By Gregg McNeill
In this series, we explore the history of photography in terms of image-making methods and various technologies available to photographers at different periods of time, leading up to the present host of available ways to make a photography. It wasn’t always os easy! In the previous entry, we talked about the paper processes. From the preceding photographic technologies, they were a step up in ease of use, but a step back in image quality.
Our story resumes in 1846. Louis-Nicolas Ménard, a gentleman scientist in France, discovers collodion. Collodion is basically nitrocellulose, or gun-cotton, dissolved in ether and alcohol, creating a sticky film (the name collodion comes from the Greek κολλώδης (kollodis), meaning gluey). In 1847 collodion was first used as a covering for medical dressing, then in the battlefield during the Crimean War. Collodion is still used today in the medical industry, as well as the Theatrical industry as a special effects make-up.
Frederick Scott Archer by Robert Cade, 1856
Enter Frederick Scott Archer. He was a Sculptor. He often used Calotypes to capture images of his work. Archer became frustrated by the lack of definition of the images and extremely long exposure times, he sought out a new way of making images of his work. In 1848, Archer began work on his Wet Collodion process. He published his process in The Chemist magazine in March of 1851. This was the first time that glass had been used as a substrate for photographs. They were called Ambrotypes.
The Chemist title page
It also should be noted that a Frenchman named Gustave Le Gray had been working on a collodion-on-glass process and had published an article about 1 year earlier. However, his article was vague as to the process and has been described as “a theory, at best”. It’s a cruel irony that we have a wealth of fantastic images from Le Gray and less than 100 images known to be made by Archer.
Gustave Le Gray, Tree, Forest of Fontainebleau, 1856
The first step in the Wet Collodion process is to grind down the cut edges of the glass plate, then meticulously clean the plate with a solution of alcohol and calcium carbonate.
Collodion is flowed carefully onto the glass plate, allowed to partially set, then lowered into the silver bath.
Inside the silver bath, the bromides and iodides in the collodion react with the silver nitrate to form a light sensitive emulsion on the plate. After about 3-4 minutes, the plate is sufficiently sensitized to create an image.
Under safelight conditions, the plate is removed from the Silverbath and loaded into the plate holder. Since collodion is only sensitive to the green blue and some of the UV spectrum, exposure times are determined by experience.
Developing the plate is done by removing the plate in safelight conditions and pouring developer onto the plate. Once developing is complete, water is poured over the plate to arrest development.
Plates can be fixed in either Sodium Thiosulfate (photographic fixer) or Potassium Cyanide (KCN). This is the part of the process where you can see the image turn from negative to positive, right before your eyes.
The plate will lose sensitivity to light if the collodion dries, so all of the above steps have to be accomplished while the chemistry is still wet.
Once the image on the plate is dry, you must protect the delicate collodion emulsion by varnishing. This is done with either a sarandac, or lacquer varnish. After heating the plate over an open alcohol flame, flow the varnish over the plate and allow it to set. Heat the plate again to cure the varnish. Many modern Collodionists use Renaissance Wax instead of varnishing since it doesn’t darken the image on the plate like most varnishes. The downside of this is that the image layer isn’t as protected as it is with varnish.
The Ambrotype represented a sea change in photography. Prints from these glass negatives could be reproduced hundreds of times and unlike the Calotype, held a fantastic amount of detail.
Ante Room of Great Hall, Frederick Scott Archer, 1851
Wet and Dry Collodion, The Precursor to Film will be published in two parts. Keep an eye out for the next chapter!
Reilly, James M. The Albumen & Salted Paper Book: The history and practice of photographic printing, 1840-1895. Light Impressions Corporation. Rochester, 1980
A Silver Salted Gelatine Emulsion, Richard L. Maddox, British Journal of Photography, September 8, 1871