Phoebe Philo's influence extends from the highest echelons of style—is there an editor in the front row who hasn't bought Celine's structured two-handle tote?—all the way to the high street. (At the fast-fashion stores in New York and London, her brand of minimalism rules.) Backstage, she insisted that she hasn't noticed—"Don't have time to shop," she said. Still, if what she did on her runway today wasn't an intentional rebuff to her copy artists, she's just made their jobs a whole lot more difficult.

How? By embracing the artisanal. You saw glimpses of that in her Resort collection, which featured a great big blanket poncho worn over an evening dress. For Spring, it came across most strongly in two items: a vest and a coat, both beautifully handwoven in silk, apparently by a Frenchwoman who's been doing such things for decades. Other examples of Philo's new back-to-fabrics mentality: quilting, raw canvas and denim, even the long fringe on scarves. Prints are another area of interest the designer began exploring in the pre-collection. The geometric designs—riffs on vintage foulards—had a graphic sportiness that played counterpoint to the craft.

But don't be fooled, there was plenty of that already-signature Celine sparseness—a feeling that was heightened by the predominance of white, ivory, and other pale shades. Still, Philo has loosened things up a bit. Pants are long and more flowy, with deep hems. And with the exception of a super blazer-cape hybrid, she's mostly rejected tailored jackets in favor of tunics, popover tops, and even a Baja jacket. "It's about freedom, getting away," she said of the show's relaxed, summery mood. A (just slightly) below-the-knee shift with plunging V's in front and back and a streamlined racerback all-in-one were as dressed-up as it got for evening.

There will be some who miss the urbanity of Philo's first two collections, but this show qualifies as a well-considered success in its own right. It at once expanded the world of Celine (all the way to the rock festival) and confirmed Philo's mastery of the codes of her hugely influential brand.