A petite woman with great warmth, impeccable taste, and an unerring instinct for people, she left her mark on the museum and the nearly 700 volunteers she mentored and promoted, including guides and membership, development, Rodin Museum and Park House volunteers.
"She was a wonderful human being," said Joan Sall, 80, a guide for 35 years who became a friend. "She knew how to manage people. When you think about a hundred women running around the museum happily working together, no backbiting, no squabbles. . . . That was her leadership."
Mrs. Gladstone began as a secretary to the guides in 1964, then transformed the job into a full departmental position, building a program in which guides undergo rigorous training and must work 100 hours a year.
Cindy Blank, another longtime volunteer, said Mrs. Gladstone's vision led to a program that is one of the nation's largest and best organized.
"People do it without remuneration, so there has to be some other reason to do it," Blank said. "She nurtured all of those other reasons: the social climate, the feeling of value from the institution. She made sure we all understood how important we were and that other people acknowledged how important we were."
An art-history graduate of Wilson College, Mrs. Gladstone did graduate work in art and archaeology at both the University of Pennsylvania and at Princeton University.
She and her husband of 47 years traveled extensively both before and after her retirement, going to Europe three times a year and maintaining an apartment in New York City.
Her husband called his wife's career "a joy . . . almost what she would have done if she hadn't been paid for it."
"It was such an unbelievable fit for her, for her love, for her gifts," he said. "She had the privilege of being an art lover working in an art museum, and being appreciated for it."
At her retirement party in 2009, security officer Nelson Hammond called Gladstone "one of the originals, one of the legends of this place." She herself said on that day that she never lost her enthusiasm for a job that let her hang a Mary Cassatt in her office and spend lunch hours with Monet and Cezanne.
In addition to her husband, she is survived by a brother, and nieces, grandnieces, and a grandnephew.
A memorial service will be held at the museum at 5 p.m. July 26.
Donations may be sent to the Philadelphia Museum of Art, Attn.: Development Department, Box 7646, Philadelphia 19101.
Contact Amy S. Rosenberg at 215-854-2681 or email@example.com and on Twitter @amysrosenberg.