Although the Philadelphia Museum of Art's modern design collection has grown to be the biggest and best-regarded of any general museum in the country, it has lived mostly under the radar.

Even the name of the group largely responsible for that hefty trove has kept a low profile.

Starting Saturday, that era is over.

"Collab," the 40-year-old, all-volunteer committee of design professionals who have helped build the collection of more than 2,500 contemporary objects, will get its own exhibition.

"We are looking to bring Collab out from the shadows and into the limelight," says Lisa S. Roberts, a member since 1992 and, with her husband, David Seltzer, the patron behind the Perelman Building's Collab Gallery and a new book about the museum's modern collection. "I think it is the future of the museum's audience. We attract people who are interested not just in design, but because these are everyday objects . . . the things that we live with."

The exhibition, "Collab: Four Decades of Giving," includes the iconic Up 5 chair by Gaetano Pesce, which is shaped like a woman's lap; Milton Glaser's 1966 poster of Bob Dylan with kaleidoscopic hair; and the Valentine Typewriter, the first "designed" piece of office equipment, by Ettore Sottsass.

"It's never an easy thing to develop a collection at an institution that collects so many areas and has so many needs," says Timothy Rub, the museum's director and chief executive. "Having a group that is an advocate for design but also helps acquire pieces is a way of establishing a lasting and very significant legacy."

What started in 1970 as the Inter-Society Committee for Twentieth Century Decorative Arts and Design - made up mostly of interior designers - has evolved to reflect the diversity of Philadelphia's design community. The 14 current members include an architect, a graphic designer, a curator, an artist, a professor of merchandising, and two design historians.

What they all have in common, says Collab chair Eileen Tognini, is they're all "design passion-istas."

The one constant throughout the last four decades is Kathryn Heisinger, the museum's curator of European Decorative Arts after 1700 and author of Collecting Modern: Design at the Philadelphia Museum of Art Since 1876. In the book, Heisinger tells the story of the shifting fortunes of the decorative arts and design field at the museum.

Decorative arts were a major focus when the museum was founded in 1875 as the Pennsylvania Museum and School of Industrial Art, and the first trustees modeled the collection after the Victoria and Albert Museum in London. Acquisitions included textiles, ceramics, and metalwork, and in 1932 the museum was the first in the country to stage an exhibition of contemporary domestic furnishings, called "Design for the Machine."

However, in the following decades there were hardly any advocates, on staff or on the board, save for a few "heroic souls," Heisinger says.

The tide turned again in 1963 with the appointments of Calvin Hathaway, a curator who had been director of the Cooper-Hewitt design museum in New York, and Evan Turner, the new museum director, who had an interest in all aspects of modernism. Seven years later, interior designer Cynthia Drayton formed the Inter-Society Committee - the group that eventually was named Collab - and the wheels started rolling. The three advocates, through fund-raising efforts and campaigning for the collection, "helped push the modern decorative arts movement at the museum forward," says Heisinger.

In 2007, the Perelman Building opened, and with it a permanent modern and contemporary gallery twice the size of its former space in the main building.

"The new gallery space has allowed Collab to become much more public," says Hilary Jay, executive director of DesignPhiladelphia, a 10-day citywide festival that promotes Philly's design culture. "To have a museum of this caliber with a permanent showplace for contemporary design is a real boon for the city."

The new space kick-started another modern design resurgence at the museum, as have Collab's increasingly high-profile annual exhibits, curated by recipients of the committee's Design Excellence Award, given out since 1993. (That also was the first year of its accompanying student design competition, which has since become part of the curriculum at eight to 10 college-level design programs each year in Philly and New York.)

Collab was one of the first to recognize German lighting designer Ingo Maurer when it gave him the award in 2002. The group invited Maurer to light the museum's 18th-century French period room, which he did with a chandelier made of broken porcelain dishes.

In 2004, Collab cajoled 87-year-old designer Florence Knoll Bassett out of retirement to curate the first solo exhibition of her own work - remotely. The intensely private designer hadn't participated in anything similar since retiring in 1965, so she sent a model of the gallery as she'd like it installed. The exhibit received widespread media attention.

In 2009, larger-than-life Dutch designer Marcel Wanders curated "Daydreams," his first solo exhibition in the United States. Last fall Collab honored Alberto Alessi, patriarch of the eponymous Italian home accessories manufacturer - and a pioneer in the now widespread trend of commissioning high-profile designers to create everyday objects. And for what is expected to be the largest Collab exhibit in the committee's history, Pritzker-Prize winner Zaha Hadid will come to Philadelphia in September to accept the award.

A secondary advantage of these annual exhibitions is the resulting donations, as many award-winners leave pieces behind. This is one way Collab has been instrumental in building the museum's collection - the more than 250 objects the group is directly responsible for acquiring represent, Tognini says, "history foretold."

"Deciding what to acquire next involves trying to comb through and identify what future generations will view as examples of design icons," says Tognini. "It's about having a crystal ball."

Collab: Four Decades of Giving Saturday to winter 2012, Ruth and Raymond G. Perelman Building, Fairmount and Pennsylvania Avenues. Opening party is Sunday and includes a lecture by Kathryn Heisinger and a tour of the exhibition by organizer Diane Minnite, collections and research assistant of European decorative arts. For more information: www.philamuseum.org