CINCINNATI — “I cannot imagine someone hanging out their underwear and having it immortalized.”

Katrina Marshall, the digital services team leader of the Public Library of Cincinnati and Hamilton County, was awestruck by the sight of a pair of 163-year-old bloomers on a balcony clothesline, a detail in the library’s newly conserved daguerreotype of two miles of Cincinnati riverfront. The cityscape was photographed by Charles Fontayne and William S. Porter on a Sunday in September 1848.

At a ceremony on Saturday, after the daguerreotype spent decades in storage, the library returned its jewel to public view, where it will be permanently displayed alongside new touch-screen computer displays that can zoom in on its details.

In its day and now, “The Cincinnati Panorama” has been considered one of the finest examples of North American cityscapes from photography’s earliest decades. It is also thought to be the oldest surviving example of such a work.

“An iconic American treasure” is how Ralph Wiegandt, a senior project conservator at the George Eastman House International Museum of Photography and Film in Rochester, described the panorama in a recent interview.