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A particle accelerator is uncovering the faces of individuals in 150-year-old photographs, whose details were once lost to the passage of time, as reported by Science News .
For the first time, Madalena Kozachuk, a Ph.D. candidate at Western University in Canada, and her team of scientists utilized a synchrotron accelerator to scan daguerreotypes, an early form of photography that predates modern methods.
Kozachuk et al. in Scientific Reports, 2018Invented by the French artist and scientist Louis Daguerre, daguerreotypes were widely used from the 1840s to the 1860s. These photographs were produced by exposing a silver-coated copper plate, treated with iodine to make it light-sensitive, to a camera. Subjects had to remain still for 20 to 30 minutes to capture their likeness, a significant improvement over the eight-hour exposure time required before Daguerre refined the process. Photographers could then develop and fix the image using a combination of mercury and table salt.
Daguerreotypes, being made of metal, are susceptible to tarnishing. While scientists can sometimes recover historical daguerreotypes by analyzing surface samples, such methods are often destructive and ineffective, Kozachuk explained in a paper published in Scientific Reports.
Kozachuk discovered that using a particle accelerator provides a more precise and non-destructive approach. Though some researchers have employed X-ray machines to scan other historical artifacts, these machines are too bulky to scan daguerreotypes. To read the fine details on a daguerreotype's surface, a micron-level beam is needed—something only a particle accelerator can produce. By following the mercury deposit patterns on the tarnished plate, the team managed to uncover the hidden image and create a digital replica of how the daguerreotype originally appeared.
Kozachuk et al. in Scientific Reports, 2018“When the image became visible, it was breathtaking,” Kozachuk shared with Science News. “I squealed when the first face emerged.”
Scanning just one square centimeter of each 8-by-7 centimeter plate required approximately eight hours. Although this method is time-consuming, it offers the potential for museums and collectors to restore ancient daguerreotypes with minimal risk of damage.
“The ability to recover lost images will allow museums to enhance their knowledge of daguerreotype collections, as severely deteriorated plates would otherwise remain inaccessible to scholars and viewers,” Kozachuk stated.
