Roger L. Easton, Jr.
revised 30 September 2016

Imaging of Historical Manuscripts
I have worked for several years of the application of modern imaging technologies to recover writings from historical manuscripts. I started in this work as a collaboration with the late Dr. Robert Johnston of RIT and Dr. Keith Knox, formerly of Xerox Corporation in Rochester, NY and now retired from the USAF Research Laboratory in Kihei, HI. Our early activity concentrated on the Dead Sea Scrolls, but most of my effort now is devoted to imaging of the Archimedes Palimpsest and the Sarvamoola granthas.

The work involves both collecting the spectral imagery and processing it. We use the Megavision imaging system ( for collecting 50Mp data at a variety of wavebands in  reflection, transmission, and fluorescence.

The image datasets are processed to look for combinations of the bands that enhance the feature(s) of interest, often erased "undertext" of a palimpsest. The primary processing software tool is ENVI from Harris Geospatial, which has a variety of useful tools for statistical spectral analysis (principal component analysis - PCA, independent component analysis - ICA, minimum noise fraction - MNF, among others). Image renderings are also adjusted using Adobe Photoshop.

Many new projects are not considered here as yet, including work on the Syriac-Galen palimpsest, the palimpsests from the "New Finds" at St. Catherine's Monastery, the 1491 Martellus Map at the Beinecke Library at Yale University, the Waldseemüller Map at the Library of Congress, Les Échez d'Amour, and others.

Archimedes Palimpsest  

  098v-102r    098v-102r_sharpie
   Images of f.098v-102r before and after processing. Copyright retained by the Owner of the Archimedes Palimpsest

Archimedes Data Sites
The entire dataset from the Archimedes Palimpsest is available online, posted under a Creative Commons Attribution 3.0 Unported License.

Official Project Webpage:

Official Project Data:    (note carefully that the TIFF files posted here are NOT the original 16-bit data, but rather 8-bit compressed files. I urge STRONGLY that anyone wishing to process the image data access the files from the "Data Site" listed below).

RIT pages: The first two sites are intended for viewing and contain JPEG-compressed files with an interface that is intended to be user friendly.
            Webpage for original (pre-2007) project data in JPEG format:

            Webpage for final (2007) project data in JPEG format for viewing:

            Data site with original 16-bit TIFF images for image processing:

I led the imaging team for this project that had the goal of helping scholars read the original text in the Archimedes Palimpsest, which is a 10th-century manuscript containing the oldest copies of seven of Archimedes' treatises. Included among these is the only known copy of a treatise generally known as "The Method of Mechanical Theorems," where Archimedes described his use of physical analogues to prove mathematical hypotheses. This treatise may be renamed based on readings of the title from the images in this project. Videos describing the work are now available on YouTube, including a description of my part of the effort.

The original manuscript was copied onto pages of parchment (treated animal skin) from an earlier manuscript that may have been a papyrus scroll -- the parchment manuscript is formatted in columns as a scroll would have been. The leaves of the original Archimedes codex were approximately the size of a sheet of standard notebook paper. The pages were bound into a book and kept in a library in Constantinople (now Istanbul).  In those days, parchment writing materials were so valuable that they were commonly reused when the book was considered "out of date" or if the subject was judged inappropriate or less valuable.

The book was disbound and erased in the 12th century, probably after Constantinople was sacked in April 1204 during the Fourth Crusade. The pages were erased by scraping the ink off with a solvent (perhaps orange juice), cut in half down the center, and rebound as a smaller book, along with pages from other important writings, including speeches by the Attic orator Hyperides and a commentary on Aristotle's "Categories" by Alexander of Aphrodisias (news featured on the websites of the BBC and National Geographic). The pages were overwritten with the text of a Christian prayer book, the Euchologion. Such overwritten manuscripts are called palimpsests, from the Greek word palimpsesto ("scraped again").  From the image of the colophon of the Euchologion made during this project, we have found that the prayer book was dedicated on April 13, 1229.

The book spent the next 700 years at various religious shrines in the holy land. Its existence first became known to western civilization in the middle 1800s when its existence was recognized by Constantin von Tischendorf, who is better known for discovering the Codex Sinaiticus (a Greek manuscript of the Bible) at Saint Catherine's monastery on Mount Sinai. The Archimedes Palimpsest was studied extensively by Johan Ludvig Heiberg in 1906. The translation of Heiberg's transcription of Archimedes' treatise The Method has been posted on Google Books. 

After Heiberg's work, the book disappeared again and was feared lost until it resurfaced in the late 1990s. It was sold at auction by Christies in 1998 to an anonymous American collector, who has made the book available for study. An international team of scholars, conservators, and imaging scientists is currently studying the palimpsest to recover the original writing.

