Assignment 1: Process: Wet Collodion Negatives

Wet Collodion Negatives

CD Hess, 1868. Matthew Brady

Inventor

Frederick Scott Archer is credited as the inventor of the wet collodion process. He published in The Chemist papers an article on the use of pyrogallic acid in photography and in March of 1851 published the wet collodion process in its entirety. [4] Archer published his findings free from patent restrictions and was often called upon to share his process with other photography enthusiasts, which he did openly. However, other photographers who had experimented with the use of collodion (gun cotton mixed with aether - see process below for more details) in photography tried to take credit for the invention, and Fox Talbot event attempted to claim Archer's process was covered by the calotype patent. [4]

Unfortunately for Archer, "a very inconspicuous gentleman, in poor health, with a somewhat sorrowful look..."[4] he died at age 44, impoverished with little fame or recognition for his advancements in photography.  

Process

The wet collodion process quickly replaced the daguerreotype in popularity but it was still finicky and had its own set of advantages and disadvantages. However, the process is still practiced today, with classes being offered at the George Eastman House in Rochester and is often referenced in alternative photographic process textbooks/manuals.

Steps

1. Mix guncotton (cotton, nitric and sulfuric acid) with alcohol and ether to create collodion. (Before photography collodion was used in medical practices!)

2. Coat a glass plate with collodion by pouring the liquid across the plate, evenly coating it and letting gravity aid in the process.

3. Sensitize the plate by placing it in a bath of silver nitrate. 

4. Load plate (while still wet!) into the camera.

Note: Steps 3 and 4 must be completed in complete darkness.

5. Expose the plate (exposure time ranged from 2 seconds to 1.5 minutes [6])

6. Develop the plate (in darkness or red-filtered light) immediately (plate should still be wet) using pyrogallic acid (by 1860 ferrous sulfate was used as developer). [7]

7. Fix the image using sodium thiosulfate or potassium cyanide. (Again, plate should still be wet.)

8. Wash the plate with water.

9. Bleach or enhance image, if necessary

10. Coat plate in varnish to protect.

Advantages

• Shorter exposure times
• Slightly less toxic than mercury (though cyanide is still not fun)
• Glass plates allow for multiple printings
• The process allows for high detail and large negatives
• Glass is generally more durable than paper
• Overall, the process is cheaper than a daguerreotype

Drawbacks

• Glass is fragile, large plates are heavy and transporting them could be difficult
• Steps 3 and 4 needed to be completed quickly in complete darkness while the plate was still wet. This meant photographers needed to bring their darkrooms with them wherever they went and be fairly dextrous and quick with the moderately complicated process
• The process is particularly sensitive to blue light, which means skies often appeared completely white in images. Photographers would use separate negatives to add detail to the sky in later prints.
• Collodion could not be painted onto the plate, it needed to be poured and flowed over the glass. This could get messy and lead to uneven distribution of the emulsion
• If the plate dried, your photo would not turn out.

Typical Use

Short exposure times allowed this process to be even better for portrait work, particularly once experimentation in developers and fix began to take hold. On top of that, large plates as negatives allowed photographers to capture an enormous amount of detail in their images. The cheaper chemicals and fact that plates could be made "on the go" (so long as you brought your darkroom with you...) allowed photographers to take photographs outside of the traditional portrait studio. 

Photography also started to become a popular hobby around the mid 1850s and began to find its way into engineering and military establishments. It was used to document travels by the East India Trading Company and even began to see use in medicine. [4]

Photographers

Many, many photographers used the wet collodion process to create their negatives, and many printed their photographs different ways since then. A few photographers that I particularly enjoy from this time period however are:

• Julia Margaret Cameron 
• Samuel Bourne
• Felix Tournachon (Nadar) 
• Roger Fenton
• Matthew Brady

Identification

If it's a negative on a piece of glass, it's probably a collodion negative. (If it's a positive, it's probably a collodion process but called another name!) However, since there are two types of collodion negatives, here are some tips for distinguishing wet collodion negatives.

• Earlier collodion negatives were medium-brown in color. Underexposed negatives could appear as a dull positive against a dark background
• Negatives were often bleached to bring out stronger highlights and sometimes tinted to different shades of browns.
• Before the use of ferrous sulfate developer to reduce exposure times (early 1850s) the process was preferred for landscape photography. 
• After potassium cyanide became used as a fix (end of the 1850s) negatives became a more yellow-brown color and bleaching was no longer necessary. 
• Because collodion needed to be flowed onto the plate, often the corners of the glass will not have been sensitized. Look for corners without any emulsion on them.
• Also because of the flow of collodion, plates may not be a uniform thickness.
• The glass plates themselves are often ground, but can have uneven edging and may be sharp.

Preservation Concerns

• Glass is easily breakable: cracks, chips, shattering, flaking, etc. can occur.
• Plates should be individually stored in envelopes, then placed on their longest edge between thick dividers to prevent excessive movement/abrasions.
• Multiple glass plates are heavy - shelves need to be sturdy and glass plates should not be stacked on top of one another.
• Plate sizes can vary from small portraits to large landscapes. 
• Heat and humidity can cause deterioration of collodion images, as well as cause glass to become brittle and more likely to break.
• Because so many combinations of chemicals were used in early collodion printing, image stability may be a concern. An expert may need to be consulted in regards to chemical makeup and best practices for preserving individual plates.

Bibliography

[1] Bahnemann, G. (2012, March 21). The Preservation of Glass Plate Negatives. Retrieved from https://www.webjunction.org/documents/webjunction/The_Preservation_of_Glass_Plate_Negatives.html

[2] Davis, K. (2007). The Origins of American Photography 1839-1885: From Daguerreotype to Dry-Plate. New Haven, CT: Yale University Press.

[3] George Eastman House. Collodion Process. Retrieved from http://notesonphotographs.eastmanhouse.org/index.php?title=Collodion_Process#Wet_Collodion_Process

[4] Gernsheim, H. (1988). The Rise of Photography 1850-1880. London: Thames and Hudson, Ltd.

[5] Mora, G. (1975). Photo Speak: A Guide to the Ideas, Movements, and Techniques of Photography 1839 to the Present. New York: Abbeville Press.

[6] Scharf, A. (1976). Pioneers of Photography. New York: Harry N. Abrams, Inc.

[7] Valverde, M. (2003). Photographic Negatives: Nature and Evolution of Processes. Retrieved from https://www.imagepermanenceinstitute.org/webfm_send/302