Collection Care blog

Multi-spectral imaging at the British Library has revealed a figure, in previously unseen detail, on a folio of a notebook belonging to Leonardo da Vinci. Da Vinci expert Professor Martin Kemp believes the sketch may be part of a series of 'fugitive images' occasionally unearthed on da Vinci's work.

Figure 1: A comparison of the erasure as seen by the naked eye (left) and the revealed figure (right) after multi-spectral imaging.

Leonardo da Vinci (1452 – 1519) was a prolific note-taker with over 7,000 pages of his thoughts surviving today. The British Library is custodian of a notebook known as Codex Arundel 263 after its English collector Thomas Howard, 14^th Earl of Arundel. These notes and sketches come from different periods in da Vinci's life, though most date to 1508, and cover a range of topics including mechanics, astronomy, optics, architecture and the flight of birds.

Codex Arundel 263 was not originally a bound volume, but was put together after his death. The variation in folio type and size show how many of da Vinci's ideas, studies and inventions were observed outdoors as he went about his day. The notes are written in Italian showcasing his famous left-handed mirror writing. Folios 137v and 136r, housed together and currently on display in the British Library Treasures Gallery, were taken for multi-spectral imaging analysis to enhance and potentially reveal a hidden sketch in a small area of discolouration visible in the lower half of folio 137v.

Figure 2: Imaging Scientist Dr Christina Duffy with Codex Arundel 263.

The smudge measures no more than 6 x 3 cm and has been suspected by scholars to contain an elusive sketch of a figure by da Vinci - possibly erased by himself.

Figure 3: Codex Arundel 263 folio 136r and 137v showing notes, calculations and diagrams including a mechanical organ and timpani/drums.

The analysis took place at the British Library Centre for Conservation where high resolution images of the folios and region of interest were captured. Multi-spectral imaging is one of the many tools our Conservation Science team use to non-invasively and non-destructively increase the body of knowledge on collection items for scholars, curators and conservators. The da Vinci sketch was placed underneath the monochrome sensor camera and exposed to light of various wavelengths ranging from the ultraviolet at 365 nm to the near infrared at 1050 nm.

Figure 4: The Multi-spectral Imaging system is based in the British Library Centre for Conservation. 

These wavelengths reside on what is known as the Electromagnetic Spectrum - a wide spectrum encompassing radio and X-rays. The human eye can only detect light within the visible region of this spectrum limiting our ability to see potentially faded or invisible information. Multi-spectral imaging therefore enables the capture of detail which we cannot see with the naked eye.

Figure 5: The British Library imaging system acquired multiple images of the folio at several different wavelengths from the ultraviolet to the near-infrared.

Filters placed underneath the camera's lens were also used in combination with the lights to capture images of fluorescence resulting in the generation of vivid images highlighting the fugitive figure on folio 137v. The images raise fascinating questions about why the figure was drawn here, and why great efforts were made to erase it.

Figure 6: This pseudocolour image was generated by combining three monochrome multi-spectral images captured using ultraviolet light with a red, green and blue filter respectively.

Multi-spectral imaging is an incredibly exciting process and has revealed many secrets from our collections to date, including recovering once thought lost text from the 'Burnt Magna Carta' last year. It is an incredible privilege to work with some of the world's most valued treasures and subject experts. Everyday brings new discoveries to light (quite literally!) and the prospect of unlocking more secrets from the British Library's vast and varied collections is thrilling.

The entire Codex Arundel notebook has been digitised and is available to view online. 

Dr Christina Duffy (@DuffyChristina)

The British Library conservation team that worked on the Magna Carta project attended a glamorous awards ceremony at the Institution of Mechanical Engineers last night. The team were shortlisted for the Institute of Conservation (ICON) Anna Plowden Trust Award for Research and Innovation, which went to Tate for their impressive Rothko Conservation Project. A huge congratulations to the Tate team and to the Imperial War Museum who were also in our category for their amazing space vacuums, air bazookas and duster drones project in the War Against Dust.

Left to right: Cordelia Rogerson, Christina Duffy, Gavin Moorhead, Julian Harrison

The Magna Carta Project was a collaborative process of sophisticated research and innovation that enabled a pragmatic solution for rehousing and displaying an iconic document. Our biggest challenge was overcoming long held preconceptions and expectations that a high profile artefact required an expensive high-tech approach. You can read more about our work here.

It has been a great privilege to work with Magna Carta and the curatorial team in the build up to the British Library's most successful exhibition Magna Carta: Law, Liberty, Legacy.