The investigation and significance of the Archimedes Palimpsest is the subject of the program "Infinite Secrets" broadcast by PBS on NOVA on 30 September 2003. A low-resolution copy of the program is currently available on YouTube in six segments  (1, 2, 3, 4, 5, 6 -- the imaging work is described in segment #5). The DVD is available from many vendors, including the WGBH store and

The work was selected as one of the imaging "Solutions of the Year" by Advanced Imaging Magazine in January, 2003.

So far, we have successfully extracted approximately 80% of the text using multispectral imaging, which combines images taken under a variety of conditions and at different wavelengths. We also are using more exotic techniques to try to read the remaining text, including x-ray fluorescence imaging (XRF) at the Stanford Synchrotron Radiation Laboratory. Some photos of the process at SSRL are shown here. An article by Mary Miller that focused on the XRF imaging was published in Smithsonian Magazine in March 2007.

Another imaging session was held at the Walters Art Museum in Baltimore on 11-21 November 2006, including experiments with a large-format digital back (Leaf Aptus, 32 Megapixels) lent by Leaf Imaging (thanks to Kevin Stuts of Leaf for his essential assistance), an experimental imaging spectrometer supplied by Greg Bearman of JPL, and experiments with raking-light and LED illumination. Dr. Jud Herrman from Allegheny University was there and able to give quick feedback on the usefulness of the images to read the writings of Hyperides. A report on Jud's effort was published in the New York Times and the International Herald-Tribune.

The entire manuscript was imaged in August 2007 at the Walters Art Museum using light-emitting diode illumination (LEDs) fabricated by Bill Christens-Barry of Equipoise Imaging LLC and a camera system from Stokes Imaging. Most of the text was recovered by applying a deterministic technique of pseudocolor rendering that was developed primarily by Keith Knox. Text on the leaves of the commentary on Aristotle were recovered by a statistical technique implemented by Kevin Bloechl, then a first-year undergraduate in the Carlson Center for Imaging Science.

The raw and processed images are now posted on the Archimedes Palimpsest website, though the original 16-bit data are available on a different site ( The original pre-2007 data are available online at and the final data with a user-friendly website are online at

cover of "The Archimedes Codex"      

The Archimedes Codex, by Dr. Reviel Netz of Stanford University and Dr. William Noel of the Walters Art Museum was published in the UK on 10 May 2007 and in the USA in September 2007. The paperback is now available. The book covers the history of the Archimedes Palimpsest and the efforts made to read the text

The palimpsest was the subject of cover stories in the British Institute of Radiology News in Winter 2006 and in the Los Angeles Times on December 26, 2006. It was featured in RIT's "University Magazine" in Spring 2007.

Additional information is available at the Archimedes Palimpsest website, the cover story in the London Sunday Times Magazine of 17 June 2001, the cover story in Physics Today, of June 2000, and in an ABC News Report on 20 October 2000. Will Noel, Mike Toth, and I presented a talk at the Googleplex in Mountain View, CA, on 7 March 2006 that is available on YouTube. 

Will Noel and I presented the talk  Infinite Possibilities: Eight Years of Study of the Archimedes Palimpsest as part of the Walter L. Robb Symposium for Promoting Useful Knowledge for the American Philosophical Society in Philadelphia on 25 April 2007.  The webcast has been posted.

Military History Quarterly published an article about the significance of the Hypereides speech On Diondas about the Battle of Chaeronea in 480 BCE in the issue for Winter 2008 (Vol. 20, #2, pp. 28-35).

Natalie Tchernetska of University of London, Eric Handley of Trinity College Cambridge, Colin Austin of Trinity Hall Cambridge, and László Horváth of ELTE Eötvös József Collegium, Budapest, published "New Readings in the Fragment of Hyperides' Against Timandros" in Zeitschrift für Papyrologie und Epigraphik, 162, p. 1, 2007.

Will Noel's discussion of The Archimedes Codex on BookTV is available on the BookTV website.

Will Noel and Reviel Netz discussed The Archimedes Codex on a  podcast of "The Writing Show" by Paula B, which also is available in the podcast section of the iTunes Store.

K-12 Activity based on the Archimedes Palimpsest

Diane Kucharczyk, formerly an undergraduate student at the Chester F. Carlson Center for Imaging Science, and Russell Knox, then a student at Brighton High School, NY, developed a K-12 classroom activity based on the work to extract text from the Archimedes Palimpsest. This is available as an HTML Powerpoint file.

