![]() "I think most people use well-controlled laboratory-grade circulating convection ovens when they do this," he said.ĭavis also subjected the samples to other, more cutting-edge analysis techniques, such as scanning calorimetry to measure changes in temperature. While there is an obscure account from a 1990s audio magazine of a DIY hack using a hairdryer attached to a cardboard box to bake degraded reel-to-reel tapes, and Davis has been asked if a toaster over would suffice, he is skeptical that these were ever common methods. The first stage naturally involved baking the tape samples. He used small samples from those tapes for this project. Fortunately, his division has a collection of tapes set aside specifically for scientific research, making it possible to conduct even destructive scientific tests. "It became very clear that no one really understood the underlying mechanisms of how that thermal treatment worked," said Davis. He found that the LOC's audio curators had various methods on the best ways to bake a degraded reel-to-reel tape, and he also learned that heat-treated tapes will quickly revert back to their degraded condition if they aren't immediately processed. They form a sticky residue that can damage both the tape and playback equipment. The primary culprit for the degradation is known as "sticky shed syndrome," in which the binders used in a magnetic tape to hold the iron oxide casing to the plastic carrier deteriorate. "If you have that physical object, that's always something you can come back and re-listen to, or reprocess, if the need arises." Advertisementĭavis was visiting one of the LOC's offsite facilities, the Audio Preservation Consideration Center in Culpeper, Virginia, when the issue of degraded reel-to-reel tapes came up in the discussion. "It's not impossible that the digitized version might disappear, might get corrupted, or might become inaccessible 10 to 20 years from now," Davis said. They are simply obscure enough that they might only be digitized if the LOC receives a request to listen to them.Įven for those with a digital copy, preserving the originals as long as possible is still important. While the LOC continues to digitize its vast collection, there is still a large number of tapes in the archives that are still in their original format. ![]() "We span everything from simple analytical tests, like determining the kind of ink used on paper, to testing all building and construction materials, and ensuring the stickers on the barcodes don't damage books," Davis told Ars.ĭavis emphasizes that the audiotape collection is well-maintained and tapes are not literally decaying on the shelves as I type he works to ensure that they remain in good condition. The R&D division is responsible for providing the scientific groundwork for that mission, similar to how the Smithsonian Institute employs research scientists to maintain its collections. The LOC's mission is to ensure its collections continue to be accessible to the public, either in their original or reformatted mediums. Project leader Andrew Davis is a polymer chemist who works in the LOC's preservation research and testing division. Now scientists at the US Library of Congress have determined precisely why this method seems to work, presenting their findings earlier this month on the American Chemical Society's SciMeetings online platform. It's well known that applying heat can often reverse the damage sufficiently to enable playback, usually by baking the tapes in an oven. Reel-to-reel tapes are experiencing a resurgence of interest among audio buffs, but they are prone to degradation, which has been a topic of active research for many years.
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