Dr Christina Duffy explores the use of multispectral imaging at the British Library, and how it recovered erased illustrations from the margins of Add MS 26957, a 15th-century CE Hebrew prayer book.

What are marginalia? Marginalia Marginalia [1] may be part of an original work but can also be added later by scribes, artists or readers to insert corrections, omissions, translations, glosses, annotations, decorations, coats of arms, diagrams, personal notes, doodles, or demonstrations of artistic skill. Marginalia are of great interest to scholars and depending on the nature of the imagery can be viewed as either enrichment or desecration of the original. Layout and decoration of the marginalia can inform us on authorial and scribal practice in particular regions. Historic conservation treatments may have been noted down by conservators as a record of the manuscripts’ past and condition, while more modern shelf marks and institutional stamps may have also found their way onto the margins. Details of ownership including names and dates are often found as annotations on the flyleaves. [2]

Later scholars may have omitted any record of marginalia as it was not considered to be part of the original work and therefore not a requirement for documentation. This has enabled scholars to discover details often found which are not described in the accompanying catalogues.

Many illuminated manuscripts contain marginalia with obscenities and blasphemous or sexual imagery. While certainly interesting to us today, these may have been a cause of embarrassment or thought to be an insult to the original work. Sometimes attempts were made to erase or deface the images by subsequent owners, often leaving unattractive grubby stains in their place. Other erasures were made to conceal true ownership, or alter text which may have had financial or political implications. Once considered lost forever, new imaging techniques such as multispectral imaging are being used to shed new light on these ancient mysteries.

What is multispectral imaging? Multispectral imaging is a scientific imaging technique used at the British Library to non-invasively increase our body of knowledge on collection items for scholars, curators and conservators. It enables us to capture high-resolution digital images of features which are invisible to the human eye by identifying differences in the chemical signature of materials. It allows us to uncover hidden or water-damaged writings, determine origins and provenance, monitor and track colour changes of an item, and highlight other physical characteristics of substrates including paper, parchment and papyrus. It is also used to separate text in palimpsests.[3]

Our multispectral imaging system is comprised of two tripods mounted with LED light panels either side of an imaging table. The item is placed underneath a high resolution camera with a monochrome sensor. The LED light panels enable light of specific colours to be selected. Each colour represents a different wavelength of light. The colours range from ultraviolet at 365 nm to the near infrared at 1050 nm. The human eye can only detect light within the visible region, which is a subset of a much wider spectrum including radio waves and x-rays. Each light colour interacts with ink, pigments, paper and parchment in different ways. A series of images is captured, each one differing slightly under each light colour. Raking light can also be used to aid in text recovery. Raking light uses light from just one of the LED tripods to cast tiny shadows in any regions of surface topography on a page such as folds, tears or bends. This technique can highlight details missing from standard digital images.

Filters are used in combination with lights to capture images of fluorescence. Fluorescence occurs when ultraviolet light falls on organic materials whose molecules absorb the light and re-emit at a different wavelength. This is how glow-in-the-dark materials work; they require a period of light exposure before they are able to re-emit light, or ‘glow in the dark’. The material begins to fade as all of the absorbed light is re-emitted. For cultural heritage imaging, the organic material is usually parchment – a writing material made from animal skins. Parchment absorbs ultraviolet light and begins to glow. This fluorescence of the parchment is blocked where ink resides resulting in the ink appearing darker and more legible. Filters underneath the camera enable us to capture this fluorescence resulting in the production of vivid images highlighting faint inscriptions.

Revealing the hidden margins of a Hebrew prayer book Multispectral imaging was used on collection item Multispectral imaging was used on collection item Add MS 26957, a Hebrew language prayer book (siddur) with Italian rite dating to 1469 CE. Specialist imaging revealed marginalia erasures on ff. 15v and 71r. The prayer book was written by the scribe Joel ben Simeon Feibush showcasing punctuated Ashkenazic square, unpunctuated Italian semi-cursive and punctuated Sephardic square script. The parchment codex, measuring just 140 x 95 mm, contains eight textual drawings in the margins, five drawings of animals or dragons accompanying initial words and numerous decorated initial words and initial word panels. These decorative details are finely drawn with a thin nib, most likely in iron-gall ink.

Prayer book (siddur) Marginal drawing showing a young man holding the maror (bitter herb) and pointing to the word maror at the beginning of the passage ‘This bitter herb’ (Add MS 26957, f. 45v) View images from this item (15)

Usage terms Public Domain

While most of the marginalia are clear to see, there are some regions where just a small trace remains giving a tantalising glimpse into what may lies beneath. This was the case for ff. 15v and 71r and so the manuscript was taken to the imaging lab for multispectral imaging.

Usage terms Public Domain

Prayer book (siddur) Colour image showing the erased decoration in the margin (Add MS 26957, f. 15v) View images from this item (15)

Usage terms Public Domain

Under ultraviolet light a figure was discovered in the margin of f. 15v. A man wearing a crown and pointed shoes is observed resting his head on his right hand. He appears contemplative with a banner drawn overhead filled with text.

Prayer book (siddur) Ultra-violet image of the erasure showing a figure resting his head on his hands with a banner overhead (Add MS 26957, f. 15v) View images from this item (15)

Usage terms Public Domain

On f. 71v another figure was discovered in the margins. Here a wide-eyed young boy is depicted with a hat decorated with a feather. The boy is playing a hunting horn which he balances against his face with his right hand. No details of the lower half of this figure were recovered, so it is likely that this was an unfinished drawing.

Usage terms Public Domain

Prayer book (siddur) Colour image showing the erased decoration in the margin (Add MS 26957, f. 71r) View images from this item (15)

Usage terms Public Domain

Prayer book (siddur) Ultra-violet image of the erasure showing a figure playing a horn (Add MS 26957, f. 71r) View images from this item (15)

Usage terms Public Domain

While the significance of these figures is still under investigation, it is clear that multispectral imaging is successful both as a preservation tool and for enabling scholars to interpret our collection without damaging it. An important part of running a multispectral imaging system is the management of data. Even if images captured do not immediately reveal faded or lost text, they can be processed using techniques such as Principal Component Analysis[4] to further refine legibility. Other image processing techniques can be applied to the images to enhance particular features. For example, an infrared light image where ink is all but invisible can be assigned a colour and blended with an ultraviolet image assigned to another colour. These pseudo-colour images provide scholars with a clearer view of the faded information.

Textual marginalia often reveal the reader’s immediate response to a text. These notes can be considered a documentation of the student’s or scribe’s thought process. Illustrative decorations in the margins are powerful additions which can shift our interpretation of the corresponding body of text.

Modern research and the move to digital scholarship have removed the need to scribble in the margins. All the more reason why these ancient and erased marginalia mysteries are so fascinating to us.

Footnotes Latin for ‘things in the margin – refers to handwriting or decoration found in the margins of a manuscript

A blank page at the beginning or end of a book

Centuries-old reused texts with the original writing scraped away to make way for new (and often less significant) content

A method of analysis which involves finding the linear combination of a set of variables that has maximum variance and removing its effect, repeating this successively

Written by Christina Duffy

Christina Duffy is the British Library’s Imaging Scientist on the Conservation Science and Research team in Collection Care. She graduated with a degree in Physics with Astronomy from Dublin City University before completing a PhD on Meteoritics and Planetary Science from Imperial College London. Her final thesis Characterising Primitive Chondrite Components describes a range of analytical techniques applied to meteorite samples in the process of classification. Christina uses a range of imaging techniques and post-processing methods to enhance and recover faded or lost information from British Library collection items.