Literature results of chemical bronze analyses originating from Near Eastern excavation sites have been assembled to obtain a general overview of the Mesopotamian bronze technology during the 3rd millennium BC. Results show that at the end of the 4th and at the beginning of the 3rd millennium BC arsenic alloys with an arsenic concentration up to 5% were generally into use, while tin bronzes were introduced during the middle of the 3rd millennium. This introduction appears almost synchronously over the entire region of Mesopotamia, although there is an indication that the tin bronze introduction was slightly later in southern Mesopotamia.
One of the most important Roman opus sectile (inlaid of stones and other materials to make a picture or pattern) is the both figurative and geometric decorated panel ensemble dating to the end of the 4th century A.D., discovered in 1959 near Porta Marina (Ostia, Rome) and now exposed in the National Museum of Early Middle Ages in Rome.A recent revision of the 190 panels provided an opportunity for a careful examination of the materials used. The only nonstone material used in the decoration is vitreous paste: it was used to make the entire mosaicated ceiling and in some other areas beside opus sectile. Monochrome vitreous materials of varying colours have been identified (among them several red tones), as well as polychrome materials imitating marbles (serpentino and red marble), precious stones and mosaic materials (gold foil tesserae and opaque glass pastes coloured in several shades from green to blue and less frequently in red and black). Forming, cutting and shaping techniques of the vitreous materials were also investigated. Furthermore, analytical investigation of glass pieces and mosaic tesserae was performed in order to ascertain which melting, colouring and opacifying techniques were adopted to prepare these materials.
A geochemical study, including a detailed investigation of Fe by Mössbauer spectroscopy, was undertaken to characterise the different varieties of the stones in the cathedral of Évora (Portugal). Ten representative stone samples were collected. Bulk analytical techniques, including ICPES, INAA and XRF, were performed, as well as Mössbauer spectroscopy. The stones have consistent linear geochemical variations, well constrained by a limited number of inter-element ratios involving Ti, Mg, Fe and Al. Taking into account the REE distribution, the Mg, Fe and Ti contents and the Fe3+/Fe2+ ratio, two types of stones were distinguished. The type-1 stones show REE normalised patterns with negative Eu anomaly, and are relatively Al rich. The type-2 stones without Eu anomaly, more REE fractionated, are relatively LREE, TiO2, MgO and Fe2O3 rich. In agreement with the geochemical results, the Mössbauer data have shown that the Fe3+/Fe2+ ratio was correlated with the magmatic differentiation and further suggested that the presence of Fe (Ti) oxides is related to a higher magmatic evolution. Both stone types have a MgO/TiO2 ratio close to 2, which is characteristic of calco-alcaline granite. The chemical inter-element variation along the same constant ratio, as well as the REE pattern and the Fe oxidation state, seems to indicate a magmatic filiation from type-2 to type-1 stones. The combination of REE patterns and Fe/Mg, Ti/Mg and Fe3+/Fe2+ geochemical indexes could be used as efficient discrimination tools for other stones of monuments built of granite.
It is increasingly the case that assessments of large salt deteriorated objects, such as wall paintings, involve sampling and analysis to determine the object's salt content. However, the usefulness of this is somewhat compromised by the fact that the salt distribution within the object is apt to change. This paper presents a new approach to salt sampling, using statistical and experimental design techniques to determine the degree to which analytical results are potentially affected by factors such as the sampling location and prevailing environmental conditions.A series of site investigations were undertaken to assess the spatial and temporal variability of the salt distribution within the thirteenth century wall paintings in the Sacristy at Cleeve Abbey, Somerset, UK. Analysis of variance (ANOVA) techniques were applied to the sampling data, and conclusively demonstrated that the salt content of the wall paintings varied significantly, not only with location, but also with depth, and over time. This has important implications for site assessment methodology, since analytical results can be strongly affected by factors such as the type of object under investigation, the sampling strategy, and the season during which the investigation is carried out.
For the laser ablation of crust on historical sandstone samples contaminated due to prolonged interaction with the environment, and also for specimens covered by artificial crust layers, the potential of acoustic monitoring is examined. Measurements of the snapping sound amplitude vs. the deposited laser energy carried out for dry, moistened and wet samples at laser fluences in the range of 0.1–3 J cm–2 (Nd:YAG, 6 ns, 1064 and 532 nm) confirm the advantages of wet cleaning. The exponential decay of the signal corresponds to a similar decrease of the crust thickness, characterized by an average rate of about 10–14 μm per pulse, and the data of original samples reveal better reproducibility compared to those of the model crust. From data analysis, a narrow band of the reference signal of 8.5–11% of the maximal one follows, which corresponds to the crust-free surface, and for parabolic dependences of both sound amplitude and cleaning speed vs. laser fluence, the clear maxima agree with optimal processing parameters. The strong correlation observed between the acoustic signal and the ablation progress supports the conclusion of the usefulness of acoustic monitoring for laser cleaning of stone artefacts.
For thousands of years, people throughout the world have built homes, communities and temples using earth materials, mainly in arid and semi-arid lands where generally other building materials were quite scarce. In the arid regions of Peru, from the 3rd millennium B.C. to Inca age, several civilizations shaped sand, clay and water into bricks (known as adobe) to build ceremonial centres, pyramids and towns. The detection of adobe archaeological buried remains by means of remote sensing techniques is a challenge as difficult as engaging, since the adobe has a composition quite similar to the neighbouring earth material. In this paper, Very High Resolution (VHR) satellite imagery have been used to identify archaeological features linked to the presence of shallow and outcropping adobe structures in some test sites selected from within the Ceremonial Centre of Cahuachi (Southern Peru). Both vegetated and non-vegetated areas were investigated. The promising results we obtained pointed out that the use of Earth Observation (EO) technologies can open new perspectives to detect adobe settlements.
