... Between 1907 and 1915, Prokudin-Gorskii rode through even restricted parts of pre-revolutionary Russia in his specially fitted dark-room rail car, shooting color photos (a technology still in its infancy) by a method of his own invention. He took three consecutive photographs of his subjects with three separate filters—red, green, and blue—and then combined them into full-color projections, thereby capturing a huge range of architecture, infrastructure and people.

After the czar was murdered in 1918, Prokudin-Gorskii fled Russia with 22 crates of glass plates and eventually settled in France, where he died in 1944. The Library of Congress bought his plates shortly after his death, but it wasn’t until the advent of digital imaging that it
could restore them, a process finished in 2001 and exhibited online
here: http://www.loc.gov/exhibits/empire/