dr. kathryn e. piquette, cologne center for ehumanities, universität zu köln: illuminating the...

Illuminating the Herculaneum Papyri with New Digital Imaging Techniques

Dr. Kathryn E. Piquette Cologne Center for eHumanities, Universität zu Köln

kathryn.piquette@uni-koeln.de

Outline

• Theorising images

• Reflectance Transformation Imaging (RTI): What and why

• Herculaneum papyri

• Recovering writing from carbonised papyri: problems and possibilities

• Entangled relationships between writing and material ‘support’

• Future directions

• RTI: Increased reflexivity and rigour in the research process

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Theorising Cultural Heritage Images

• Documentation, illustration, preservation, unique perspectives, enhanced visualisation

• Move beyond notion of “images as resources”

• Situate image in reciprocal relationship:

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• Processes of visualising and seeing underpin empirical work, but often neglected (Melissa Terras 2006; Jon Wagner 2006)

• Critical awareness of image architecture (cf. Michael Shanks 2013)

• Creation, provision, consumption!3

• (Focus: artefacts and small-medium size surfaces)

Image

Information

Knowledge construction

Visualising & Seeing

Incised gneiss(?) vessel fragment, c.2800 BCE, Egypt, 1977.112.296, World Museum Liverpool (Piquette 2014,

in Dodson et al.)

Dr. Kathryn E. Piquette (kathryn.piquette@fu-berlin.de)For analysis and downloadable RTI image file see Piquette 2014: https://www.academia.edu/4770946/Scribal_Practice_and_an_Early_Dynastic_Stone_Vessel_Inscription_Material_and_aesthetic_implications

Visual Perception, Environmental Conditions

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Light and Control • Fixity • Position • Angle • Intensity

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What is Reflectance Transformation Imaging (RTI)?

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Reflectance Transformation Imaging (RTI)

• Method of structured light photography

• Digital images taken of target object with camera in fixed position; illumination applied from different locations

• Multiple captures combined to produces interactive, relit record of surface

• Improved visualisation, archival record, preservation and conservation tool

• Legibility, physical structure • First algorithm for photo amalgamation developed by Tom Malzbender

et al. of HP labs in 2001: Polynomial Texture Mapping (PTM) Malzbender, T., Gelb, D. and Wolters, H. 2001. Polynomial Texture Maps. In Proceedings of the 28th Annual Conference on Computer Graphics and Interactive Techniques (SIGGRAPH 2001), 519–528.

Highlight Reflectance Transformation Imaging

• “H-RTI” • Fixed camera • Fixed target • Handheld light source • Reflective spheres • Measuring string • Optional computer

control • 36-48 exposures

Set-up in Ashmolean Museum, Oxford

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RTI Capture Sequence

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RTI Fitting Process

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RTIBuilder Version 2.0.2 (Mac, PC): http://culturalheritageimaging.org/

RTI Viewing

RTIViewer Version 1.1 (Mac, PC): http://culturalheritageimaging.org/

• Non-contact acquisition of data

• Clear representation of 3D shape

• Better discernment of surface detail than direct physical examination

• Visualisation through interactive viewing tools

• No data loss from shadows and specular highlights

• Higher resolution on the object surface than usually obtainable with 3D scanners

RTI Benefits

Happa J., Mudge, M., Debattista, K., Artusi, A., Gonçalves, A. and Chalmers, A. 2010. Illuminating the Past: State of the art. Virtual Reality 14(3): 155-182.

Bone comb from Nile Valley, World Museum, Liverpool, Piquette forthcoming

Kathryn E. Piquette

Cultural Heritage Applications

• Stone • e.g. rock art, inscriptions, lithics

• Mineral • Selenite curse tablet

• Metal • e.g. coins, implements, tablets • Magical curse on lead

• Wood • Wax on wooden tablet

• Clay • e.g. cuneiform tablets • Impressed sealing

• Skeletal & botanical remains • Textiles, parchment, paper, papyrus

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All above, Kathryn E. Piquette

Courtesy Trustees of the British Museum

Herculaneum Papyri• Vesuvius eruption 79 CE • Largest preserved library from ancient world

• c.1800 rolls • Epicurean philosophical treatises

http://www.bbc.co.uk/news/magazine-25106956

Carbonisation: Blessing & curse• Exposed to extreme heat but not consumed by fire,

charcoal-like appearance

• Preservative effect but reduces contrast between ink and papyrus, extremely fragile

