Global Groove pix

In the living area of a New York loft by Ghislaine Viñas Interior Design, a fiberglass cocktail table sits in front of a leather-covered sofa on a steel platform.

Harry Bertoia wire chairs, wrapped in industrial rubber piping by Douglas Homer, and a Marcel Wanders floor lamp.

Krassa's mirror hangs on a nylon cord in the sitting area by the kitchen. Hella Jongerius designed the porcelain vase.

The sitting area's vintage Arne Jacobsen chairs face a 5-foot-square walnut table.

The master bathroom's new Thassos marble counter and existing Carrara marble floor.

Born in the Netherlands and raised in South Africa, Ghislaine Viñas has built up a downtown clientele dedicated to her confident way of using bright colors to spice up minimalist architecture. "I adore colors that pop, that are as far from subtle as possible," she says—quickly adding that she doesn't like anything garish, either. Sure enough, this loft has plenty of intensity, with pink and green rooms and one long yellow focal wall. Yet her high-wattage palette is grounded by furnishings that are, more often than not, a calming white, gray, or black.

Like any bachelor aspiring to eternal cool, this one showed Viñas pages from Wallpaper. Being Korean, he also wanted a few Asian touches. Clearly, he was ready to make his mark with this apartment—in a show of determination, he even shipped all his old furniture to his sister.

The 4,000-square-foot loft was not a blank slate, however. Gluckman Mayner Architects had converted the loft six years before, and Viñas admired both the scale of the layout and the precision of the detailing. "It's been an honor working in this space," she says, pointing out how the master bath's open shower door aligns perfectly flush with a cabinet. While she did update the cabinetry, hardware, and lighting in the kitchen, she kept the Carrara marble walls and the stainless-steel island. Adjacent to the kitchen, she preserved an L-shape banquette, reupholstering it in a buttery-as-leather white vinyl.

Another keeper, a long walnut dining table, had belonged to the previous owners. "I never would have picked it myself. I would have gone with something black or white," Viñas admits. "But I love the givens. They make each job unique." She did contribute the dining area's Eero Saarinen white Tulip chairs and, for a touch of swinger style, a cluster of six Tom Dixon mirrored pendant globes—in three sizes, at three heights.

With huge windows spread across three exposures, there's room for a seating group on both sides of the dining area. The banquette corner is the go-to place for hanging out near the kitchen. The bachelor-casual living area is where the client and his friends watch TV, a 65-inch flat screen right over the fireplace. To liven up the matching black leather-covered sofas, Viñas added two Harry Bertoia wire lounge chairs sprouting yolk-yellow industrial rubber piping. As Viñas puts it, "Humor and texture!"

"Yellow has happy vibes," she explains. Which is why she settled on a bold shade for the Venetian plaster of the focal wall in the public spaces—then lined it with rows of round ceramic fixtures. "Not many clients would have the courage for that, but he wasn't afraid," she adds. "So I pushed the envelope as far as I could." Convincing him to suspend his bed from nothing but four spaghetti-thin steel cables was easy, she says: "Most Westerners have to have headboards but, coming from Asia, he was completely comfortable without one."

Shopping for furniture was as much a learning experience for her as for her client. Despite being on his BlackBerry the whole time, he didn't miss a beat. He knew exactly what he liked (and didn't) the instant she showed it to him. Halfway through the job, he went ahead and bought a chaise longue right off the front page of the New York Times House & Home section—the angular, aerodynamic Zero by Nolen Niu. How would that look in black? OK, Viñas conceded. But bright green would be so much more fun.

PROJECT TEAM: VAN BECIDYAN. SOFAS (LIVING AREA): NUBE FURNITURE. SOLID PILLOW FABRIC: CRATION BAUMANN. OTTOMAN: THROUGH JOHN DERIAN. RUG: DANSKINA. RECTANGULAR COCKTAIL TABLE, SIDE TABLE, BENCH (LIVING AREA), CONSOLE (ENTRY): DUNE. STRIPED PILLOW FABRIC (LIVING AREA), CHAIR FABRIC (ENTRY): MAHARAM. STOOL (LIVING AREA), CHAIR (OFFICE): VITRA. LAMP (LIVING AREA): CAPPELLINI. BENCH FABRIC: BERGAMO FABRICS. ROUND COCK-TAIL TABLE (LIVING AREA), CEILING FIXTURES (OFFICE): SUPERIEUR. PENDANT FIXTURES (DINING AREA): TOM DIXON. CHAIRS (DINING AREA), STOOLS (KITCHEN): KNOLL. LIGHT WALL INSTALLATION (ENTRY): J PRICHARD DESIGN. VASE (SITTING AREA): HELLA JONGERIUS. PILLOWS: TING. CHAIRS: THROUGH LOST CITY ARTS; CASTEL (FABRIC). CUSTOM RUG: THROUGH ARONSONS FLOOR COVERING. LAMP: ARTEMIDE. CHAIRS (ENTRY): THROUGH ABC CARPET HOME. CUSTOM RUG: NANIMARQUINA. CUSTOM RUG (OFFICE): WATERFORD CARPETS. COATRACK (BEDROOM): ERICH GINDER STUDIO. CUSTOM BED: BERNSTEIN ARCHITECTURE. TABLE LAMPS: YAMAGIWA CORP. SCONCES: FONTANA ARTE. WALL COVERING: FLAVOR PAPER. GENERAL CONTRACTOR: CUADRO INTERIORS.