Chemical characterization and AMS radiocarbon dating of the binder of a prehistoric rock pictograph at Tadrart Acacus, southern west Libya

The analysis of the amino acid (AA) content in fragments derived from a prehistoric rock pictograph (Lancusi rock shelter) at Tadrart Acacus, southern west Libya, revealed the presence of material containing peptides differing in solubility in hot acidic or alkaline solutions, as well as in AA composition and racemization. Water-soluble components were constituted of low molecular weight peptides with high racemization of aspartic acid and alanine, whereas the water insoluble material consisted of species of a more complex AA composition and a different degree of racemization. The proteinaceous materials were assumed to originate from matter that had undergone over time different diagenetic processes. The water insoluble peptide-containing material was separated from the rock substrate by acid hydrolysis, dried and the resulting residue submitted to radiocarbon analysis. Accelerator mass spectrometry (AMS) yielded an approximate age of 6145 ± 70 years B.P. (before present), which is consistent with archaeological inference and the climatic reconstruction of central Sahara. To our knowledge the present work represents the first attempt of direct radiocarbon dating of rock art in the Sahara desert.     

Laser cleaning of terracotta decorations of the portal of Palos of the Cathedral of Seville

Laser cleaning has been used to restore the soiled terracotta statues and decorations of the tympanum of the portal of Palos of the Cathedral of Seville in Spain. A simultaneous laboratory study performed on a representative sample helped to identify the optimum laser conditions to remove the dark soiling layer produced by air pollution. It was found that irradiation at 1064 nm with a Q-switched Nd:YAG laser was more effective than the harmonic wavelengths of 532 or 266 nm. LIBS and Raman microscopy gave information on the composition of terracotta and identified the presence of a protective layer made of gypsum and calcite. As detected by Raman spectroscopy, laser irradiation caused the elimination of the carbon component of the soiling layer and the appearance of an anhydrite component in the laser irradiated gypsum layer applied over the terracotta substrate for protective purposes. Local heating of the surface caused by laser irradiation at 1064 nm, the laser wavelength used for restoration of the portal, might be responsible for a process of partial dehydration of gypsum into anhydrite.     

La Medusa by Caravaggio: characterisation of the painting technique and evaluation of the state of conservation

The oil painting “La Medusa” executed by Caravaggio at the end of the XVI century on a wooden shield, was investigated by integrated physical–chemical and analytical methodologies in order to obtain scientific data capable of elucidating the state of conservation and the painting technique. Optical (OM) and electronic (SEM-EDS) microscopy, micro-FT-IR spectroscopy, gas chromatography–mass spectrometry (GC–MS) and pyrolysis GC–MS were applied on two microfragments and some organic samples obtained by solvent extraction using the swab cleaning technique. The obtained results indicated that Caravaggio probably reused an old shield as a previous gypsum preparation layer has been detected under the original painting layers. He used white lead, natural earths, verdigris and lead–tin yellow type I mixed with drying oils to paint. The considerable amount of amorphous particles of copper chlorides found in the green pigment verdigris suggests that it could have been produced according to the ancient recipe of verde salsum described by Theophilus. Mordant gilding has been identified on the upper part of the shield that can be related to an abandoned experiment to give the painting a mirror-like reflecting effect. Three different varnishes layers have been detected above the painted surface. The original and restoration varnishes have been identified and they contain a mixture of drying oil, mastic and turpentine and some beeswax. Cleaning tests, performed with different organic solvents, suggest the use of isopropyl alcohol as cleaning agent because it is less efficient in comparison to others solvents; thus it ensures a careful and controlled removal of the varnishes.     

Diagnostic analysis of the lesions and stability of Michelangelo's David

This work presents an account of the results of diagnostic analyses on the lesions that were first detected in Michelangelo's David in the mid-1800s. After summarizing the events that may have affected the statue's stability and the state of deformation, the authors present the results of the Finite Elements Method (FEM) tests conducted on the digital model of the statue's surface. The analysis of these results made it possible to identify the static conditions that generated the cracks in the lower part of the left leg and in the tree trunk of the David. Lastly, the current situation was analyzed from the perspective of both deformation and stresses, evaluating the statue's stability also as regards its structural response to the seismic activity at the level expected for the Florence area.     

