Moments before the Abaeté show was to begin Saturday afternoon, fashion assistants were scurrying about, arranging clothes on racks backstage. Along the walls, white placards bore detailed instructions for each of the models walking in the show: “Elena keeps shoes,” “Put ring on finger,” and “Button top of dress.”

The Abaeté collection by designer Laura Poretzky featured patent leather for voluminous dresses of black, stark white, and silver. Ms. Poretzky said her futuristic collection took cues from the work of the American minimalist artist Dan Flavin, whose sculptural objects and installations were created from fluorescent lights.

“I was really inspired by [Flavin’s] use of darkness and shots of light and neon,” the petite raven-haired designer said. Ms. Poretzky added that the collection would suit a “modern, edgy girl.” But a slip of a dress in black paillette and a series of beautiful silk frocks shown in turquoise, emerald, and eggplant will likely prove more wearable.

At Sass & Bide, a romantic collection of gathered minidresses and shifts were shown in a palette of black, cream, and flashes of copper and bronze, offset by geometric patterns of silver sequins. Many of the dresses shown Saturday night were cinched at the waist with black bows and shown with black tights and dark platform heels, both trends that show no signs of abating for fall. The duo behind the collection, Brits Sarah-Jane Clarke and Heidi Middleton, continue to demonstrate a keen sense for what fashion-forward urban women want to wear — although black silk harem pants may be too difficult for most shoppers to pull off.

Hundreds of people braved a long line and frigid temperatures for a glimpse at the Rock & Republic collection, which was unveiled at Cipriani in Midtown on Saturday. Inside, the show opened to a pounding metal remix of rapper Jay-Z’s “99 Problems,” catcalls, and a chorus of ooohs and aaahs. Models marched down the runway in perilously high, anklestrapped stilettos and metallic skinny jeans, and crystal-andlace halter tops and bustiers. A black studded tuxedo jacket for men was a showstopper. The brand stayed true to its denim roots with classic fitted jeans that featured gold piping detail and jackets with fluffy fur collars. The raucous show concluded with models popping bottles of bubbly on the runway.

The long weekend began Friday morning with the 2007 Red Dress Collection, sponsored by the Heart Truth, a campaign aimed at raising awareness of heart disease in women. Celebrities including Kelly Ripa and Kristen Chenoweth walked the runway in dresses by Calvin Klein, Oscar de la Renta, Donna Karan, and Betsy Johnson, who modeled a dress of her own design. Billie Jean King, in a shimmery red pantsuit and black-and-red Adidas sneakers, drew the loudest cheers as she strutted to the tune of Michael Jackson’s “Billie Jean.”