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.
Triple portrait of Alexander H. Phillips (Class
of 1851), Hugh W. Henry (Class of 1851), and William Wallace Phillips,
ca. 1850s. Half-plate daguerreotype. Photographer unknown.
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
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
From left to right, top to bottom, Portraits
of Abram Hoogland LaMonte, Charles Russell Clarke, John Craig
Schenck, William Erskine Skinner, Silas Merchant, Jr., Alfred
Eli Lewis, Charles Thomas Haley, Patrick Henry Rutledge, and Samuel
Alexander McElhinney, all members of the Class of 1853. 1853.
Sixth plate daguerreotypes. Photographer unknown. [Before treatment]