mtDNA analysis of the human remains buried in the sarcophagus of Federico II

The sarcophagus containing the remains of Federico II, located in the Cathedral of Palermo (Sicily, Italy), was opened on 1998 to perform a multidisciplinary survey [1]. Next to the remains of Federico II and in close contact with them were laying two other skeletons belonging, according to historical records, to Pietro II di Aragona and to an anonymous person (“The Third Individual”), probably a woman. The bones appeared severely deteriorated. Chemical analysis performed on bone samples excluded that the bodies underwent some kind of embalming process. The analysis of mtDNA from bone samples taken from the three skeletons was successful in only one of the two labs involved. The HVR1-mtDNA sequence (region: from nt 16,035 to nt 16,395), obtained from the bone samples of Federico II and “The Third Individual” appear identical but bear double peaks at the same nucleotide positions, suggesting mixing (i.e. contamination) of different mtDNA types. The HVR1 sequence obtained from the bone sample of Pietro II di Aragona does not present double peaks and differ from the Cambridge Reference Sequence (CRS) at six nucleotide positions. Cloning experiment of the Federico II amplicon demonstrated that the mixed mtDNA types are only two: one identical to CRS, the other identical to the sequence of Pietro II di Aragona. A reconstruction of these data are proposed in the Discussion. Due to the problematic context in which this study was carried out (mixed and deteriorated biological material, failure to replicate results in two different labs), our results and reconstruction can only be offered on a tentative basis. It is hoped that the data presented in this study will reveal useful, for future comparison, if further molecular genetics research will be carried out on the royal dynasties that ruled Sicily in the early centuries of the past millennium.     

The sound of the cathedral-mosque of Córdoba

In all cultures, and in many different ways, man has searched for God, and architecture has been a fundamental element in this search. The cathedral-mosque of Córdoba is a unique example of this particular history of the search for God through architecture: first with its choice of a horizontal space on a human scale, adapted to the praying practices of the Islamic period, and then with a vertical space, symbolizing the grandeur and spirituality of the Christian period. The different religions that have been accommodated in this building in the course of its history have brought with them different conceptions of space and different liturgies. These needs, peculiar to each form of worship for the propagation of the faith, imply different acoustic conditions for the particular space. The aim of this study is to look at the sonic characteristics of the space and analyze the evolution of its acoustic characteristics and their adaptation to the different liturgical needs of each period.     

A study on a set of drawings by Parmigianino: integration of art-historical analysis with imaging spectroscopy

Due to the extreme fragility of paper-based artefacts, few techniques are available for scientific investigation and characterisation of ancient drawings or paper-based artefacts. Image reflectance spectroscopy represents an almost unique tool for scientific analysis on precious drawings, for which even micro-invasive techniques of analysis cannot be used. Indeed, beside the high fragility of the support, drawings and graphical works are typically characterised by a very limited number of artistic materials, which in principle could give information on the work of art. In this paper an interdisciplinary study on a set of drawings by Parmigianino (1503–1540), selected from the collection of the Uffizi Gallery in Florence, is presented. Non-invasive measurements of image spectroscopy (IS) have been employed to support the work of art-historians in the critical re-examination and interpretation of the graphical work of the artist. The multispectral analysis has been carried out over the extended spectral region (400–1700 nm), in order to provide simultaneous indications both on the pictorial materials and on possibly underlying hatches. The data processing has been performed by means of Principal Component Analysis (PCA) and the elaboration of each case has been addressed to specifically respond to questions related to the art-historical problem.     

The funerary klinai of tomb 1 from Amphipolis and a sarcophagus from ancient Tragilos, eastern Macedonia: a physico-chemical investigation on the painting materials

Optical and SEM-EDS microscopy, X-ray powder diffraction and micro FT-IR spectroscopy investigations of the funerary klinai (couches) of Tomb 1 from Amphipolis and a stone sarcophagus from ancient Tragilos—two painted monuments made by Macedonian craftsmen of the Early Hellenistic period—identified the original materials and painting technique, as well as synthetic materials used as consolidants during past restoration treatments. The original organic binders and the superficial modern coatings have been identified by micro FT-IR spectroscopy applied directly to the sampled powders or tiny fragments and to their solvent—soluble fractions. The pigments identified on the couch of Amphipolis are: red and yellow ochre, cinnabar, Madder lake, paratacamite and antlerite, carbon black, calcium carbonate, kaolin and gypsum. The identification of egg and animal glue confirms the application of tempera and secco techniques. The detection of polymers such as polydimethylsiloxane, polyvinyl acetate and alkyd resins, is related to modern restoration products. The pigments attested on the paintings of the Tragilos' sarcophagus are: red and yellow ochre, Egyptian blue, malachite, carbon black, calcium carbonate and gypsum. The absence of organic binders combined with the constant presence of calcium carbonate in all the examined samples suggests the use of lime as the binding medium in the painted decoration of the sarcophagus. The presence of Paraloid B72 is related to recent conservation treatments.     

