There’s nothing cut and dried about what’s in vogue in Vogue

Notorious Vogue editor-in-chief Anna Wintour and her team go about creating the most influential tome of fashion in The

Anna Wintour’s eyes are green, we learn from the documentary “The September Issue,” in which she actually takes off her trademark, oversized sunglasses and even lets a smile slip loose from time to time.

But that doesn’t mean the notoriously icy editor-in-chief of Vogue magazine ever truly puts down her guard.

Director R.J. Cutler and his crew spent eight months roaming the halls of the Conde Nast publication and accompanying Wintour to meetings, fashion shows and glamorous events with designers and stars. We also ride along in the back of her chauffeured car on the way to the office and see her at home interacting with her daughter, Bee Shaffer — who, amusingly, says she wants nothing to do with this business, despite being as thin and stylish as her mother.

While that kind of intimate access provides a glimpse at some quiet moments and juicy showdowns, it never really allows us to understand what inspires this enormously influential figure. Wintour is quickly decisive but seems to operate on the whim of her preferences in dictating what’s in style and what isn’t; if that process is maddening for us during a brief time, imagine what it must be like to work for her every day. (To her credit, though, she acknowledges her businesslike nature — and she doesn’t seem as withering as the editor in “The Devil Wears Prada,” a character supposedly modeled after her.)

What we do come away with is an appreciation for clothing and photography as art forms and the kind of work and emotion that go into each issue, especially the September issue, the largest each year for its fall fashion features. Cutler follows the creation of the September 2007 Vogue, the most voluminous edition.

Wintour comes off as the brains and muscle of the operation (and, arguably, the entire $300 billion fashion industry), but longtime creative director Grace Coddington is clearly its heart and soul. She and Wintour started at Vogue on the same day in 1988 and have worked side by side ever since. Each acknowledges the other’s strengths, but they’re also not shy about challenging each other, a privilege Coddington alone seems to enjoy among Vogue staffers. “I think I know when to stop pushing her,” she says. “She doesn’t know when to stop pushing me.”

Coddington is the heroine of “The September Issue,” a champion of art over commerce. She’s not thrilled about having Sienna Miller as the September issue’s cover model, for example, and she’s generally resistant to the trend of featuring actresses as models, which Wintour pioneered.

Having said that, Cutler’s documentary itself is mercifully free of the kind of dazzling flash and quick editing that accompany so much coverage of fashion and celebrities. Yes, “The September Issue” offers plenty of eye candy, but Cutler seems more interested in the creative process, in documenting the way the elite machinery works.