This is a tremendous resource. From a technical point of view, one of many interesting things there is the discussion of how the separately-made color frames w

This is a tremendous resource. From a technical point of view, one of many interesting things there is the discussion of how the separately-made color frames were stitched into RGB images (he made separate R, G, and B exposures with a few seconds between them, so in many cases his models changed position, etc.): http://www.loc.gov/pictures/collection/prok/process.html http://www.loc.gov/pictures/collection/prok/process.html (While merging similar images with the same color response is a fairly well-studied problem, merging different channels is an interesting challenge. Consider, for example, trying to algorithmically merge separate R, G, and B exposures of an Italian flag flapping in the breeze. It’s slightly, although not very much, like interpolating the Bayer array in a consumer camera.) Another interesting bit of metadata here is the rights, from http://www.loc.gov/rr/print/res/237_prok.html http://www.loc.gov/rr/print/res/237_prok.html : There are no known restrictions on the use of these images. The issue of copyright was not addressed during the purchase of the collection from Prokudin-Gorskii's heirs in France in 1948. French law is unclear as to whether the heirs own any rights. However, they have expressed concern about "commercial use," and, as a courtesy to them, the Library is supplying interested researchers with the following contact information: [address given]. P.s.: the LOC’s photo and print collections in general are outstanding. They make extremely high-res scans of things like Matthew Brady’s Civil War portraits, political cartoons from the Russo-Japanese War, Hiroshige’s ukiyo-e prints, and Dorothea Lange’s dust bowl photos available for free over HTTP.