A note on the use of crystal engineering to increase the opacity of terra verde inpainting pigment: Adulteration of green earths Publication date: Available online 16 October 2019 Source: Journal of Cultural Heritage Author(s): Gregory Dale Smith, Heidi Kastenholz Abstract Micallef et al. recently described in this Journal [38 (2019) 1–7] the use of crystal engineering methods to increase the opacity of terra verde (green earth) pigment for conservation inpainting purposes. In contrast to their chemical characterization of the pigment as comprising only natural inorganic minerals, this research shows that the commercial Verona green earth pigment used in their experiments contains a significant quantity of the synthetic organic pigment adulterant, copper phthalocyanine green (PG7 form). This bright green additive provides most of the color of their source pigment and is shown to be a common additive to so-called “green earth” colorants sold to artists and conservators. Their results must be reassessed in light of this oversight.

Moisture regime of historical sandstone masonry — A numerical study Publication date: Available online 10 October 2019 Source: Journal of Cultural Heritage Author(s): Tomas Vogel, Jaromir Dusek, Michal Dohnal, Michal Snehota Abstract Rising damp causes deterioration of masonry walls in many historical buildings. Although the phenomenon of capillary rise in porous structures is relatively well understood, reliable numerical modeling of the moisture regime, applicable to the assessment of current state as well as to the predictions of changes induced by various corrective moisture-reduction measures, remains a challenge. This paper presents the results of a numerical modeling study dealing with the moisture regime of a masonry wall of the baroque Church of All Saints in Heřmánkovice. The numerical approach used is based on general concepts of mass conservation and Darcian flow of capillary water in porous media. The model was parameterized and validated using experimental data obtained by on-site survey, laboratory analysis and monitoring. The modeling results confirmed our hypothesis that, in a long-term perspective, the second-stage evaporation—controlled by the hydraulic properties of the masonry—prevails over the first-stage evaporation—controlled by the atmospheric conditions—for most simulation scenarios conducted. Of the two corrective moisture-reduction measures considered, i.e. a closed drain versus open drain installation, the latter was found to be significantly more effective, leading to a greater reduction of moisture in the masonry.

Simultaneous non-destructive identification of multiple elastic and damping properties of spruce tonewood to improve grading Publication date: Available online 5 October 2019 Source: Journal of Cultural Heritage Author(s): Romain Viala, Vincent Placet, Scott Cogan Abstract The tonewoods used in musical instruments are finely selected and are subject to current and upcoming availability issues. Wood grading assesses the quality of the tonewood and depends on both subjective and objective criteria. Traditionally, grading criteria based on mechanical properties consider mainly the longitudinal direction. This paper investigates the elastic and damping properties of spruce wood used in the making of acoustical guitars and violins. In this context, the mechanical grading properties will be studied in multiple directions. A non-destructive vibrational characterisation method is used to simultaneously identify at least six mechanical properties of wood and leads to the determination of the elastic and damping parameters of wood along the different material directions. The main objective is to quantify the variability of the mechanical properties in different material directions as a function of the grading attributed by the wood seller. The results show that material anisotropy decreases as the grade decreases. This is attributed to strong increase of the specific elastic modulus in the radial direction and the specific shear modulus in longitudinal and radial plane. Moreover, grading seems to be assigned as a function of specific elasticity and loss factor in the longitudinal direction, which is tied in with the preferences of instrument makers. Following the assumption that high specific modulus is desirable, the classification based on instrument makers choices can be improved for new grading criteria that consider directions than longitudinal. Moreover, the substitution of wood species and the proposal of new materials exhibiting equivalent elastic and damping properties can be proposed.

Instrumental techniques in the analysis of natural red textile dyes Publication date: Available online 26 September 2019 Source: Journal of Cultural Heritage Author(s): Pilleriin Peets, Signe Vahur, Anneli Kruve, Tõiv Haljasorg, Koit Herodes, Todd Pagano, Ivo Leito Abstract Various dyes present in historical objects can be indicative of different usage, age and origin of the artifacts. Knowledge about the composition and origin of textile dyes is essential for the preservation and conservation of the items. In this paper, we compare different instrumental techniques to detect and identify natural red dyes from historical textiles without the need for standard substances of the dye components. Several instrumental techniques were used, including liquid chromatography with photodiode array, fluorescence and mass-spectrometric detectors, as well as Fourier transform ion cyclotron resonance mass spectrometry with electrospray ionization and matrix-assisted laser desorption/ionization sources. Seven natural red dye sources were investigated, including dyer's madder, redwood, logwood, sandalwood, kermes, American cochineal and bloodred webcap (Cortinarius sanguineus). The dye components of the latter source have not been characterized before with all of these analytical techniques. A substantial library of chromatograms and mass spectra, along with absorption and fluorescence spectra (altogether 113 chromatograms/spectra), of dyes and/or dye components were recorded and a comparison of the utility of the different analytical techniques in the analysis of the dye sources is provided. The usefulness of the assembled library of chromatograms/spectra is demonstrated on the analysis of several historical textile samples from museum artifacts. Graphical abstract

