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Matching seals Klaus Wagensonner (Freie Universität Berlin) Timeline 3000 2000 1000 0 Previous work • Cataloguing • published catalogues of physical seals in major and smaller collections in Europe and the United States • Tagging seal impressions on cuneiform artefacts with unique identifiers • Imaging • Digitisation of 1,200 physical seals in the Ashmolean Museum, Oxford and several hundred of seals in other smaller collections • Continuous scanning of sealed documents in collections • Developing • Investigating feasible and efficient digitisation methods for physical seals Cataloguing • Using published catalogues • Online databases (open museum databases) • (Enquiries) Issues: • Completeness • Change of location (e.g., of previous 
 private collections) Presentation of seals • black/white photos of modern seal impressions • occasionally photos of cylinders themselves (mostly in case there is an irregular feature) • usually no representations of top and bottom Pierpont Morgan Library, New York (Online catalogue, Seal 773) Major seals collections in central Europe Museum collections • Excavations • Acquisitions (antiquities market; auctions; former private collections) Private collections • Acquisitions Some examples are … British Museum • around 2,000+ cylinder seals • online search (“cylinder+seal +mesopotamia”) = 2,204 results • c. 1,800 published in 5 monographs in the series Western Asiatic Seals • I: 156 seals (Uruk and ED) • II: 489 seals (OA and Ur III) • III: 656 seals (OB) • (IV: Kassite seals) • V: 401 seals (NA and NB) • VI: 92 seals (Achaemenid) former “Lambert” collection • in the British Museum • bequeathed by W. G. Lambert 2013 • 732 results 
 for cylinder seals Ashmolean Museum • approx. 1,200 physical seals • two thirds originating from excavations (mainly Kiš) • Catalogued and published: • Briggs Buchanan, Catalogue of Ancient Near Eastern Seals in the Ashmolean Museum (1963)
 > 1,116 seals (including a selection of sealings) • P. R. S. Moorey and 
 O. R. Gurney, “Ancient Near 
 Eastern Cylinder Seals 
 Acquired by the Ashmolean 
 Museum, Oxford 1963-1973”, 
 Iraq 40 (1978)
 > 83 seals Musée du Louvre, Paris • around 5,000–10,000 seals • only partially published • L. Delaporte, Catalogue des Cylindres. Cachets et Pierres Gravées de Style Oriental. I: Fouilles et Missions (1920) • L. Delaporte, Catalogue des Cylindres. Cachet et Pierres Gravées de Style Oriental. II: Acquisitions (1923) • Musée Guimet (see L. Delaporte, Catalogue du Musée Guimet, Cylindres Orientaux [1909]) > 156 seals Bibliothèque Nationale, Paris • approx. 2,000 seals • to a large extent unpublished and uncatalogued: • L. Delaporte, Catalogue des cylindres orientaux et des cachets assyro-babyloniens, perses det syro-cappadociens de la Bibliothèque nationale (1910) > c. 600 seals • collection Seyrig (unpublished) Musées Royaux de Bruxelles Royal Museums of Art and History Brussels (Belgium) • approx. 3,000 seals E.6853 • L. Speleers, Catalogue des intailles et empreintes orientales des Musées Royaux du Cinquantenaire, Bruxelles 1917 For interactive 3D model, click on the image • L. Speleers, Catalogue des intailles (use Adobe Acrobat reader) et empreintes orientales des Screenshot of 3D image: Impression of a cylinder seal with radiance scaling filter of Meshlab applied. Musées Royaux d’Art et d’Histoire. Supplemént, Bruxelles 1943 • Carmentis database of GLYPCOL Screenshots of 2D images: Impressions of a cylinder seal with sketch2 & color-sharpen filter of PLD-viewer applied. - Images generated by Portable Light Dome; 3D model (u3D) decimated to 500.000 faces per model - © Royal Museums of Art and History, Brussels Vorderasiatisches Museum • more than 2,000 cylinder and stamp seals • about half of this collection published in Moortgat (1940), Vorderasiatische Rollsiegel and Jakob-Rost (1975), Die Stempelsiegel im Vorderasiatischen Museum • digitized by TOPOI • no information about the remaining part (e.g., share of cylinder or stamp seals, periods, etc.) Bibel+Orient Museum, Fribourg • 253 seals from former Peters collection • + acquisitions (former collections Erlenmeyer, Marcopoli, Tabet etc.) • in total 455 cylinder seals Former “Kist” collection • former private collection of Joost Kist • 442 seals catalogued (b/w photographs of modern impressions) • no representation of the cylinder itself; no information on the drill hole • now in the Allard Pierson Museum, Amsterdam 2003 Representation(s) of seals Black & white photograph of modern impression Cylinder seal, Old Akkadian period Buchanan 1966, No. 320 Representation(s) of seals Black & white photograph of modern impression + (interpretative) drawing Cylinder seal, Old Akkadian period b c a M. M. Hussein, Nimrud. The Queens’ Tombs, Chicago 2015, Pl. 192 How to present a seal? • Conventional photo of modern impression
 (+ one image of the seal itself) • RTI image of modern impression (changing light) • 3D model of modern impression (e.g., Glypcol) • Digital rollout of conventional/HDR photos
 + one image of the seal + top and bottom • Digital rollout of RTI captures
