Picture Imperfect

Researchers at Western University in London, Ontario, report that they have improved upon a recently developed technique that has been successful in restoring badly corroded daguerreotypes.

Daguerreotypes were the first type of widely available photographs and are made without negatives on thin sheets of silver-plated copper. Popular from 1839 to the mid-1850s, they are fragile and vulnerable to corrosion.

A restoration process using a micro-focused synchrotron X-ray beam to map the distribution of elements on the daguerreotype was first announced in 2018.

“Since then we improved the capabilities of these techniques, and we can get much better images,” said chemistry professor T.K. Sham. “In order to do that we have to use much softer X-rays.” Sham and his colleagues were able to obtain softer X-rays using instrumentation — known as beamlines — from the Canadian Light Source at the University of Saskatchewan.

The new findings were published in the Journal of Cultural Heritage this year.

Most daguerreotypes are portraits, some of well-known historical figures. Sham said being able to retrieve images from damaged daguerreotypes offers insight into the lives of people who lived long ago.

“There are extensive collections of daguerreotypes in public museums, galleries, and archives around the world, including at the National Gallery of Canada,” said Sham. “Some are in excellent condition, but others are not. Retrieving the images from those that are tarnished would greatly increase their value as cultural heritage.”

Sham envisions students, young researchers, and technical staff from museums, galleries, and conservation laboratories becoming proficient in using synchrotron radiation, thus leading to “the emergence of a new breed of researchers and a thriving community.”