Many thanks to all colleagues across the British Library and other institutions who helped progress the project into something we are all very proud of. Thanks to ICON and their sponsors Beko for organising a terrific night celebrating an incredible range of conservation work going on around the UK.

Congratulations to all the entrants, shortlistees and winners!

Christina Duffy

A CT scan of the St Cuthbert Gospel – the earliest intact European book dating to the early eight century - has been published in a ground-breaking new book launched this week: The St Cuthbert Gospel: Studies on the Insular Manuscript of the Gospel of John, edited by Claire Breay, Head of Ancient, Medieval and Early Modern Manuscripts at the British Library, and Bernard Meehan, Head of Research Collections and Keeper of Manuscripts at Trinity College, Dublin. Colleagues from Collection Care and Medieval Manuscripts took the pocket gospel to the Natural History Museum for CT analysis to understand the structure of the ancient gospel, which was found inside the coffin of St Cuthbert in 1104.

Figure 1: The British Library project team at the Natural History Museum. From left to right: Claire Breay, Flavio Marzo and Christina Duffy.

X-ray computed tomography (CT) is a non-destructive technique which creates 2-D cross-sectional images from 3-D structures. The St Cuthbert Gospel was scanned using a Metris X-Tek HMX ST 225 CT scanner with an operating voltage of 225 kV at the Natural History Museum.

To protect the gospel during scanning it was placed inside a custom-made phase box and then secured upright in a bespoke piece of polyethylene foam.

Figure 2:  The St Cuthbert Gospel was placed in a phase box which was secured in a piece of foam.

A facsimile of the gospel produced by Jim Bloxam and Kristine Rose was generously made available to the team during the CT scan. This enabled a direct comparison of materials known to be used in the facsimile with those unknown in the original St Cuthbert Gospel. Both volumes were placed inside the CT chamber on a precision rotation stage between an X-ray source and a detector.

Figure 3:  The two copies were placed side-by-side in the CT chamber.

As the volumes rotated on the stage through 360⁰ a conical beam of X-rays took digital projections in 0.5⁰ increments. The CT image pixels are displayed in terms of their relative radiodensity allowing us to scroll through the image slices revealing the materials underneath the leather binding.

Figure 4:  The results were poured over in the lab. From left to right; Christina Duffy, Claire Breay, Nicholas Pickwoad and Dan Sykes.

The results were initially examined by the British Library team and Professor Nicholas Pickwoad, whose chapter in the new publication draws on the CT scan results and discusses how the central motif on the binding appears to have been made using a clay-like material, rather than gesso or cord as previously thought.

Figure 5:  The St Cuthbert Gospel with raised plant-motif decoration examined under high magnification.

Figure 6: Analysis of the internal structure of the binding.

CT datasets contain vast amounts of information and samples can be visualised in many ways using various software tools. Drishti, which stands for vision or insight in Sanskrit, is an open source volume exploration and presentation tool. It allows volumetric data sets to be both explored and used for presentation of results.

Figure 7: A screen shot showing the St Cuthbert Gospel as visualised in Drishti.

CT scanning can provide tremendous amounts of information on the condition and construction of books and their bindings. This level of detail is unavailable through visual examination and can often lead to speculation. More information about the project can be found over on the Medieval Manuscripts blog. The new publication, The St Cuthbert Gospel: Studies on the Insular Manuscript of the Gospel of John, can be bought in the British Library shop or ordered online.

Christina Duffy (@DuffyChristina)

We’re delighted to announce that the conservation team behind the work done on the British Library collections in our latest exhibition Magna Carta: Law, Liberty, Legacy will be speaking at a public event on Friday 26 June 2015 18:30 - 20:30 to share their findings. Speaking on the night in the British Library Centre for Conservation will be Head of Conservation Cordelia Rogerson, conservator Gavin Moorhead, conservation scientist Paul Garside and imaging scientist Christina Duffy. Book your place here.

Join our project team of conservators and scientists on 26 June 2015.

The project spanned over three years in preparation for this year’s 800th anniversary of the 1215 Magna Carta and involved the reframing and scientific analysis of all of the Magna Carta charters held in our collections, including the two 1215 original versions.

Conservator Gavin Moorhead works on the 1215 Articles of the Barons (Additional MS 4838).

The team undertook an initial examination of the original frames to determine their structure and composition. At the event you’ll hear how probes were manually inserted into the frames to take samples of the air inside in order to determine what kind of micro-environment the charters were living in! The stability and compatibility of new materials, which would be used for mounting in the new frames, was ensured using infrared spectroscopy, pH tests, and lignin tests.