 + RTI of seal + top and bottom • 3D model of seal Drill holes • hardly any information on tops and bottoms of cylinder seals in published catalogues: • Do drill holes show signs of wearing? • Does the drill hole go completely through the cylinder • Are there remains of handles attached to the seal and made of other material? • … First attempts Turntable built by Kirk Martinez (University of Southampton) A step forward Provisional set-up for seal imaging with manual rotation of seal on top of a support Ashm Buchanan 1966, No. 502 Stitching of 20-30 images with commercial software PTGui Pro Representation(s) of seals Digital rollout 
 (panoramic stitching of HDR images) Cylinder seal, Old Akkadian period Buchanan 1966, No. 320 High Dynamic Range (HDR) mi dd le short exposure u re os x p e long Merging together at least two captures using different exposure lengths High Dynamic Range (HDR) Morgan Seal 8 conventional images per 360 º 575 Conventional photos vs. HDR Ashm 25–30 High Dynamic Range (HDR) images per 360 º Buchanan 1966, No. 557 (or approx. 40 conventional images per 360 º on turntable) Issues: Heavily grained stones Ashm Buchanan 1966, No. 557 HDR digital rollout Morgan Seal 575 (rotating view) Desaturated result Carvings are hardly visible due to grain of stone! Issues: Heavily grained stones Ashm Buchanan 1966, No. 675 Issues: Translucent stones • chalcedony Del 354 32 High Dynamic Range (HDR) images per 360 º Stitching software usually unable to identify enough matching points between overlapping photos Issues: Translucent stones Stitching software: comparison to seals made of other material vs. Del 354 (manually set control points) Del 89 (automatically set control points) Issues: Translucent stones • rock crystal • carving and drill hole shine through Issues: Translucent stones • rock crystal • carving and drill hole shine through How to present a seal? • Conventional photo of modern impression
 (+ one image of the seal itself) • RTI image of modern impression (changing light) • 3D model of modern impression (e.g., Glypcol) • Digital rollout of conventional/HDR photos
 + one image of the seal + top and bottom • Digital rollout of RTI captures
 + RTI of seal + top and bottom • 3D model of seal Reflectance Transformation Imaging? • heavily grained stone • stitching the ptm files: Possible? • interim solution: stitching together one set of raw files and applying a template to create a full set of rollouts for each light angle. RTI camera dome work station at the Louvre RTI images allow to adjust the light angle RTI Specular Enhancement Reflectance Transformation Imaging Digital rollout vs. Seal impression • grain of stone • no information on material • loss of 3D nature of medium • loss of 3D nature of medium MNB 1348 (mirrored horizontally) How to present a seal? • Conventional photo of modern impression
 (+ one image of the seal itself) • RTI image of modern impression (changing light) • 3D model of modern impression (e.g., Glypcol) • Digital rollout of conventional/HDR photos
 + one image of the seal + top and bottom • Digital rollout of RTI captures
 + RTI of seal + top and bottom • 3D model of seal (based on photogrammetry) The way to a 3D model • Aligning source images (detecting matching points) • Building a point cloud & dense cloud Photogrammetry The way to a 3D model Photogrammetry Source images for 3D reconstruction are identical to those for the stitching process The way to a 3D model • Building a mesh (polygonal net for modeling 3D objects) • Adding the texture Photogrammetry The way to a 3D model Cylinder seal, Durham, Oriental Museum Elamite Point cloud Dense cloud Textured The way to a 3D model Cylinder seal, Durham, Oriental Museum Elamite How to match seals? Obstacles Physical seal vs. Seal impression • cylindrical • flat and linear • mirrored • intended direction • texture/grain • only surface topography • negative • positive + (in case of ancient sealings) • incomplete Registering seal impressions • Case study (Old Babylonian legal documents) Seal 5 Seal 1 Seal 6 Seal 2 Seal 7 Seal 3 Seal 8 Seal 4 Seal 9 CBS 9478 Seal 10 Seal 11 Registering seal impressions • Case study (Old Babylonian legal documents) • unique ID for each physical seal Seal 5 • unique ID for each impressed seal Seal 6 Seal 7 O.457 (Courtesy: GLYPCOL) Seal 8 Seal 9 CBS 9478 Seal 10 Seal 11 O.457 (Courtesy: GLYPCOL) Impression left by seal on soft surface The physical seal unrolled 3D-rendering Matching seals Impression left by seal The physical seal on soft surface unrolled positive negative Further issues • Differences between modern and ancient seal impressions Modern vs. Ancient • complete • partial • clean • disturbed (damage, worn-off surface, inscription) • straight • usually crooked, squeezed etc. Morgan No. 575 How to match seals? (2) Proposed workflow Data collection Data processing Data analysis Data dissemination Recognition Cataloguing Tagging Imaging Stitching Physical seal Preparing for web presentation sealing modern seal impression 3D model How to present a seal? • 3D model of modern impression based on RTI • 3D model of cylinder seal using photogrammetry • Digital rollout of HDR photos + additional images (= source images for 3D model) ADVANTAGE • 3D model and HDR rollout use the same set of source images, hence only one capture