Dining out can be a little bit like going to the prom.

Sure, your date and your dress are important - but it's the experience that reigns.

Enter the age of the restaurant designer.

Bolstering the fish and chips at Stephen Starr's Dandelion, the spinach gnocchi at Marc Vetri's Vetri, or the house lamb merguez at Michael Solomonov's Zahav is the power of atmosphere - and it can be the difference between feeling like you took a typical trip to the corner bistro or nabbed a plane ticket to a comfortably worn British pub.

So who are the aesthetic czars behind the scenes of these Philadelphia hot spots? And even more tantalizing: When you are a person who curates backdrops that thousands flock to, what do you come home to at night?

Michael Gruber, designer for Marc Vetri restaurants Vetri, Osteria, Amis, and Birreria 600, scheduled to open in late 2011

The Havertown house Michael Gruber shares with his wife, Roberta, is elegant and comfortable in a midcentury style - and not at all what you'd expect from the mastermind behind the industrial-chic Vetri restaurants.

Gruber, cofounder of the Rittenhouse-based design studio JAGR Projects, is quick to admit that his personal style has nothing in common with the restaurants he designs. He remembers once telling a college professor that he thought of himself as a "Victorian modernist" because "I like 'stuff' and modern isn't really about stuff. It's about purging . . . the absence of stuff."

If Gruber, 60, doesn't go home to butcher-block tables and concrete floors, at least one trend is consistent between work and home: his affinity for found objects. Amis, Vetri's Italian restaurant in Washington Square West, won the first-place interior design award from the Pennsylvania East Chapter of the American Society of Interior Designers for its found-object aesthetic, and Gruber predicts that Birreria 600 (to open at 600 N. Broad St.) will build upon it to an even greater extent, creating "an entire found environment."

In Gruber's home, the aesthetic is less pronounced, with found objects making up small vignettes rather than ecosystems. Mixed among the classic Bertoia chairs are objects, often unidentifiable, chosen for unusual form: There are the old machinery cogs that sit on top of the George Nakashima sideboard, and a gadget in the powder room that has stumped guests - and even Gruber himself.

"I don't know what it is, but it's great regardless," he said. "It just seemed like a Louise-Nevelson-meets-Rube-Goldberg or something - I've showed it to numerous people and nobody can figure out what it is. It works, it does stuff . . . but I have no idea what."

Other unique touches have been introduced by his wife, the head of the fashion design and merchandising department at Drexel University. Her sartorial flair is responsible for the wool suitcloth that covers the walls from floor to ceiling in the den. She also created the fashion drawings that hang over the couple's Nakashima headboard, which Gruber said will "always survive my regular design purges. It's our best investment if our stocks and everything else we've invested in goes south."

Not everything survives Gruber's critical eye intact. He chromed the legs on an original midcentury T.H. Robsjohn-Gibbings ottoman in the den because he "thought it worked better with chrome."

"A lot of people would say I'd ruined it," he said. "But I don't. If I think it looks better that way, then I'll do it."

He's applying a similar philosophy to Birreria, which is "the roughest-looking design of all," with concrete floors, steel trusses, brick walls, and (if he gets his way) an explosion of graffiti.

"It'll be the best of industrial cool."

Elisabeth Knapp, architect-designer for Steven Cook and Michael Solomonov restaurants Zahav, Xochitl, and Percy Street Barbecue

The daughter of humanitarian workers, Elisabeth Knapp has her globe-trotting parents to thank for her diverse design aesthetic. Born in Germany and raised in Italy, Libya, Iraq, Iran, and Lebanon, Knapp pulls from myriad cultures and traditions in her designs for Cook and Solomonov's Israeli-themed Zahav and Mexican hacienda-style Xochitl.

But whether it's her Middle Eastern upbringing or her favorite Mediterranean influences, Knapp, who owns Elisabeth Knapp Architect L.L.C., said restaurant design is all about making an impact in a short time.

"It's essential to be able to distill the essence of what you have to communicate into a two-hour experience," Knapp, 55, said. "You figure out where you can have the most impact, and then design around that focal point."

In the Swarthmore house she shares with her husband, John, a health-care attorney, the impact is more subtle. Sculptures, paintings, textiles, and other curiosities collected from her travels lend an eclectic flavor to the 1930s stone Colonial that has been her family's home for 18 years, influencing the design aesthetic without overpowering it.

