Filmmakers have raised questions about the new policy, which can bar independent commercial documentary makers from more than incidental use of Smithsonian materials. When someone wants to make a full program about a Smithsonian object or curator, the Smithsonian can deny access or press the producer to take the project to Showtime.

The contract calls for a new service, Smithsonian on Demand, to offer about 100 programs a year, starting in December, to households with digital cable. Showtime is investing millions of dollars in the programming, said Smithsonian spokeswoman Linda St. Thomas, and is giving the Smithsonian an annual flat fee.

If successful, said [Lawrence M. Small], the productions will give the Smithsonian a way to harness some of the new ways the public gets its information. "This whole approach stems from the desire to get the Smithsonian involved in a very fast-growing segment of the world of video on demand and, frankly, reach many more families than the Smithsonian gets as visitors," he said.