Electro-clean Conservation Technique

The third and most intensive conservation technique performed on the daguerreotypes in the Princeton University Archives was the process of electro-cleaning. The conservator removed the plate from its enclosure and dusted the surface with air using an ear syringe. The plate was bathed in water, and then was electro-cleaned. This entails immersing the daguerreotype plate in a solution of ammonium hydroxide and deionized water, and applying a weak electric current through a thin silver bar above, but not touching, the surface of the plate, removing the corrosion from the plate. Once this was complete the plate was dried by a series of solvent baths, the cover glass was cleaned, the plate re-sealed and returned to its original enclosure or placed in a new one.

At some point this daguerreotype plate lost its case, preserver and mat. The resulting corrosion, oxidation, and fingerprints all but obscured the portraits of the three young men who are barely visible.

Once the daguerreotype plate was electro-cleaned, the newly visible details of the three young men emerged. Their eyes, hair, hands, and clothing now appear with great clarity.

Hover over the image with your mouse to see the image after treatment.

These nine daguerreotype portraits represent a handful of the original twenty portraits taken of members of the Class of 1853. They were made during the students' last year at Princeton. Found years later in a building on campus, the plates had lost their enclosures and, as seen here, had become covered with corrosion. The decision was made to electro-clean these images, and the results were stunning.