The director of the International Center of Photography (I.C.P.) announced on Tuesday that he would step down from his post due to health reasons. Willis E. Hartshorn, known to many by his nickname "Buzz," was diagnosed with Parkinson's disease in 2004.

According to Kelly Heisler, Director of Marketing Communications at the I.C.P., Hartshorn will transition to a different full-time executive role at the center due to his Parkinson's.

“I feel very fortunate to have had the opportunity to build on the legacy of Cornell Capa, working with a talented staff and engaged Board,” Hartshorn said in a statement. “I particularly appreciate their support, as I look ahead to continuing to serve the institution in new capacities.”

Hartshorn, 60, who has been the I.C.P.'s director since 1994 and on staff since 1982, said he would not leave his post until the center had found a new director. Under his leadership, the center more than tripled its exhibition and education programs, and the collection doubled to more than 100,000 photographs.

Updated 8/24/11