The Stomachion    001v-002r, Copyright retained by the Owner of the Archimedes Palimpsest
This treatise in the Archimedes Palimpsest had been thought to describe a game similar to "Tangrams". Reviel Netz of Stanford University has suggested that the Stomachion really is about geometrical "combinatorics", which is the study of the number of combinations of shapes that produces a specific result. This work was reported in a cover story in the New York Times of December 14, 2003.

X-Ray Fluorescence Imaging at the Stanford Synchrotron Radiation Lab (SSRL)

Uwe Bergmann of the Stanford Synchrotron Radiation Laboratory (SSRL), which is part of the Stanford Linear Accelerator Center (SLAC), is leading the effort to image the most difficult and important pages of the Archimedes palimpsest using X-Ray Fluorescence (XRF). A page of the palimpsest is raster scanned through the X-ray beam. The X rays are "scattered" by atoms in the palimpsest; the incident X ray ionizes an inner shell electron from the atom and another electron drops into the resulting "hole" while releasing another lower-energy X-ray photon.  The energy of the emitted photon is characteristic of the ionized atom. In this way, a map of the constituent materials in the palimpsest may be constructed. The results obtained thus far have been very encouraging, allowing much previously unreadable text on the first folio to be read.

Two imaging sessions have been held at SSRL-SLAC and two more are planned. In the session in March 2006, the name of the scribe who copied the Euchologion was read. The imaging run is rather intense, because the system is running 24/7 for nearly two weeks.

XRF of Stub, Copyright retained by the Owner of the Archimedes Palimpsest  Example of XRF imaging of a stub of an Archimedes leaf (click for larger image). The visible and pseudocolor images of the verso side show no text at all, but writings from BOTH sides of the page are visible in the the XRF image. There is a fragment of a diagram on the verso side (shown in white) and characters on the recto side (shown in cyan).

maging at SSRL in March 2006

Imaging at SSRL in July-August 2006

The Archimedes Palimpsest Imaging Team joined with SLAC and the Exploratorium in San Francisco to webcast the X-ray fluorescence imaging of the palimpsest at SLAC on August 4, 2006. The Exploratorium has a very nice website on the palimpsest, and the archived webcast is available in Real and Windows Media formats at the Exploratorium webcast website. A number of news stories were filed on the imaging run, including two by the San Francisco Chronicle (one on the imaging, one on the webcast), National Geographic News,  the Baltimore Sun, and the San José Mercury-News, and others.

Archimedes Imaging Sessions

Imaging at WAM, November 2006

Imaging at WAM, August 2007

Archimedes Conference in Budapest, September 2007

 Sarvamoola granthas:

Image of one palm leaf
An image of one side of one page of the Talavakara, one of the palm leaf manuscripts, after processing and digital stitching. The image has been subsampled from its original width of 14000 pixels.Click on the image to view a larger zoomable image.

Shri Madvacharya (1238-1317) was a philosopher whose ideas had a profound impact on Indian society. His philosophy, known as Dvaita, is a synthesis of ideas from other holy texts that believes that the structure of the spirit serves as the backbone of the diversities of the world. His insight shows the importance of logic and faith in God to mankind. He authored several works including 36 that are collectively called Sarvamoola granthas. These manuscripts were incised on palm leaves using a metal stylus and the characters filled with ink. The manuscripts were stored at several monasteries in and near the town of Udupi on the western coast of India in the state of Karnataka. Unfortunately, in the ensuing 700 years, many of the original manuscripts were lost or damaged by deterioration of the palm leaves. The only remaining copy is stored at Sri Krishna Temple in Udupi.

In the summer of 2005, Dr. P.R. Mukund of the Department of Electrical Engineering at RIT proposed a collaboration to image this remaining copy, which is comprised of approximately 350 palm leaves. Dr. Mukund, Dr. Keith Knox, and I traveled to Bangalore and Udupi in December, 2005 to perform some preliminary imaging experiments. This was the first trip to India for me, Keith, and Keith's wife Dale Stewart and was a wonderful experience. Everyone we met was very nice to us. We flew back to Bangalore and drove to Udupi to image the entire manuscript in June 2006, taking more than 7500 digital images of both sides of 336 leaves in five days. Keith, Dale, and I flew to Delhi afterwards to visit the sights in Agra, including the Taj Mahal,

This project has been very rewarding. Keith, Dale, and I were able to help preserve writings of great significance to many millions of people who were genuinely appreciative of our efforts. We also were introduced to a very rich culture (and, not incidently, wonderful food!) that was completely new to us and we met many unforgettable people. The entire experience has been a gift of grace.