Organic binding media found in paintings exhibit characteristic fluorescence properties that strictly correlate with their chemical composition and may vary as a function of the ageing time. The aim of this work was to investigate the capability of microspectrofluorometry to distinguish between different binders. Linseed oil and protein-based media, deposited as thin films on microscope glass slides both in the presence and in the absence of inorganic pigments, were examined before and after artificial photo-ageing. Cross-sections of some paint layers were also examined. The article points out that microspectrofluorometry coupled with deconvolution analysis can be a useful tool for distinguishing between oil- and protein-based media. The curve-fitting analysis furnished a fine characterization of each binder/pigment combination, and highlighted the small spectral differences between their fluorescence signals.
Laser cleaning of ancient marble and stone monuments is nowadays a well-accepted procedure in conservation. Operators and specialists are presently divided between those giving maximum confidence to this method of cleaning and others who, in contrast, are strongly critical and emphasise possible drawbacks and damages caused by laser. As any other method of cleaning, laser also offers advantages but at the same time is limited by drawbacks. Most conveniently, it should be integrated with the other methods. On the basis of the above considerations, the authors are proposing a combined procedure using laser cleaning as a first step – in this way removing the relevant part of black gypsum encrustation – followed by chemical methods as a final step. The latter, conveniently, could be accomplished by means of anion exchange resins, better than ammonium carbonate. An experimental check-up was made of four different methods applied on three different lithotypes on the façade of the Florentine Cathedral. Laser, micro-sandblasting, ammonium carbonate and sodium EDTA were the cleaning methods compared, whilst Carrara marble, green Serpentine (Verde di Prato) and a red limestone were the three lithotypes. Results are commented by showing differences in the advantages and drawbacks among the different methods on the various lithotypes.
This article presents a new method for labeling archaeological material, based on the use of data matrix (DM) codes. The information that identifies an artefact (site name, level or archaeological unit and consecutive number) is coded on very small labels (3 × 3 mm and 4 × 4 mm). This information is captured by a laser reader, which inputs it directly into a computer database. The system has been successfully applied to the pilot study presented here. Its use greatly improves provenance information and management of the archaeological record, and results in the more accurate processing of artefacts in fieldwork routines, laboratory activities and museum storage.
The present study was conceived for an evaluation of the effectiveness of laser cleaning techniques applied to samples collected from numerous monumental buildings in the city of Siena (Palazzo Pubblico, Cappella di Piazza, Baptistery, Logge del Papa and Palazzo Spannocchi). All the characteristic lithotypes of Sienese architecture are represented: Montagnola Senese marble, Cavernous limestone, Pliocene sandstone and Red Ammonitic limestone. The tests were devised so as to have the widest variability of situations in relation to the colour and composition of the lithotypes, the state of deterioration of the samples and the level at which to stop the cleaning. The tests were preceded and followed by detailed petrographic analyses. In the introduction to the work, we underline the importance of an accurate reconstruction of the stratigraphy of the external horizon of deterioration of the stone for an appropriate choice of the cleaning intervention; the potential advantages of laser techniques are consequently further emphasized.
Invertebrate fouling communities called concretions form on archaeological metals submerged in marine environments. The concretions are inhabited by bacteria that play a role in formation and persistence of the concretion layer. We analyzed the bacterial community in concretion samples collected from the external hull of the USS Arizona in Pearl Harbor, HI. Variability in the size of the bacterial community was high and the concretions appear to harbor approximately 106 bacteria/g. Analysis of 16S rDNA clones indicated that the community consisted of bacteria related to three phyla: Firmicutes, Bacteroidetes, and Proteobacteria. The low bacterial diversity may indicate a late-succession stage community within the stable concretion. Alternatively, the low diversity could be the result of residual antifouling chemicals applied to the ship hull. It is likely that the bacterial community detected in these concretions plays an important role in the continuing corrosion of the USS Arizona.
The “Terracotta Army” is a worldwide known archaeological finding in China. It is a part of the burial complex of the emperor Qin Shihuangdi (259–210 BC), which is still under excavation and study. The fact that the sculptures, chariots and weapons of the First Chinese Emperor's Terracotta Army were originally all painted in bright colours is still not widely known. The chemical characterisation of the paint medium was performed through an analytical procedure based on GC-MS. The proteinaceous binder was identified for the first time through a desalting procedure used in proteomics. The identification of egg as a paint binder is extremely interesting in terms of the historical significance of the work of art itself and important in terms of the method of conservation. Moreover it represents one of the first steps towards an understanding of the painting technique used on ancient sculptures in China, of which – despite their fame – nothing is yet known.
The Grotta of Buontalenti (GB) was built at the end of the 1500s during the Medicean period. One of the rooms that constitutes the Grotta is decorated with mosaics composed of tesserae of stained glass. The GB underwent several restorations, which took place between the end of the 1700s and 1980s, which are poorly described and documented, leading to some uncertainties about the extent and phase(s) of restorations of the mosaics. The original tesserae and mortars of the GB were analysed for their mineralogical and chemical composition. Results indicate that glass tesserae have a common sodic base composition. Cluster analyses, however, performed considering the glass base composition (i.e. SiO2, K2O, Na2O, MgO, CaO, and Al2O3), identify three groups of samples: A, B, and C. A and B are characterised by chromophores such as Se and Cr suggesting a recent age (50–150 years) of the tesserae. On the contrary, chromophores (Fe, Mn, Cu, Co) and opacifiers (mainly SnO2, Pb2Sb2O7, Ca2Sb2O7) of the third group (C) indicate a preparation procedure known since ancient times. Based on their mineralogy and petrography, four different types of mortars were recognised. The mortars cannot be precisely dated. However, by matching their composition with that of the glass tesserae, it can be concluded that one type of mortar may be of the Medicean period, whereas the others are relatively recent, probably of this century. This evidence, in accordance with historical data, points to a Medicean age of group C tesserae. Restorations of the GB involved partial substitution of the mortars whereas the glass tesserae were largely recycled with limited addition of new materials.
