As the Fall shows got under way last month, one thing became abundantly clear to us fairly early on: Casting agents are feeling a little dark this season. The brunette brigade of Kati Nescher, Marie Piovesan, and Nadja Bender showed up big in New York, where it seemed as though even girls who already had brown hair were going even richer with the help of a few talented colorists—call it the Girl With the Dragon Tattoo effect, which has recently manifested itself in the collections as well as in their corresponding beauty looks.

First, Eugene Souleiman and The Whittemore House’s Victoria Hunter transformed Patricia Van der Vliet’s long, flaxen locks into a deep espresso just days before the shows started; then Redken creative consultant Guido Palau promptly took things to the next level backstage at Calvin Klein, razor-cutting Van der Vliet’s hair into a bob—with micro bang—and dyeing it almost black (several other models, like natural blonde Dempsey Stewart, were also given the raven-haired treatment). Somewhere in between, Paul Hanlon took girls-of-the-moment Melissa Stasiuk and Kel Markey “slightly darker and more matte” at Proenza Schouler for a look that he described as “quite cool.”

Brunette dye jobs are thriving across the pond, too. Right before Milan, Karl Lagerfeld favorite Heidi Mount paid a visit to Gina Gilbert at Serge Normant, and cashed in her ashy blonde tresses for an impactful chestnut. Mount debuted her new shade at the Fendi show and has gone on to rack up Paris bookings including Dior and Guy Laroche (her Chanel cameo later this week is a given). Shades of deep chestnut haven’t worked wonders for every catwalker, of course; Arizona Muse has debatably lost some of her spark since ION Studio’s Kimberley Pierce turned her ebony before Derek Lam, although it clearly hasn’t hindered her tally of runway appearances.

While this is probably just the latest saga of “as the hair color pendulum swings” (need we remind you that it was just three seasons ago that Kasia Struss, Britt Maren, and Abbey Lee Kershaw were reaping the benefits of Spring 2010′s Balenciaga blonde?), all signs seem to point to the longevity of the current brunette-is-better movement, not least because platinum can be so detrimental to hair quality. “I needed makeup to feel pretty with [white blond] hair. But with this, it’s always good,” says Struss, who went brunette for Balenciaga last Spring and has stayed the same dark auburn shade through the Fall shows with tremendous results. “When I’m dark, I’m more mysterious,” Querelle Jansen, another blonde-turned-brunette success story, told us last night at Lanvin. If the “dark glamour” that has ruled backstage in Europe this last week has taught us anything, that’s a very good quality to have.