She mixes countries and cultures boldly. A jade mask from Thailand, a copper-and-steel candelabra from Finland, and an antique Moroccan window shutter make up a design scenario in the dining room. In the comfortable living room, the clean lines of two Marcel Breuer chairs from the '20s face a Persian miniature engraved on an elephant tusk. On another shelf, contemporary glass pieces are displayed next to three pieces of ancient Etruscan glass, a gift to her parents from Italian priests.

"I sort of just put it all together without thinking too much about it," Knapp said. "I love combining old details with renovations that complement, but don't necessarily mimic, the original style."

Proof of this is on the ceiling. A daring sculptural expanse of track lighting winds its way around the den (the only add-on to the original structure), culminating in chandelierlike spiral pendants made of Murano glass. It's an arrestingly modern system in what is an otherwise fairly traditional room, and required Knapp to draw by hand the shape of the track curves directly on the room's plywood subflooring, assembling it on the floor before installing.

"I was intrigued by this lighting system, and because we move things around frequently, I wanted something that was flexible and a little bit playful," she said.

She is also a firm believer in using light levels to reinforce atmosphere. (She hints at the sheer number of circuits that enable everything from "laboratorylike brightness to dramatic party-level lighting.")

"Rooms have to be able to have all sorts of different moods to them, and to do that, you need to use light in a flexible way," she said. "One of the things I love most about designing - and this is particularly true here in Swarthmore, where there are so many old houses - is combining different styles without worrying whether or not they go together. I've never been afraid of giving a contemporary treatment to a pretty traditional setting."

Richard Stokes, principal architect for Stephen Starr

Only the most observant would notice that Richard Stokes' rowhouse door doesn't quite match its neighbors on its respectable Rittenhouse Square block.

But that's the only outside hint that the architect behind Starr's trendy restaurants harbors a secret love for midcentury modernist design. Or, to put it in Wildwood terms, Stokes has a real soft spot for doo-wop.

It's an affinity for which Starr likes to tease Stokes, despite the popularity of the 1950s-style kitchen and living room that is the crowning touch at the entrepreneur's Continental Mid-town. Stokes confides that the original plans included a bedroom, too - "complete with a water bed and everything" - but that idea was quickly scrapped, he said with a laugh.

You'll see Stokes' design preference in his home's back exterior, which he transformed in a 2006 renovation into California modernist.

"It's kind of bipolar in that way," said Stokes, 48. "The front side blends into the fabric of the street. You don't really know from the outside what's going on inside. ... "

Of course, being an architect and founder of Stokes Architecture means constant contact with industrial objects, many of which have been incorporated into Stokes' decor.  A thick slab of frosted glass supported by dowel rods stands in for a coffee table in the living room, salvaged from the floor in the University of Pennsylvania's Furness Library, which in its pre-electricity days was glass from top to bottom. "It's always fun getting little pieces of projects along the way."

Other reclaimed objects are scattered throughout the house: a few of the vintage glass bottles from Pizzeria Stella at Second and Lombard; a graphic ceiling panel from Irvine Auditorium at Penn; an old chair from the Houston Hall student center at 34th and Spruce. He also has plans to make a wall feature in his garden using old wood scraps from Talula's Garden, the Starr/Aimee Olexy beer garden project in Washington West scheduled to open Monday. "Thinking about it, I could probably do a complete renovation with material left over from projects . . . if I had the time," he said.

A George Nelson lamp (which matches those he chose for Starr's Old City office and main lobby) hangs in Stokes' stairwell, and a clever Ikea knockoff of the popular Alvar Aalto armchair lends a trendy air to the house. But it's the unbranded objects that Stokes seems to appreciate most: the North Carolina tobacco thrasher on the kitchen wall  - "I love the textures and the shadows it makes" - or the stovepipes salvaged from an old mining ghost town outside of Seattle. "I like the everyday objects that you can turn into art," he said. "You put it on the wall and put good lighting on it and the texture and material just work together. Sometimes that happens at work too, where one found object will change the concept and theme of a project entirely."

On the way out, he points out a final treasure - a vintage pull-cord clock. It has no hands. It used to, according to Stokes. "But I found I liked it better as an art object than as a clock," he said.