The following is a post by Gwen dePolo, a Preservation Scientist in the Preservation Research and Testing Division (PRTD).
This spring, the Library’s Preservation Research and Testing Division (PRTD) brought heritage science to life with a series of hands-on activities designed to spark curiosity and connect the public with the science behind preserving the Library’s vast collections. Organized around two key themes—materials (what we study) and instrumentation (how we study it)—these interactive experiences invited visitors to explore, touch, see, smell, and even hear the science in action.
Though the Library’s collections are made from a plethora of different media, both traditional and unique, the interactive stations focused on paper, pigments, and audio-visual materials and showcased analytical instrumentation like different imaging techniques, gas chromatography mass spectroscopy, and predictive aging testing.
Visitors learned about the paper-making process and how different factors impact its longevity. Raw materials like cotton rag, hemp, and wood pulp were displayed along with the resulting sheets of paper. These samples, from PRTD’s Cultural Heritage Analytical Reference Material (CHARM) collection, allowed guests to touch and feel the tactile differences between them. Participants could guess which papers would be the strongest before witnessing them being tested by a fold endurance tester, which folds a strip of paper repeatedly until it breaks, giving a sense of how strong the paper is.
Jars filled with plants, bugs, rocks, and metals demonstrated how pigments and colorants are made. Participants matched the sample jars to painted cards representative of common colorants in the Library’s collection. This activity provided an opportunity to talk about the challenges in identifying a pigment on a collection item, like when a color is faded and not easy to detect using non-invasive methods, or when pigments are mixed together to create a new color. Visitors were encouraged to use a handheld microscope to investigate two different types of color mixtures under magnification and how they could each produce the same color. (Previous blog posts talk about source materials for colors such as green, yellow, red, and orange, and even how food is used to create pigments.)
Understanding what the Library’s collection is made of is only half the story—just as crucial is knowing how these materials will stand the test of time. To peer into the future, PRTD can simulate aging by exposing reference materials (not actual collection items) to light, heat, and humidity. These controlled experiments help us predict how objects might change over decades or even centuries—so we can take steps today to protect them for tomorrow. Participants witnessed the impact of these conditions firsthand. Light meters showed the difference in intensity between ambient room light and a desk lamp and how different types of light can cause colors to fade over time. Temperature and humidity data loggers showed how easily conditions could fluctuate in a space with a lot of people and how that compared to a very dry environment inside of a sealed jar. These demonstrations facilitated discussion about the importance of controlled storage and exhibit environments so that collections are preserved for as long as possible.
Visitors were surprised to learn the origins of the “old book smell” phenomenon – and that PRTD can measure it. Odors, produced both by collection objects themselves and the materials they’re housed and exhibited in, are called volatile organic compounds (VOCs) and are a result of certain materials breaking down and degrading over time. Using certain instrumentation, PRTD can identify the origin and assess the volatility of these compounds, ensuring these materials won’t off-gas (release) anything potentially harmful to the collection object long-term. PRTD created an activity to demonstrate this process and had participants guess an ‘unknown’ material via smell. The material was placed in dark brown bottles and a graph was provided that showed what compounds were present in the smell, which most participants recognized as the aroma of coffee beans.
In between the past and the future is understanding and preserving the current condition of the Library’s collections. Not all of the Library’s collection items are pristine. Some have been subjected to annotations, redactions, stains, and fading over their lifetime so far. But a technique called multispectral imaging can help reconstruct content that has become obscured by capturing images in light beyond just the visible spectrum. Participants could interact with this technique by creating their own redactions on scrap paper with two different black pens. Using a handheld microscope and infrared light, the camera could see through the cross out and read the text below. Additionally, guests could use a similar imaging technique to find watermarks on printed paper.
To highlight the evolution of audio and video recording over the past 140 years, one station featured some exemplary formats from PRTD’s reference collection. From wax cylinders to vinyl records and compact discs, these objects offered a hands-on way to explore how technology has transformed the way we capture and experience sound and video, sparking engaging conversations about the science behind preserving these diverse formats. 5x scale replicas of early experimental grooved recordings that led to media like vinyl records, shellac discs, and wax cylinders were created using a 3D printer. These allowed guests to visualize the difference between grooves that recorded sound vertically (cylinders) from those recorded laterally (records and discs).
Another replica contained a significant crack and was used to demonstrate how preservation technology could still recover and recreate the audio using a non-contact 2D and 3D imaging methods with the IRENE System (Image, Reconstruct, Erase Noise, Etc.).
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PRTD took these interactive heritage science activities for a test drive during a recent themed ‘Live! At the Library: Discovery Night’ event. Ten PRTD staff members engaged with hundreds of visitors over the course of the evening. One mother visiting with her family on spring break mentioned that her son, “loves history and [was] so excited to see just how much overlap there can be between science and history.”
Not only did the visitors have many opportunities to learn and engage, but so did the PRTD staff volunteering during the evening. “I enjoyed the unique ways that the visitors engaged with my table and their experiences they shared to relate to the content in a perspective I hadn’t considered before,” commented Meghan Hill, Preservation Science Specialist. “Part of my table explored historic and modern inks, and one participant was engaged through his interest of fountain pens. I had never thought about pen and ink conventions before, but now I can’t wait to go and learn about samples we could add to our reference collection.”
Kelli Stoneburner, Preservation Science Specialist, also reflected that, “folks seemed surprised and fascinated by the all the work that goes into testing the materials used to build the exhibit cases as well as how the design of them (like the presence of sorbents or airflow) can impact the preservation of collections.”
The strong interest and engagement with these interactive tables at Discovery Night affirmed their value as effective tools for public outreach. PRTD looks forward to incorporating them into future programs and tours throughout the Library. These activities have proven to be a meaningful way to communicate the critical role that science plays in the long-term preservation of the nation’s collections, and we’re excited to continue encouraging public understanding through future outreach events.
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