Two laser-based analytical techniques, Laser Induced Breakdown Spectroscopy (LIBS) and Raman microscopy, have been used for the identification of pigments on a polychrome from the Rococo period. Detailed spectral data are presented from analyses performed on a fragment of a gilded altarpiece from the church of Escatrón, Zaragoza, Spain. LIBS measurements yielded elemental analytical data which suggest the presence of certain pigments and, in addition, provide information on the stratigraphy of the paint layers. Identification of most pigments and of the materials used in the preparation layer was performed by Raman microscopy.
This paper details the processes involved in the conservation of a polychromed wooden Buddhist sculpture. The treatment of polychrome sculpture has for many years raised fundamental issues about methods of conservation due to the conflict between conserving the outermost surface and wishing to reveal more about the earlier structure which may lie beneath. We have decided not to physically intervene with the original sculpture but instead to recreate the past appearance of the sculpture in a virtual environment. By using the technique of 3D laser scanning, we have recorded the surface of the sculpture to sub-millimetre detail. The scanned data can then be used to generate a computer model of the sculpture that then acts as a framework onto which surface colour and texture may be added. The educational value of the computer model may be further enhanced by the addition of missing elements or the removal of later restorations. By taking non-destructive surface colour measurements and by examining the layer structure of minute paint samples under magnification, it is proving possible to build a clear idea of how the sculpture may have appeared in previous centuries.
The study of the interaction between silica glass and saturated Ca(OH)2 solutions can be a useful approach to resolve the problem of the adhesion between lime-sand mortar and clay bricks. Since it is reasonable that the silica–calcium hydroxide system well simulates a brick–mortar system, experimental observations concerning the interaction of silica glass and this strong basic solution should be of value for the comprehension of the chemical reactions that could take place at the mortar–brick interface, maybe affecting the adhesion between the two building materials. We demonstrated the effects of saturated Ca(OH)2 solutions on commercial pure silica glass (fused silica) and on silica films obtained via a sol–gel process by means of dip-coating. Silica samples were dipped in the solutions at different temperatures (room temperature, 60 and 80 °C) and at different time intervals (1 and 21 h) and then they were analysed by means of surface techniques: X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and atomic force microscopy (AFM). It has been shown that Ca(OH)2 reacts with the silica glass network. The experimental results clearly show a very different behaviour of sol–gel silica with respect to fused silica, probably because of their different nanostructure. Many problems concerning the interaction of silica and Ca(OH)2 are still to be solved, but the results of this research strengthen the idea that adhesion between lime-sand mortar and clay bricks is caused not only by carbonation of calcium hydroxide contained in the mortar, but even by some chemical reactions involving the brick constituents and calcium hydroxide itself. The final products, calcium silicates, may induce a chemical continuity between lime-sand mortar and clay bricks.
This paper describes the adaptation and evaluation of three chemical tests for tannins characterisation in vegetable tanned leathers. Tests were performed on fibres of new leathers tanned with different known vegetable tannins and historic leathers. Rhodanine test, nitrous acid test and acid butanol test, developed to identify, respectively, gallotannins, ellagitannins and condensed tannins, are described. Ferric test and vanillin test, the two traditional tests used for vegetable tanned leathers characterisation, were also performed and their usefulness discussed. Gallic acid, ellagic acid and catechin, structural constituents of the different classes of tannins were also tested. Results of the developed methodology allowed the identification of tannins’ chemical class in new and historic leather samples studied. Data obtained permitted to verify the information on tanning materials used in new leathers. Vegetable tanning technology was confirmed in historic samples and tannins were characterised. This study shows that these tests are useful and can be a valuable source of information to evaluate new vegetable tanned leathers quality for conservation and restoration purposes as well as historic leathers tanning technology.
SMART CLEAN is an innovative Nd:YAG laser system that has been designed to optimize laser cleaning procedures, especially for the treatment of altered stone surfaces. The project, originated by the co-operation of researchers and enterprises involved in optoelectronics system development, was aimed at improving the intrinsic features of the laser source, as well as some practical aspects, in order to facilitate laser application in the restoration yard. Emission characteristics were suitably tailored to obtain effective removal of alteration layers, and to minimize possible side effects. In particular, the pulse duration of the SMART CLEAN laser was set at 20 μs, by means of a proprietary design of the power supply. This was in order to reduce the risk of both mechanical and thermal damage to the artwork substrate, which is more likely to occur with short and long laser pulses, respectively. Moreover, this pulse duration permitted a reliable transmission of high laser energy through long optical fibres (50 m), which allowed easy cleaning operations on façades. The laser system was tested on a large variety of lithotypes and in operative cleaning interventions on Italian monuments.
Potentials and limitations of the near-UV pulsed laser cleaning of parchment (wavelength 308 nm, pulse duration 17 ns) are demonstrated by the application of scanning electron microscopy (SEM), colour metrics and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) at model contamination/pigment/parchment systems. Pigment-binder systems stable and unstable against near-UV laser treatment could be identified. A chemical degradation threshold fluence of a goat parchment model substrate was determined which practically coincided with its ablation threshold fluence. This indicates that the fluence range of destructionless laser cleaning at 308 nm is almost not impaired by chemical modfications below the ablation limit. Nevertheless, spectroscopic diagnostics are necessary to guarantee destructionless cleaning for practical cases where the chemical conversion threshold fluence deviates from the ablation threshold to lower values.