Silica glass interaction with calcium hydroxide: a surface chemistry approach

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.     

Ontology-based shape-grammar schema for classification of caravanserais: a specific corpus of Iranian Safavid and Ghajar open, on-route samples

As part of research in progress on the study and design of an ontology knowledge model, this paper focuses on development of a shape-grammar schema for extracting attributes of spatial organization of a subset of cultural heritage relics, namely, caravanserais, from a selected corpus with a common architectural language of design. First, shape-grammar rules for classification of caravanserais of the selected corpus are developed and are represented in drawing by using Auto CAD tool. Shape rules as a natural-language equivalent are then devised by describing design functions and clarifying the topology of shapes. Based on these shape rules in given text, the hierarchy of a shape-grammar schema in the Protégé knowledge representation tool is designed, and each shape rule is defined as an interconnecting individual (or instance) in OWL language. This schema will enable us to extract computer-based semantics of shape-grammar rules. To illustrate this innovative approach, a selected corpus was classified by using the shape-grammar schema with the support of knowledge extraction tools.     

Alteration behaviour of glass panes from the medieval Pavia Charterhouse (Italy)

The stained glass windows of the Pavia Carthusian Monastery are an important testimony of medieval glass making in which a wood-ash flushing component was used. Glass surfaces reveal alteration processes extending to depth, with evidence of microbial corrosion. Electron microprobe analyses coupled with EDS data allow the identification of different steps in the alteration process. Microbial attack occurs in an early stage and determines component leaching of the glass, with the development of reactions in which the crystallisation of gypsum is favoured.     

Chemical and lead isotope compositions of lead artefacts from ancient Thracia (Bulgaria)

Using inductively coupled plasma–atomic emission spectrometry (ICP-AES), atomic absorption spectrometry (AAS) and instrumental neutron activation analysis (INAA) the concentration of Ag, As, Au, Bi, Cu, Fe, Ga, In, Ni, Sb, Sn, and Zn in 53 samples taken from archaeological finds dated to 4th–2nd century BC and found in the territory of ancient Thracia was determined. Additionally using inductively coupled plasma–mass spectrometry (ICP-MS) and MS for determination of the lead isotope ratios in the samples was carried out. On the basis of these analytical results using cluster analysis for grouping the samples on the bases of the similarity in chemical and isotopic content and the available data from the literature for lead ore deposits in the Balkan Peninsula, the geological origin of the investigated archaeological finds was evaluated. That confirms the expectation that sources of lead might be almost all possible deposits of lead ores on the Balkan Peninsula—from Lavrion through Chalkidiki to the Rhodope mountain. The result indicates that the Thrace did not utilize one single lead source continuously but that lead was provided according to availability from different production centers.     

Archaeomagnetic investigation of a metallurgical furnace in Pisa (Italy)

An archaeological excavation has been carried out at Pisa (Italy), unearthing an ancient metallurgical workshop. Since archaeological burnt materials provide important records of direction and intensity of the Earth's magnetic field in the past and they can be used to better improve geomagnetic secular variation curves (SVCs), an archaeomagnetic study has been performed. This small copper-alloy furnace presents a circular concave shape covered with a thin layer of mortar, with some traces of heated clay surrounding the feature that confirms the high temperature reached inside it. Archaeological context dating points to the last firing of the furnace between the last quarter of the 13th century and the first quarter of 14th century AD, when then the metallurgical workshop was transformed in a warehouse. Archaeomagnetic sampling has been performed using the modified Thellier method, by collecting several, large and independently oriented aliquots of heated clay, forming the bottom part of the circular wall of the structure. Laboratory treatments have been conducted at the IGG-CNR ARCHEO_LAB (Pisa, Italy) and at St. Maur Palaeomagnetic laboratory (Paris, France). Analytical measurements of the thermo-remanent magnetization index acquired from the samples have been performed using a large cell induction magnetometer for large samples, and the characteristic remanent magnetization (ChRM) has been successfully isolated after an alternate field demagnetization cleaning procedure for each sample. The final mean archaeomagnetic direction has been calculated at sampling site (D = 6.9°; I = 52.8°; N = 9; k = 305; α₉₅ = 2.6°) following the Fisher Statistics, and it exhibits a perfect agreement with some coeval already published directions obtained from Mt. Arso lava flows, these latter being an important anchor point in the preliminary Italian secular variation curve. Comparison with the preliminary Italian SVC, the French SVC and the SCHA.DIF.3K archaeomagnetic regional model have permitted to define an archaeomagnetic absolute age confirming the conventional archaeological age, underlining the importance of this result into the Italian archaeomagnetic data set.     

