19th Century Photographic Processes and Formats

Working within the Special Media Division presents many challenges. Not only do staff strive to become experts on the subject matter covered within our holdings, but also the physical format and the processes that made them. In the Still Picture Branch, we have a wide range of photographic formats and processes that provide unique preservation challenges, including proper storage, proper handling and reproduction strategies. Most prominent of these are our 19th and early 20th century holdings where you will find almost every early photographic process, including daguerreotypes, tintypes, ambrotypes, wet-collodion glass plates, gelatin dry plates, albumen prints, gelatin silver printing out prints, collodion silver printing out prints, matte collodion prints, platinum/palladium prints and cyanotypes. Photographic prints can be found in different print formats such as stereographs, cartes-de-visite and cabinet cards. For this post, I’ll be concentrating on the most prevalent processes and formats in our holdings. We do have a small number of daguerreotypes (direct positive process on silver plated copper), tintypes (direct positive process on a thin sheet of lacquered iron), and ambrotypes (underexposed glass plate placed against a dark background), but they are not as frequent as the other processes.

Wet-Collodion Glass Plates and Albumen Prints

Let’s first look at two of the more popular 19th century photographic processes, wet-collodion glass plate negatives and albumen prints, which are widely represented in our Civil War holdings.

(Wet-Collodion Plate) Photo No. 111-B-4975; Crowd of citizens, soldiers, and etc. with Abraham Lincoln at Gettysburg

The above image is a scan created from a copy negative made directly from the original wet-collodion glass plate negative. The photograph, reportedly showing Lincoln at Gettysburg, is found within our Mathew Brady Civil War collection. The wet-collodion process is one of the earliest photographic processes. Photographers created their own glass plates and coated them with a solution of collodion (cellulose nitrate) and a soluble iodide. The plate was then immersed in a solution of silver nitrate in the darkroom.  The plate was still wet when exposed and then immediately developed and fixed. Finally, a protective varnish was applied. When working in the field, photographers needed to use portable darkrooms, in many cases horse-drawn wagons. With many of our wet collodion plates, you can even still see the photographers thumb print in the corner where they held the plate. Due to preservation concerns and high historic and intrinsic value, original wet-collodion plates are rarely if ever served in the research room and researchers must use reference prints, copy negatives or digital copies when available.

Photo No. 77-KSP-46; Photograph of Timothy O’Sullivan’s Ambulance Wagon and Portable Darkroom on the Sand Dunes of Carson Desert during the King Survey, 1867

(Albumen Print) Photo No. 165-SB-23; Maryland, Antietam, President Lincoln on the Battlefield

In the 1860s through the mid-1880s, albumen was the dominate print format. One example from our holdings can be found in Alexander Gardner’s Photographic Sketchbook of the Civil War. This famous image shows Lincoln with General George McClellan and other Union officers not long after the Battle of Antietam. The photograph also features a young George Armstrong Custer leaning near the tent. To create albumen prints, paper was floated in a mixture of fermented chloride and egg white, dried and then floated on a solution of silver nitrate. The paper would then be placed in a frame in direct contact with the negative. Sunlight was used during the exposure process. Albumen can sometimes be one of the easier print formats to identify in our holdings. Image tones will sometimes change towards yellow brown with yellow highlights due to deterioration. Paper fibers are also visible. The viewing and reproduction options for albumen prints are limited in our research room due to preservation concerns. For those with high historic value, only reference copies can be used.

Collodion Silver Printing Out and Gelatin Silver Printing Out Prints

The next photographic processes to look at overtook albumen in the mid-1880s, the collodion printing out and gelatin printing out print processes. It can sometimes be extremely difficult to distinguish between the two. Like the albumen print, they were contact printed under sunlight.


Photo No. 26-LG-22-82B; Cape Hatteras Lighthouse in North Carolina, May 20, 1893

Photo No. 26-LG-27-3; Charleston Light (Morris Island) in South Carolina, June 6, 1885

Unlike albumen prints, paper fibers are obscured due to a thick baryta layer. Collodion tends to hold up better, with gelatin more susceptible to fading and discoloration. That being said, collodion is more susceptible to abrasions. Additionally, you might see what a former colleague called an oil slick pattern when holding collodion prints up against a light source. Like all photographic processes, levels of deterioration can sometimes be traced back to processing work performed by the photographer and ultimately storage conditions. Once our building reopens, I can examine each of the above prints and update this post with the specific process, collodion or gelatin. The fate of the two lighthouses pictured were certainly different. Cape Hatteras was moved more inland in 1999 to protect from the encroaching sea and Charleston Light on Morris Island was decommissioned in 1962 and due to erosion now stands a few hundred feet offshore.