The aim of this work is to analyse the evolution of the concept of cultural heritage in West European states. In the last decades of the 20th century, the term “heritage” was characterised by expansion and semantic transfer, resulting in a generalisation of the use of this word, frequently used in the place of another, such as, monument and cultural property. However, all these terms are not able to cover the same semantic field. Starting by the reflection on the semantic evolution of the notion of cultural heritage in France, we approach to the international definition of heritage given by the directives, charters and international resolutions in order to define a global outline of the meaning of heritage that is not just limited to a particular national dimension. From a purely normative approach, one went to a less restrictive approach, one based on the capacity of the object to arouse certain values that led the society in question to consider it as heritage and therefore, to a further step in which heritage is no longer defined on the basis of its material aspect. This development has also made it possible to recognise intangible cultural heritage, which was ignored for a long time, as heritage to be protected and safeguarded.
Historical evidence on the use of mortars to meet several needs has existed for millennia. With reference to the characteristic historical periods of the city of Rhodes, mortar sampling was performed on historical constructions, masonry and architectural surfaces. In the present work the different mortar technologies are investigated aiming to answer questions regarding their finality, i.e. whether their differences arise mainly from the various historical periods of construction or from the purposes they had to serve, imparting to the mortars the properties required by their function in the structure. Mineralogical, chemical, physical and mechanical investigations have been performed on characteristic samples after gradation. The exponentially declining function of the ratio CO2/H2O structurally bound to the CO2 content shows a continuous evolution of the kinetics governing the various mechanisms of carbonation of the binder or the formation of hydraulic components during setting, hardening and ageing of the mortars. The grouping of mortars in well-distinct ‘hydraulic levels’ is ascribed to the physico-chemical cohesion and adhesion bonds developed at the matrix and matrix/aggregate interfaces, respectively, allowing for the mortars to either bear continuous stresses and strains as joint mortars or provide compact impermeable renderings which harden even more on contact with water. Hence, parameters determining the diversification of the resulting mortar/matrix types concern the raw materials employed as binding materials and the production processing.
Optical (OM) and Scanning Electron Microscopy (SEM-EDS), μFT-IR spectroscopy and Gas Chromatography-Mass Spectrometry (GC-MS) have been used to ascertain, at molecular, nano- or micrometric level, the state of conservation of the mural paintings at the Kariye Museum in Istanbul. The characterization of the original organic and inorganic materials used in the painting preparation and plaster layers allows to define the painting techniques. Furthermore, the nature and the extent of the degradation phenomena and the materials used in subsequent restorations have been identified. The poor state of conservation of the pictorial cycle, due to quite severe deterioration processes, noticeable detachments, presence of salts, etc., strongly calls for a prompt intervention, guided by an exhaustive and appropriate scientific approach.The present study offered the possibility to compare the results obtained by different techniques on the same samples, in order to evaluate performance, advantages, limits of each of them.
On-line monitoring or even closed-loop control is necessary to avoid over-cleaning in case the ablation process is not self-limiting. Therefore, the laser-induced breakdown spectroscopy (LIBS) was used. Basic investigations were carried out on original sandstone samples (Elbsandstein) with strong encrustations as well as medieval stained glass samples (13th century from Cologne Cathedral). The spectroscopic study has shown that the plasma emission can be used for determination of the elemental composition of the ablated material. The plasma was initiated by 248-nm pulses of an KrF-excimer laser (30 ns FWHM). For the spectroscopic analysis, a grating spectrograph in combination with an optical multichannel analyser was used. For the glass and stone samples we obtained a continual alteration of the LIBS spectrum (vanishing of peaks and generating of new element peaks) during the removal process. Thus, certain element peaks can be used to distinguish between encrustation layer and valuable underlying material. To show the potential of LIBS we designed an experimental laser cleaning set-up including closed-loop LIBS control and demonstrated successful automatic cleaning of an original glass fragment.
It has become a common practice to include diagnostics and archaeometric studies during a masterpiece restoration. The advantages and limits of this approach are now topic of discussion in the community of researchers that is growing up quickly. The bronze burial monument of Pope Sixtus IV (1471–84) by Antonio del Pollaiolo, now in the Treasure Museum in the Vatican was intended to be located at the center of a chapel, this explains its apparent asymmetry: lack of height and large base. The restoration of the burial monument started in May 2007, it was carried out by first fulfilling a series of non-invasive analyses using a transportable EDXRF to map the composition of the alloy and evaluate the diagnostic capabilities for deterioration processes of the bronze surface. As a consequence of the first non-invasive diagnostic campaign, a second campaign of micro invasive tests was planned and carried out. The samples were analysed with SEM-EDS and XRF techniques. In this article some of the results of the EDXRF tests will be shown together with the procedures set up to maximize the diagnostic information obtained and minimize the need of microsampling from the artefact. The results and the statistical analysis of data show that a straightforward planning of the measurements can give several, sometimes unexpected, results in the definition of the state of conservation of the monument and also from an archaeometric point of view. With a high amount of data, the use of statistical analysis is necessary, for example in our case, the analysis of the variance confirmed the hypothesis of the use of different alloys for the elements of the panels.
This paper presents the results of a multidisciplinary study on two 14th century canvases attributed to Lorenzo Veneziano. In particular, two non-invasive spectroscopic techniques have been employed, imaging spectroscopy (IS) and X-ray Fluorescence (XRF). In order to perform the analysis in situ, the employed instruments were transportable. The purposes of this analytical approach were mainly to corroborate the authorship and to study the painting materials and execution technique of these two canvases. These two artworks are considered precious because they represent two evidences of the early use of the canvas support in this early period in the North of Italy. Since the paintings are in very delicate conditions, the principal objective of the investigations was to gather as much information as possible avoiding invasive analytical procedures. The paper discusses the potentialities and limitations of the integration of a mobile XRF spectrometer with a transportable IS device, developed to study large-sized surfaces. By means of the elemental composition given by XRF and the colourimetric data and reflectance spectra collected by IS, it has been possible to identify different materials (gypsum, azurite…) and to achieve a better understanding of the employed painting technique. The data confirm that the two canvases have been produced with painting materials and technique which are in good agreement with those of Lorenzo Veneziano. The obtained results illustrate the suitability of the integration of XRF with IS to solve similar analytical issues when sampling is not possible.
