Journal of Cultural Heritage最新文献

Artificial intelligence can lend a helpful digital ”hand” in the restoration process of deteriorated cultural heritage items as well as towards an increased visitor interest in the museum exhibits. To this purpose, the present paper proposes a deep learning approach to repair the missing content and to recreate a visual counterpart of a degraded artefact by a 3D rendering of the semantic inpainted version. The new approach is constructed by means of some of the most recent and successful deep learning models for image inpainting and 3D reconstruction, namely stable diffusion and neural radiance fields. The method is tested in the scenario of ceramic artefacts, where the end visual result has a bigger impact. The ability of the novel technique to creatively reproduce a realistic and plausible 3D surrogate of broken archaeological objects shows the potential that AI has in supporting specialists with preserving the cultural heritage and bringing the museums into the public spotlight.

The archaeological site called El Pueyo de Marcuello (Huesca, Spain) is an Iron Age urban settlement, geographically situated in inland Iberia, and dated of the second half of the first millennium BCE. The nature and manufacture of their archaeological remains allow identifying this site as a contact point for relevant exchanges, with remarkable connections with Central and Western Mediterranean cultures. These cultural influences and exchanges were investigated through the characterisation of the ceramic objects found during the archaeological excavations. More than forty fragments were studied, including some of the most peculiar ceramic types, and analysed by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and Mass Spectrometry (ICP-MS). The petrographic observations of the thin-sections highlighted two ceramic fabrics, with a similar matrix and mineralogy, but the second one using sparite crystals of crushed calcite as intentionally added temper. The statistical treatment of the chemical data supported the identification of two main compositional subgroups; both included very similar low-calcareous clay bodies. All these data allowed for highlighting a main production, with two body fabrics, but both used to produce all ceramic types, either traditional or ceremonial. These objects could have been largely manufactured in local workshops. The materials from El Pueyo de Marcuello highlighted the extent of the relationships in areas of the Iberian inland, also connected to the rhythms of Mediterranean world, during the Iron Age.

Emerald green pigment was widely used in painted cultural artifacts during the 19th and 20th centuries. However, this pigment is inherently unstable, leading to a certain degree of degradation, thereby capturing the widespread attention of research scholars due to its degradation mechanisms. Previous studies primarily relied on the compositional analysis of individual samples, thus only observing the results of the degradation at a certain stage without reflecting the dynamic process of change. The Sichuan region in China hosts a large number of grottoes and cliff statues, many of which have undergone modern repainting. Focusing on the green pigment from these cultural relics, this research aims to capture the degradation products of emerald green at different stages. This approach promises a more systematic and comprehensive understanding of the degradation process, consequently advancing the exploration of its degradation mechanisms. In this study, 15 green pigment samples from five different painted grottoes in the Sichuan region were collected for analysis. Employing technological analytical methods, the presence of emerald green pigment (Cu(C₂H₃O₂)₂·3Cu(AsO₂)₂) was identified, along with several other substances containing Cu and As elements, such as Lavendulan (NaCaCu₅(AsO₄)₄Cl·5H₂O), copper arsenate (Cu₃(AsO₄)₂), alkaline arsenate copper compounds Cu₃(AsO₄)(OH)₃, Cu₂(AsO₄)(OH)·3H₂O and Cu(AsO₃OH)·2H₂O. The elemental compositions, chemical structures, and Raman spectra of these substances exhibit obvious connections and progressive relationships. This study, for the first time, elucidates the diverse degradation products of emerald green pigment from cultural artifacts within similar coexistence environments. It outlines a tentative degradation route, namely: (1) Oxidation and decomposition of Cu(C₂H₃O₂)₂·3Cu(AsO₂)₂ → Formation of Cu₃(AsO₄)₂, alkaline arsenate copper compounds and Ca(C₂O₄)·H₂O; (2) Transformation of Cu₃(AsO₄)₂, alkaline arsenate copper compounds→ Formation of NaCaCu₅(AsO₄)₄Cl·5H₂O. Throughout this process, the macroscopic color changes from green to blue.

Leather artifacts, mainly composed of collagen and tanning agents, possess significant historical importance. However, external factors could lead to the aging of such artifacts during preservation. Therefore, it is crucial to examine the impact of various factors on leather aging. In order to know the effects of high temperature and humidity conditions on the changes of leather artifacts, the traditional vegetable tanning agents (chestnut, tara, quebracho, and mimosa) were used to tan the pickled sheepskins to prepare leather artifact model samples. The leather artifact model samples were aged for 0, 2, 4, 8, 16, and 32 days at 80°C and 40–80 % relative humidity (RH). The changes in appearance, structure and thermal stability of the vegetable-tanned leather samples under the synergistic impact of temperature and RH were analyzed using total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), chromatography, and scanning electron microscopy (SEM). The thermal degradation of the samples before and after being tanned with vegetable tanning agents was analyzed using thermal gravimetric analyzer (TGA) analysis. Furthermore, the shrinkage temperature (Ts), tensile strength and elongation at break of the samples were investigated during different aging periods. The study aims to provide valuable insights into the stability of leather artifacts during long-term storage, as well as guidance for their restoration and conservation.

