The technique could aid restoration efforts
Left: National Gallery of Canada; Right: M.S. Kozachuk et al/Scientific Reports 2018
With the aid of a particle accelerator, scientists are bringing back ghosts from the past, revealing portraits hidden underneath the tarnished surface of two roughly 150-year-old silver photographic plates.
Researchers used an accelerator called a synchrotron to produce strong, but nondamaging beams of X-rays to scan the damaged photographs, called daguerreotypes, and map their chemical composition. This allowed chemist Madalena Kozachuk of Western University in London, Canada, and colleagues to trace mercury deposits in the plates and create digital copies of the hidden images, the team reports June 22 in Scientific Reports. One image revealed a woman; the other, a man who had been completely obscured by tarnish.
An early form of photography, daguerreotypes were popular from the 1840s through the 1860s. Photographers crafted the images by making a silver-coated copper plate and