Platinum Prints and Cyanotypes

Two other print processes created in the 19th century are prevalent in our holdings. First the Platinum Print, which used high-quality paper coated with iron and platinum salts. It eventually saw a decline in the early 20th century with the rising cost of platinum. Platinum prints have no binder layer and were coated directly on the paper support. They have a matte surface and the paper fibers are visible under close examination. Many platinum prints in our holdings have held up extremely well over time and many look like they could have been exposed yesterday. Platinum prints are also famous for leaving ghost images on adjacent paper housings and this phenomenon was subject to a research project by NARA conservators (https://www.archives.gov/preservation/past-projects).

  (Platinum Print) Photo No. 26-PR-2-8B

  Opposite page

The second print process is the cyanotype, which can be easily identified by its cyan image color. Cyanotypes, which are basically photographic blueprints, were mostly popular in the late 19th, early 20th century. They were an easy way to make contact prints to proof negatives.

(Cyanotype) Photo No. 26-LG-23-26; Nansemond River Light Station, Virginia. Photographed by Major Jared A. Smith, May 21, 1885.

Like Platinum prints, cyanotypes do not rely on the light sensitivity of silver. The cyanotype process relies on iron salts. Cyanotypes are extremely sensitive to light and will fade quickly, so viewing them in our research room is very limited. I have been told that the process is reversible, but we do not plan on testing it out.

Gelatin Dry Plate (Negatives and Lantern Slides)

Now it’s back to glass plate negatives with the gelatin dry plate negative, which replaced the Wet Collodion plate as the most used glass plate process. Popularity started in the 1880s when George Eastman started mass producing plates with his new company, Eastman Film and Dry Plate and eventually Eastman Kodak.

(Gelatin Dry Plate Negative) Photo No. 418-G-8; Administration Building Center Hall, St. Elizabeth’s Hospital, ca. 1900

You can find gelatin dry plates in our holdings up into the 1920s and 1930s. We even have one series of 14” x 14” glass plates created in the 1950s at Palomar Observatory in California. Plates maintained their popularity in astronomy photography well into the 20th century. Dry plates consist of silver halides suspended in a gelatin binder and when compared to wet collodion plates, dry plates have a short exposure time of one second or less. Common deterioration includes silver mirroring, which is a metallic sheen in reflected light. In addition to dry plate negatives, we also have many dry plate transparencies in the form of lantern slides, which were either contact printed, reversal processed, or the negative was photographed. Below is scan of a hand-tinted lantern slide.

(Lantern Slide) Photo No. 370-D-11C-54-306; People, Pribilof Islands, Alaska 

Cabinet Cards and Cartes-de-visite

I would like to end this blog by looking at several print formats found throughout our holdings. The first two are the cabinet card and the carte-de-visite. Both are very similar with the main difference being their size. The cabinet card is usually mounted on a 4-1/4” x 6-1/2” card mount. While the carte-de-visite is mounted on a 2-1/2” x 4” card.

(Cabinet Card) Photo No. FL-FL-22; Frederick Douglass, ca. 1879

(Carte-de-visite) Photo No. 165-JT-273; Secretary of State William H. Seward

(Carte-de-visite) Photo No. 87-PC-29; Photograph of Angilina Arsena

Ms. Arsena’s photograph is found in one of several series from the Secret Service related to individuals arrested for counterfeiting and currency offenses in the late 1800s. She was arrested for using a counterfeit coin, but not all arrests were related to currency. The most unique is for those arrested for counterfeiting butter with oleomargarine (margarine). In some cases, entire families were arrested, including children.


This last format is one of my favorites, the stereograph. These cards would give a three-dimensional effect when viewed with a stereoscope. Always reminds me of the ViewMaster I had as a kid.

(Stereograph) Photo No. LL-CC-486; The Original Monitor After Her Fight with the Merrimac

(Stereograph) Photo No. VGT-VGG-16; Photograph of General Merritt and Officers of the Fifth Cavalry

Resources consulted for this blog include the Image Permanence Institute’s Graphic Atlas and the Care and Identification of 19th Century Photographic Prints by James M. Reilly (1986).

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