Preservation Research and Testing Division

Independence, DC, United States

Preservation Research and Testing Division

Independence, DC, United States
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Ponce A.,University of Maryland University College | Brostoff L.B.,Preservation Research and Testing Division | Gibbons S.K.,University of Maryland University College | Zavalij P.,University of Maryland University College | And 5 more authors.
Analytical Chemistry | Year: 2016

Synthetic, structural, spectroscopic and aging studies conclusively show that the main colorant of historical iron gall ink (IGI) is an amorphous form of Fe(III) gallate·xH2O (x = ∼1.5-3.2). Comparisons between experimental samples and historical documents, including an 18th century hand-written manuscript by George Washington, by IR and Raman spectroscopy, XRD, X-ray photoelectron spectroscopy, and Mössbauer spectroscopy confirm the relationship between the model and authentic samples. These studies settle controversy in the cultural heritage field, where an alternative structure for Fe(III) gallate has been commonly cited. © 2016 American Chemical Society.


PubMed | Israel Antiquities Authority, ANE Image, University of Piemonte Orientale and Preservation Research and Testing Division
Type: | Journal: Journal of analytical methods in chemistry | Year: 2016

Today the long-term conservation of cultural heritage is a big challenge: often the artworks were subjected to unknown interventions, which eventually were found to be harmful. The noninvasive investigation of the conservation treatments to which they were subjected to is a crucial step in order to undertake the best conservation strategies. We describe here the preliminary results on a quick and direct method for the nondestructive identification of the various interventions of parchment by means of direct analysis in real time (DART) ionization and high-resolution time-of-flight mass spectrometry and chemometrics. The method has been developed for the noninvasive analysis of the Dead Sea Scrolls, one of the most important archaeological discoveries of the 20th century. In this study castor oil and glycerol parchment treatments, prepared on new parchment specimens, were investigated in order to evaluate two different types of operations. The method was able to identify both treatments. In order to investigate the effect of the ion source temperature on the mass spectra, the DART-MS analysis was also carried out at several temperatures. Due to the high sensitivity, simplicity, and no sample preparation requirement, the proposed analytical methodology could help conservators in the challenging analysis of unknown treatments in cultural heritage.


PubMed | Preservation Research and Testing Division and University of South Carolina
Type: Journal Article | Journal: Analytical chemistry | Year: 2015

Audio recordings are a significant component of the worlds modern cultural history and are retained for future generations in libraries, archives, and museums. The vast majority of tapes contain polyester-urethane as the magnetic particle binder, the degradation of which threatens the playability and integrity of these often unique recordings. Magnetic tapes with stored historical data are degrading and need to be identified prior to digitization and/or preservation. We demonstrate the successful differentiation of playable and nonplayable quarter-inch audio tapes, allowing the minimally invasive triage of tape collections. Without such a method, recordings are put at risk during playback, which is the current method for identifying degraded tapes. A total of 133 quarter-inch audio tapes were analyzed by attenuated total reflectance Fourier transform-infrared spectroscopy (ATR FT-IR). Classification of IR spectra in regards to tape playability was accomplished using principal component analysis (PCA) followed by quadratic discriminant analysis (QDA) and K-means cluster analysis. The first principal component suggests intensities at the following wavenumbers to be representative of nonplayable tapes: 1730 cm(-1), 1700 cm(-1), 1255 cm(-1), and 1140 cm(-1). QDA and cluster analysis both successfully identified 93.78% of nonplayable tapes in the calibration set and 92.31% of nonplayable tapes in the test set. This application of IR spectra assessed with multivariate statistical analysis offers a path to greatly improve efficiency of audio tape preservation. This rapid, minimally invasive technique shows potential to replace the manual playback test, a potentially destructive technique, ultimately allowing the safe preservation of culturally valuable content.