This article illustrates a preventive conservation methodology for wooden collections and objects based on the respect of the historic climate, as established by the European standard EN 15757:2010. This requires the knowledge of the past indoor climate that should be kept unchanged in the present and the future, because discontinuities would be noxious for conservation. To this aim, a very vulnerable object, i.e. a wooden inlay bookcase cabinet built by G.M. Platina in 1477 AD has been considered. The paper illustrates the methodology used to reconstruct the historic climate, i.e. with proxy data from 1500 to 1715 and from 1716 to 2009 with instrumental observations. For the present, the indoor climate of the exhibition room and the cabinet response have been investigated to remove the perturbing factors that are damaging the cabinet. For the future, the ENSEMBLES model has been used for a probabilistic forecast of the temperature and humidity over the next century, the sustainability and the potential risk for conservation connected with the expected climate change. This research constitutes an example of a novel methodology based on the relevance of the Historic climate, and includes a synergistic effort of climatologists, material scientists and conservators, to be applied for preventive conservation and to evaluate and face the negative impact of the expected climate change.
In this paper, we present an application of the infrared thermography to the study of illuminations. In particular, we analyze a 15th century antiphonary from the Biblioteca Angelica of Rome to characterize the conservation state and the structure of the illuminations on the occasion of its planned restoration. We show the results achieved from the stratigraphic investigation of the gilded surface, the parchment substrate and the underdrawing. The obtained information have been, then, used to direct the necessary restoration steps and also to assess the effectiveness of the treatments by a comparative analysis of the thermograms recorded before and after the restoration.
Fifty crucible fragments and 10 fragments of the melting furnace of the forest glassworks of Südel (1723–1741, Ct. Luzern), were analyzed by petrographic, mineralogical and chemical techniques in order to assess the temperature reached in the melting chamber and to find out which raw materials were used to make the crucibles and the melting furnace. Since the crucibles were used in the melting furnace, the temperature estimations were based on both the crucibles and the refractory fragments, as they were parts of the same system. The temperature range in the melting chamber, estimated by the structural order of the new-formed cristobalite, points to a temperature range between 1350 and 1500 °C. However, three crucible samples recorded extreme temperatures as high as 1650 °C, suggesting very high flame temperatures for wood fuel. The analyzed red bricks were made with local calcium-poor clay. One of them was tempered with refractory fragments, demonstrating an in-house production and the recycling of such a material after its use. The crucibles and the refractory bricks were made with the same refractory clay. The former using unprocessed clay and the latter blending clay with chamotte. A comparison with Sidérolithique clayey sand samples from the Swiss Jura, shows strong affinities which may rule out the archaeological hypothesis of an exclusive provenance of such clays from Germany, suggesting an import from the Swiss Jura mountains.
This paper presents a study regarding the hygro-thermal conditions to which the violin Guarneri “del Gesù” (1743), known as the “Cannone”, is subjected during its conservation and occasional use in concerts with special attention on its mass and dimensional variations. Several environmental measurement campaigns were planned and carried out using relative humidity and temperature probes. The violin mass variation was measured continuously inside the display case where it is conserved, and before and after concerts by means of a special exhibition frame integrating a precision balance. These measurements enabled reproducing the thermal and hygrometric variations to which the violin is normally subjected using a purposely-developed portable climatic chamber, and also enabled measuring the consequent hygroscopic and thermal deformations in selected points by means of a purposely-developed measuring frame. An empirical model for computing the mass variations according to the variation of environmental conditions was implemented and verified and the typical mass variation consequent to the use of the violin during concerts was also determined. The violin's thermal and hygroscopic deformations were measured in selected points for given temperature and relative humidity steps. The paper includes a discussion about the possible impact of hygro-thermal variations on violin conservation.
To assess the possible effects of mechanical loading on the conservation of historical wooden musical instruments, a research project was carried out on the violin Guarneri “del Gesù” (1743), known as the “Cannone”. This paper refers to the results obtained by studying the deformations to which a violin is subjected after being tuned, with special attention to the viscous and mechano-sorptive behaviour (as in a concert environment for example). The amount of viscoelastic creep was quantified under normal tuning conditions, and the mechano-sorptive creep was quantified using a dead mass resulting in 55% of the elastic deformation obtained after tuning. The viscoelastic and mechano-sorptive deformations were clearly observed. These deformations were completely recovered once the violin was unloaded, demonstrating that this violin structure is appropriately dimensioned for the applied stresses.
A chance discovery beneath Christ Church Cathedral, Oxford has brought to light some very well-preserved 17th century van Linge enamel-painted glass fragments. Deterioration was in most cases minimal and largely limited itself to the blue areas of the fragments. Here, cracking in both the enamel and the glass surface beneath it was observed, which resulted in detachment of the painted enamel and of some of its underlying glass in the more severely affected areas. This study investigates the deterioration mechanisms involved and demonstrates that cracking was probably brought about by different levels of expansion and contraction experienced by the paint layer constituents in response to fluctuations in temperature. Differences between the thermal expansion coefficients in the enamel paint and glass are thought to induce the formation of microcracks within the enamel. Certain physical properties of the blue enamel were expected to increase these thermal expansion coefficient differences, making this colour more susceptible to deterioration, resulting in the selective detachment observed in these painted fragments.