Diammonium hydrogen phosphate (DAP) as a consolidant in carbonate stones: Impact of application methods on effectiveness Publication date: Available online 26 September 2019 Source: Journal of Cultural Heritage Author(s): Arianna Murru, Rafael Fort Abstract New products such as diammonium hydrogen phosphate (DAP) have yielded good results as consolidants in construction stone used in the architectural heritage. Their effectiveness, which depends on the characteristics of the stone substrate and product concentration, is likewise impacted by the application technique used, which may or may not favour penetration into the stone. This study explored the effectiveness of brush, immersion and poultice application of a 3 M concentration of DAP on limestone and marble. Ultrasonic pulse velocity, colour change, porosity and pore size distribution as well as the variations in anisotropy, roughness and the alteration index were analysed to establish the efficacy of carbonate stone consolidants. Both stones were penetrated most deeply when the consolidant was applied with a poultice, while the pore structure of limestone favoured more intense penetration. Applying a poultice yielded good results in marble, improving its mechanical properties without inducing variations in colour or surface roughness. In limestone in turn, immersion delivered the best results, leaving colour unchanged while raising mechanical performance to levels similar to those for the unaltered stone. Graphical abstract

A novel technology for the corrosion protection of iron archaeological artefacts using parylene base removable bilayer Publication date: Available online 23 September 2019 Source: Journal of Cultural Heritage Author(s): Lucie Blahová, Jakub Horák, Radek Přikryl, Jan Pekárek, Jakub Tkacz, Přemysl Menčík, František Krčma Abstract Combinations of different acrylic resins and microcrystalline waxes are most often used for conservation and preservation these days. However, their properties are not sufficient and satisfactory in many ways. A novel barrier coating for the conservation of iron archaeological artefacts composed of parylene C polymer and Laksil lacquer is proposed within this article. Parylene C is a commercial name of poly(chloro-p-xylylene) polymer, and it was prepared via modified chemical vapour deposition. Parylene removability was ensured through the xylene soluble interlayer made of Laksil silicone-acrylic lacquer which was applied between a protected iron model substrate and parylene thin film. The corrosion tests in salt spray showed excellent barrier properties of Laksil/parylene bilayer. The surface roughness measured by the profilometry and the surface morphology shown by the SEM displayed the synergic effect between the Laksil and parylene layer which leads to the exceptional barrier and anticorrosion function of Laksil/parylene bilayer. First, the Laksil layer flattened out rough surface of a substrate; second, thereon deposited parylene film became smooth and defect free and acted as a good diffusion barrier. The colouristic measurements proved that the bilayer does not change the appearance of item, in terms of colour. The EDX and TGA confirmed entirely successful removal of bilayer and thus the reversibility of conservation treatment is enabled. The characteristics of Laksil/parylene bilayer were compared with the conventional conservation coating composed of Paraloid B72 acrylic resin and Revax microcrystalline wax prepared by professional conservators. The Laksil/parylene bilayer demonstrated significantly superior properties in this comparison.

Spectroscopy investigations reveal unprecedented details in the corrosion of AISI 1012 UPN profiles installed in a modernist building of beginning of 20th century Publication date: Available online 12 September 2019 Source: Journal of Cultural Heritage Author(s): José I. Iribarren, Francisco Liesa, Álvaro Meneguzzi, Carlos Alemán, Elaine Armelin Abstract In the present work, the corrosion affectation of an artistic and historical building, declared UNESCO World Heritage Site and constructed with AISI 1012 UPN profiles, was investigated. Micro-Raman and microscopy approaches highlight the complementarity and versatility of these techniques to evaluate the macroscopic and microscopic effect of the corrosion products in such reinforcing structures. The rust phases have been assessed by separating the oxide layers according to their environment placement and contaminants contact. The composition of iron oxides and oxyhydroxides in the metal surface depend not only on the oxygen concentration, but also on other elements that penetrated into the porous layers, as for example, chorine ions, sulfur ions, and microorganisms. Taking into account the scarce information on the indoor corrosion of AISI 1012 steel, results obtained in this work are expected to help for understanding the long-term impact of such oxides and oxyhydroxides on the material durability, as well as on its structural maintenances.