Marengo E.,University of Piemonte Orientale | Manfredi M.,University of Piemonte Orientale | Zerbinati O.,University of Piemonte Orientale | Robotti E.,University of Piemonte Orientale | And 5 more authors.
Analytical Chemistry | Year: 2011

The aim of this project is the development of a noninvasive technique based on LED multispectral imaging (MSI) for monitoring the conservation state of the Dead Sea Scrolls (DSS) collection. It is well-known that changes in the parchment reflectance drive the transition of the scrolls from legible to illegible. Capitalizing on this fact, we will use spectral imaging to detect changes in the reflectance before they become visible to the human eye. The technique uses multivariate analysis and statistical process control theory. The present study was carried out on a "sample" parchment of calfskin. The monitoring of the surface of a commercial modern parchment aged consecutively for 2 h and 6 h at 80 °C and 50% relative humidity (ASTM) was performed at the Imaging Lab of the Library of Congress (Washington, DC, U.S.A.). MSI is here carried out in the vis-NIR range limited to 1 μm, with a number of bands of 13 and bandwidths that range from about 10 nm in UV to 40 nm in IR. Results showed that we could detect and locate changing pixels, on the basis of reflectance changes, after only a few "hours" of aging. © 2011 American Chemical Society.


Marengo E.,University of Piemonte Orientale | Manfredi M.,University of Piemonte Orientale | Zerbinati O.,University of Piemonte Orientale | Robotti E.,University of Piemonte Orientale | And 5 more authors.
Analytica Chimica Acta | Year: 2011

A new approach for monitoring the state of conservation of cultural heritage objects surfaces is being developed. The technique utilizes multi-spectral imaging, multivariate analysis and statistical process control theory for the automatic detection of a possible deterioration process, its localization and identification, and the wavelengths most sensitive to detecting this before the human eye can detect the damage or potential degradation changes occur. A series of virtual degradation analyses were performed on images of parchment in order to test the proposed algorithm in controlled conditions. The spectral image of a Dead Sea Scroll (DSS) parchment, IAA (Israel Antiquities Authority) inventory plate # 279, 4Q501 Apocryphal Lamentations B, taken during the 2008 Pilot of the DSS Digitization Project, was chosen for the simulation. © 2011 Elsevier B.V.


Manfredi M.,University of Piemonte Orientale | Bearman G.,CA Technologies | France F.,Preservation Research and Testing Division | Shor P.,Israel Antiquities Authority | Marengo E.,University of Piemonte Orientale
International Journal of Conservation Science | Year: 2015

In this paper a non-invasive quantitative multispectral imaging technique was used for monitoring the degradation of parchment caused by light exposure. The parchment samples were aged for 24, 48, 72 and 120 hours in a weather-ometer ageing chamber to simulate a long term sunlight exposure. The effect of light exposure when a ultra violet (UV) filter is used was investigated. The degradation was monitored by using Light Emitting Diode (LED) multispectral imaging coupled to multivariate statistical methods and infrared spectroscopy, gas chromatography-mass spectrometry (GC-MS) and thermo-gravimetric analysis (TGA) techniques in order to elucidate the mechanism of the parchment ageing and to correlate chemical and imaging data. A description of the effect of light exposure is given: the degradation of collagenous phase and thermo-oxidative phenomena are not involved in the photo-oxidation process and, as expected, the UV radiation accelerates the ageing effects. Moreover the non-invasive imaging methods used for the detection of ageing and the monitoring of the conservation state of the parchment surface were able to identify the nonvisible degradation long before possible detection by other common analytical techniques.


France F.G.,Preservation Research and Testing Division
Materials Research Society Symposium Proceedings | Year: 2011

Developments in non-invasive analytical techniques advance the preservation of cultural heritage materials by identifying and analyzing substrates and media. Spectral imaging systems have been used as a tool for non-invasive characterization of cultural heritage, allowing the collection of chemical identification information about materials without sampling. The Library of Congress has been developing the application of hyperspectral imaging to the preservation and analysis of cultural heritage materials as a powerful, non-contact technique to allow non-invasive characterization of materials, by identifying and characterizing colorants, inks and substrates through their unique spectral response, monitoring deterioration or changes due to exhibit and other environmental conditions, and capturing lost and deteriorated information. The resulting image cube creates a new "digital cultural object" that is related to, but recognized as a distinct entity from the original. The range of data this object contains encourages multidisciplinary collaboration for the integration of preservation, societal and cultural information. © 2011 Materials Research Society.


