Well, there is almost always something photographic on exhibit at the Philadelphia Museum of Art. Often, as in this case, they are in a gallery in the Perelman Building, an adjunct facility across the street from the museum. (It's an early 20th C Art Deco former insurance company building, interesting in itself.) The museum website shows:

35mm: Photographs from the Collection
February 11, 2012 - May 27, 2012

From the first roll-film Leica in the 1920s to the familiar disposable cardboard Kodak, the handheld 35mm camera became a ubiquitous and indispensable photographic tool in the twentieth century.
[ . . . much snippage . . . ]
Included are photographs by European and American photographers working in the 1930s and 1940s—the decades in which the 35mm camera rose to prominence—as well as black-and-white and color work by more than thirty photographers from the 1950s through the present. Highlights include work by early 35mm practitioners Henri Cartier-Bresson and Walker Evans, images by photojournalists Robert Capa and Mary Ellen Mark and street photographers Robert Frank and Lee Friedlander, journalistic series by Eric Avery and Edward Quinn, and work by Danny Lyon.

Full description.

There is also photography by Zoe Strauss thorugh April 22, but the phrase "Inkjet print" suggests it may not meet your requirement.

The Allentown Art Museum (about an hour or so north of Philly) shows
Who Shot Rock & Roll: A Photographic History, 1955 to the Present - on display through May 13. (I assume in 1955 it wasn't digital!)
And Lydia Panas Photos - up through April 22. No comment as to the ultimate medium, although another site suggests she uses large format color.

The Berman Museum of Art at Ursinus College (NW of Philly) has acquired a small collection of classic works. See "Picture Making" on this page. I have not checked those out and I'm not sure whether they are just walk in or need a pre-arranged contact. (I live near there, I suppose I should find out!)

There may very well be others. I live far enough outside the city that I don't get down there as often as I should.