Spectral Imaging of Shakespeare’s “Seventh Signature”

A guest post by Roger L. Easton, Jr.

One of the many treasures at the Folger Shakespeare Library is a copy of William Lambarde’s Archaionomia, a book on Anglo-Saxon law published in 1568 and acquired by the Library in 1938. Buried amidst the decorative border of the title page is a faded signature that has been judged by several authorities to be from the Bard himself. (All images in this post are taken by the Lazarus team; a digital reproduction of the entire volume is part of the Folger’s digital image collection.)

Visual appearance of f. 1 Recto of Lambarde’s Archaionomia, with detail showing signature

The dominant evidence that supported this view for years has been a reversed photograph of the ink that seeped through to the verso side of the page, where the characters were not obstructed by the printed decoration. The visual appearance of the signature on the verso side is shown, here reversed so that it reads in the legible direction:

Ink showing through from recto to verso side of leaf (image has been reversed left to right)

The value of clarifying the signature on both sides of the page arguably is self-evident. The proposal to image this page was made by Mr. Andrew Henning, a senior in the Sally Barksdale Honors College of the University of Mississippi, as a result of his senior thesis. The trip was organized by Dr. Gregory Heyworth, Associate Professor of English and Head of the Lazarus Project, whose mission is to image culturally important artifacts. Team members included two other students in the Honors College, Kristen Vise and Mitchell Hobbs, Robert Jordan (photographer), Dr. William A. Christens-Barry (Chief Technical Officer of Equipoise Imaging LLC in Ellicott City MD, who designed the spectral illumination panels), and myself.

With the support of Renate Mesmer, the Folger’s Head of Conservation, and the staff of the Library, our team brought a scientific digital camera, spectral illumination panels, and processing computers to the Library on 12-13 March to collect and process images of the front and back of this page. This effort is similar to work previously performed by members of the team on a variety of manuscripts and printed material, including the Archimedes Palimpsest , the 1507 Universalis Cosmographica by Martin Waldseemüller at the Library of Congress, the David Livingstone Nyangwe Diary, and palimpsests at St. Catherine’s Monastery. During our work at the Folger, we hoped at minimum to contribute new evidence that could be assessed by scholars about the authenticity of the signature. If successful, this might also help the Folger assess the value of spectral imaging for use with other books and manuscripts in the collection.

The imaging system illuminated the object with 12 bands of light generated by light-emitting diodes (LEDs) with dominant wavelengths ranging from the near-ultraviolet region (just shorter than the range of visibility of the eye), through the visible spectrum, and into the near-infrared region of the spectrum at wavelengths longer than the eye can see. The digital camera used a 39-megapixel monochrome digital sensor (7216 × 5412 pixels), which has the distinct advantage over a color sensor of utilizing all light reflected from the paper, thus minimizing the exposure of the fragile object.

Since the collection of images just finished as I write these words, we have implemented only the most preliminary processing of the data, but the images provide encouraging results. The processing demonstrated here is based upon the statistics of the pixels over all 12 collected bands. These statistics are used to construct an equivalent set of 12 images from weighted sums and differences of the original bands. The first processed monochrome image includes the widest possible range of contrast over the original 12 bands of data and often resembles the black and white version of a color TV image. The second band shows the widest range of image contrast that is independent of the first. The process is repeated until 12 bands are constructed. Since the highest-order bands include the smallest range of contrast, they often include random variations due to noise. After the processing is completed, objects of similar “color” tend to be grouped together in the processed images, which may allow segmentation of overlapping objects whose appearances differ only in subtle ways. The bands produced from this statistical process are the principal components and the algorithm is principal component analysis.

The first seven (of 12) principal component bands of the front side of the page are shown below; note that the faded signature is readily visible, and separated from the printed decoration, in bands 4, 5, and 6. Some details are more obvious in this image than on the image from the verso side, such as the letter “m” following the flourish of the “W” which is not visible in the reversed image from the verso side.

First 7 (of 12) principal components calculated from the 12 bands of spectral data. Note that the signature is readily visible in bands 3 through 6

To further assist examination of the text, different image bands may be selected for rendering in “pseudocolor,” which then may be varied dynamically by changing the display parameters. This is most usefully performed by the user in real time, but the animation gives some feeling for how the visibility of the text varies with the rendering. Note that different features of the handwritten signature may be more readily visible at different times in the image sequence.