Mounting materials were tested before incorporation into the new frames. Join us to find out what the blue and red colours indicate.

With the frames removed the team had a rare opportunity to investigate the condition of the manuscripts using near-infrared spectroscopy and high resolution digital microscopy. Unpublished images of the ink and parchment at up to 200 times magnification will be shared with the audience.

What does 800-year-old ink look like at 200 times magnification? 

You will also delve deep into the exciting world of multispectral imaging and see versions of the charters and their seals under ultraviolet and infrared light. The incredible results of the text recovery project on the damaged 1215 Canterbury Magna Carta, from which much of the ink was lost, will be shared.

Once our tests were complete it was time to rehouse the charters – you’ll hear from our conservator Gavin Moorhead about the challenges and decisions required to mount for display one of the most recognised manuscripts in the world which would feature as the dramatic finale to the exhibition.

The British Library's London Magna Carta at our exhibition, Magna Carta: Law, Liberty, Legacy.

Don’t miss out on this great event and book your place now! We look forward to meeting you!

Christina Duffy

With the recent multispectral imaging of the burnt Magna Carta hitting the headlines following our blog post on the 800 year old Magna Carta revealing its secrets, there has been a lot of interest in the conservation work required to protect such items. The so-called “burnt” Magna Carta (Cotton charter xiii 31a) suffered fire damage in Ashburnham House in Westminster on 23 October 1731. This 1215 exemplification formed part of an exquisite library assembled by English antiquarian Sir Robert Cotton during his lifetime (1571-1631). Cotton’s library forms the basis of our collections at the British Library today, and a recent conservation survey of the burnt material has allowed us to categorise items based on their relative condition, enabling us to immediately identify items suitable for digitisation. This has vastly improved our workflow allowing digital access to a wider audience in a shorter time. 

This piece includes material from an article published by Taylor & Francis Group in Journal of the Institute of Conservation on 29 November 2013, available online at: http://www.tandfonline.com/doi/abs/10.1080/19455224.2013.815122#.VFDzZvmsWtB.

The burnt 1215 Magna Carta suffered fire damage and subsequent interventive treatment. The vulnerable wax seal of the charter melted and distorted in the intense heat. 

 

In the Ashburnham House fire a quarter of the manuscripts were either damaged or destroyed in the blaze, and attempts to extinguish it exacerbated that damage. The documents suffered shrinkage and distortion, bindings were carbonised, ink was lost, soot and dirt was ingrained, tide marks formed on the leaves, and parchment (animal skin) gelatinised. Gelatine is the brownish end-product of a rapid degradation of parchment collagen. Remedial work caused further damage with many of the manuscripts broken up and rebound during salvage. Incorrect reassembly impacted on the codicological history of many of the manuscripts. The darkened gelatinous material which formed along the edge of the parchment was trimmed away from some manuscripts. Unidentified fragments were gathered and put into drawers.

The collection was untouched until the establishment of the British Museum in 1753, where over the coming years invasive treatments were recorded. To separate the leaves which had glued together by gelatinisation, about 40 manuscripts were immersed in a hot aqueous solution (likely to be ethanol in water). Incisions along the parchment edges were made to allow the leaves to dry flat under pressure. Despite the efforts, leaves remained brittle and fragile. Inlaying of parchment fragments into paper was completed in 1856, but a huge number of fragments remained loose and unidentified. While the edges of loose fragments were protected by this inlaying method, over time the degradation of materials caused further concern. The brittle fragments were susceptible to break with every page turn, and acidic paper in heavy volumes tended to cockle preventing the volumes from closing.

Cotton Tiberius A. XII. Parchment fragments were attached to paper in the nineteenth century and incisions were cut along the sides to allow the leaves to lay flat.

 

Our conservators surveyed 243 items from the Cotton Collection, including 21 paper manuscripts. Items were graded on their physical, chemical and overall conditions based on an assessment of the state of the binding and parchment substrate, and thus rated for treatment priority.

Results of the survey of 243 Cotton Collection volumes. From Figure 2 and 5 in The conservation of the burnt Cotton Collection in the Journal of the Institute of Conservation, 2013

Pattern of damage where D (High degree of damage) accounts for 61% of the total items examined. From Figure 2 and 5 in The conservation of the burnt Cotton Collection in the Journal of the Institute of Conservation, 2013.

