The Russia of Sergueï Prokoudine-Gorsky
“Mémoire” is the historical column in 6mois, archives that “inform today”. For their first edition, the review chose to highlight the little known process, tri-chrome.
“After the theoretical discoveries made in the 19th century, several technical processes were developed to capture color in the early part of the 20th century, with differing principles.
The Lumière brothers launched their “autochromes”, glass plates drenched with a sort of mush made from potato yeast. It was a process easily accessible to the general public. After each use, the plates, after having been treated by the Lumière laboratory, could then be used by amateurs as slides.
But the autochromes lacked sensitivity and degraded with time. Prokoudine-Gorsky used a method developed in 1869 by Charles Cros and Louis Ducos, known as “subtractive tri-chrome”. This more complex process, reserved for professionals, provided superior results.
Each shot required three plates, each with different colored filters (red, green, blue). They resulted in three black and white shots, projected with a special three-filtered projector equipped with three converging lenses. Approximately one second was necessary to complete the three shots. And when the subject “moved”, (like the smoke on page 318), the colors separated.
Later, Prokoudine and his children would develop a camera with a set of mirrors that would allow for the three plates to be printed at once”.
By courtesy of « 6mois »