Background:
When we look at a document, what we normally see is not necessarily all that is there. The unaided eye cannot always identify important characteristics such as colorants, or detect features such as inks that are erased, hidden by overwriting or varnish, or faded because of environmental factors. Such features on photographs, manuscripts, maps, and other materials are often important for scholars, authentication, “fingerprinting” and the care of collections. Looking at documents at various magnification levels and in various types of light (raking, transmitted and different wavelengths) can capture these elusive features. The application of hyperspectral imaging to the preservation analysis and study of paper, parchment and other materials is a powerful, non-invasive, non-destructive technique to assess treatments, colorants and environmental factors. Imaging with LED lighting, in 16 spectral bands and raking light for preservation studies, provides a system with safe conservation lighting that is integrated with the camera to minimize light on the object. Hyperspectral images have been used to analyze the Waldseemüller 1507 world map, the L’Enfant plan of Washington D.C., the rough draft of the Declaration of Independence and many other significant Library collection items.
Contributing Study:
The Archimedes Palimpsest Project 
Project Description: High resolution hyperspectral imaging (HSI) measures the spectrum from ultraviolet, through visible to infrared and can detect variance at any wavelength or combination of wavelengths. The images in this image cube can be digitally combined with or subtracted from each other to form images for precise analysis. This allows components to be characterized based upon their specific spectral response, discriminating between similar compounds, identifying and possibly quantifying materials present in the image. HSI allows the establishment of baseline data where deterioration assessment techniques can be linked to micro-analysis. The accurate determination of parameters associated with inks, pigments, colorants and base materials over time from a baseline response without sampling is critical to the assessment and preservation of many international items of cultural heritage. This provides essential information and data for object investigation and authentication in analyzing the ink composition, and layers of information retained on the document or object.
Instrumentation Analysis Resources (for the hyperspectral instrumental information)
Outcomes/Findings:
Imaging has allowed for a range of analyses to be undertaken:
- Capturing hidden and previously unknown information from historic documents
- Identifying the response of specific characteristics of the maps, including printer inks, pigments, iron gall, effects of treatments, and other aspects
- Tracking changes due to the impact of environment or conservation treatments before these can be observed with the unaided eye
- Using raking-incidence illumination to enhance the visibility of any “topographic” features, e.g. relating to the wood block printing of the Waldseemüller map and any other mechanical contact
- Using advanced processing techniques such as principle component analysis and multivariate analysis to create pseudocolor images to map specific components, and regions of interest
- Development of new protocols for imaging of watermarks, substrate features and other areas of interest
- Establishment of standards for the integration of data for digital access, with defined metadata and robust processes for validating and refining data into a central repository and archive to the production of digital data for preservation and analyses
Support: Library of Congress Preservation Directorate
Acknowledgements: The team from R.B. Toth Associates; Michael B. Toth, Dr. Roger Easton (RIT). Dr. William Christens-Barry (Equipoise Imaging), Dr. Keith Knox (Boeing), Douglas Emery (Emery IT), Kenneth Boydston (MegaVision)
Update and Images:
August 2013: Fenella France presented a keynote at “The 26th International Cartographic Conference”, Dresden, Germany, entitled "The Waldseemüller Map - A Gift of Germany to the World".
April 2013: Fenella France presented a paper at The Imaging Science and Technology Conference, Washington, D.C., entitled “Access and Preservation: Addressing Challenges of Linking Cultural Heritage Datasets”.
July 2012: Fenella France presented an invited presentation at the Eighth Islamic Manuscript Conference, Cambridge, U.K., entitled “Technologies that Reveal Links between Science and Manuscripts of Science”. January 2009: A paper on the new integrated camera technology was presented at SPIE in San Jose, CA.
June 2009: A paper on the “digital cultural object” was presented at Digital Humanities in College Park, MD
