Imaging Ancient Worlds

Imaging Ancient Worlds MUSEUMS, COLLECTIONS, AND THEIR DIGITIZATION KLAUS WAGENSONNER Yale Babylonian Collection The Yale Babylonian Collection at Sterling Memorial Library in New Haven, CT, houses about 45,000 objects. Most of these objects – 37,000 – are inscribed with cuneiform and date from c. 3300 BCE to 100 CE. Other artifacts are clay plaques, sculpture, and particularly cylinder and stamp seals. Since 2017, the Babylonian Collection is officially affiliated with the Peabody Museum of Natural History. Photo: Carl Kaufman SOURCES CUNEIFORM C. 500,000 cuneiform texts in collections worldwide: • Iraq Museum (c. 100,000+) • British Museum (c. 130,000) • Istanbul (c. 50,000) • Berlin (c. 35,000) • Yale (c. 35,000) • University of Pennsylvania (c. 25,000) • Louvre (c. 16,000) Cuneiform Digital Library Initiative (CDLI) http://cdli.ucla.edu / https://cdli.mpiwg-berlin.mpg.de CUNEIFORM THROUGHOUT TIME DIGITIZATION WHAT IS IT GOOD FOR? Digitization is the recording of information in a digital form. Digitization therefore applies to many different contexts. Here, we focus on the digital capture of small to medium-sized archaeological artifacts. Digital recordings can be stored for posterity, shared and disseminated, annotated, and manipulated. WRITING MATERIALS CLAY IN MESOPOTAMIA How to write a tablet A stylus made of reed was probably the standard. Its texture can very often be seen in the impressions left on the clay tablet. Cammarosano 2014: 66, Fig. 8 & 11 CLAY IN MESOPOTAMIA left edge WRITING MATERIALS obverse Inscribing the tablet A simple cuneiform tablet has six faces. Five of its faces are active writing surfaces: 1. Obverse: the scribe starts in the left upper corner and writes in lines from left to right and top to bottom. 2. The tablet is flipped on its horizontal axis (not like a book page, although there are exceptions). bottom edge reverse top edge Economic text, 21st cent. BCE CLAY IN MESOPOTAMIA left edge WRITING MATERIALS obverse Inscribing the tablet A simple cuneiform tablet has six faces. Five of its faces are active writing surfaces: 3. Before starting on the reverse, the scribe can also put text on the bottom edge. 4. If the space on the reverse does not suffice, then the scribe can use the tablet’s top edge and finally the tablet’s left edge. bottom edge reverse top edge Letter, 7th cent. BCE DIGITIZATION WHAT IS IT GOOD FOR? What are the reasons for digitization? DIGITIZATION WHAT IS IT GOOD FOR? What are the reasons for digitization? u Documentation u Research u Outreach u Publication u Education u ... DIGITIZATION DOCUMENTATION Many museum collections focus on a mere documentation of their holdings. Even a photo taken with a phone may already account as a digital asset. Museum databases often also release archival photographs. DIGITIZATION OUTREACH DIGITIZATION OUTREACH & EDUCATION DIGITIZATION OUTREACH & EDUCATION Virtual Reality tours through exhibition space. DIGITIZATION RESEARCH TEXTS NOS. 1540~3024 2037: NBC 3119 (AS3 U V 1) 2034: NBC 3116 (AS9 U) obv. 1 5 gigur zi3-da esir2 su-ba obv. 1 nu-banda3 gu4 Lugal-ku3-zu kišib Ur4-ša3-ta-lu2 2 ĝuruš ša3-gu4 siskur2 Ku8-ba-tum rev. 5 nu-banda3 gu4 Lugal-iti-da ša3 bala-a 5 mu en dNanna Kar-zi-da ba-huĝ seal še ĝiš e3-a ki-su7-ra saĝ-du3 rev. Ur4-ša3-ta-lu kurum7 aka u4 1-še3 ugula Lugal-ukkin-ne2 dumu Ur-šu-ku3-ga gudu4 iti ri 10 2035: NBC 3117 (IS1 U X) obv. 1 5 ĝuruš ša3-gu4 ki Ba-za-ta seal mu us2-sa Ur-bi2-i3-lumki ba-hul Lugal-ku3-zu 2.00 udu niga 1 1/2 sila3-ta dub-sar u4 28-še3 dumu Ur-niĝarĝar kuš7 še-bi 16;4.0 gur 1.13 udu niga 1 sila3-ta 5 2038: NBC 3120 (AS5 U) u4 [16]-še3 [še-bi 3;4.2] 8 sila3 rev. obv. 1 Diĝir-an-dul3 u4 12-še3 ki Urdu2-ta kišib Ur-ĝišgigir šabra še-bi 2;4.0 gur 10 3;0.0 še-ba gur 1.10 udu niga 1 sila3-ta šu-niĝin2 še-bi 23;2.2 8 sila3 gur rev. 5 ĝiri3 dŠara2-a-mu še-ba zag-mu mu En-unu6-gal-dInanna ba-huĝ iti ezem dŠul-gi Ur-ĝišgigir seal mu dI-bi2-dSuen lugal dub-sar dumu Bar-ra-AN 2036: NBC 3118 (AS9 U) obv. 1 3 ab2 ga 2039: NBC 3122 (ŠS2 U VIII) 1 gu4 ga obv. 1 1 dur3 ga 5 ke4 šu2-luh aka ĝiš apin-še3 zu2 keš2-ra2 1 1/2 sar pa4 a-da-ga Nita-mu i3-dab5 rev. 2 5/6 sar sahar pa4 a-da-ga a-bu3-du-du- amar gu4-DU.