Preliminary study of water mist suppressing ghee flame in historical building in the northwest China

In order to protect historical buildings in the northwest China from fire, the most of which are temples for Buddhism, water mist suppression system is chosen due to less damage on water-soluble decorations. This study is to investigate the feasibility and efficiency of water mist suppressing fire occurred in historical buildings. Eternal ghee lamp over the years is serious fire hazard for these temples. In this paper, the interaction of water mist and ghee flame under different external radiant heat fluxes is studied. Water mist was generated by a downward-directed single pressure nozzle. The heat release rate, carbon dioxide and carbon monoxide concentrations, and other important parameters of the interaction under various experimental conditions were measured with cone calorimeter. It is indicated that water mist can assuredly suppress ghee flame. But ghee combustion is enhanced for a short time just on discharging water mist, and then ghee flame is extinguished quickly under continuous water mist application.     

Financing the culture in Italy

The paper deals with financing the culture in Italy. The public expenses for the culture are shared as expenses of the government, of the regions, of the provinces and of the municipalities. The relationships of the cultural organisations with the public sector are very strong because they belong to the public sector, or they broadly depend on public funds.A specific attention is devoted to other forms of financing, about the role of the entrance fees and the entrances of the game “Lotto”, which subsidy the cultural goods and the Interministerial Committee for the Economic Planning (CIPE) allocations to the depressed areas. We will also be faced up to the examination of other sources of private financing as the sponsorships, the entrances of collateral services about museum visits (coffee and bookstore) and the supply of banking foundations. The fiscal incentives refer directly to the cultural institution or to the external financing of the nonprofit institutions by donations or sponsorships. Finally, the cultural institutions will have always to operate more and more by a strategic vision of financial and managerial field, on the basis of high qualitative standards. The activities and cultural projects will have to be able to attract additional sources of income in addition to the public one; the search of private financial resources is developed in a situation of increasing competition among the institutions, while tools of innovative finance have to be used to satisfy the increasing demand of culture. It is difficult nevertheless to define the possible best method of public–private financing, if you take consideration of the distinctive features of the different institutions and interests of the operators who are involved: artists, cultural institutions, public bureaucracy, besides the economic effects which follow alternative choices. The recent evolution of the institutional, financial and managerial models of the culture in Italy plans a larger integration between public and private sectors for a great involvement of individuals, enterprises and foundations about the financing of the cultural services offer.     

Investigations regarding the behaviour of historic glass and its surface layers towards different wavelengths applied for laser cleaning

The application of lasers for the removal of superficial deposits from historic stained glass is a comparatively new field of scientific interest. Experimental studies concerning the behaviour of glass substrates and the corresponding superficial deposits towards different laser wavelengths were carried out. The experiments were performed using wavelengths of λ = 193 nm (ArF-Excimer), 308 nm (XeCl-Excimer), 355 nm (Nd:YAG third harmonic) and 1 064 nm (Nd:YAG fundamental) in comparison to λ = 248 nm (KrF-Excimer). This comparison is due to the fact that the present knowledge is based on the 248 nm wavelength. Specially prepared model glass samples representing the original fragments and samples of organic polymers (formerly used as a protective material for historic stained glasses) were used to study the effects of laser radiation and were subsequently characterised by optical microscopy.     

Deacidification of paper using dispersions of Ca(OH)2 nanoparticles in isopropanol. Study of efficiency

The efficiency of a recently described non-aqueous method for paper deacidification using Ca(OH)₂ nanoparticles in isopropanol was evaluated by pH and colorimetric measurements and by the analysis of the degree of polymerization (DP). Samples of plain paper and paper with iron gall ink were tested. The results were compared with non treated samples and samples submitted to the traditional treatment with saturated aqueous Ca(OH)₂ solution. By comparing the two conservation methods, the aqueous one shows higher neutralization reaction kinetics than the non-aqueous one. The iron gall ink samples maintain their coloration closer to the original after the non-aqueous Ca(OH)₂ nanoparticles treatment, in contrary to the aqueous treatment that changes the ink aesthetics considerably. Artificial aging tests revealed a general increase in the aging stability of deacidified paper samples. The Ca(OH)₂ nanoparticles treatment can be an alternative for papers who can not be treated by the classical aqueous treatment, e.g. papers with water soluble components.     

