Johannes Vermeer's celebrated portrait "Girl With a Pearl Earring" captures the imagination through the questions it elicits and leaves unanswered. The painting, which hangs in the Mauritshuis, a museum in the Hague, depicts a beautiful young woman posing simply against a black background, wearing a turban-like kerchief on her head and a single, giant pearl. The young woman looks directly at the viewer with a mysterious, doe-eyed gaze.

Who was she? And what was her relationship to Vermeer?

To this day, we still don't know the answers -- but the questions spurred Tracy Chevalier to write a book that imagined the story behind the painting. Her 1999 novel, also called "Girl With a Pearl Earring," became a worldwide bestseller. Now Peter Webber, a British director, has made Chevalier's book into a movie that opens here Friday and stars Colin Firth as Vermeer and Scarlett Johansson as Griet, the young woman who becomes Vermeer's obsession and, eventually, his artistic muse.

The facts we know about Vermeer's life are sparse. He was born in Delft in 1632 and died in 1675, converted to Catholicism to marry his wife, Catharina Bolnes, and left behind 11 children and something like 35 paintings. Most of what we can divine of the painter's sensibility comes from his paintings -- often quiet scenes of reflective women, framed in soft daylight, doing everyday tasks.

"One of the most wonderful things about Vermeer's paintings is that they are removed, in a certain way, from time and place," says Arthur K. Wheelock Jr., curator of northern baroque painting at Washington's National Gallery of Art and organizer of the museum's acclaimed 1995-96 Vermeer show.

But the girl with a pearl poses a special enigma for viewers.

"She is in a costume that is not specific to any particular culture," says Wheelock. "She is almost like a sibyl, a kind of ideal figure from another world."

And, unlike many of Vermeer's women, the girl looks straight at us "with a very personal, very open look," says Wheelock.

Her gaze prompted Chevalier, a native of Washington, to start writing her book. "I've had the poster of that painting up on my wall for years," Chevalier said by phone from London, where she now lives.

"One morning I was wondering, 'Why does she have this ambiguous look, where you can't tell if she's happy or sad?' And I suddenly thought, 'The look on her face is the story of a relationship between the model and the painter.' "

In her novel, Chevalier invented the character of the model. She spun a story in which 16-year-old Griet becomes a maid in the Vermeer household in Delft to help out her parents financially. At first, the remote painter, who is in constant flight from his brood of children and his temperamental wife, takes little notice of her.

Slowly, however, Vermeer realizes that Griet has an aptitude for color and light. She becomes his secret assistant, grinding his pigments and even adjusting the position of objects he paints. As their unspoken attraction grows, so does his wife's jealousy. The storm breaks when Vermeer clandestinely begins to paint Griet wearing his wife's pearl earring.

When British screenwriter Olivia Hetreed was given a galley proof of Chevalier's book, she read it in about two hours. "It was so gripping that I felt as though I didn't breathe," she recalled. "I thought of it as a domestic thriller."

Hetreed's husband, producer Andy Paterson, and his partner, Anand Tucker, bought the film rights for their company, Archer Street Ltd.

Hetreed wrote the screenplay, which in turn inspired Webber, who had never directed a feature film before and was known in England mainly as a director of documentaries and TV dramas.

"When I read the script, I thought, 'This is a wonderful tale about an innocent girl coming of age, and there's this fascinating dark undertow that I can bring to the story,' " Webber said, sitting on a sun-drenched patio during the Toronto International Film Festival in September.

It's an undertow that the film might not have had, if Webber hadn't directed it.

"What happens when people are in love but can't express it?" he said. "What happens when power and money get in the way of love and sex? I think all of that is very contemporary, and I wanted to try to make a period film that felt, somehow, not 'period' at all."

But Webber also wanted to convey the strict social mores of Vermeer's time, where the free expression of emotion between master and maid would be, as he put it, "an impossibility."

"Griet can't express what she feels, nor can Vermeer," he said. "The drama in this story comes from that. What I was trying to do was show the way that something grows between two people. Vermeer sees something in this girl that is far more than just sexual, and she, who's so restrained in that household, finds her world opened up by him. And, with her willing participation, he uses his obsession with her to create a masterpiece."

To convey this hothouse of stifled emotion, Webber needed the right actors. He set out on an extensive search for Griet, seeing, by his count, more than 100 actresses. When he first met Johansson, who was 17 at the time, she was en route to a New York Knicks game -- a far cry from the 17th century.

But her very modernness fascinated Webber. "I realized that what would work was to take this intelligent, zippy girl and repress all that," he explained, "putting her in a situation where all that energy and joy are trying to burst out."

Johansson arrived on the set in Luxembourg directly from "Lost in Translation" with very little time to prepare. "I got there and thought, 'Welcome to the 17th century,' " she said with a laugh, on the phone from Los Angeles.