<DU> gub-ba 5 d mu en Nanna Kar-zi-da e2-gir-gi4-lu-ka šu2-luh aka 11 ĝuruš kab2-ku5 Na-ra-am-dSuen ba-huĝ gub-ba 275 DIGITIZATION RESEARCH PLATE LIV 407 T h.4 ,, , . , 409 . . T Th~T 5 R.WMvWtH . 10 to. E. Lo. L I',r 410 15 20 f: -l TfT O---' - Lo. E. , at-~~ U. 408 R. fX- t ^ 4C 44V f< 411 WYr 10%~~~~ A I^^wf XX4 TWYC(_ ^ R.^f~w^^^ I ^ -~ ^0 r .Wgo -tE T Dougherty 1923 DIGITIZATION RESEARCH PLATE LIV 407 T h.4 ,, , . , 409 . . T Th~T 5 R.WMvWtH . 10 to. E. Lo. L I',r 410 15 20 f: -l TfT O---' - Lo. E. , at-~~ U. 408 R. fX- t ^ 4C 44V f< 411 WYr 10%~~~~ A I^^wf XX4 TWYC(_ ^ R.^f~w^^^ I ^ -~ ^0 r .Wgo -tE T Dougherty 1923 I DIGITIZATION RESEARCH 5 10 2 0. 10 15 20 25 Clay 1920 I DIGITIZATION RESEARCH 5 10 2 0. 10 15 20 25 Clay 1920 DIGITIZATION RESEARCH NBC 557 YBC 977 MLC 2317 NBC 5279 (Mayr 1995: 295, no. 316) NBC 5231 DIGITIZATION RESEARCH Seal of Lu-duga u Currently impressed on 57 artefacts u Unique ID S002825 NBC 557 (Mayr 1995: 295, no. 316) YBC 977 MLC 2317 NBC 5279 NBC 5231 DIGITIZATION WHAT IS IT GOOD FOR? The tools and methods for the successful digitization of archaeological objects depend on several aspects: u Purpose of digitization effort (cataloguing, research, outreach, publication, ...) u Costs (staff costs, equipment costs, ...) u Time u (long-term) storage u Quality u ... DIGITIZATION TOOLS DIGITIZATION IMAGE QUALITY Flat-bed scanner HDR photo RTI image DIGITIZATION OBSTACLES NO archaeological object equals another. Several aspects influence its digitization: u State of preservation: archaeological objects such as cuneiform tablets, papyri, metal artifacts, etc., may be rather fragile and a digitization method needs to be chosen that does not do further harm to the object. u Significant changes in the condition of an object should be documented (e.g., before-and-after conservation treatment such as repairs, cleaning, etc.) DIGITIZATION PRESERVATION Sometimes, objects can deteriorate over time and digitization becomes the last resort to preserve the information contained in them. Published drawing (1979) DIGITIZATION SIZE 1 cm 1 cm Prism with name list, Ur III (NBC 11202) Messenger tablet, Ur III (NCBT 2067) Old Babylonian copy of Early Dynastic List Plants (CBS 7094) Base Text 3 mm 6 mm 1 cm Annotation 2 mm 3 mm DIGITIZATION SIZE The dimensions or other physical characteristics (e.g., weight, mobility) of the object to be recorded require different approaches. E.g., large, freestanding objects can be digitized using conventional photography, photogrammetry, or highlight Reflectance Transformation Imaging (RTI). All these approaches have their own challenges (e.g., light conditions, etc.) FOCUS A camera focuses on one point. The transition between a sharp image and areas that appear increasingly blurry is gradual and can be influenced, e.g., by the lens’s aperture, the so-called Fstop. FOCUS A smaller aperture (i.e., higher F-stop numbers; e.g., F/16) widens the Depth-ofField (DoF): areas closer and farther away from the focus point appear sharp. A larger aperture (i.e., lower F-stop numbers; e.g., F/2.8) narrows the DoF: only areas near the focus point appear sharp. DIGITIZATION FOCUS F 2.8 F 16 Focus plain Cuneiform artifacts are threedimensional objects. The Depth-of-Field (DoF) is therefore an important criterion for image capture. Economic record, 24th cent. BCE (MLC 1476) FOCUS A smaller aperture lets less light through the lens. Hence, it is necessary to compensate with a slower shutter speed. Even a higher F-stop may sometimes not be enough to get all areas into focus. FOCUS Different focus points can be merged and aligned thanks to focus stacking. F1 F2 F3 F4 F5 F6 F7 O1 F8 O3 O2 FOCUS STACKING DIGITIZATION QUALITY Depending on the artifact recorded, the correct light angle(s) may be crucial. Work station with two dimmable light sources and two separate LED lights as counter balance (or reflecting surface) Sale contract, 7th cent. BCE (YBC 11404) CUNEIFORM Cuneiform is a three-dimensional script. Scribes impressed the stylus to form vertical, horizontal, and slanted wedges. Each impression consists of a triangular “head” usually located towards the top or the left, and a “tail” extending. i (?) ii (?) Hemerology and omens, mid-first mill. BCE (NBC 1886) 1 cm DIGITIZATION TOOLS IMAGING TECHNIQUES FLATBED SCANNING Use of a conventional flat-bed scanner in order to scan all faces (6 for tablets) of cuneiform artifacts. Quality Effort Storage IMAGING TECHNIQUES FLATBED SCANNING Advantages uEasy to train staff in capturing many artifacts in a short period of time uEasy and effective storage of archival files uEasy processing to representation (so-called "fat-cross") Issues uLoss of "focus" or details in areas farther away from the scanner uScratches on scanner show up in results quite soon; also dust may obstruct text DIGITIZATION IMAGING METHODS Since the distance to the scanner is always the same, flatbed scanning has an advantage for joining fragments across collections. Example 1 Perfume recipes – Fragment 1 in Berlin – Fragment 2 in Paris DIGITIZATION IMAGING METHODS Example 2 Letter with its envelope – Tablet in Oxford – Envelope at Yale IMAGING TECHNIQUES IMAGE QUALITY Flatbed scan Producing higher quality images allows for an image record to be used for more than just documentation. It can be source for research and publication. Account text, 21st cent. BCE (YBC 9818) HDR photo DIGITIZATION TOOLS IMAGING TECHNIQUES HIGH DYNAMIC RANGE (HDR) PHOTOGRAPHY long middle Quality short NBC 7688 Effort Storage IMAGING TECHNIQUES HIGH DYNAMIC RANGE (HDR) PHOTOGRAPHY 2+ raw images with different exposures are merged together to create higher contrasts. ... IMAGING TECHNIQUES HIGH DYNAMIC RANGE (HDR) PHOTOGRAPHY Processing ‣ Most of the image processing can be automatized, which helps to reduce time and costs of digitization. Duration: approx. 1 min IMAGE CAPTURE Duration ‣ small to medium-sized tablet: 1 min ‣ large, multi-column tablet: 3–5 min ‣ prism, barrel cylinder: 5–10 min IMAGE CAPTURE Duration ‣ large, multi-column tablet: 3–5 min Multi-column tablet with culinary recipes, c. 17th cent. BCE (YBC 8958) IMAGE CAPTURE Duration ‣ cylinders (and prisms): 5–10 min Funerary inscription, 7th cent. BCE (YBC 2151) Clay barrel cylinder, 6th cent. BCE (YBC 2243) DIGITIZATION TOOLS DIGITIZATION Quality Effort Storage IMAGING METHODS Reflectance Transformation Imaging (RTI) The same motif is captured multiple times while the position of the light source is modified between each shot. Capturing of Ebih-Il of Mari, Louvre (May 2017) DIGITIZATION IMAGING METHODS u The RTI camera dome takes as many images as there are LEDs installed. The dome at Yale produces 76 images. u All images are merged together to a Polynomial Texture Map (PTM), which creates a dynamic image that allows to change the light angle. u The PTM can be shared online or to colleagues thanks to completely open source software. Gilgamesh P Gilgamesh Y DIGITIZATION SIZE Selection of representative light angle 11A 11B 11C DIGITIZATION SIZE 11A 11B 11C Overlapping areas/points Creating one Panorama u Move base images (parts of the panorama) for one light angle (!) into PTGui Pro. u Start alignment Creating Template in PTGui Pro u Menu File, Save as Template (Filename, e.g., YBC02345.pts) u Menu Tools, Batch Builder u In the ensuing dialog choose Generate new projects ... u Browse and select parent folder of raw images and enter number of images per panorama (here, 3) Batch Builder u Important: Select the template saved earlier in the Dropdown menu Use. This template will be used for all 76 panoramas. u The project is sent to the Batch builder, which creates 76 files. New Original Captures 11 28 63 74 Micro-RTI-Stitching (Optional) Next Steps u Photoshop adjustments of the newly created panoramic images (rotation, cropping, etc.) via Actions that can be applied to all images. u Same method can be used for combination of views in one RTI (e.g., fatcross) and/or annotation of images. Cylindrical objects Turntable Cylindrical objects 11_top 11_seal 11_impression 11_bottom 11_rollout Cylindrical Objects Cylindrical Objects Capturing Cuneiform u Highlight Reflectance Transformation Imaging only requires small equipment u Essential is a glossy sphere in each photo that reflects the changing light source and serves to calculate the x, y, z coordinates of each light position u