Animation to illustrate variation of the pseudocolor rendering generated from the principal components

We will be very interested to hear any reactions from scholars about the value of these images; these comments will help us improve and adapt the processing. We also look forward to future collaborations with the Library.

ROGER EASTON is Professor at the Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology.

Author: Guest Author

"Guest Author" is the byline used for guests at The Collation, including Folger fellows, program participants, and readers who wish to share their research on collection items. Please see the end of each post for information about that author.


  1. This brings to mind the ongoing problems caused by the Collier forgeries, and the Ireland forgeries before them.

  2. So, did Shakespeare own this book? Some books said to be owned by his contemporaries are signed in this way.

  3. Multi-spectral imaging has many potential research uses beyond the study of Shakespeare’s signature–the Lazarus Project team thought this might be an interesting first foray for them into the early modern period. We’re hoping to use the technology to decipher ownership marks and passages that have been obliterated by later owners, among other things.

    There are many things that are strange about the Archaionomia signature, including its location on a decorative border, the fact that the ink seeped through the paper and is more visible from the back than the front, and the awkward formation of some of the letter-forms. We certainly shouldn’t rule out the intervention of W.H. Ireland or John Payne Collier! In fact, the Lazarus Project is returning at the end of next week to take images of some of our Ireland forgeries, in order to compare “spectral fingerprints.” So the goal of their project (in my mind) is not to authenticate the signature, but to learn more about how this technology can be used to “reveal” text that has been intentionally or unintentionally obscured over the years.

    • In the late 1990s while still a graduate student, I attempted to persuade the Folger to participate in ink tests on the de Vere Geneva Bible, as well as possibly employ photographic techniques (ultraviolet?) that might help faded inks to show better in reproduction.

      At the time, George Anderson, a chemist, even prepared protocols and was ready to raise funds for non-destructive ink testing. The answer from the Folger was an emphatic “We will not do that.” I’m just curious why certain books receive the special privilege of high tech treatment, even when they seem likely to be forgeries, while others that are clearly not forgeries are ruled off limits for any kind of special conservation or documentation procedures. I should think that the Folger would wish to confirm that the inks in the de Vere Geneva Bible are authentically 16th century in origin.

  4. When I start stumbling around the internet by clicking whatever links catch my eye, I never know where I’ll wind up.

    Today I had the good fortune to land on this fascinating article.

    It seems likely this site attracts a rather scholarly crowd. But how fortunate that those of us who snuck out of high school with a C-average can learn from it as well !

    Thanks for providing an online oasis in the desert of my dim-wittedness.

  5. Not much mention of the words written above signature. Any clue what they say?

    The signature very much resembles the Shakespeare signatures found on the famous Northumberland Manuscript.

    As a resident of Oxford, MS, I’m proud to see the local university involved in such a fascinating project.

    • No one has quite worked out what this says, as far as I know. One of the middle words is entirely obliterated due to damage, which makes it even more difficult. The sentence reads something like: “This to be kept for the Impression is [-------] nor [like to] be [renewed?].” I’m particularly skeptical about that last word, so if anyone else has other suggestions, do let the Folger know! One theory is that this sentence has something to do with the many variant states of this edition, and was added by a later collector. The hand seems fairly early though. Even though Lambarde is known to have made corrections to other surviving copies of it, the hand does not appear to be his.

  6. I have heard a rumor that this book contains quite a number of annotations in an italic hand. Is that correct, or have I been misinformed? If so, would it be possible to post some photos of those annotations? Thanks for your assistance.

    • Yes, it does contain some annotations in an italic hand. The book has been fully digitized, available at http://luna.folger.edu/luna/servlet/s/5m030n. See the image for sig. C2v, for example (you can go straight to it by searching for digital image filenmae 53324). So sorry for the delay in answering your question!

  7. Just discovered a great old #Collation entry on using spectral imaging to authenticate a possible Shax signature http://t.co/MaTRaMta3Y

%d bloggers like this: