Why do the “dates worked” have gaps, such as 1880s, 1900s?
We may not know if a photographer was in Minnesota during the gap in time. Sometimes photographers went to a neighboring state such as North Dakota or Wisconsin before returning to Minnesota. Sometimes a photographer left the business to pursue another occupation, before returning to photography at a later date. We could not fill in gaps unless we found evidence to confirm that a photographer was working in Minnesota during a particular time period.