!1.Herculaneum papyri: c.79 CE, c.1800 rolls 2. Petra papyri: 6th century CE, c.20 rolls

3. Egyptian Delta and Oxyrhynchus: Ptolemaic-Roman

Periods, c.300 documents

!15 http://www.bbc.co.uk/news/magazine-25106956 Kathryn E. Piquette

Unrolling the Papyri

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Kathryn E. Piquette

Kathryn E. Piquette

Methods for Writing* Recovery•Hand copying •Conventional photography •Multispectral imaging

• Infrared, visible, ultra violet • Infrared imaging: photography, reflectography, transmitted !

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* And other physical features

http://www.worldwidetelescope.org/Interact/Spectrum

Infrared photography: Pros and cons

• Vastly improved legibility but… • Light fixed, surface appears flattened • Holes vs. ink • Details obscured by self-shadowing • Difficult to discern layers • ‘Sottoposti', ‘sovrapposti’: reconstruction • Registration problems !18

Brigham Young University

Brigham Young University

Highlight Reflectance Transformation Imaging (H-RTI)

• Pilot tests

• February 2014: Visible H-RTI

• June 2014: Infrared H-RTI

• Cooperation between Universität zu Köln and the Biblioteca Nazionale di Napoli

!• Fixed camera

• Fixed target

• Handheld light source (IR LED)

• Reflective spheres

• Measuring string

• Computer control

• 48 exposures

UCLDH lens

Kathryn Piquette & H-RTI set-up in BNN, Naples

Photo: Gianluca del Mastro

P.Herc. 862, Cornice 1 Stitched

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Infrared fixed light photograph, with “filter 7” (950 nm)

(IR photograph: Brigham Young University)

Infrared Reflectance Transformation Imaging (IR RTI), with 950nm filter

(RTI photograph: Kathryn E. Piquette)

Image Comparison: P.Herc. 862, Cr. 1, Pz. I

IR RTI Addresses Shortcomings of Previous Photography

• Increased contrast combined with clear representation of 3D shape

• Clear discernment of holes that can otherwise be confused with ink

• Distinguish layers with greater precision

• Count layers

• Discern sovrapposti, sottoposti

• Alleviate problem of self-shadowing

• Artificial enhancements

• Better understanding of written content in relation to physical structure

• More robust analysis and documentation of research process using RTIViewer annotation tools

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Kathryn E. Piquette

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RTI Tools for Supporting the Research Process

• Four aspects of work on the papyri

• Discovery, preservation, editing, interpretation

• Robust documentation

• Method of preservation

• Condition reporting/monitoring

• Systematic study

• Legibility

• Artefactuality

• Augments previous documentation methods

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Richard Janko

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• Process of seeing more systematic and rigorous • Bookmark viewing conditions + annotation • Reflexivity: Provokes new questions, raises new problems • Shareability of hypotheses, replicability of visual experience by

other researchers • High quality reproduction • Eventual citation of bookmarks in publication

Image: active, mediating, situated

• User interviews: benefit of emulating physical interaction with the artefact, 2D+ emphasises materiality, provokes multi-sensory engagement

RTIViewer:

Summing Up• RTI offers powerful visualisation tools for taking Herculaneum

papyri research forward (larger project now in planning stages) • Emulates physical interaction with the artefact • 2D+ emphasises materiality, provokes multi-sensory

engagement • Fosters critical making and use of images • Transparency and replicability of viewing experience &

conditions of interpretation

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Acknowledgements

• Institut für Altertumskunde and Cologne Center for eHumanities, Universität zu Köln

• Academy of Sciences and Arts of Nordrhein-Westfalen in Duesseldorf

• KölnAlumni - Freunde und Förderer der Universität zu Köln e.V.

• Biblioteca Nazionale di Napoli

• Special thanks to Sofia Maresca, Gianluca Del Mastro, Michael McOskar, Richard Janko and BNN staff

• Lindsay MacDonald, Stuart Laidlaw, Eleni Kotoula and Antonino Cosentino

• UCL Centre for Digital Humanities

• UCL Institute of Archaeology

• Cultural Heritage Imaging (CHI): http://culturalheritageimaging.org/

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