice,” which starred a then-unknown actress, Tilda Swinton.

In “The Souvenir,” the young Hogg, er, Julie as she is called, is played by Honor Swinton Byrne, Swinton’s daughter, quite good in her first major film role. She is as unformed as Julie, which is apt. Swinton has a supporting role as her mother.

朱莉是沉迷于电影。她发现dependent classics. She is energized by discussions with her professors. She spends significant time in her apartment typing ideas, scripts and proposed budgets and taking voluminous notes, gradually finding her voice as an artist.

She meets Anthony (Tom Burke), a freelance journalist who has had adventures in far-flung places such as Afghanistan. He once published a book, years ago. About a decade older than Julie, he is nattily dressed, seemingly sophisticated and is a connoisseur of wines and fine dining.

Julie is drawn to Anthony, who appears to be traveling for his work. One day — they have not yet begun dating — he asks to stay at her apartment for a spell as he works on a project. He never leaves.

At first, Julie is clueless about Anthony’s drug use. Sure, his behavior is sometimes odd. But she is so innocent about such matters that when she sees needle marks on his arm, she thinks it’s just some kind of infection.

Anthony begins borrowing money. One afternoon she arrives at the apartment to find it has been robbed. Of course, we know how that happened, even if Julie doesn’t. Julie’s film school studies and her dreams become derailed as she gets sucked into this obviously dysfunctional relationship, which is at times hard to watch.

As previously mentioned, the most passionate love affair in “The Souvenir” is with film. Hogg uses an almost cinema verite style, with a visual look of the grainy kind of 16mm film an ’80s film school student would work with. Her style is reminiscent of early Olivier Assayas, or Éric Rohmer’s “The Green Ray” (1986), an acknowledged influence.

And Julie never looks more passionate or engaged than when she is working with film, either staring at strips of celluloid or working with those bulky, complex editing consoles of decades past. This was an era where not anyone could pick up a cell phone and make a film.

Not that making a film is super easy today, but certainly in those days it took a special kind of perseverance, dedication and strength of will. It was hard, but as Julie discovers, not as difficult as being asphyxiated in a toxic relationship that leaves you gasping for air.

N“The Souvenir”:Drama. Starring Honor Swinton Byrne, Tom Burke and Tilda Swinton. Directed Joanna Hogg.Theaters and showtimes(R. 119 minutes.)