REDMOND, Wash. — Leah Erickson let out an exasperated growl when she spotted a banner advertising "Microsoft System Center Essentials 2007" crookedly thumbtacked above a row of photographs framed and lit with museumlike care.

Erickson, the archives manager for Microsoft Corp.'s art collection, enlisted a colleague to help yank it from the designated "art wall." Earlier, the two hoisted a cardboard Windows Vista sign from in front of a painting and shoved lobby chairs away from a sculpture.

Hanging in the halls of Microsoft's sprawling corporate campus are 4,500 pieces of contemporary art, some by such artists as Chuck Close, Takashi Murakami and Cindy Sherman. The software company spends just a sliver of its billions on art, so full-time curator Laura Matzer is working with what she's got to gain respect for the collection in the art world, while balancing the quirks — like those ubiquitous posters — of working within a 76,500-person global corporation.

"I know my place here. Microsoft is first and foremost a software company," Matzer said.

Microsoft's art collection began in 1987 to brighten the walls of what was then a six-building campus. Before then, financial institutions that wanted to project a "forward-thinking" image were the main corporate collectors of art, according to Susan Abbott, a consultant and author of "Corporate Art Collecting."

Deutsche Bank AG and Progressive Casualty Insurance Co. have two of the best-known corporate collections today. Among the 50,000 pieces in Deutsche Bank's collection are works by Pablo Picasso and Gerhard Richter; Progressive owns a Mao serigraph by Andy Warhol.

By the late 1970s, companies started buying art to stimulate employees sequestered in office parks. Around the same time, government money for the arts was on the downswing, and museums turned to blockbuster shows with mass appeal to boost attendance, Abbott said.

"Wherever you looked, it became fashionable to be knowledgeable about art," she said. "That's when the whole corporate art collecting really went crazy."

At Microsoft, a committee of employee-volunteers oversaw new acquisitions until 1999, when the company hired its first full-time curator, New York gallery owner Michael Klein.

To keep costs down, Klein chose works by emerging and midcareer artists instead of established stars. To reflect the company's global footprint, he bought objects from around the world, while continuing a tradition of supporting Northwest artists. He acquired photos, prints, paintings and sculpture, but ruled out the overtly political, religious and sexual to avoid offending employees from different cultures.

When asked why Microsoft collects art, Klein answered, "Because they can. And they should. They are involved in culture. Technology is culture. And the art informs the culture."

Matzer, who joined Microsoft's staff from the Amon Carter Museum in Fort Worth, Texas, emphasized that the company doesn't buy art as an investment. She said the collection hasn't been appraised as a whole, but did say prints by Jacob Lawrence, a well-known 20th-century American painter who spent his later years in Seattle, had quadrupled in value since their purchase. Klein said the prints were originally bought for a few thousand dollars.

Microsoft, Matzer said, collects as a benefit to employees. Her aim is to spark creativity and to give workers, who spend so much time in the plastic environment of phones and computers, access to contrasting, tactile objects.

Nicholas Dodge, a software tester on Microsoft's Web search team, said that when he moved into Building 88 in December, there was no art on the walls.

"It felt kind of industrial," he said. "Now it feels more lived in, just kind of more alive."

After succeeding Klein in 2004, Matzer continued to use his guidelines as she sought out new works. She's also interested in artists who use technology in interesting ways. She recently bought "Easeful City," by Japanese artist Satoru Aoyama, who rendered a decaying cityscape with delicate embroidery stitches.

Unlike the typical museum, which hangs less than 10 percent of its collection at a time, Microsoft keeps only a small percentage of its works in a climate-controlled vault. As a result, Matzer's budget is constrained by how fast Microsoft expands in any given year. (Matzer declined to give specifics about her budget, but Klein said during his last year he spent about $1.2 million.)