Multi-technique investigation of historical Chinese dyestuffs used in Ningxia carpets

In this article, an extensive work is presented concerning the characterization with both chromatographic (high-performance liquid chromatography) and spectroscopic (surface-enhanced Raman spectroscopy and visible reflectance spectroscopy) techniques of historical Chinese dyestuffs in several carpets, mostly coming from the Ningxia region in Northern China and dating to the seventeenth–nineteenth centuries. Notably, the color of the background of these fine artifacts has been an object of debate since, while being depicted as bright red in the ancient iconography, nowadays it appears as orange/yellow. Therefore, in addition to the identification of all the colorants used in the carpets, the present study investigated the reasons of this apparent inconsistency, pointing out an explanation based on the joined use of the yellow dye obtained from the pagoda tree and a “fugitive” dye obtained from brazilwood.     

How an integrated diagnostic approach can help in a correct evaluation of the state of preservation of waterlogged archaeological wooden artefacts

Artefacts made of wood coming from archaeological excavations provide insights into human cultural behaviour of the past. They show how man utilised natural resources and how the development of woodworking techniques and artistic endeavour were developed. Within archaeological contexts, waterlogged anaerobic conditions generally preserve the appearance of artefacts, although wood is subject to severe decay processes. The said conditions can transform the original material into a new one, thus demonstrating specific differences from those of the “fresh” wood of the same species. In order to assess these new properties correctly, an integrated diagnostic approach is needed, one which includes a multidisciplinary (micromorphological, physical and chemical) evaluation of the state of preservation.     

Interdisciplinary approach for reconstructing an alder-based historical agricultural practice of the Eastern Ligurian Apennines (NW Italy)

Data from four soil profiles studied through pollen and macroscopic charcoal analyses were used to identify specific palynological assemblages associated with a traditional land-use system documented in the Eastern Ligurian Apennines (NW Italy) between the 18th and early 20th century, concerning a cyclical use of grey alder plots for temporary cultivations involving to the use of controlled fire. This is the first attempt to verify on palynological evidence some hypotheses raised by previous historical ecology studies about the consequences of this agricultural practice (recently named alnocoltura) on past and present vegetation. Our investigations underline (1) high percentages of anthropogenic pollen indicators, (2) increase of Ericaceae percentages, (3) low pollen percentages of Alnus, (4) high macrocharcoal concentrations and (5) high values of palynological richness during periods affected by the alnocoltura cycle according to the historical sources. Similar patterns are also detectable in pollen diagrams from two adjacent peat bogs. The paper shows the strength of an interdisciplinary methodology (field observations, cartographical and archival historical data, palynological and archaeological investigations) for studies of past land-use systems. By demonstrating the necessity of a long-term prospective in environmental reconstructions for the preservation of the cultural landscape, one of the important elements of this research is its potential contribution to issues of habitat management and nature-conservation policy. Further analyses are needed to test the replicability and reliability of the hypotheses derived from this study.     

From Boatyard to Museum: 3D laser scanning and digital modelling of the Qatar Museums watercraft collection,Doha, Qatar

This article presents the results of a project to 3D laser scan and digitally model 14 watercraft from the Qatar Museums collection, comprising a range of regional vessels: most had not been surveyed previously. The project used the resulting point clouds generated 2D naval lines and orthographic records of the vessels in their current condition, and photorealistic 3D digital models for gallery display. This case study provides illustrative examples of the intermediate stages and final outputs. It assesses the pros and cons of 3D laser scanning as a survey technology for nautical scholars in terms of the time, cost, and skillset, as well as logistical considerations. It also compares the accuracy of traditional hand survey methods.     

Digital heritage research re-theorised: ontologies and epistemologies in a world of big data

ABSTRACT

This article provides the first theoretical treatment of the ontologies and epistemologies of digital heritage research at the time of the interconnected and social web, based on extensive empirical and analytical investigation. We draw on observations and concepts developed while conducting the first study of public experiences of the past that utilised big data – over 1.4 million Facebook posts, comments and replies – to revisit or generate new theory from the ground up. We expect that this will help scholars from a range of fields in the humanities, social and computing sciences who are interested in undertaking digital heritage research to understand the deeper implications of their work, the complexities and limitations of the knowledge they create, and its value in exposing the processes via which heritage is made and assessed.     

Experimental Characterization of Ancient Metal Tie-Rods in Historic Masonry Buildings

Metal tie-rods play a decisive role in the control of horizontal thrusts in historic masonry buildings. The main goal of the present study is to investigate the relationship between metallurgical and mechanical properties of original tie-rods in order to contribute to a wider study on ancient building stability and their restoration protocols. This article presents the results of an experimental test campaign carried out on 14 historic tie-rods (dating back from 16^th–19^th century) recovered from restoration works or building demolitions. Stress-strain mechanical tests showed that the elastic modulus of the material is comparable to that of modern structural steel, while the strength and the elongation capability are significantly lower, with a large scatter. Further analyses based on metallography allowed us to assess that this mechanical behavior depends on the heterogeneous nature of the material, which can eventually be compared to a composite with vitreous elongated particles in a ferritic or ferrito-pearlitic matrix. The origin of such metallurgical condition is related to the iron making based on direct smelting from ores.     

Two Byzantine Albanian icons: a non-destructive archaeometric study

The present work is part of a project aimed at studying the pigments and painting techniques used by Albanian iconographers to produce Byzantine and post-Byzantine icons dating from the fourteenth to the nineteenth centuries; the state of conservation of these icons was also explored. Inorganic pigments are identified by means of X-ray fluorescence, reflectance spectrophotometry and UV fluorescence analysis. These analysis techniques were performed to discriminate between pigments on the basis of their typical features. Moreover, the study of the optical properties of paintings is of fundamental importance for correct restoration. This work enabled us to recognise the palette used in two artworks by anonymous painters of the fourteenth and fifteenth centuries. Only three small samples were taken from the edge and the back of the wooden tables in order to achieve information on preparatory layers. Twelve to fourteen non-destructive measurements were made to characterise the palette used by the two anonymous painters.