Earlier this year, I had the opportunity to learn a little bit more about some historical photography processes while preparing to teach a class. This is not in any way my area of expertise, but I wanted to share both what I learned and also examples I uncovered in our ISU collections (which, while far from comprehensive, do contain more formats than I thought they would!).
If this is a topic you find interesting, know that there are a ton of other fantastic resources out there, both online and within our library and the ISU community. I’ll include a few of these throughout the post and then note more at the end.
So, the earliest format for which we have an example is the daguerreotype. (Pronounced duh-gair-oh-type.)
Artifact #2001-R001. Daguerreotype of Benjamin Gue.
Daguerreotypy was not the first photographic process to capture scenes with a camera, nor even the first to succeed in permanently fixing the image to a chemically-prepared surface. The latter honor belongs to another French process called “heliography” (aka “sun-writing”), and you can see an example in the Harry Ransom Center collections at the University of Texas in Austin. However, the daguerreotype process was the first to become available to the public.
With the case closed. Artifact #2001-R001.
The daguerreotype was invented in Paris in 1837 by Louis Daguerre, when he discovered that a silver-coated copper plate could be made light sensitive when exposed to chloride of iodine (now known as iodine monochloride) and chloride of bromine (now known as bromine monochloride). After exposure, the plate would be developed in a dark room via heated mercury fumes, and then fixed in a bath of hyposulphite of soda (now known as sodium thiosulfate).
There were two main draw-backs to this process, however. The first, since the exposed plate itself became the finished product, was that the process created no negatives, which meant that each image was entirely unique and could not be reproduced. The second was that these plates were incredibly fragile. The cases in which they were mounted were primarily protective, not decorative, and thus, unlike photo frames of today, vital to the photograph’s survival.
Diagram of a daguerreotype case. Photographs: Archival Care and Management by Mary Lynn Ritzenhaler and Diane Vogt-O’Connor
In addition, exposure time for this process lasted an excruciatingly long time by today’s standards. Resources differ in their estimations, and it seems that the process shortened over its lifespan, but exposure could reportedly last anywhere between 90 seconds and 20 minutes, during which the subject of the picture had to keep absolutely still. Behind-the-scenes sketches of the studio set-up often feature torturous-looking headrest devices, shaped like display stands for collectible dolls, to hold the subject’s head and neck in place.
Nevertheless, the daguerreotype was wildly popular during its short life from 1837 to about 1860, after which it was replaced by less expensive and less cumbersome formats.
This 2012 YouTube video from the Getty Museum offers a fantastic overview of that period and allows you to see the process in action. The video is titled “Early Photography: Making Daguerreotypes”, and can be accessed through the link here if the embedded version isn’t work for you.
Our ISU example of a daguerreotype, located in the artifacts collection (#2001-R001), aptly demonstrates some key identifying features of the format.
A behind-the-scenes look in into our artifact collection.
As discussed previously, with only a few rare and very early exceptions, all daguerreotypes will be contained in a protective case, often with an attached cover that swings closed on a hinge.
It is worth noting, however, that while nearly all daguerreotypes will have these protective cases, not all photographs contained in such cases are daguerreotypes. Ambrotypes, a slightly later format, were also typically sealed in cases. The visual distinction between the two, then, lies in the tonal range and the reflective quality of the surface.
An ambrotype is a glass plate negative developed via the wet collodion process and then displayed against a black velvet background, which creates the illusion of a positive image. Consequently, its tonal range will be much more muted than that of a daguerreotype, with the whites appearing less white and more of a creamy gray.
Unfortunately, we don’t have examples of this format in our archives, but here is a visual from the book I have referenced previously:
Ambrotype. Photographs: Archival Care and Management by Mary Lynn Ritzenhaler and Diane Vogt-O’Connor, page 35.
Because ambrotypes are negative images developed on a glass plate and daguerreotypes are positive images developed on a silver-coated copper plate (i.e. shiny metal on shiny metal), the surface of a daguerreotype is also much more reflective than that of an ambrotype — almost giving the impression of a ghost-image emerging through a mirror, depending on the angle from which it is viewed.
Me photobombing Benjamin Gue . . . about 200 years after the fact. Artifact #2001-R001.
The presence of this mirror-like quality also means that daguerreotypes are better viewed from a side-angle, and/or with an object or piece of paper held up to block reflective glare (e.g. my phone in the picture immediately above), than they are straight on. So, if you find yourself tilting the photo this way and that to see an image of something other than your own face, this is probably the format you are dealing with.
Contrary to common knowledge, daguerreotypes also come in a variety of sizes, from a “whole plate,’ which is about 8.5 inches by 6.5 inches, to a “sixteenth plate,” which is about 1 inch by 1 inch. Also, while the original images will all be in black and white, you’ll find that some were hand-colored after development. You’ll see this most often in portraits, where a tiny bit of pink has been dabbed onto the subjects’ cheeks to make them look more lifelike.
Close-up of Artifact #2001-R001.
And that about wraps things up, so I hope you’ve enjoyed learning about daguerreotypes as much as I did.
If you’d like to examine our portrait of Benjamin Gue in person, feel free to stop by the archives any time that we are open, and we can assist you with the process of handling such an artifact (hint: you’ll be using gloves!). Or if you’d like to learn more, check out some of the resources below.
Benjamin Gue’s personal papers can be found in the archives at RS 1/3/52. You can also view the finding aid, including biographical information, here.
The book with which I supplemented images to this post is Photographs: Archival Care and Management by Mary Lynn Ritzenhaller and Diane Vogt-O’Connor with Helena Zinkham, Brett Carnell, and Kit Peterson. We do not have a copy in our general collections, but you can access reviews here, or buy a copy here.
In addition to an extensive collection of the daguerreotype format (contrasted with our one artifact!), the Library of Congress links to more online resources here, describing the process in more detail, showing digitized examples, and inviting you to join The Daguerreian Society (because, yes, apparently that is a thing).
If you have additional questions about identifying, storing, handling, or repairing historical photograph formats, the staff in our Preservation department at Parks Library are very knowledgeable. Both Sonya Barron and Cynthia Kapteyn helped me out with preparation and activities for the class which inspired this post. You can visit the Preservation department page here for contact information. And, as a side note, they also run a blog, full of fascinating updates on current projects, which you can find here.