Case File: Detecting Daguerreotypes


I recently came across some daguerreotypes of Sioux from my region on an auction site and knew I had to have one for my collection. But when it arrived, something just didn’t seem right, especially the case it came in—it looked like it was made from plastic!  Could I have been duped? - J. Duffy, St. Paul, Minnesota


I knew I would first have to figure out if it were a real daguerreotype. I went to the Daguerrian Society , a reputable and keen group of collectors. Since daguerreotypes are made on a polished silver plate they reflect just like a mirror. I looked closely at the photo (it was beginning to tarnish around the edges. ) and could see my reflection in it. That was hopeful.  I noticed a name on the union case: James E. Martin.

My local library has many newspapers from the area on microfilm dating back to the early nineteenth century. My picture was dated 1859, so I began perusing the local papers that were available from that year. I randomly chose the St. Paul Pioneer and Democrat.  It was a bit grueling to plow through the paper randomly. That said, more than once I found myself utterly engrossed in the news stories of the day. I focused on the ads dotted throughout the paper and saw a few for daguerreotypers. Finally, I saw an ad for James E. Martin’s “Excelsior Gallery.” According to the ad it was located across from Combs and Brothers book store. I was thrilled.

However, suspicious by nature and still doubtful of the protective case it came in (known often as a “union case” I learned from my research), I wanted an expert eye to look at it. I then contacted the Daguerreian Society and got a recommendation for a local expert. When I brought the image to him he reviewed it carefully and reassured me that to the best of his knowledge I had a  genuine daguerreotype, along with—and this was even more surprising—a genuine case. He did, however, warn me that buying daguerreotypes on auction sites—especially images of Native Americans—was a risky business, with the general belief among experts that many of them are fakes.

It seems that the “Union Cases” that were used to protect daguerreotypes from shattering (they resemble a woman’s make-up compact) were an example of early thermoplastic technology. While some reputable websites refer to these cases as “gutta-percha” the term preferred by collectors is “union case” or even “thermoplastic.” They were made from a mixture of wood and shellac that was pressed into a mold. The result was a plastic-like product that still looks good one hundred and fifty years later. Amazing!

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