Ambrotypes
This selection is specifically of ambrotypes, or ambros. They are comprised of different sizes but all should be enclosed in Union cases, lockets, or other metal, wooden, or resin plastic protective cases. Ambros had a shorter span of popularity in the US before the invention of the tintype.
Depending on the source, the ambrotype process was either invented in 1847 in Cincinnati, OH by Ezekiel Hawkins, or in1851 by Frederick Scott Archer, sculptor and inventor of the collodion process, along with Peter Fry. The ambrotype, also known as “ambros”, was given credit for introduction into the United States and was named after photographer James Ambrose Cutting, who in 1854 patented a superior variety at the time. Many others developed the process as time passed. With the invention of the ambrotype the decline of the daguerreotype was now underway. In Great Britain it was called “collodion positive”, as the ambrotype was the first wet-plate collodion process.
The ambrotype was developed from the daguerreotype. The ambrotype and tintype are essentially the same, with the difference being the former, developed first, were done on glass plates, which were more fragile. The tintype was an improvement to the ambro in that it was developed onto thin pieces of iron. Tintypes are stronger and cheaper to produce.
Like the daguerreotype process, plates had to be carefully prepared before being placed into the camera for exposure. They are then developed, fixed, treated, and sealed in a glass-front protective case. To prepare, a thin clean glass plate is covered to the edges with a thin layer of iodized collodion. It is then made light sensitive by dipping in a silver nitrate solution. It is then quickly placed into the camera before the emulsion can dry. The exposure times are anywhere from several seconds to a minute, depending on lighting and other factors. The plate is then developed by immersing it into a solution of water, protosulphate of iron, nitrate of potass, and acetic acid. It is then desensitized to light with a fixing solution of water and hyposulphite of soda, now known as sodium thiosulphate. A negative image resides on the plate after exposure and development and the light areas of the image appear dark, while the dark areas appear light. Either the back is painted black or a black background is placed behind the glass and the light contrast reverses, bringing the image to life.
While still of very good quality, generally ambrotypes were less detailed, had less depth, and darker than daguerreotypes. They had no shiny reflective surface but were often hand-tinted, or painted. Like dags, ambrotypes are very fragile and have to be sealed from air, excessive light, humidy, extreme temperatures, smudges, etc. in metal, wooden, or resin plastic protective cases (Union cases were very popular).
Ambrotypes came in different sizes, 1/6 plates and 1/9 plates being the most common. They were classified as double plate (between 8 1/2 to 13 inches), whole plate (between 6 1/2 to 8 1/2 inches), half plate or 1/2 plate (between 4 1/4 to 5 1/2 inches), quarter plate or 1/4 plate (between 3 1/4 to 4 1/4 inches), sixth plate or 1/6 plate (between 2 3/4 to 3 1/4 inches), ninth plate or 1/9 plate (between 2 to 2 1/2 inches), and sixteenth plate or 1/16 plate (between 1 3/8 to 2 5/8 inches).
Most you find today will be unsigned. To tell an ambrotype from a tintype online is not always easy. The most obvious way to tell is if the photo image is on the glass plate, as opposed to being on a sheet of iron, it is an ambros. Also, unlike ambrotypes, most tintypes will not be framed and housed in latched decorative cases, and if they are, the cases are generally thinner than that of an ambro.
The short time period of ambrotypes in the United States was early to mid 1850s to early 1860’s, but continued its popularity throughout the rest of the world. In the United States the cheaper and stronger tintype and the popular carte de visites (CDVs) would dominate as the photo of choice.