Over the rainbow? Micro-CT scanning to non-destructively study Roman and early medieval glass bead manufacture

Ngan-Tillard, D.J.M.; Huisman, D.J.; Corbella, F.; Nass, A. Van

doi:10.1016/j.jas.2018.07.007

Cited by 17 publications

(10 citation statements)

References 24 publications

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“…Volumetric quantification of objects in archaeological studies using microCT, whether experimental tools/materials, actual artifacts, organic remains, or fossils, is proving to be a valuable analytical tool for researchers. In the majority of cases, microCT is used on the macroscale, primarily for morphometric reconstructions and analyses of the shapes, dimensions, and/or internal structures of bone, shell, tooth, ceramic, glass, plant, stone, and wood (e.g., Abel et al, 2011;Agostino et al, 2016;Arnaud et al, 2016;Beck et al, 2012;Bello and Galway-Witham, 2019;Bello et al, 2013aBello et al, , 2013bBosch et al, 2019;Bradfield, 2013Bradfield, , 2015Calo et al, 2019;Dreossi et al, 2010;Guzzo Falci et al, 2020;Gerlach et al, 2006;Kahl and Ramminger, 2012;Karl et al, 2014;Machado et al, 2017;Mizuno et al, 2010;Ngan-Tillard et al, 2018;Viallet, 2019;Woods et al, 2017;Xing et al, 2018).…”

Section: Micro-computed Tomography (Microct) and Archaeologymentioning

confidence: 99%

Revisiting lithic edge characterization with microCT: multiscale study of edge curvature, re-entrant features, and profile geometry on Olduvai Gorge quartzite flakes

Macdonald

Bartkowiak

Mendak

et al. 2022

Archaeol Anthropol Sci

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The angle and shape of lithic tool edges have long been used as a method of inferring prehistoric tool function. However, accurately measuring and characterizing edge angles of lithic tools is notoriously difficult. Studies using goniometers, calipers, or morphometrics often rely on twodimensional representations of edges. Furthermore, there have been limited attempts to quantitatively document stone tool edges based on surface metrology, most notably edge curvature. In this study, we use microCT to capture models of the complex geometry, or 'freeform' surfaces, of experimental quartzite flakes from Olduvai Gorge (Tanzania) to document and mathematically calculate edge curvature using multi-scalar length-scale analysis. Through this analysis, we also explore the quantification of re-entrant [overhang] features on lithic edge cross-sections. On lithic tools, especially coarse-grained rocks with complex surface topographies such as quartzite, traditional techniques for edge angle measurement are incapable of capturing re-entrant features on edge profiles. Here we present the first archaeological study that addresses the measurement of these re-entrant features, using novel length-scale and curvature analysis methods of calculating edge angles for complex freeform surfaces. With these new methods for measuring edge angles, we can consider the impact of complex geometry, including re-entrant features, on the function of lithic tools in the past.

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Section: Micro-computed Tomography (Microct) and Archaeologymentioning

confidence: 99%

Revisiting lithic edge characterization with microCT: multiscale study of edge curvature, re-entrant features, and profile geometry on Olduvai Gorge quartzite flakes

Macdonald

Bartkowiak

Mendak

et al. 2022

Archaeol Anthropol Sci

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“…Moreover, starting from the 1970s, the introduction of computed tomography (CT) added a new powerful non-destructive X-ray technique for the investigation of 3D artworks [2]. The application of CT was introduced to the art and archaeological fields primarily as a tool for analysis of human and animal remains [3][4][5][6][7][8], and then to study other kinds of objects made with various materials, such as glass, metal, clay, and wood [9][10][11][12][13][14][15][16]. Although portable instruments are the best solution to analyze artworks on-site avoiding the transportation of fragile objects [3,17], in the framework of large restoration centers, where hundreds of important artworks are treated every year, it is useful to install a fixed apparatus.…”

Section: Introductionmentioning

confidence: 99%

X-ray Imaging Investigation on the Gilding Technique of an Ancient Egyptian Taweret Wooden Statuette

Vigorelli

Guidorzi

et al. 2021

J. Imaging

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Diagnostic physical methods are increasingly applied to Cultural Heritage both for scientific investigations and conservation purposes. In particular, the X-ray imaging techniques of computed tomography (CT) and digital radiography (DR) are non-destructive investigation methods to study an object, being able to give information on its inner structure. In this paper, we present the results of the X-ray imaging study on an ancient Egyptian statuette (Late Period 722–30 BCE) belonging to the collection of Museo Egizio in Torino and representing an Egyptian goddess called Taweret, carved on wood and gilded with some colored details. Since few specific studies have been focused on materials and techniques used in Ancient Egypt for gilding, a detailed investigation was started in order to verify the technical features of the decoration in this sculpture. Specifically, DR and CT analyses have been performed at the Centro Conservazione e Restauro “La Venaria Reale” (CCR), with a new high resolution flat-panel detector, that allowed us to perform tomographic analysis reaching a final resolution better than the one achievable with the previous apparatus operating in the CCR.

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“…This suggests that even further integration of methods designed for the imaging of different materials could be of further benefit to conservation practice. Other studies that successfully integrate both of these approaches include the characterisation of pigments in furniture [90], characterisation of Roman quarried stone [91], in the characterisation of historical glass beads [92] among many other examples. The number of such studies appear to be on the rise, suggesting that the integration of XCT and chemical analysis techniques is a growing trend of high value to cultural heritage professionals.…”

Section: Discussionmentioning

confidence: 99%

X-ray computed tomography (XCT) and chemical analysis (EDX and XRF) used in conjunction for cultural conservation: the case of the earliest scientifically described dinosaur Megalosaurus bucklandii

et al. 2018

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This paper demonstrates the combined use of X-ray computed tomography (XCT), energy dispersive X-ray spectroscopy (EDX) and X-ray fluorescence (XRF) to evaluate the conservational history of the dentary (lower jaw) of Megalosaurus bucklandii Mantell, 1827, the first scientifically described dinosaur. Previous analysis using XCT revealed that the specimen had undergone at least two phases of repair using two different kinds of plaster, although their composition remained undetermined. Additional chemical analysis using EDX and XRF has allowed the determination of the composition of these unidentified plasters, revealing that they are of similar composition, composed dominantly of ‘plaster of Paris’ mixed with quartz sand and calcite, potentially from the matrix material of the Stonesfield Slate, with the trace presence of chlorine. One of the plasters unusually contains the pigment minium (naturally occurring lead tetroxide; Pb 2 2+ Pb 4+ O 4 ) whilst the other seems to have an additional coating of barium hydroxide (Ba(OH) 2 ), indicating that these likely represent two separate stages of repair. The potential of this combined approach for evaluating problematic museum objects for conservation is further discussed as is its usage in cultural heritage today.

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Over the rainbow? Micro-CT scanning to non-destructively study Roman and early medieval glass bead manufacture

Abstract: A. (2018). Over the rainbow? Micro-CT scanning to non-destructively study Roman and early medieval glass bead manufacture.

Cited by 17 publications

References 24 publications

Revisiting lithic edge characterization with microCT: multiscale study of edge curvature, re-entrant features, and profile geometry on Olduvai Gorge quartzite flakes

Revisiting lithic edge characterization with microCT: multiscale study of edge curvature, re-entrant features, and profile geometry on Olduvai Gorge quartzite flakes

X-ray Imaging Investigation on the Gilding Technique of an Ancient Egyptian Taweret Wooden Statuette

X-ray computed tomography (XCT) and chemical analysis (EDX and XRF) used in conjunction for cultural conservation: the case of the earliest scientifically described dinosaur Megalosaurus bucklandii

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