Facial reconstruction of mummified remains of Christian Saint-Nicolosa Bursa Publication date: Available online 11 September 2019 Source: Journal of Cultural Heritage Author(s): Josipa Marić, Željana Bašić, Ivan Jerković, Frane Mihanović, Šimun Anđelinović, Ivana Kružić Abstract In addition to forensic science, facial reconstruction also plays an outstanding role in the historical and archaeological context. Precisely, it the most exact method to reconstruct the appearance of the people that lived in the past and a popular way of presenting results not only to scientific community but also to a broader public. The main purpose of this study was to reconstruct the appearance of Saint-Nicolosa Bursa, a Christian saint whose mummified remains are kept in Church of Saint-Blaise in Vodnjan (Croatia). The additional aims were to validate the methodology and to provide a realistic model of the Saint's face that could be used for exhibition and presentation of the research results to a broader public. The mummified remains of the saint were scanned with multislice computed tomography (MSCT). The MSCT images were used to develop a skull model which was 3D printed and used for facial reconstruction. The facial appearance recovery was accomplished using the Manchester method by the progressive layering of clay on the ABS model according to the anthropometric data, specific for sex, age, and ancestry. After the clay model was done, it was used to create a realistic gypsum sculpture appropriate for the presentation of results on exhibition. When the model was compared to the photographs of the mummified remains of the Saint, it showed to be consistent in all facial traits that could be considered. Unfortunately, additional data were not available due to the preservation degree of soft tissue remains as well as the lack of pictorial or written sources about the appearance of the Saint. However, this research showed, that although the facial reconstruction is always only an approximation of the actual person's appearance, it is essential in historical context as an only existing method that can show us how a certain historical figure could look. In the present study, it enabled us to conduct the first reconstruction of the appearance of the Saint from the mummified remains and develop sculpture that will be used for exhibition and presentation of results.

A marine geoarchaeological investigation for the cultural anthesis and the sustainable growth of Methoni, Greece Publication date: Available online 10 September 2019 Source: Journal of Cultural Heritage Author(s): Panagiotis Gkionis, George Papatheodorou, Maria Geraga, Elias Fakiris, Dimitris Christodoulou, Konstantinia Tranaka Abstract The ‘Evolved GE.N.ESIS Project’ highlights the underwater cultural heritage resources off the coast of Methoni, Greece that could locally drive sustainable socioeconomic growth. An integrated marine geophysical survey, a hydrographic survey, and a GNSS survey were conducted off Methoni, recording six historic wreck sites, artefacts, the ruins of a submerged prehistoric settlement, and the town's ancient harbour/breakwater, as well as the geophysical properties of the underwater environment. The preliminary project results present bathymetric surfaces, backscatter intensity and magnetic maps, drawings, and seismic reflection profiles of the underwater antiquities and of the seabed, all fused in a 3D geographical platform. The results also shed light on the archaeological potential of the site, the nearshore physical processes, and their effect on the underwater archaeological resources. The project outcomes have shown that the establishment of an underwater archaeological park and diving sites at the cultural heritage sites will support cultural tourism development in the area and will have a positive impact on local socioeconomic development. The underwater archaeological park should comply with the basic principles of a site management plan – one that is established in the context of an integrated coastal management plan that identifies the maritime synergies or conflicts among human activities, archaeological resources, and the local environment, and utilises the 3D synthesis of marine knowledge from the project outcomes as a decision-making tool.

Study of the influence of water and oxygen on the morphology and chemistry of pyritized lignite: Implications for the development of a preventive drying protocol Publication date: Available online 7 September 2019 Source: Journal of Cultural Heritage Author(s): Giliane P. Odin, Oulfa Belhadj, Frederik Vanmeert, Koen Janssens, Alain Wattiaux, Alexandre François, Véronique Rouchon Abstract Lignite constitutes a unique testimony of past diversity and evolution of land plants. This material, usually waterlogged, is particularly difficult to dry because of its mechanical sensitivity to moisture changes. In addition, lignite may contain organic and inorganic sulfides, which are susceptible to oxidation once excavated. As a result, the conservation of lignite is particularly complicated and lignite remains scarce in paleobotanical collections. We experimentally test different drying protocols on waterlogged pyritized lignite, while documenting the respective role of water and oxygen on their morphology and chemistry. The results reveal that inorganic sulfides (pyrite) are more prone to oxidation than organic sulfides (thioethers). Critically, water is the main factor responsible for this oxidation, provoking sulfate efflorescence when samples are further exposed to oxygen. On the other hand, an abrupt removal of water provokes significant mechanical damage while sulfur remains mostly present as reduced compounds. The control of water and oxygen exchanges is thus critical for conserving lignite without physical damage and efflorescence. We successfully achieved this by storing the samples in hermetically sealed plastic bags made of semi-permeable films, which slowly release humidity while allowing a gradual influx of oxygen. We advise curators to quickly handle lignite once removed from its waterlogged environment because of the fast kinetics of oxidation, and to choose a drying protocol according to the purpose of the lignite treated. Finally, once dried, we advise to store the lignite in an anhydrous environment.