The work was described in articles published by MSNBC, Ascribe, the Rochester Democrat and Chronicle, The Times of India (Bangalore), and the BBC (note photo of Ajay Parsupeleti and Keith Knox). It was featured in RIT's University Magazine in Spring, 2007.

Trips to Udupi

    Imaging at Udupi in December 2005

    Imaging at Udupi and trip to Taj Mahal in June 2006

    Imaging in Bangalore, November 2007 (et seq.)

Martellus Map (1490)
Martellus Map
The "Martellus 'World Map" dates from circa 1490 and probably was consulted by Christopher Columbus before his first voyage. The text on the map, which is on linen-backed paper, was written using many different colors of pigment and most has faded to the point where it cannot be read.

Martellus Imaging Team
Under the direction of Chet Van Duzer, the team of Ken Boydston of MegaVision, Inc., myself, Michael Phelps of the Early Manuscripts Electronic Library (EMEL), and Gregory Heyworth at the University of Mississippi, imaged the world map by Henricus Martellus Germanus at the Beinecke Library at Yale University in August 2014. The images were processed over the next six months and reveal significant text that had been lost. Examples of text in Africa and in Asia are shown below; note the difference in appearance of the processed images because of the different algorithms required for the different colors of pigment in the writing.

Martellus Africa Processing
Martellus Asia Processing


Some results are expected to be published in Smithsonian Magazine in May, 2015 and Chet Van Duzer is about to submit a book on the map that will include new results obtained from the imaging.

Waldseemüller Map:

The Waldseemüller Mapis a wall map of the world by Martin Waldseemüller in 1507 that is now on display at the Library of Congress. This map and the Martellus map just mentioned have significant similarities and differences. A team of imaging scientists and conservators imaged this map to assess its baseline condition in November 2007. Some photos of the imaging session are available online. A video story about the map also has been posted.
Waldseemuller Map (small)

Previous Work on other Manuscripts

Temple Scroll:
The Temple Scroll was discovered in 1947 in Cave 11 near Qumran. It is the longest of the Dead Sea Scrolls -- originally 28' long in 67 columns. We processed color transparencies of images taken by Bruce and Ken Zuckerman. We projected the 3-D color data at each pixel (i.e., the RGB gray values) to an opponent color space (luminance, red-green, and blue-yellow) From these images, we have been able to distinguish 18 characters that had not been recognized previously by Biblical scholars.Our efforts to clarify the so-called Temple Scroll were reported in an article "Imaging the Dead Sea Scrolls" in Optics and Photonics News, 8(8), pp. 30-34, August 1997.  This article was awarded the Archie Mahan Prize for the best paper published in in OPN that year.

Mar Athanasius Samuel Fragments:

Samuel Fragment

In 1997, Dr. Robert Johnston arranged with Dr. James Charlesworth of Princeton Theological Seminary for us to image several fragments of the original cache of Dead Sea Scrolls, which were discovered near Qumran in 1947. The original scrolls were purchased by Mar Athanasius Samuel, who was the Syrian Orthodox Archbishop in Jerusalem in 1947. He kept several fragments and bequeathed them to the Syrian Orthodox Cathedral in Teaneck, NJ, where they were in the custody of Father John Peter Meno. The fragments are encased between sheets of glass and thus may not be imaged using ultraviolet light.

We took Bob's first-generation Kodak DCS-100 digital camera to the library of the seminary, with a resolution of 1280 ×1024 8-bit monochrome pixels (1.3 Megapixels). Father Meno brought the fragments from Teaneck.  As shown in the images, portions of each fragment were darkened by damage and difficult or impossible to read. As it happens, the reflectance of the darkened parchment is larger in the near infrared region of the spectrum. By using an infrared-transmitting filter over the camera lens, the contrast of the text in the damaged region is restored.

Images of Mar Athanasius Samuel Fragments

Khaboris CodexKhaburis p.008

The Khaboris Codex is the oldest known copy of the New Testament written in the original Aramaic, dating from the 10th century. We worked with Michael Ryce to image the manuscript and develop a public website where the images would be available for scholarly study. A webpage with the pages of the manuscript is available at

Colophon from a Siddur from Florence, Italy:   Florentine siddur

We have collaborated with Evelyn Cohen from the Jewish Theological Seminary of America to reveal the writing on the Colophon (which is a page of dedication from the scribe to the patron) of a Hebrew Siddur copied in Florence, Italy. Evelyn published a paper on the significance of this work, Gallico's Identity Exposed: Revealing an Erased Colophon from a Renaissance Prayer Book, Ars Judaicapp. 85-90, 2005.

A short summary of this work is available as a PDF document.

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