In May and June of 1912, two itinerant photographers arrived in Dubuque and began shooting the photographs that would become the Klauer Collection. For three weeks they traveled throughout the city with a large-format camera and a magnesium-powder flash lamp taking approximately 440 photographs of workers in factories, offices, shops, saloons and even the operating room at Mercy Hospital. We don't know the photographers' names, although they each posed as customers as needed, leaving us with several self-portraits. This type of workplace photography was not unusual in 1912 – itinerant photographers traveled the country photographing cities large and small. However, the fact that most of the glass negatives did survive together, intact for 100 years, is unusual. Itinerant photographers could not carry their solid glass plates with them and instead sold them to junk dealers who scraped the emulsion clean and resold them. Fortunately, the Dubuque photographers sold the plates to Peter Klauer, then President of Klauer Manufacturing Company, who stored them in one of his warehouses. In the 1970s, at least two sets of contact prints were made and in the 1980s, Peter’s grandson, William, donated a set of contact prints to the Center for Dubuque History. Later, 330 of the glass plates - all that remained - were also donated.