I remember seeing those Russian empire pictures somewhere else ("Smithsonian"??) in an article in connection with an exhibition. The important thing to note is the quality. First, this guy was a great photographer. Second, the color is true, saturated, and beautiful. In fact, the color is better than what we get from most films today. Compare them to the autochromes also shown in the web page. For an early technology, this work is almost unbelievable. I'm sure a lot of that has to do with the photographer's hard work and uncompromising quality control, but still. I wonder what the technical details of the work were. (Has someone seen the exhibit catalog or other documentation? Maybe the LOC web site has something.) Just thinking: the photographer had to calibrate his plates to get a decent separation with the poor red sensitivity of the emulsions of that era.