Portrait of Wi-ga-sa-pi, 2004.1.125.33
As a research institution, the Peabody Museum hosts hundreds of research visits every year. This post from our Senior Archivist, Katherine Satriano, tells us about a past visit from Dr. Arthur McClelland of Harvard’s Center for Nanoscale Systems. Arthur visited the Peabody Museum Archives this past spring to study salted paper prints, a rare early photographic format, as part of a research project he developed with Elena Bulat of the Harvard Library’s Weissman Preservation Center.
Introduced by William Henry Fox Talbot in 1839, salt prints were created by the first photographic technique to use a negative to create a positive image on sensitized paper. The “salt” refers to the sodium chloride solution used in combination with silver nitrate to coat the paper, making it sensitive to light.
The goals of Arthur’s research are to increase knowledge of historical photographic processes and help inform their preservation today. One of the salt prints he studied is the portrait of a Ponca man, Wi-ga-sa-pi, seen above, photographed by Julian Vannerson.
Arthur performed non-invasive, specular reflectance Fourier transform infrared (FTIR) analysis to determine the chemical composition of coatings applied to the salt prints by the photographers for protective and aesthetic purposes. FTIR is used to examine organic or inorganic materials that have large reflective surfaces–the technique measures the energy that is reflected off a surface to determine the chemical composition and better understand the morphology. The initial proof of concept for this analysis technique on coated salt prints was demonstrated using the Harvard class albums in the Harvard University Archives and was published by Arthur and Elena in the Journal of the American Institute of Conservation in October 2019.
This optical micrograph of one of the salt prints shows the coating on the paper fibers.
And the spectral library match seen below shows that the photograph’s coating is comprised of beeswax with lavender oil.
Thank you to Arthur for this fascinating close look at some of the Peabody’s collections. You can learn more about salt prints in Harvard’s collections on the Salt Prints at Harvard website.
Authors: Katherine Satriano and Arthur McClelland
Micrograph and spectral library images courtesy of Arthur McClelland