She bleached her eyebrows so that she would look more like the girl in the painting, but did not read Chevalier's novel because it is written from Griet's point of view and "I thought it was better not to have that first-person narrative, so that I could start with a clean slate," she said.

Once filming started, she said, she realized "that my character is completely in love with Vermeer." Despite the stretch across centuries, her empathy for Griet allowed her to give an emotionally wrenching performance using very few words. "I think it was really to my advantage that I didn't have that much dialogue. It was a lot easier for me to allow whatever I was feeling to play across my face -- Griet's longing, her frustration and hurt."

Johansson stresses that her character is no victim.

"She's a force to be reckoned with," she said. "She's one of the strongest characters I've ever played."

Unlike Johansson, who could define Griet for herself, Firth had the difficult task of playing an actual historical figure placed in a fictional context. The biggest challenge, he said, was creating a concrete character for Vermeer. He did a lot of research on the artist's life, which yielded more mysteries than answers. "Vermeer's incredibly elusive as an artist," he said. "I agonized about it: What kind of man was he?"

While trying to solve this mystery, Firth immersed himself in the painterly process, learning to hold a brush correctly and to handle paints. In the end, Vermeer's paintings themselves held a key. "This man was painting quiet paintings in a noisy house," he said. "He had 11 children, and yet his paintings very rarely feature children. That tells us something: He must have had two lives."

He paused. "I think that Vermeer saw things in a very specific and extraordinary way. He's a painter who stands back. In some ways, what makes his paintings so achingly mysterious and passionate is that you're not close to his models, even though you would get closer if you could. There's a lot of passion there, but also a kind of distance."

Drawing on these clues, Firth portrayed a deeply reserved man who, in the film, gradually admits Griet into his private world. For the scenes set in Vermeer's studio, cinematographer Eduardo Serra used a different film stock and diffused lighting to re-create the magical luminosity of Vermeer's paintings.

In crafting the sets, Webber and Ben van Os, his production designer, also looked to Vermeer's work for inspiration, as well as to the works of other Dutch artists of the period, such as Gerard ter Borch. Because Delft has changed since that time, only a few of the exteriors could be shot there. Vermeer's house was built on a set in Luxembourg.

"We were trying to reflect that quiet, sober, almost moralizing ethos that you see in Dutch paintings," said Todd van Hulzen, the set designer. "There are very few films where you get that intense Northern European Calvinist aesthetic. It's a dark look -- lots of ebony -- but also very rich, because the Dutch were the ruling empire of that time."

But Webber was also intensely aware of the dangers of becoming overly slavish to period details. "There's a certain kind of English period film that I detest, which is all about the frocks and the horse and the carriage," he said. "So I tried to strip down some of the ruffly clothes and bring the film to life. I wanted you to be able almost to smell the meat in the market."

In so doing, he has managed a fresh take on the sometimes overwrought genre of films about artists, according to Piers Handling, the director of the Toronto International Film Festival. "What I like about Webber's film is that it very much situates Vermeer in his domestic situation," he said, "rather than depicting the cliche of the artist as mad genius."

Webber may be an iconoclast, but he is thoroughly grounded in film history. He says laughingly that he was a "pretentious teenage intellectual" who cut his teeth on double bills of Jean-Luc Godard and Yasujiro Ozu.

Slim, dark-haired and "thirtysomething," as he puts it, Webber has a cheeky, forthright manner and a restless intelligence. He grew up in West London and, after getting an art history degree, did a graduate program in film and worked as a film editor. He made a wide range of television documentaries (mainly about topics in science and music) before moving into TV drama.

Webber finally got attention -- a lot of it -- in 2001 with "Men Only," a searing two-part series that followed several lower-middle-class British chaps who meet weekly to play soccer and who, spurred on by drink and drugs, gang-rape a young woman.

When "Men Only" aired in England, critics were explosively divided between those who lauded its honesty and those who were, frankly, shocked. "I remember one editorial that said it was a vile piece of pornography, all the worse for being so well acted and directed," said Webber, looking pleased at the memory.

In directing "Girl With a Pearl Earring," Webber has again confounded people's expectations. "It surprised a lot of people when I did this film, because they only knew my 'tough' side, so to speak," he said. "But people are complex: We don't have only one side. Now film executives who had passed on the script of 'Girl With a Pearl' come up to me and say, 'Oh my goodness, we read that script, but we really didn't see this movie in it at all.' "

True to form, even in the wake of his new success, Webber still wants to keep people guessing. "What's important for me is to have a new challenge each time and not get bored," he said, smiling. "I want people, when they see my next film, to say, 'Hang on, is that really the same filmmaker?' "

Scarlett Johansson strikes the famous pose of the "Girl With a Pearl Earring" in the new movie.Delft touch: Director Peter Webber brought a "fascinating dark undertow" to the story.Scarlett Johansson and Colin Firth as muse and painter in "Girl With a Pearl Earring," and the enigmatic Vermeer portrait that inspired the movie and a best-selling book.