The scientific and multidisciplinary approach to the restoration of Bernini's Cornaro Chapel, at Santa Maria della Vittoria church in Rome, is reported as a fruitful example of the synergic cooperation between scientists and restorers for the planning and implementation of suitable conservative interventions.

This study reports the cycle of scientific and diagnostic investigations carried out on the great Baroque masterpiece before the restoration started in 2020.

Before the restoration, the technique of execution, the raw materials, and the state of preservation of Bernini's extraordinary sculptural cycle were scrupulously investigated with different and complementary analytical techniques on suitably selected micro-samples. Specifically, the original constituent materials were characterized, sometimes together with those resulting from decay processes or previous restoration interventions, through different techniques such as polarizing optical (OM) and fluorescence microscopy (FM), Electron Probe Microanalyses (EPMA) coupled with Energy Dispersive Spectrometry (EDX) and Fourier Transform Infrared Spectroscopy (FT-IR).

Particular attention was paid to the frescoed vaulted ceiling of the chapel, enriched by scenes modeled in white stucco and gilding, to better understand the manufacturing as well as the accuracy adopted by Bernini in layering, investigating from the most superficial to the innermost layers.

Scientific and diagnostic analyses were successfully performed to design the most convenient restoration intervention, to verify its correctness and ensure the use of non-invasive cleaning and conservative procedures. The results obtained from nine micro-samples, mainly composed of stucco and fragments of frescoes, contributed to dispelling the doubts raised by restorers, especially regarding the use of specific raw materials (notably the gilding, type of binder and aggregates, superficial patinas, etc.) and the presence of retouches in certain areas of the masterpiece, deriving from previous conservation interventions. The identification of these raw materials and the layering of the samples supported cleaning and restoration interventions through the use of suitable materials compatible with the originals.

To tackle the ageing phenomena of precious artworks, the binding media have been increasingly explored in cultural heritage. When siccative oils are employed as paint media, medium-chain dicarboxylic fatty acids (DFAs), also known as dioic acids, are generated from unsaturated fatty acyl chains by hydroxyl and hydroperoxyl radicals during the drying process. Hitherto, gas-chromatography coupled with mass spectrometry (MS) has represented the foremost technique for the investigation of DFAs upon proper derivatization reactions, yet the current work aims to introduce an alternative approach based on reversed-phase liquid chromatography, negative-ion-mode electrospray ionization with high-resolution/accuracy MS and tandem MS. Painting reconstructions of linseed oil mixed with common inorganic pigments such as chrome yellow and cadmium red were investigated for their content of suberic (C₈), azelaic (C₉), sebacic (C₁₀), and undecanedioic (C₁₁) acids. For the identification of these DFAs as unbounded species, retention time data followed by confirmation of their accurate m/z measurements and a detailed analysis of their fragmentation patterns via tandem MS were used. To estimate the quantity of DFAs, samples were spiked with a suitable internal standard before lipid extraction. This analytical strategy was successfully applied to three 50-year-old oil paintings, using samples of only a few milligrams (i.e., 25–50 mg). Notably, a difference in DFA profiles was observed within the artwork, with yellow pigments exhibiting relatively lower content compared to red ones. Spectroscopic techniques revealed alterations relevant to the chemical composition of these pigments during the ageing process. Likely the chromate ion, a component of chrome yellow pigment, undergoes oxidation which may hinder the generation of hydroxyl and hydroperoxyl radicals by the Fenton reaction, as the iron catalyst naturally occurring in the drying oil is potentially affected.

With the increase in extreme climatic events globally in recent years, the increased frequency of flood hazards has had a great impact on immovable cultural heritage sites (ICHs) due to their prolonged exposure to the disaster environment. This poses a risk management challenge, especially on large scales. Most existing flood risk assessment models for ICHs are determined using common natural hazard methods directly and focus less on the characteristics of ICHs. In this paper, we propose a modified geographical weighted regression (MGWR) model to assess flood risk at ICHs, and this model considers the spatial and age properties of the ICHs. These two properties were used for the construction of the weight matrix in the MGWR model. Eleven selected indices and loss survey data with 417 sample points, including 5 types of ICHs, were utilized for model training and testing in Shanxi Province, China. The results showed that the MGWR model had good accuracy with an R2 of 0.928. A comparison between the MGWR and normal GWR models indicated that the accuracies of the older ICHs improved more in the MGWR than in the GWR. We also found that the proposed model performed better than the normal GWR model using age as an index. Moreover, in comparison with three machine learning methods (decision tree, logistic regression, and random forest), the MGWR model still performed better and was less limited by the number of training samples. This paper provides evidence that the characteristics of ICHs are crucial in the construction of flood risk assessment models, and the proposed model can benefit the risk management of various types of ICHs at large spatial scales.

