This is not a hand-tinted photograph. It is genuine colour, taken in 1912.

Sergei Prokudin-Gorsky, a Russian chemist and photographer, used a camera that took three black-and-white exposures in quick succession through red, green and blue filters. Projected together through matching coloured light, the three plates recreated a full-colour image. With the backing of Tsar Nicholas II, he travelled across the Russian Empire photographing churches, factories, peasants, landscapes and people in a world that was about to disappear in war and revolution.

Here he photographed himself, sitting by a river in Georgia. If you look closely at moving things like water and leaves, you sometimes see coloured fringes — those are the tiny differences between the three exposures.

The Library of Congress bought his glass plates in 1948, and digitally combined them about a century after they were made. The result feels like time travel: not a faded past, but a sunny afternoon that happens to be more than a hundred years old.