The scientific approach to the restoration and monitoring of mural paintings at S. Girolamo Chapel – SS. Annunziata Church in Florence

The scientific approach to the restoration and monitoring of mural paintings, at S. Girolamo Chapel – SS. Annunziata Church in Florence, is reported as a fruitful example of the synergic collaboration between restorers and scientists in the planning and development of conservative interventions. Before restoration, the painting technique and the state of preservation of the pictorial cycle have been investigated firstly by close examination of the painted surfaces and then by optical and/or SEM-EDS microscopy and μFT-IR spectroscopy on appropriately selected samples. In particular, the original constituent materials and those belonging to subsequent restorations were characterized together with those originating from decay processes. In this mural painting cycle, a peculiar “fresco” technique has been used although an auxiliary binder for pigment distemper has been also employed. The use of this technique, sometimes in an improper way together with uncorrected restoration interventions, are the main responsible of the unsatisfactory state of conservation of many painted areas. Preliminary conservation trials and scientific studies were carried out to design the most convenient restoration intervention and to verify the correctness and non-invasive of the necessary operations. Special attention was devoted to cleaning procedures, continuously monitored by a physico-chemical methodology, mainly based on microinvasive, microscopic and spectroscopic investigations, to evaluate the efficiency, advantages and drawbacks of the proposed cleaning procedures and define the most appropriate ones. Finally, specific decay markers have been recognized, by a comparison of the results obtained from the detached samples with those deriving from artificially aged models, to be used for a correct future monitoring and maintenance of the wall paintings.     

Water dispersed polymers for textile conservation: a molecular, thermal, structural, mechanical and optical characterisation

With the aim of identifying new water dispersed polymers for textile conservation, the structure and properties of three commercial polyacrylates and one commercial polyvinylacetate were analysed. The characteristics of these materials, not previously used in the conservation and restoration fields, were compared with that shown by Primal AC33 and Mowilith DMC2 and SDM5, widely used as consolidating or adhesive agents of ancient textiles. To achieve a thorough characterisation of each polymer, molecular, thermal, structural and mechanical investigation techniques were applied on film samples, obtained from polymer water dispersions through water casting at room temperature and/or compression moulding. The photo-oxidative resistance of these materials was also assessed by artificial weathering of water cast films and by measuring the Yellowing Index (YI) as a function of the exposure time under xenon-arc lamp. Collected data were used to appropriately compare the performances shown by these polymers when applied on artefacts consisting of natural fibres. In particular it was found that, among the products not previously used in the conservation and restoration fields, a high potential for carrying out treatments on textiles is shown by the samples commercialised with the trade names of Acrilem RP6005 and Acrilem 30WA. These products, in fact, exhibit properties that make them suitable as substitutes for Primal AC33 and Mowilith DMC2 and SDM5, respectively, depending upon conservation needs. It was very interesting to note that Acrilem 30WA, also after aging, shows YI values lower than that shown by Mowilith DMC2 and SDM5.     

Monitoring detaching murals in the convent of Müstair (Switzerland) by mirror micrometry

In a parallel study, it has been shown by comparison of successive TV-holography campaigns that murals in the convent of Müstair (Switzerland) have progressively detached from their substrate over a time interval of 5 years (J Cult Herit 2009). Here, we focus on the dynamics of the ongoing detachment processes. In order to regularly measure small surface displacements in situ over a long duration of several years, a new method that we call Mirror Micrometry (MM) has been designed and implemented. This method monitors the reflection of a light beam by a mirror that is mounted to the surface of interest for the duration of the experiment. The mirror is designed to rotate about a pivot as small displacements in the detaching surface occur, thus deflecting the reflected light beam. Measurements over more than three years in the Convent Church and in the Holy Cross Chapel reveal various types of surface displacement perpendicular to the wall surface. These are correlated with relative humidity (RH) changes in the room climate. Reversible short-term variations of approximately ±5–10 μm occur with periods of one to several weeks and relate primarily to weather changes. Reversible long-term variations of ±5–10 μm correspond to averaged seasonal humidity changes. Irregular and irreversible movements in increments of 20–30 μm record very localised progressive detachment steps. A semi-quantitative correlation of approximately 1 μm surface displacement per 1% RH change is calculated. Based on the fact that nearby measuring points can simultaneously move in opposite directions, a geometric model is drawn to explain deformation by hygric swelling and shrinking of different shapes of detached layers.