Portrait in profile of Evert Marsh Topping, ca. 1850s. Quarter plate daguerreotype. Photographer unknown
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Conservation Techniques
The daguerreotypes and ambrotypes in the Princeton University Archives
underwent various levels of conservation depending on their condition.
Most of the ambrotypes and a number of the daguerreotypes were in
good repair and required only basic stabilization -- a minimum of
cleaning and the creation of new protective enclosures in which to
store the images.
A number of daguerreotypes, however, required more intensive treatment.
Over time the seals around many of the daguerreotype packages weakened
and allowed air and moisture to come in contact with the silver coated
copper plate. This caused the surface to darken, corrode, and become
embedded with debris. In some cases the glass protecting the plate
had deposits of corrosion. Additionally, previous attempts at cleaning
the daguerreotypes -- through cyanide or thiourea, for example --
often caused irreparable damage to the plates.
All of the daguerreotypes receiving conservation treatment were first
cleaned using the dry method, their glass
cleaned, and resealed. Two groups of daguerreotypes required further
treatment. One group, with only minimum corrosion or accretions, was
bathed in a water wash. Another group, requiring
more intensive treatment, was electro-cleaned.
The following sections describe each of these treatments, and some
show "before" and "after" examples of treated
daguerreotypes.
It cannot be stressed enough that these images were treated by a
professional photograph conservator. Much of the earlier damage to
these images was caused by untrained individuals who attempted to
clean or conserve the daguerreotypes themselves. For information on
finding a qualified conservator, individuals are urged to contact
the American Institute
of Conservators or an archive in their area.
continue with dry clean method
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