“With Instagram and all this technology, I see a huge hunger for process and handcraftsmanship,” said Zac Posen backstage before his spring show. It could sound affected, sure, but consider the fact that Posen still produces his entire main collection in New York, his hometown. For a global business, that’s pretty remarkable. The proximity also allows the designer to work at a level that, for a ready-to-wear collection, approaches couture. Many of his dresses are pleated, knotted, and sewn by hand and, for spring, that lent itself to a few dozen pieces steeped in what felt like a fairy tale.