Fire is one of the most damaging deterioration agents in a short time of action. It can cause considerable damage, leading to the loss of lives and possessions. Concerning fire safety recommendations, buildings must be protected by an integrated system of passive and active measures. Two passive measures widely used in many industries are fire-retardant and fire-resistant coatings. These systems provide a fire-protective layer to the surfaces of flammable and non-flammable materials, delaying or preventing their ignition, reducing the heat transfer from the source to the substrate and decreasing the flame spread and the release of smoke and toxic gases. When exposed to fire, according to the different mechanisms of action, fire-protective coatings (FPC) can be classified as non-intumescent and intumescent. Despite being widely mentioned in heritage fire safety guidelines, studies on their application in the field are still scarce. Namely, research on the safety and efficacy of their application near collections (in support materials) and systematic studies comparing different formulations. Therefore, this research assembles interdisciplinary studies on the use of FPC to deepen knowledge and theoretically identify the feasibility of their application in collection support/storage materials or exhibition furniture (bookshelves, cabinets, plinths) in heritage environments.

From fires to floods, from invisible inks to redactions, information has been accidentally or intentionally obscured on countless documents, maps and photographs, in collections from archives, libraries, and museums across the world. Removed from catalogues and reading rooms and therefore inaccessible to researchers and the general public, what new knowledge would these obscured documents reveal if we were able to read them? This paper demonstrates that current imaging technologies can be used to unlock this lost content.

We used High Resolution Multiband Imaging (MBI), Reflectance Imaging Spectroscopy (RIS) and micro X Ray Fluorescence (µXRF) imaging to reveal illegible letter-forms and whole words written in iron gall ink on parchment from medieval documents relevant to the 'Virtual Record Treasury of Ireland' project, a digital reconstruction of archives destroyed in 1922 at the Public Record Office of Ireland at the outset of the Irish Civil War.

The readability of text in historic documents with faded iron gall ink and/or parchment obscured by damp stains and ingrained dirt was successfully enhanced with MBI techniques, such as UV-induced visible luminescence (UVL) and UV reflected (UVR) imaging, which were able to recover the contrast of the ink. However, visualising text in documents showing chemical damage caused by the application of reagents for ink enhancement in the 19^th century (a practice known as “galling”) was more challenging because of the similar composition of the ink and the staining. RIS proved helpful to read documents with moderate to severe chemical damage, particularly after applying Principal Component Analysis (PCA). Text in documents that were severely damaged by galling was also recoverable with µXRF imaging of the distribution of iron from the ink. This also posed several challenges, such as minimising movement of the parchment during overnight scans and separating the data corresponding to iron on the front of the parchment which was combined with the signal from the back. Through subtraction of elemental maps during post-processing, we managed to tackle the latter issue. The combination of these different imaging techniques enabled palaeographers and medieval records specialists to identify individual characters and whole words, thereby recovering the meaning of texts that were previously indecipherable.

Further research will adapt the methodology to the broad range of causes of information loss, including other reagents historically used for ink enhancement, as well as the variety of document media and temporalities, which require an extensive and multi-faceted approach of advanced imaging and post-processing techniques, in balance with the preservation needs of these fragile and invaluable historic materials.

This research aims to comprehensively analyse the interaction between a 2940 nm wavelength Er:YAG laser and several commercial varnishes commonly used in the mid-twentieth century. A selection of triterpenoid, poly(cyclohexanone), poly(cyclohexanol) and poly(isobutyl methacrylate) resins was chosen to make dammar, Ketone Resin N, MS2A and Paraloid B67 varnishes. Before creating varnish films, thermogravimetric analysis (TGA) was performed to determine the thermal stability of the resins as received from the manufacturer. The resins were measured at six different heating rates, and the kinetic activation energies (E_a) were calculated using the Flynn-Wall-Ozawa method. Also, differential scanning calorimetry (DSC) was performed to determine the resins' glass transition temperatures (Tg). After a 170.6 klux·h dose of radiation (λ>310 nm) simulating daylight through window glass of approximately 53 museum years, the varnish films were irradiated with an Er:YAG laser. The laser was used in the Very Short Pulse (VSP ≃ 100 µs) and Short Pulse (SP ≃ 300 µs) modes. The 2940 nm laser beam with a 4 mm diameter was fired onto dry and prewetted varnishes using a working distance of 20 cm. Single laser pulses with fluences ranging between 0.5 and 2.7 J/cm² were used. A prewetting solution of 1 % v/v Tween®20 surfactant in deionised water was applied to the varnish films. Er:YAG transmission through the aged varnishes was monitored in real time and showed that the transmitted energy increased almost linearly with fluence, except for the Paraloid B67 films which did not interact with the laser. Chemical changes were monitored using Attenuated Total Reflectance/Fourier Transform Infrared (ATR/FT-IR) spectroscopy. A reduction in hydroxy groups and carbon-hydrogen bonding was observed as a function of fluence for dammar and Ketone N films, while no change was observed for the dry and prewetted MS2A films. FTIR was also employed to experimentally determine the absorption coefficient of the varnish films. Optical Microscopy and low-vacuum Scanning Electron Microscopy (SEM) in the Backscattered Electron (BSE) mode were used to compare the dry and prewet irradiated spot areas. These analyses revealed that laser spots were less noticeable on prewetted varnishes than on dry-irradiated films.