Icons, manuscripts and liturgical objects of rare quality and variety constitute the cultural heritage of Eastern churches. For the first time, a very unique set of data on the Near-East icon painting technique is made available through this publication. It includes analyses of wood support, canvas and painting layers of about 18 icons painted in the region from the 17th to 19th centuries. Through the implementation of a variety of photographic and analytical methods (IR and UV imaging, X-Ray, xylological analyses, staining tests, SEM-EDX, XRD, μ-Raman), the icon making technique is investigated. Walnut tree appears to be the preferred wood employed in this region to make the icon support. The latter is often of very good quality and special care is given to the assembling technique. The presence of canvas soaked in size is frequent in Melkite icons. The gilding technique on bole is especially used and various punches, chisels or grained patterns creating sophisticated decorative ornamentations are often employed. In all the icons analyzed, about 15 different pigments have been found. A characteristic of these Near-East icons is the systematic presence of orpiment in mixture with other pigments to obtain a green coloration.
Throughout the history of mankind, ports have been the hub of coastal towns and the changes undergone there have reflected the town's historical, social and economical evolution. Nevertheless, building and adapting them implies a constant battle between technology and the forces of nature, requiring the application and development of the most advanced techniques in the construction process. Taking this into account, it seems paradoxical that, despite their indisputable cultural, historical and technical value, in cities port constructions that compose the seafronts of our cities are forgotten cultural heritage. These assets required technical, human and economic resources for their construction far superior to those necessary for building their surroundings, as is shown in the case study, and are a true reflection of the inheritance of past generations, helping us to understand a town's history and identity. For this reason, it is thought necessary to claim the right to the heritage of these constructions and contribute to the study of underwater cultural heritage in ports, so that this may be a basis for appraising and conserving it where necessary. In order to achieve this, it is fundamental to establish which aspects it is necessary to know in these building works. It is especially of interest to know what building systems were used and how they were put into practice, not forgetting the materials used in the construction process. This article has been written with the aim of bringing the latter to light.
The case study of the port of Cartagena set out in this paper is intended to demonstrate the scientific, technical and cultural value of these constructions and so to contribute to the study of the unknown Mediterranean underwater cultural heritage as a prerequisite and essential step towards the promotion of its value and conservation. The need to erect an arsenal in the city of Cartagena during the 18th century required the construction of an artificial basin in the hidden Mandarache Sea. This project involved a technical struggle against nature requiring the latest expertise for its construction at that time. The study of the designed building solutions, the techniques carried out and the organisational processes performed in these works prove that they are an example on applying the latest know-how at that time by some of the most prominent scientists and technicians in the country. These works were performed by military engineer Mr. Sebastian Feringán Cortés in cooperation with sailor and scientist Mr. Jorge Juan and Santacilia and further consulting with Mr. Antonio de Ulloa. Such significant underwater works in the Arsenal of Cartagena are stated in the records of the time. Mr. Sánchez Taramas (1769) accounts them as unique and considers their study as utterly useful for training future engineers. This article was performed upon the analysis of different historical dossiers found in the Simancas General Archive (Valladolid, Spain), containing manuscripts written by the architects responsible for the building work whose results achieved highlight their historical and technical value and can be applied to other works of similar features around the Mediterranean basin.
The Temple of the Emerald Buddha in Bangkok, Thailand is noted for its glass mosaic decorations on exterior walls and statuary. The original mosaic artwork dates to the early 19th century and is composed of variously-colored, mirrored glass pieces. In this work, we examine the chemical composition and optical properties of the red glass manufactured at that time. Through the use of X-ray and optical spectroscopies, we demonstrate evidence that the 19th century craftsmen produced “ruby-gold” glass, wherein the red coloration is caused by the dispersal of nanoscale metallic gold particles throughout the glass matrix.
The floor in a building is an integral part of the interior and is usually considered as a very valuable component of decoration. The flooring style, construction, manufacturing technologies, finishing and maintenance reflects local traditions, available resources and craftsmanship. Traditional techniques of parquet surface finishing were used in manor houses of South-Eastern Poland until the 1st half of the 20th century. Unfortunately, the major part of historical wooden parquets was irreversibly destroyed due to the introduction of collective property and the expropriation of manor houses after World War II. It is necessary to develop the knowledge related to the chemical, physical and mechanical properties of antique floor heritage, for its proper conservation. Near infrared spectroscopy was applied here for rapid and non-destructive recognition of natural finishes traditionally applied for the protection of the wooden floors. The system was capable to correctly identify the reference finishes applied on contemporary wood samples. However, analyses of antiques floors were more problematic. The set of samples of original antique decorative wooden flooring was collected from manor houses in Tarnowiec and Falejówka. Both houses contained well preserved wooden flooring that had not been subject to restoration in the past. The method shows great potential, even if in some cases an ambiguous classification was obtained. The reasons included natural deteriorations of floors during service life. Originally used substances might change their chemical composition during lifetime as a result of aging, weathering, usage and external contaminations. Given that, it was concluded that the results of spectroscopic evaluations might provide valuable assistance to conservators and facilitate decisions on the proper object maintenance.
A comparative study on the removal of three different types of encrustation on marble has been carried out using infrared and ultraviolet nanosecond laser pulses. The fundamental and 3rd harmonic of a Q-switched Nd:YAG laser system have been used to remove dark dendritic, thin black compact and biological encrustation on marble. These three types of encrustation on Greek monuments have been previously described and relevant experimental work has been carried out. In the present work, samples from completion of Balanos restoration of Parthenon, from the Temple of Apollo Epicures as well as other regions have been used. It has been shown that both thin crust and biological deposits were adequately cleaned using the 3rd harmonic of the Nd:YAG system. The yellowing effect observed when using the 1064 nm pulses is definitely avoided in this case. However, the fundamental wavelength appears more efficient when dendritic thick black crust must be removed. To evaluate the results, X-ray diffraction (XRD) analysis has been carried out, while optical microscopy, cross-section analysis and scanning electron microscopy (SEM) were used to examine the irradiated areas and determine the cleaning efficiency of the two wavelengths applied.