The nineteenth century treatments have been fundamental to the preservation of the Cotton Collection, and many items thought to be lost have since been rediscovered. The condition survey enabled us to quantify the damage and develop a strategy for the long-term preservation of the burnt Cotton Collection. Items identified as being fragile were immediately withdrawn from library use, while research to determine the best methods of stabilising and housing the items was undertaken. The use of analytical techniques such as near-infrared (NIR) spectroscopy for assessing the deterioration or parchment has enabled a better awareness of the nature and condition of these manuscripts. This information has helped to support the choice and realistic scope of conservation methods. In the case of the burnt Cotton Collection, the future project is now directed towards a preservation approach, including digitisiation and multispectral imaging, rather than an interventive conservation one.

Christina Duffy (@DuffyChristina), Imaging Scientist

Further reading

The conservation of the burnt Cotton Collection, Mariluz Beltran de Guevara and Paul Garside, Journal of the Institute of Conservation, 2013. Vol. 36, No. 2, 145 –161, http://dx.doi.org/10.1080/19455224.2013.815122

Collection Care fired up for BBC Four appearance, Christina Duffy: http://britishlibrary.typepad.co.uk/collectioncare/2013/08/collection-care-fired-up-for-bbc-four-appearance.html

Crisp as a Poppadom, Ann Tomalak: http://britishlibrary.typepad.co.uk/digitisedmanuscripts/2013/02/crisp-as-a-poppadom.html

‘Their Present Miserable State of Cremation' the Restoration of the Cotton Library, Andrew Prescott: http://www.uky.edu/~kiernan/eBeo_archives/articles90s/ajp-pms.htm

The Lindisfarne Gospels is one of the most magnificent manuscripts of the early Middle Ages. It was written and decorated at the end of the 7th century by a monk named Eadfrith who would go on to become Bishop of Lindisfarne and serve from 698 until his death in 721. An Old English gloss between the lines translates the Latin text of the Gospel and is the earliest surviving example of the Gospel text in any form of the English language. This translation was a late (mid-10th century) addition by Aldred, Provost of Chester-le-Street.

As one of the Treasures of the British Library the Lindisfarne Gospels undergoes strict condition assessments to ensure it is kept at ideal environmental conditions. Part of this assessment involves using microscopy to take a detailed look at the pigment behaviour. We posted some images in a previous post: Under the microscope with the Lindisfarne Gospels, and here we share some of the exceptional exuberance found on folio 3r.

Folio 3r

 Folio 3r of the Lindisfarne Gospels, Cotton MS Nero D IV. Examine in full detail here

The abstracted decoration found throughout the Lindisfarne Gospels is a spectacular example of Anglo-Saxon art. There are five major decorated openings in the manuscript, the first of which is found on ff. 2v – 3 and introduces the letter which St Jerome addressed to Pope Damasus. It was Pope Damasus who requested a revision of the Latin Bible text during the late 4th century. Folio 2v consists of an elaborate cross-carpet page and faces Jerome’s letter to Damasus in Latin with the opening Novum opus (New work). The intricate detail on this page has been interpreted as an act of personal spirituality and devotion. A few examples are shown below. Enjoy!

Top of folio 3r

Top of folio 3r

Folio 3r letter 50x

Folio 3r 150x

Folio 3r detail 50x

 Top: Upper section of folio 3r. Centre: Crackled pigment of lettering reading incipit prologus at 50x and 150x magnification. Bottom: Celtic-influenced spiral motif at 50x magnification

Centre of folio 3r

Tiny drops of red lead are also observed in early Irish manuscripts which heavily influenced the Lindisfarne Gospels. The Germanic zoomorphic style is evident with interlacing animal and bird patterns.

Centre of folio 3r

Folio 3r 20x

Folio 3r pigment 50x

Folio 3r red lead 20x

  Top: Central section of folio 3r from the British Library Catalogue of Illuminated Manuscripts with creature detail at 20x and 50x magnification. Bottom: Drops of red lead in a geometric pattern at 20x magnification

Bottom of folio 3r

Decorated initials exhibit yellow pigment (orpiment) bordered with drops of red lead. Craquelure is a network of tiny cracks caused by pigment shrinking due to age. When the disruption consists of perpendicular lines it is referred to as crackling.

Bottom of folio 3r

Folio 3r 30x

Folio 3r 100x

Folio 3r pigment loss 20x

Folio 3r 50x

 Top: Lower section of folio 3r. Detail of decorated initals at 30x and 100x magnification. Bottom: evidence of loss of green pigment (verdigris or vergaut) from a decorated initial at 20x and 50x magnification. Text from the reverse (f. 3v) is shown through the parchment

For more details on the pigments used in the Lindisfarne Gospels see our previous post. The entire manuscript is digitised and available online here.

Christina Duffy (Twitter: @DuffyChristina)