To create these scenes of California as it was during the early years of the Gold Rush, the best resources were not the few photographs remaining in existence, but the first-hand written and pictorial accounts of the first California pioneers. An enormous amount of information lies in the letters, sketches, maps, drawings, and reports of those who were compelled to put pen to paper.
To sort through and make use of all this information, a catalog was assembled that listed major buildings, terrain features, and ships in the harbor. Each time one of these features was described or drawn, its author's depiction was added to the aggregate of all information about that feature. Additionally, many of the author's and artist's work was also compared to known values which came from photographs and government commissioned maps, thereby creating a means to assign credibility to information in the form of a weighted score based on how well they had depicted those known baseline values.
It is because of this process that much of what is shown in F. Alan Zimmerman's paintings represents the sum of many sources, creating as complete a picture of the time and place as is possible, and one that is likely more accurate than many original depictions.
"Before I started actually painting these pictures, I spent about a year researching the city as it was in 1851, visiting the California Historical Society, the Bancroft Library, the Crocker in Sacramento, the San Francisco Public Library, and many more. I also endeavored to understand the architectural and cultural influences that shaped the city by traveling to the origin places where they can still be found: Sovereign Hill in Australia, New York's South Street, and Gold Rush towns still preserved today; like Bodie, Columbia, and Coloma. This research informs the work with what I believe is a significant level of historical accuracy."