‘B Side': Behind large-format of artist

Photographer Elsa Dorfman is known for her large-format Polaroid portraits, created on 20-by-24-inch instant film, using one of the five cameras originally built by the company, which stopped making the specialized film after it went bankrupt in 2008. Dorfman stockpiled as much of it as she could get her hands on, but as it ran out, the artist, now 80, decided to retire a couple of years ago.

Directed by the idiosyncratic documentarian Errol Morris, “The B-Side: Elsa Dorfman's Portrait Photography” is a love letter to Dorfman, who is also the filmmaker's friend. Both are based in Cambridge, Mass., where Morris and his family have sat for Dorfman's camera many times over the years. Now it's her turn in front of the lens.

“B-Side” is for the most part, a conversation between Morris and Dorfman, who is shown pulling out one giant print after another from storage cabinets as she talks about the subjects (Allen Ginsberg and other literary luminaries) and her working methods. Typically, Dorfman offers clients a selection of two shots; one print goes to the customer, and she keeps the reject (or B-side) - which is often, as it turns out, the more intriguing of the two images.

Along the way, she stops to muse on the ephemerality of life: Ginsberg's death, Dorfman's advanced age, the demise of Polaroid and the fact that her once-vibrant prints are now starting to fade all underscore a single theme - one that's echoed in the still ­unresolved question of what will become of Dorfman's archive after she's gone. Her work is owned by several museums, including Harvard University's Fogg Museum, the National Portrait Gallery and the SFMOMA, none has yet come forward to rescue her archive from encroaching oblivion.

The most interesting parts of this conversation come when Dorf­man talks about the art of portraiture. “I'm really interested in the surfaces of people,” she says, in a departure from what many other portrait artists say about getting beneath a subject's skin. “I'm totally not interested in capturing their souls.”

The lively and loquacious Dorfman is equally contrarian about the putative “truth” of photography, insisting that it's precisely the artifice - or falsehood - of portraiture that fascinates her.

As rare and highly specialized as her instrument is, Dorfman likens the 20-by-24-inch camera to a crude tool. It's the “spoon” with which one eats, she says, not the “soup” (i.e., the art) itself. she compares photography to a hammer attempting to “nail down the now.” In a film that ultimately becomes a provocative meditation on impermanence, the artist laughs at the futility of that effort. “The now,” she says, “is constantly racing beyond you.”