Researchers at Western University in Canada have developed a method for restoring damaged daguerreotypes, including plates so degraded that no portion of the original image remains discernible to the eye. The method, the university explains, involves using rapid-scanning micro-X-ray fluorescence imaging to analyze the silver-coated plate and identify the mercury element used to develop it.

“Mercury is the major element that contributes to the imagery captured in these photographs. Even though the surface is tarnished, those image particles remain intact," explained study co-author Tsun-Kong (TK) Sham. "By looking at the mercury, we can retrieve the image in great detail."

Whereas a human hair is around 75 microns thick, the X-ray beam used in this method is as small as 10 x 10 microns, resulting in about 8 hours of scanning time per daguerreotype plate. This method can be used by art conservators to reveal a daguerreotype's image when cleaning the degraded plate is not possible.

Via: TechCrunch