At that time, serious photography of any kind involved work, typically involving large cameras on large wooden tripods exposing on glass plates. Prokudin-Gorskii's method involved taking three exposures in a row, using blue, green and red filters. He was then able to combine the plates to generate a color image that could be projected as a slide. The images have now been digitally recombined. Even with the help of computers it's an arduous process. You can read about it on the Library of Congress's website, here.
And the colors he has left us are amazing! Here's the church of St John Chrysostom in Jaroslavl:
|Prokudin-Gorskii (1911): Church of St John Chrysostom (Jaroslavl). In collection of Library of Congress.|
With good light, a photo like the one above might be completed in a second or two. This interior photo on the other hand might have taken a minute or longer. He didn't have the option of simply cranking the camera up to ISO 3200 (or any ISO, for that matter)!
|Prokudin-Gorskii (1911): Iconostasis of church in Borodino.|
This image of a Khazakhstani Emir might have taken a full second or more to expose.
|Prokudin-Gorskii (taken 1905-1915?): Alim Khan, Emir of Bukhara|
Here are the "negatives" for the photo of Emir — or rather, of the three photos of the Emir:
Whenever I find myself lying awake late and night and wondering why photography is so difficult, I try to remember what the great photographers of the past went through. Prokudin-Gorskii might have given both legs and his left hand to be able to shoot with an iPhone 5, let alone an Olympus E-M1.