France F.G.,Preservation Research and Testing Division | Toth M.B.,Preservation Research and Testing Division
European Signal Processing Conference | Year: 2011

The utilization of spectral imaging for the preservation of cultural heritage has allowed the Library of Congress to develop and adapt methodologies to reveal information from degraded ancient texts and objects. Spectral imaging systems provide a powerful tool for non-invasive, non-contact identi-fication and characterization of pigments, inks, substrates and treatments of artefacts, allowing completely non-destructive analyses for research and preservation. Detecting any changes before they are visible enables the assessment and optimization of display and storage conditions for a range of heritage materials. Advanced processing of signifi-cant manuscripts including the Waldseemüller 1507 World Map, Jefferson's draft of the Declaration of Independence, and others have revealed previously non-visible and ob-scured information, recovering lost scientific and cultural knowledge that forms the basis of modern society.


Hyperspectral imaging was originally developed for remote sensing and astronomical applications, but adaptations of this technology have been of great benefit to the preservation of cultural heritage. Developments in noninvasive analytical techniques have advanced the preservation of cultural heritage materials by enabling the identification and analysis of a range of materials, utilizing their unique spectral response to nondestructively determine chemical composition, and determining states of deterioration and change due to environmental conditions. When used as a tool for noninvasive characterization of cultural heritage, these spectral imaging systems allow the collection of chemical identification information about materials without sampling, which is a critical factor for cultural heritage materials. The United States Library of Congress has been developing the application of hyperspectral imaging to the preservation and analysis of cultural heritage materials as a powerful noncontact technique. It allows noninvasive characterization of materials, by identifying and characterizing colorants, inks, and substrates with narrow-band illumination to protect the object while also monitoring deterioration or changes due to exhibit and other environmental conditions. Contiguous illumination from the ultraviolet, visible, and infrared spectral regions allows the capture of lost, obscured, and deteriorated information. The resulting image cube allows greater capabilities for mapping and coordinating a range of complementary chemical and spectral analyses. The capabilities of this technique are illustrated by a review of results from analysis of the Waldseemüller World Map, the L'Enfant plan for Washington, D.C., and the first draft of the U.S. Declaration of Independence. © 2011 Society for Applied Spectroscopy.


Hobaica S.,Preservation Research and Testing Division
Journal of Applied Polymer Science | Year: 2013

Audio magnetic tapes that are difficult to play may be affected by a form of degradation called "sticky shed syndrome" (SSS). SSS exhibits physical symptoms during playing such as squealing, not packing tightly on the reel and possible tape material loss during playing. This research investigated attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to identify spectroscopic markers for SSS in audio magnetic tapes with poly(ester urethane) (PEU) binder layer. This article presents results for applying this technique to 50 audio magnetic tapes from the Library of Congress (LC) collections. This technique and analysis is intended to be used as a tool in identifying audio magnetic tapes with SSS from the mid 1970s through the 90s for improved preservation and to increase workflow in libraries and archives. This ATR-FTIR technique had a success rate of 71% for identifying SSS tapes and 86% for non-SSS tapes. The research also discusses spectral and chemical changes in the PEU binder layer between SSS tapes, non-SSS, and SSS tapes treated by baking including changes in hydrogen bonding of the carbonyl groups. The results support chemical/physical changes occurring in the soft segment of the PEU binder layer of SSS tapes. The absorption ratio of free to hydrogen bonded carbonyl groups was also correlated with SSS. © 2012 Wiley Periodicals, Inc.

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