This study describes the results of petrographical, mineralogical and chemical analyses carried out on coarse tempered cooking pottery, sampled in the archaeological sites of Herdonia , Posta Crusta (Ordona, FG) and San Giusto (Lucera, FG). From the latter site, two fragments of a pottery kiln, coeval with sherds (IV and V centuries AD), were also investigated. Two groups of clayey sediments of different nature (alluvial and marine) sampled in the neighbouring of the archaeological sites were also analysed. By means of the petrographical analyses, all cooking pottery and the two kiln fragments were grouped in the same coarse tempered group, characterised by the scarce presence of trachytic and glassy fragments, anhedral and zoned augitic pyroxenes and feldspars. PXRD analyses show an abundant presence of quartz and feldspars, followed by pyroxenes and variable quantities of calcite and hematite. Among clay minerals, illite plus muscovite are more abundant than smectite. XRF analyses data display SiO₂, Al₂O₃, Fe₂O₃ and K₂O as main oxides, with variable quantities of CaO. In the case of the clayey samples, petrographical investigations on thin-section of psammitic fractions outlined the differences between Argille subappennine (Marine group—Pleistocene) and the alluvial deposits of Celone River (Alluvial group—Holocene). The occurrence of volcanic products, chert, garnet, quartzarenites and limestones in the archaeological materials and in the alluvial samples, let us suppose that cooking pottery was made with alluvial clayey silt. The apparent chemical discordance between pottery and alluvial samples bulk compositions can be due to textural and compositional variability of the alluvial deposits. All ceramics were fired in oxidising conditions, although in many cases a "dark core" was still present. Textural features, observed through petrographical microscope, and PXRD analyses suggested a firing temperature between 600 and 800 °C.
Late Apulian red figured pottery  from Egnatia (Fasano, Brindisi, Italy) was studied in order to widen the view on this ceramic class in Southern Italy. Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) provided the samples elemental composition that allowed to make provenance hypotheses. Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) with Energy Dispersive Spectrometry (EDS), supplied information about the minero-petrographic features of the objects to better understand their production technology. The set of results highlighted the contemporary presence in the Apulian land in the late 4th century BC of both local and imported finds and showed the existence of two different kinds of local production, the “classic” Attic and a peculiar one, characterized by the application of an engobe layer before the black gloss. Our previous studies resulted in the discovery that an engobe layer, with similar chemical and minero-petrographic characteristics, was present in finds from another site in central Apulia (Monte Sannace). So the discovery of red engobe on fragments from Egnatia, proves that its use was not an isolated occurrence, but was quite common in the production of red figured in Apulia during the Late period, appearing as a peculiar technological mark of Apulian potters.
During the 20th century, many innovative binders have been rapidly introduced to the art world and soon became popular as artists’ paints and pictorial media. However, despite the advantages that new synthetic materials presented, oil paints have never been entirely substituted. Indeed, this paper focuses on the results provided by the scientific analysis of a group works from the oeuvre of Lucio Fontana (1899–1968), all of which created between 1960 and 1964 using oil-based media, and aims to illustrate how oils contained in the pictorial media have influenced these works’ respective ageing and degradation processes. Despite the apparent coherence in the behaviour of many of Fontana's creations, some artworks revealed discrepancies in terms of the physical and mechanical behaviour of the pictorial films and in alterations resulting from degradation processes. Samples taken from case studies belonging to the Olii and Fine di Dio series were analysed using optical microscopy, X-Ray Fluorescence (XRF), Fourier-Transform Infrared Spectroscopy in attenuated total reflectance (FTIR-ATR) and Gas Chromatography-Mass Spectrometry (GC-MS) in order to study and identify the materials employed by the artist and the products of their degradation processes. These analyses gave unexpected but useful results (such as the presence of non-drying or slow-drying oils in the paint formulations) which not only provided us with new insight into the nature of the constituent materials, but also facilitated the elaboration of correct conservation measures and suitable restoration interventions.
The study refers to the visual representation of the coastal front of the historical center of Thessaloniki in northern Greece and its changes that have occurred through the years. Most of the old town was destroyed by fire on August 18, 1917. A few years later, the French architect and archeologist Ernest Hébrard proposed the reconstruction of the city centre, but his plans were never fully implemented. Since then, a series of interventions changed the form of the old town and consequently the coastal cityscape. The research was initially based on the photogrammetric processing of archive aerial images (1938) of Thessaloniki's city centre. Besides the vertical images, high oblique aerial images dated back to 1932, proved to be a significant source of information. A rich archive of old photographic material, sketches, drawings and gravures of the coastal forehead of the city was also used. Ortho-images of the coastal front, derived from laser scanning (2010), and a 3D model of the historical city center, derived from the stereo photogrammetric process of aerial images (1990), contributed decisively at the multi temporal study of the city front. The main outcomes of the present documentation study are the 3D representation (at scale of 1:200, accuracy 5 cm) of temporal changes of a part of the coastal front of the historical center of Thessaloniki and the 2D representation (at scale 1:100, accuracy 1–2 cm) of these changes with respect to variations on skyline, lacunas, interventions in old buildings, etc.
