Technology at the Library: Long-Hidden Text Is Uncovered in Alexander Hamilton Letter (Library of Congress)

Library of Congress: Technology at the Library: Long-Hidden Text Is Uncovered in Alexander Hamilton Letter. “When the Library of Congress recently digitized the Alexander Hamilton Papers, that letter, unedited, with its 14 obliterated lines, became visible to all for the first time. However, the lines were still unreadable. To find out what lay beneath the scratchings-out, Fenella France, chief of the Preservation Research and Testing Division, and preservation staff Meghan Wilson and Chris Bolser used hyperspectral imaging. A noninvasive analysis that employs light at different wavelengths to capture information not visible to the eye, hyperspectral imaging can determine the composition of inks and pigments, track changes in documents over time and reveal faded, erased or covered writing.”