A Web site founded five years ago by a conservatory student has made a vast expanse of the world’s musical repertory available, at no charge.

The site, the International Music Score Library Project, is one of the largest sources of scores anywhere. It claims to have 85,000, or parts for nearly 35,000 works, with several thousand being added every month. That is worrisome for traditional music publishers, whose revenue comes from renting and selling scores in expensive editions backed by the latest scholarship. And the site has raised messy copyright issues and drawn the ire of established publishers.

The site operates from servers in Canada, where copyright law is generally looser than it is in other countries. The site (imslp.org) is an opensource repository , “a visual analogue of a normal library,” says its founder, Edward W. Guo, who started the site when he was 19. Volunteers scan in scores or import them from sources like Beethoven House, the museum and research institute in Bonn, Germany. Other users oversee copyright issues and perform maintenance. “It’s completely crowd sourced,” Mr. Guo said.

The site has recently begun adding recordings. And through a partnership with a publishing business in Indiana, it offers low-cost printing of the music, often at a tiny fraction of the cost of standard editions.

The library has caught the attention of music publishers.

“I don’t know if I would call it a threat, but I do believe it hurts sales,” said Ed Matthew, a senior promotion manager at G. Schirmer in New York. “It is that profit that helps us to continue to bring out more composers’ work.”

Universal Edition, a music publisher in Europe, threatened a cease-anddesist order against the site for copyright violations in 2007. Mr. Guo, now a 24-year-old Harvard University law student, took the site down and posted an emotional farewell. That, he said, galvanized followers to appeal to Universal.

Then he took action. He said volunteers checked every score - 15,000 at the time - for copyright violations. He set up a company, Project Petrucci, to take ownership of the site to remove personal liability. A disclaimer appeared, saying that the project provides no guarantee that the work is in the public domain and demanding that users obey copyright law.

“We cannot know the copyright laws of 200 countries,” Mr. Guo said. “It is up to the downloader.”

In 2008 the project came back online. Downloads have surged. Some complaints still arise, especially from Europe, Mr. Guo said. “We say we are not bound by E.U. law,” he added, referring to the European Union. “Publishers usually go away.” He said no legal challenges were pending.

“In many cases these publishers are basically getting the revenue off of composers who are dead ,” Mr. Guo said. “The Internet has become the dominant form of communication. Copyright law needs to change with it. We want people to have access to this material to foster creativity. ”

But publishers say that users of the site can miss the benefit of some modern editions that may be entitled to copyright protection - and thus not part of the public domain - because of significant changes to the music based on years of scholarship .

“You’re paying for something that’s worth more than the paper you’re receiving,” said Jonathan Irons, Universal ‘s promotion manager in Vienna. “Everybody expects somebody else to pay .”

He said Universal was unfairly maligned by its critics for doing what music publishers typically do: use revenue from the sale of old pieces to finance publishing of contemporary composers. “They think we’re sitting on our bums raking in cash, ” he said.

At least one professional group uses the site prominently. The Borromeo String Quartet plays from laptops with downloaded scores instead of sheet music. The digital music library is one of its major sources.

Mr. Guo said his drive to create a repository of music stemmed from his childhood in China, where his parents sent him to study violin at the Shanghai Conservatory. He was frustrated by how few scores were available.

After high school in Vancouver, British Columbia, Mr. Guo entered the New England Conservatory of Music in Boston to study composition. There he built an early version of the library.

Despite the reports of billion-dollar valuations for other interactive Web sites, Mr. Guo said he gave little thought to profit.

“As a musician I have a duty to promote music. That’s the basic philosophy behind it.”


By DANIEL J. WAKIN