Bill Cosby was well on his way to becoming a pariah for his alleged sexual misconduct when the Smithsonian launched an exhibit funded by Cosby and his wife that showcases art from their private collection.

After 15 months on display and a parade of questions about the cultural institution's ethics, the exhibit is drawing to a close.

Smithsonian leaders debated whether to shut down the exhibit at the National Museum of African Art amid allegations that Cosby, 78, had sexually assaulted dozens of women.

Bill Cosby

Disgraced entertainer Bill Cosby is interviewed in Nov 2014 in Washington about the exhibit featuring some of his art collection at the Smithsonian's National Museum of African Art. (The Associated Press)

Ultimately, they decided to keep the exhibit until its scheduled closing and post a disclaimer. The note to visitors, which says the museum does not condone Cosby's behaviour, was posted prominently at the entrance to the exhibit. It was revised after Cosby was charged last month with drugging and sexually assaulting a woman at his suburban Philadelphia home.

The museum's director, Johnnetta Cole — a friend of Cosby and his wife, Camille — has said she would not have launched the exhibit had she known about Cosby's alleged behaviour. But she said she kept it because it's about the art, not Cosby.

Some museum experts and critics, however, said the Smithsonian compromised its ethics for reasons that have little to do with Cosby's conduct.

"It's just generally not a good idea for museums to get into these relationships with collectors because there are these ethical issues about it," said Kym Rice, director of the museum studies program at George Washington University. "I think that they made some missteps."

Rice said the Smithsonian's most serious blunder was showing art from a sole, living collector, a practice that museum experts discourage because it can enhance the value of the collection. That, in turn, opened up the museum to more scrutiny when the allegations against Cosby made news.

The Smithsonian acknowledges that it should have been more upfront about the funding for the exhibit. A $716,000 gift from the Cosbys covered nearly the entire cost, and Camille Cosby sits on the museum's board.

Smithsonian officials only disclosed the gift when they were specifically asked about it by The Associated Press.

Richard Kurin, the Smithsonian's acting provost, said in an interview that the institution would be more transparent about such contributions in the future. "We could have been, I think, at the beginning, more explicit about the sponsorship," he said.

Smithsonian Bill Cosby

Quilts from the Bill and Camille Cosby collection at the Smithsonian's National Museum of African Art in Washington. The exhibit wrapped up this weekend. (The Associated Press)

The Smithsonian argued that the Cosby exhibit stood on its own as a curatorial product.

Kurin said the Cosbys' collection, which includes paintings and sculptures by important African-American artists, deserved to be seen.

"This really was about the artwork, and it was about these artists. It was about the artistic and esthetic dialogue between African-American artists and African artists," Kurin said.

About one-third of the art on display in the exhibit, titled "Conversations," came from the Cosbys. The rest of the pieces are drawn from the museum's collection.

Parts of the exhibit are deeply intertwined with Bill Cosby's life, including the murder of his son, Ennis, in 1997. The show includes a memorial quilt made for the Cosbys out of pieces of Ennis' clothing. There's also a birthday quilt made for Bill Cosby with pictures of him.

Visitors also learn plenty about Cosby through his taste in art and works commissioned by him and his wife. A painting by the Cosbys' daughter is on display, and several quotations from the Cosbys are posted.

The exhibit celebrates Cosby's professed devotion to family, an aspect that was pilloried by critics given his alleged behaviour.

"This was a bad show from the start. It was bad on ethical grounds ... and it was bad on curatorial grounds," critic Philip Kennicott wrote in The Washington Post in December.

The Smithsonian posted its disclaimer last summer after court documents were unsealed in which Cosby admitted he obtained Quaaludes to give to women he wanted to have sex with. But women were coming forward with sexual assault allegations against Cosby at the time of the exhibit's opening.

The museum drew more than 250,000 visitors during the time the Cosbys' art was on display, a 25 per cent increase over the previous 15 months.

Comments in a visitor book at the exhibit have been mostly positive. The museum has also received dozens of emails, many of them critical.

The exhibit was scheduled to end Sunday. However, the Smithsonian Institution announced Friday that its museums in Washington and the National Zoo would close this weekend due to blizzard conditions.