CHICAGO, ILLINOIS—Daguerreotypes may seem frozen in time, but their surfaces are living landscapes. Popular in the middle of the 19th century, daguerreotypes were a precursor to photography created by layering silver on a copper plate and exposing it to light and various chemicals, often including gold. Although daguerreotypes like the one above on the left are famous for capturing vivid portraits of their subjects, many have been damaged in the 150 years since they were made. The images can become fuzzy or faded, or even be wiped away by overzealous cleaners. Hoping to gain some insight into how to restore these delicate objects, a team of researchers used a scanning electron microscope to zoom in on the surface of daguerreotypes—and discovered life. It turns out daguerreotypes have parasites, the team reported here today at the annual meeting of AAAS, which publishes Science. The growths—one of which is pictured above on the right—appear to be mostly fungi, though some of the life forms remain unidentified. As they eat and digest the metals of a daguerreotype, they excrete gold and silver nanoparticles that can disfigure the image. But it’s not all bad news—the precise mixture of life forms growing on unattributed daguerreotypes may serve as a kind of signature, offering clues to where they were made. Plus, the researchers say, the metal-munching parasites may teach scientists new ways to manufacture nanoparticles through biological processes.
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