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Thursday, May 16 • 9:00am - 9:30am
(Photographic Materials) Analytical Testing of Heat and Solvent Set Repair Tissues

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This talk will be presented in conjunction with “Use of Heat and Solvent Set Repair Tissues” presented in the Book and Paper Specialty Session.
In this work, the National Archives and Records Administration (NARA) and the Library of Congress (LC) will report on their recent joint testing of a variety of heat and solvent set repair tissues. The goal of this research project was to provide analysis of physical and chemical changes for an assortment of well-tested and commonly employed pre-coated heat and solvent set adhesive tissues for use across a variety of paper based materials. Heat and solvent application methods were compared.

In 2013, the Library's Conservation Division was informed that adhesives used for many years to make “Library of Congress Heat Set Tissue” were no longer available. LC and NARA collaborated on a joint research project to identify replacements. At the end of the study a suitable mending tissue was identified and both institutions proceeded to use the material on their collections. Concerns were raised when it was later discovered that some of the materials used in the research project had turned brown after being stored at ambient conditions.

As noted in the 2015 AIC presentation, “Heat-Set Tissue: Finding a Practical Solution of Adhesives,” commercially available conservation adhesives have been discontinued or reformulated with disconcerting frequency. For this reason, another goal of this work was to continue evaluating the properties and behaviors of “known” adhesive compositions to assess their consistency. In addition, the authors will present suggestions for analytical testing methods of these adhesives for future quality control.

The adhesives and tissues tested here were chosen based on common usage at NARA, LC, and across the broader conservation field. Adhesives were applied to test substrates using both solvent and heat set methods, with the goal of evaluating how the application method affected adhesive properties and aging. Tests were conducted to assess reversibility after aging, blocking of mends and fills under pressure, effect on silver-based photographic materials, and color change following artificial aging. Color change was evaluated using both qualitative and quantitative methods to compare visual perception of color change with calculated ΔE CIE-L*a*b* values. Given concerns about changing formulations over time, these tests were also designed to set a baseline series of properties to monitor in the future.

Discoloration due to aging was found to be primarily a factor of the adhesive composition itself, with some additional contribution from the tissue and substrate. These discolorations were mostly found in a decrease of brightness and increase in yellowness. The application method did not significantly affect the color change. Adhesive tissues also behaved similarly in the PAT results irrespective of heat or solvent application. PAT success or failure depended only on adhesive composition and concentration.


Jennifer K. Herrmann

Senior Conservation Scientist, National Archives and Records Administration
Jennifer K. Herrmann has been a senior conservation scientist at the National Archives and Records Administration for over 10 years. She enjoys working with conservators to answer questions about the records they treat as well as investigating conservation techniques and tools to... Read More →
avatar for Katherine Kelly-[PA]

Katherine Kelly-[PA]

Senior Book Conservator, Library of Congress
Katherine Kelly is a Senior Book Conservator at the Library of Congress in Washington, DC. Previously, she has worked at the Smithsonian Institution Libraries, the National Archives, Iowa State University, Harvard University, and Cornell University. She received her MS in Information... Read More →

avatar for Alisha Chipman

Alisha Chipman

Senior Photograph Conservator, Library of Congress
Alisha Chipman is a senior photograph conservator at The Library of Congress in Washington D.C. She has published research on Paul Strand’s platinum prints, hand-colored tintypes, and treatment techniques for blocked negatives. Her conservation experience includes former employment... Read More →
avatar for Andrew Davis

Andrew Davis

Chemist, Library of Congress
Dr. Andrew Davis is a chemist and polymer scientist in Library of Congress’s Preservation Research and Testing Division. He is currently focused on collections preservation by studying the fundamental degradation science of polymer-based materials, including paper, film, and modern... Read More →
avatar for Anne Witty

Anne Witty

Lead Conservator, National Archives and Records Administration
Anne Witty is a Lead Conservator at the National Archives and Records Administration. She has worked as a paper conservator at NARA for 30 years, and for the last 17 years has served as conservation liaison to NARA's Field Office archives located across the U.S. She started her conservation... Read More →
avatar for Kate Morrison Danzis

Kate Morrison Danzis

Preservation Specialist, Library of Congress
Kate Morrison Danzis is a Preservation Specialist at the Library of Congress in Washington, DC. Previously, she has worked at Conservation Solutions in Washington DC and the National Park Service in New York City. She received her MS in Historic Preservation with an emphasis in conservation... Read More →

Lauren M. Varga

Lead Conservator, National Archives & Records Administration
Lauren Varga is a Lead Conservator in the Document Conservation Laboratory at the National Archives & Records Administration. She received a Master of Arts degree and a Certificate of Advanced Study in paper conservation from the Art Conservation Program, Buffalo State College in... Read More →
avatar for Michele Youket

Michele Youket

Preservation Specialist, Preservation Research and Testing Division, Library of Congress
Michele Youket is a Preservation Specialist in the Preservation Research & Testing Division of the Library of Congress. Ms.Youket coordinates the Quality Assurance Program, which is responsible for developing specifications and testing products procured by the Library to provide preservation... Read More →
avatar for Steven Loew

Steven Loew

Senior Conservator, National Archives and Records Administration
Senior Conservator at the National Archives and Records Administration since 2013, hired as a Conservator in 2009. Collections Conservator, Sheridan Libraries Preservation Department, Johns Hopkins University, 2000-2005. Conservation Technician, Smithsonian Institution Libraries... Read More →
avatar for Tamara Ohanyan

Tamara Ohanyan

Senior Book Conservator, Library of Congress
Tamara Ohanyan is a Senior Book Conservator at the Library of Congress in Washington, DC since 2004. Previously, she has worked as a Senior Book Conservator at the Matenadaran, Research Institute of Ancient Manuscripts in Yerevan, Armenia. She received her degree from State University... Read More →
avatar for Yasmeen Khan

Yasmeen Khan

Head of Paper Conservation, Library of Congress
Yasmeen Khan is Head of Paper Conservation at the Library of Congress. She has a BA in Middle Eastern Studies from Barnard College, and an MLIS from the University of Texas with an Advanced Certificate in Conservation. In 1996 she began working for the Library of Congress, initially... Read More →

Thursday May 16, 2019 9:00am - 9:30am EDT
Nehantic/Pequot/Paugussett Rooms Sky Convention Center, Mohegan Sun
  Specialty Session, Photographic Materials
  • Track Photographic Materials
  • Ticketed Included in Main Registration
  • Authors in Publication Order Dr. Jennifer K. Herrmann, Katherine Kelly, Alisha Chipman, Dr. Andrew R. Davis, Yasmeen Khan, Steven Loew, Katharine Morrison Danzis, Tamara Ohanyan, Lauren Varga, Anne Witty, and Michele H. Youket
  • Abstract ID 18651
  • Tags heat set adhesive,pre-coated tissue