0852 GMT August 22, 2019
To the naked eye, the portraits of a man and woman are unrecognizable, UPI wrote.
The daguerreotypes, taken as early as 1850, are too degraded by tarnish and wear. But researchers used rapid-scanning micro-X-ray fluorescence to see past the deterioration and recover the early images.
Madalena Kozachuk, a PhD student in the chemistry department at the University of Western Ontario, said, "It's somewhat haunting because they are anonymous and yet it is striking at the same time.”
The images were analyzed at the National Gallery of Canada's photography research unit, where the daguerreotypes are stored.
Kozachuk said, "The image is totally unexpected because you don't see it on the plate at all.
"It's hidden behind time. But then we see it and we can see such fine details: The eyes, the folds of the clothing, the detailed embroidered patterns of the table cloth."
The minuscule laser beam used in scanning the images produces an energy most sensitive to mercury absorption.
Despite the degradation, mercury particles from the original image remain on the silver plates.
Tsun-Kong Sham, a researcher at the University of Western Ontario, said, "By looking at the mercury, we can retrieve the image in great detail.”
Kozachuk and Sham detailed their efforts in the journal Scientific Reports.
Scientist hope their ongoing work will illuminate the different ways daguerreotypes can be degraded and the best ways to clean them.
John P. McElhone, former researcher at the Canadian Photography Institute of National Gallery, said, "A conservator's first step is to have a full and complete understanding of what the material is and how it is assembled on a microscopic and even nanoscale level.
“We want to find out how the chemicals are arranged on the surface and that understanding gives us access to theories about how degradation happens and how that degradation can possibly or possibly not be reversed."