Seeing further: digital imaging of artefacts

Rachel Wood recounts the discussions held at a workshop on Artefact Imaging: Aims, Methods, and Access, 23rd May 2017, at Wolfson College, Oxford, organised by Kathryn Kelley and Rachel Wood, and funded by the Digital Research Cluster at Wolfson College.

Among the ancient artefacts in the Imagining the Divine exhibition will be a 21st-century replication created using digital scanning technologies and 3D printing. The original is the Khosro Cup, from 6th-century Sasanian Persia, made of rock crystal, gold, garnet, and glass. The Khosro Cup is one of the most precious items in the Cabinet des Médailles in Paris, and so its replication allows it to be displayed in the context of an external exhibition. There will be much more on the making of the 3D scan and replica to follow – watch this space! –  but for now, suffice it to say that the conjunction of the replication project and another research project also associated with Wolfson College, Oxford, entitled Seals and their Impressions in the Ancient Near East (SIANE), prompted a workshop on questions surrounding digital approaches to ancient artefacts.

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A tough work environment at Wolfson.

The workshop was designed to bring together museum curators, conservation experts, archaeologists, art historians, and those in the 3D printing and 3D imaging industry, who all have a shared interest in applying digital technologies to ancient artefacts. People have been replicating ancient objects for centuries for many different reasons, whether it be antiquarianism, making a more permanent documentation, monumentalisation, publicisation and making the originals more widely accessible, or scientific investigation. But digital imaging technologies have opened up a host of possibilities in the study of artefacts. The aim of this workshop was for participants to share ideas and problems, and to form connections between people who are dispersed across different faculties and study very different material, but who have similar methodological problems. The afternoon was split into 3 sections: research aims that can be facilitated by using digital imaging, then discussing various methods and techniques, and finally considering means of access to the resulting work.

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We were glad Queen Nefertiti could join us.

A prominent theme of the workshop surrounded how to deal with difficult materials – be they fragile, reflective, translucent, or transparent – or how to maintain the texture of the original object. The advantages, disadvantages, and capabilities of many different imaging techniques were explained and discussed, including hyperspectral imaging, reflectance transformation imaging, digital microscopes, laser scanning, CT scanning, structured light scanning, photogrammetry, and 3D printing.

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Dr Elise Morero demonstrates the capabilities of a Dino-Lite portable digital microscope on a 3D printed cuneiform tablet.

Many of these techniques enable us to see things not visible to the naked eye, such as details of carving techniques or long-faded decoration. David Howell, Head of Heritage Science at the Bodleian Libraries, showed us some of the fascinating projects he has been working on using hyperspectral imaging so as to see what the human eye can’t pick up: such as whether to increase the clarity of an image, revealing hidden images, measuring colour, identifying pigments, or observing the condition of an artefact for conservation.

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Hyperspectral imaging: getting the shrimp’s eye view (Photo © Silke Baron via Wikimedia Commons)

Digital imaging, especially photogrammetry (where you take many photos of an object from all angles and then collate them into a 3D image) can help to restore, or at least give a decent impression of, the original appearance of artefacts that are now fragmented or scattered, whether small carved 3D objects such as canopic jars, or monumental 2D surfaces such as Byzantine frescoes. Beyond the world of research, 3D images of artefacts can be shared via the internet using new platforms, with the potential to engage with a far larger audience beyond the realm of the museum or the library. The copyright implications of replicating artefacts was another significant area of discussion.

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Foreground: A canopic jar 3D printed from scans of scattered original fragments. Background: unrelated human brains, 3D printed.

Steve Dey of ThinkSee3D discussed some of the potential applications of 3D printing, such as experimental archaeology: how does being able to hold or use a version of the artefact change our understanding of the original? Another benefit might be as teaching tools or to broaden and enliven public engagement with ancient artefacts, more easily conveying ideas and making those experiences more memorable. 3D prints can be used in museum displays to make objects visible away from their ‘home’ collection, or used on handling desks in galleries to better convey the sense of the object. But with the available options in 3D printing, models can also be produced that differ from the original so as, for example, using varied textures to indicate colour or other decorative elements for the visually impaired.

The over-riding methodological concern of all the talks was how to balance technological capabilities with what is practical: whether weighing the advantages of speed from automation versus the distortion it may bring, or the restrictions of time, money, specialisms, and logistics, or, crucially, the limits of data storage and processing. How do you create an image detailed enough to provide the information you need, but small enough to work on people’s computers and store on a server? The SIANE project, led by Dr Jacob Dahl, is working on a method of documenting the tens of thousands of cylinder seals that are scattered across museums and private collections. They are dealing with how to document a vast number of objects, let alone making the results accessible for study and interpretation afterwards. This question of how to present the results brought out another issue of balance pertinent to many of the talks: the need to present the information, while at the same time making clear the differences to the original object and how the original object would or could have been seen or interpreted in antiquity.

It was clear from this afternoon session that further opportunities will be available as the technological tools are refined and made more accessible, and also that there is much to be gained from conversation between the digitally-literate and those, like myself, who might dip our toes into the shallow end of the digital humanities world.

With many thanks to the speakers for their fascinating presentations, to the participants for the lively discussion, and to Louise Gordon and Wolfson College for hosting and enabling the smooth running of the afternoon. And particular thanks to Kathryn Kelley for co-organising the workshop, and to Jacob Dahl for the initial suggestion of holding such an event.

Speakers:

Jacob Dahl, Kate Kelley & Nordine Ouraghi: Seals and their Impressions in the Ancient Near East (SIANE)
Elena Ene D-Vasilescu: The frescos of Lysi, Cyprus and the digital modelling of their environment in the UK
Elise Morero: The use of the digital microscope and multi-scale observation in the study of the lapidary manufacturing techniques
Kirk Martinez & David Young: Structured Light Scanning for the capture of ancient Near Eastern cylinder seals
David Howell: Hyperspectral imaging of ancient artefacts
Steven Dey: 3D scanning (and 3D printing) ancient Egyptian and Mesopotamian artefacts using CT scanning and 3D photogrammetry
Hendrik Hameeuw: Observations when stone seals are imaged with different spectra and light angles: the consequences for the normal map estimations
Rachel Wood: Digital imaging for an exhibition: the Khosro Cup Replication Project:
Jamie Cameron: Cabinet: a new online tool for digital access to artefacts

Participants:

Daniel Bone, Ashmolean Museum, Deputy Head of Conservation
Xavier Droux, Oriental Institute
Frédérique Duyrat, Bibliothèque nationale de France, Directeur du département des Monnaies, médailles et antiques
Alex Geurds, School of Archaeology
Julia Hamilton, Oriental Institute
Solene Klein, Oriental Institute
Anna Kurmangaliev, University of Munich
Nicky Lobaton, Ashmolean Museum, Department of Conservation
Hana Navratilova, Griffith Institute
Lucia Nixon, Wolfson College
Alison Pollard, Ashmolean Museum
Michael Roaf, University of Munich
Elisa Rossberger, University of Munich
Ségolène Tarte, Oxford e-Research Centre
Roger Tomlin, Classics Faculty
Lynn-Salammbô Zimmermann, Oriental Institute

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