A reader writes:
I'm not an expert, but to my untrained eye, those "color photos" look more like photochroms. Photochroms are a combination of photography and lithography, but aren't real color photos. Essentially, they are artificially colored black and white photos. For some awesome early color photography, check out the collection of photos by Sergei Mikhailovich Prokudin-Gorskii at Wikimedia Commons, Wikipedia's sister site for media. Each of these images was itself originally three monochromatic images taken in close succession, that were projected on top of each other. These were digitally combined by the Library of Congress, to wonderful effect.
(Photo: "A picture of Alim Khan (1880-1944), Emir of Bukhara, taken in 1911.")