Number of images (i.e., light angles) is open, but 32 (4 by 8) following the outlines of a virtual dome, suffices. u Highlight-RTI Capturing Cuneiform u Highlight-RTI 4 raw images with respective light angles Capturing Cuneiform u Fitting all raw captures to dynamic image (PTM) using the free software RTI Builder u Highlight RTI Capturing Cuneiform Detecting sphere(s) in frame u Highlight-RTI Capturing Cuneiform u Highlight-RTI u Detecting highlights reflected on sphere in each capture u Fitting images to Polynomial Texture Map (PTM) Capturing Cuneiform u Highlight-RTI u Make new project. u Open raw images (the images do not need to be renamed, but should be in one directory) u Choose an image where you can see the sphere properly (a high light angle) u Add area with sphere pressing the icon u Zoom in to better visualize the sphere. Click three points along the outer circumference of the sphere. u The third point allows the app to propose the circle. u This circle can be adjusted, if needed. u Press “Find Highlights” in the Edit Menu. u A png-file will appear in the folder containing the source files. This png-file depicts a fused image of all highlights on the sphere. u These highlights provide the coordinates for each light source. DIGITIZATION IMAGING METHODS 3D-scanning and Photogrammetry DIGITIZATION u Unwrappings IMAGING METHODS Turntable Example: overlapping points DIGITIZATION IMAGING METHODS DIGITIZATION TOOLS DIGITIZATION DIGITAL EPIGRAPHY Although an interpretation of an original artifact, a (Digital) drawing often helps to enhance certain features (inscription, seal impressions, etc.). It may also compensate for the 3D-character of an object. Producing hand drawings for publication DIGITIZATION DIGITAL EPIGRAPHY Traditionally, scholars publish texts in form of drawings Henry Rawlinson K 156 + K 246 Rawlinson, H.C., The Cuneiform Inscriptions of Western Asia, Vol. II: A Selection from the Miscellaneous Inscriptions of DIGITIZATION DIGITAL EPIGRAPHY Publication of cuneiform artefacts using standardized print letters. Examples are: • The correspondence of the socalled State Archives of Assyria published by Robert F. Harper, Assyrian and Babylonian Letters (1892–1914) • The letters from Amarna (Egypt) kept at the British Museum 81-2-4, 56 DIGITIZATION DIGITAL EPIGRAPHY Incomplete drawings, in this case only the date HANDCOPIES COMPLETENESS Handcopies (in the past) tend to ignore or suppress certain features, such as (the iconography of) seal impressions. DIGITIZATION DIGITAL EPIGRAPHY Strassmaier, Inschriften von Darius. König von Babylon (1892) … Wunsch, Das Egibi-Archiv (2000) HANDCOPIES Drawing cuneiform using tracing paper HANDCOPIES VECTORIZATION Producing autographs, handcopies, drawings The quality of handcopies varies significantly. Issues • Producing a reliable hand drawing requires a high amount of skill, time, and effort • Physicality of an object were often ignored in publications • Features such as "firing holes", partly damaged signs, "correction" marks, etc., might be omitted • Seal impressions are/were, as a rule, often completely omitted • A drawing is always an interpretation Advantages • The 3D-character of a cuneiform artifact is transposed onto a 2D representation • It therefore improves access to an inscribed document • It can(!) also reduce the risk of mistakes in text editions HANDCOPIES VECTORIZATION MLC 1948 obv. HANDCOPIES Obverse VECTORIZATION u Separation of inscribed and sealed surfaces. Bottom edge Reverse HANDCOPIES VECTORIZATION HANDCOPIES VECTORIZATION Line weight for sign drawings Line weight for preserved tablet edges Dashed line for broken tablet edges Dashed outlines for erased areas Grey line for erased signs or texts running from other side of object Line weight for sign drawings DIGITIZATION Quality Effort Storage IMAGING METHODS Reflectance Transformation Imaging (RTI) The same motif is captured multiple times while the position of the light source is modified between each shot. Capturing of Ebih-Il of Mari, Louvre (May 2017) AUTOMATED RENDERING RMAH O.3707 Courtesy: Hendrik Hameeuw AUTOMATED RENDERING Using RTI data in tandem with algorithm in order to produce line art drawings.