The adhesive properties of BEVA®371 used in the lining of paintings and the reversibility and invasiveness of the operation as a function of the different application conditions has been investigated in this work. Peel and lap shear mechanical tests on specific samples were then done in order to study the adhesion effectiveness. After the tests, cross-sections of samples were observed under optical microscope to examine the adhesive distribution; moreover, the samples were examined with SEM analysis to evaluate the adhesive invasiveness. Also, a series of removal tests of lining fabrics from an original painting were done in order to establish the method allowing the highest degree of reversibility. The influence of artificial ageing was evaluated on a series of samples subjected to thermal-hygrometric stress for some months. Changes in the elastic and adhesive properties were observed, but all together the study indicates that from the mechanical point of view BEVA®371 is a quite stable material for lining operations made with properly controlled application methods.
This paper describes how some innovative methodologies have been designed and employed to support the restoration of the Madonna of Pietranico, a terracotta statue severely damaged in the 2009 earthquake. The statue, fragmented in many pieces, has undergone a complex restoration performed by a multidisciplinary working group. The contribution of digital technologies was planned from the very beginning, since the complexity of this restoration originated the design of innovative procedures for managing the reassembly and restoration process. The Madonna test bed was therefore an example of how technology innovation could be pushed by clear application needs. A first important contribution was the study of the recombination hypothesis of the fragments. This initial phase was performed on digitized 3D models of the statue fragments, with the aim of reducing fragments manipulation, preventing further damages and increasing the capabilities to rehearse and evaluate different reassembly options. The accuracy of the 3D scanned models and the new recombination procedure introduced in this paper allowed to manage this phase in the digital domain with successful results. The digital 3D models were also used to design and produce an innovative supporting structure, constructed with a rapid prototyping device. Another important contribution concerned the study and virtual restoration of the polychrome decoration of the statue; our aim was to reproduce and restore in the virtual 3D domain the very complex original polychrome decoration, on the base of the remaining traces. Consequently, new virtual painting functionalities have been designed on the MeshLab platform (an open-source tool for 3D models visualization and manipulation) for reproducing pictorial decorations over digital 3D models and have been assessed on this specific test bed. This allowed us also to investigate the complexity of the virtual repainting process and to identify further technology enhancements. Finally, computer graphics technologies have been also used to produce a video that tells the story of the restoration.
Many cultural heritage organizations responsible for providing access to large online collections recognize the potential value that social tagging systems can add to their collections. Projects such as Steve.Museum aim to give online users a voice in describing the content of publicly-held collections of digital heritage, through online social tagging and annotation tools. However, there are a number of unresolved challenges associated with re-using community tags, aggregating them within the museum's authoritative metadata stores and incorporating them within museum "metasearch" services. Although social tagging sites provide simple, user-relevant tags, there are issues associated with the quality of the metadata, the scalability compared with conventional indexing systems and a lack of interoperability across social tagging and annotation systems. In this paper, we propose an integrated system that overcomes many of the limitations of social tagging systems and maximizes their potential value-add within the context of museum collections. The Harvesting and Aggregating Networked Annotations (HarvANA) system firstly enables communities to attach tags/annotations to digitized 3D museum artefacts through web-based annotation services. The annotations/tags are represented using a standardized but extensible Resource Description Framework (RDF) model and an ontology-directed folksonomy. This approach facilitates interoperability between tags/annotations. Secondly, the system uses the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) API to automatically harvest the annotations/tags from distributed community servers. The harvested annotations are aggregated with the authoritative museum metadata in a centralized metadata store. The HarvANA system provides a streamlined, interoperable, scalable approach that enables cultural organizations to leverage community enthusiasm for tagging and annotation, augment their institutional metadata with community tags and enhance their discovery and browse services over 3D models.
The evolution of real time 3D graphics technologies in combination with high bandwidth Internet connections and modern Web browsers enable users to explore complex 3D scenes. As a rule, a virtual visitor has to manually explore the geometrically complex 3D model in order to discover points of interest. This manual exploration is a time consuming process that, in some cases, can be assisted by sets of predefined points of interest. In this paper, we propose the annotation of 3D scenes in order to equip the user with a text based 3D scene search engine. The search engine provides a query mechanism that unburdens the user from the time consuming process of manually exploring vast 3D scenes. It responds to queries by exploiting the metadata of each 3D model and returns textual and visual information along with a group of links that correspond to relative points of interest within the 3D scene. The search engine allows the virtual visitor to automatically be transferred to a specific point of interest. We have built a Web accessible prototype system that is able to handle queries related to historical data, topological relationships and architectural properties of buildings. A number of 3D reconstructions covering urban areas of cultural importance located in Northern Greece have been annotated and used in the search engine as case studies. The prototype system is based on open source technologies and on a hybrid metadata schema that is derived from the MIDAS Heritage and MACE schemas.
In the field of Cultural Heritage, image analysis represents an indispensable practice for restorers to collect information about the state of preservation of monuments and artifacts and plan restoration interventions. In addition, during the last two decades, the wide spread of remote sensing technologies and the possibility to build 3D reality-based models of artifacts allow the extension of image analysis to 3D environments. In this context, the purpose of this contribution is to show the results of investigations held in order to provide a methodology for the automatic detection of deteriorated areas within architectures and artifacts using colour images as a field of examination. Using both 2D and 3D segmentation approaches, our methodology aims at speeding and efficiently performing the automatic detection of deteriorated zones within Cultural Heritage and therefore segment 3D digital models acquired using different survey technologies. Within our investigations, we selected case studies concerning recurrent deteriorations, such as, for example, detachments, cracks and chromatic alterations; we run them both to manual and to automatic recognition and selection tests, in order to compare the results obtained using these approaches and evaluate the reliability of the automatic one. Results comparison included computational and user time, quantification of the deteriorated area error between manual and automatically detected zones. Additional parameters characterizing the specific type of deteriorations were also computed for each case study. Comparison between the automatic and the manual procedure showed that the automatic detection is faster and reliable in all our selected case studies, with evident improvements in the efficient evaluation of the entity and extension of deteriorated areas on 3D geometry.