Here is a wedding party photo, dated on the back December 1901. This kind of image is called a cyanotype, and was popular in the 1890s through the 1920s, though the process was invented way back in 1842 and made public in 1849. It is the same process as architects used for ‘blueprints’ before the computerized cad-cam systems replaced hand drawn plans. The prints are most often blue, but they can be brownish or yellowish.
In this photo we see the wedding couple near the center, surrounded by their friends, as they stand in front of the layered wedding cake. They all sport the early 1900s style tall upright collar — an unusual congruence of male and female fashion — almost everyone was covering their necks with these abysmally uncomfortable stiff collars! Womens waistlines are high, with full sleeves but not absurdly so, as had been the fashion a few years earlier. Skirts are not so bulky as they had been in the 19th century, but still reach nearly to the floor — though that is not evident in this image. The men are all clean-shaven except the groom, who sports a long mustache.
