Preservation of the Daguerreotype Collection

In 1985, Dr. M. Susan Barger of the Library's Conservation Research and Testing Office surveyed the Library's daguerreotype collection and made recommendations for treatment. The Brady daguerreotypes were treated by Sarah Wagner in 1992. The remainder of the collection was treated between 1992 and 1994 by photo conservator, Barbara Lemmen.

BRADY DAGUERREOTYPES

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The Library received the majority of the Brady daguerreotypes as a gift from the Army War College in 1920. When they arrived, the daguerreotypes were uncased and many did not have cover glasses. The plates were scratched and abraded. They were also discolored from previous cleanings.

The Library's conservators devised a new housing system for the Brady daguerreotypes in consultation with the Library's curatorial staff, photographic conservators from other institutions, and a contemporary daguerreotypist. A functional housing design was developed that also included a presentation mat. The package consists of an inner polypropylene sinkmat. The daguerreotype rests in the sinkmat, and is held in place with Mylar corners. A sheet of glass is placed on both sides of the package. This package is then sealed with Permacel J-Lar 910 tape. A face mat of acid-free matboard is affixed to the outside of the package. In this housing, the entire plate, front and back, can be viewed.

CASED IMAGES

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The conservation survey of the Library's cased daguerreotypes revealed two main problems: deteriorating cover glasses and unsealed daguerreotypes. The Library's conservators, in consultation with conservators from other institutions and Library curators, decided to retain the original cover glasses, rather than replace the cover glasses with new glass. (New glass gave a distinctly different feel to the object and was only used when the old glass was cracked or badly damaged.) Since the daguerreotypes are stored in a stable environment, where the temperature and humidity levels are monitored, it is believed that little if any deterioration will occur. When the daguerreotype package was reassembled, a sheet of Mylar was placed between the glass and the brass mat to prevent the possibility of future corrosion damaging the daguerreotype. Another piece of Mylar was placed behind the plate to limit the contact area of the sealing tape. The daguerreotype package was then taped together with Permacel J-Lar 910 tape. The taping process was carried out in a room with a low relative humidity (less than 40%) to insure that dry air would be trapped in the daguerreotype package. The preserver was replaced around the sealed daguerreotype and the daguerreotype package was inserted into its case.