According to Paul Auster, "The truth of the story lies in the details."1 The crutch of any book is the grand sweep of its storyline, but the veracity is found in the finer points. The same is true of movies: their biggest impact often resides in the smallest of gestures, in the subtlest of shots. What instrument then is best suited to study such details? You don’t take a sledgehammer to a single shot: you study it by carefully wielding a scalpel. The scalpel of film studies may well be the cinemagraph.

Cinemagraphs2 are animated gifs in which the animation is limited to only a (small) part of the image. Most of the image is still, but some minor movement is repeated in a loop. The cinemagraph combines the best of two worlds: it facilitates the analysis of a shot by freezing it in time but preserves the motion of a relevant portion to illustrate its particular power.

"The course of our lives can be changed by such little things." This thought is put to paper by Lisa Berndl (Joan Fontaine), the female protagonist in Letter from an Unknown Woman (Max Ophüls, 1948). Even though that movie is one of heightened passion and sweeping sentiment, it is director Max Ophüls' eye for "such little things" that elevates it above mere melodrama. The stormy love affair at the heart of the movie is played out in the subtlest of breezes. Literally, because a gentle gust weaves through the story as an airy motif. Cinemagraphs are ideally suited to capture that draughty pattern.3

Lisa is just a teenager when her world is shaken up by the arrival of a new neighbour. Stefan Brand (Louis Jourdan) is a successful concert pianist. Lisa is immediately infatuated with the sophisticated musician, but Brand is a ladies' man who never notices his youthful neighbour. When movers are unloading Brand’s belongings, a nosy Lisa goes through them. Even before she has laid eyes on him, the new neighbour seems to move her . . . or her hair, at least. While she is rummaging through the household effects, her hair bobs in a breeze. Certainly, she is out in the street, but she is the only one affected by the current of air. It's the windy herald of the love that will blow her away.

Throughout the movie, Ophüls repeatedly uses this airy motif to clue in the audience on Lisa's emotional state. The cinemagraph illustrating this text is a perfect example. Lisa's attraction to Brand is as musical as it is romantic. She takes to sneaking out of her room at night to sit at his window and listen to him practicing his piano playing. When she opens a window to better hear his musical exercises, a breeze blows through her hair. She is outdoors but the wind only picks up when she opens the window, as if it is the music itself that wafts its way outside, fanning the strands of her hair. To a physicist, this gust of air is completely illogical. To a romanticist, it is genius.

Over the course of several years, the flame of Lisa's fascination keeps burning and her hairdo keeps catching the wind. When her mother informs her of the family's plans to move to Linz (away from Vienna, and from Stefan Brand), Lisa is understandably distraught. Even before her actions and words make this clear, her restless hair gives her away. Although the scene is set indoors, there is again a current of air ruffling her hair. Only Lisa is affected: her mother's coiffure seems set in stone.

Years later, the ill-fated couple finally meet. They spend a single evening (and night) together. Stefan takes Lisa on a romantic date. They wind up on a fair and together they embark on an amusement ride. In a make-believe passenger coach they train from Venice to Switzerland: painted backdrops operated by a man on a bicycle. Even though their carriage is stationary, Lisa's hair again moves in a breeze.

In that same scene Max Ophüls wraps up his airy motif with crushingly tender elegance. A single, subtle, small gesture removes all doubt as to who or what is the cause for those recurring currents through Lisa’s hair. Stefan takes a seat next to Lisa, and as they chat and flirt, the musician casually blows through her hair. Lisa looks up at him, with the same innocent smitten expression she had years before. It's a whiff that makes her believe she can become his wife.

That, of course, is not to be. The two drift apart after their brief encounter. Stefan goes back to his philandering ways. Lisa marries and settles into the safety of a sheltered society life. Her hairdo changes: her flowing locks of hair are neatly coiffed into immobility. The hat that she wears often shields her hair from breezes. When Lisa and Stefan meet again, years later, their chance at romance has blown past. Stefan barely remembers Lisa. This time, his flirtatious ways fail to put a breezy dent in her hair.

Letter from an Unknown Woman has long been a staple of film studies. It is analysed for its adherence to the classical Hollywood style, for its importance within the genre of the woman’s film and even for its grand camera movements. But the truth of its story lies in minutiae like Ophüls' mastery of a breeze. Such aspects have mostly eluded the texts, tomes and documentaries dedicated to this film. The fine-grained cinemagraph, itself an airy format, is the ideal way to catch wind of these details.