Journal of Cultural Heritage最新文献

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.

Aerial lime is one of the oldest binders discovered and used in mortars. In different regions of the world, there is a substantial number of historic masonry constructions comprising binders based on aerial lime. The carbonation process has essential relevance on the behaviour of this material. In this sense, an experimental program done by the research group is adopted to support the numerical simulation of the evolution of carbonation phenomenon. Initially, a strategy modelling presented in literature is adopted. In sequence, an iterative process is done to achieve the set of parameters to fit the experimental data using the results from cylinders tested at three different depths with thermogravimetric analysis at four different ages. With a new set of parameters and functions, the numerical model could reproduce reasonably the data from the thermogravimetric analysis. Then, the modelling strategy with the fitted parameters is used to study the evolution of the carbonation in five series of specimens with different sizes, tested with phenolphthalein indicator. Various values of equivalent reaction degree (R∼20% to R∼60%), in terms of numerical results, were obtained for the phenolphthalein test.

A paint palette of the 20th-century Chinese modern artist Wu Guanzhong (1919–2010) was studied with an integrated spectroscopic approach, macro-scale non-invasive techniques hyperspectral imaging (HSI) and macro X-ray fluorescence (MA-XRF), complemented with Raman spectroscopy. The palette is revealed to be comprised of synthetic inorganic and organic pigments, typical of the 20th century modern palette that is dominated by azo and phthalocyanine pigments. HSI datasets of the paint palette and those of Wu's oil painting ‘Xidi Village’ (2001) were then processed within one unsupervised Uniform Manifold Approximation and Projection (UMAP) model, in an attempt to identify connections between the artefact and the artwork, so that known pigment results of the palette may provide preliminary pigment assignment for the painting. This study describes the steps taken to establish this automated assisted pigment analysis workflow, which involves processing multiple HSI datasets within one UMAP model, density clustering, non-negative least square (NNLS) fitting to extract endmembers (EM) spectra and to generate distribution maps. The approach to perform micro-sampling pigment analysis on the artist's palette (or artist's materials) is considered less invasive to the integrity than that from artworks, the results of which have demonstrated to serve as a critical resource to support further pigment analysis studies of the artist's paintings via non-invasive analytical techniques.

This study proposes a systematic approach to evaluate the value of industrial heritage under conditions of uncertainty. This approach primarily incorporates cloud theory and Dempster–Shafer theory (D–S theory), allowing managers to predict the direction of heritage renovation. Moreover, through this method, corresponding renovation measures and management methods can be formulated based on value levels and probabilities. The normal cloud distribution in cloud theory is more associated with people's judgment of things, while the subordinate cloud is employed to describe the basic probability distribution of factors at different value levels. The D–S theory has considerable advantages in terms of integrating information from multiple sources. This study uses the Shenyang Aircraft Factory as a case study to demonstrate the applicability and effectiveness of both theories. The results demonstrate that the combination of these two models can integrate knowledge and data, and the results of the value assessment model are in good agreement with the actual situation. In addition, this study provides a useful tool for dealing with uncertainty, randomness, and fuzziness in decision-making, making it easier for managers to develop appropriate building renovation plans.

This article focuses on the development and application of intelligent software for image and sound recognition to perform iconographic and audiographic analyses of the work of video art pioneers Steina and Woody Vasulka (the Vasulkas). The AI epistemological tool Vasulka Live Archive is designed to provide unique results that benefit from the synthesis of automatic statistical analysis across the dataset and application of predefined categories that are the results of aesthetic evaluation of the Vasulkas’ videos and inspired by terminology of video art aesthetics (Weibel, Krauss). The advantages of this AI tool reveal themselves particularly when the tool is used for transmedia analysis of the whole dataset (the Vasulkas’ work) as the accuracy and completeness of its results are out of reach of an individual human researcher. We argue that this kind of AI tools can contribute to more exact and data-based findings on media art aesthetics, it can contribute to establishing a new field augmented iconology (Spratt) as well as expanding the sphere of AI tools application towards digital collections of experimental and conceptual art of 20th and 21st centuries.

While deterioration due to the generation of “black spots” is reported, consensus on the specific corrosion products comprising black spots and underlying deterioration mechanisms is lacking. This study investigated the deterioration of copper objects by analysing the black spots that appeared on them and proposes environmental conditions to suppress the appearance of black spots. Bronze artefacts excavated from a marine archaeological site, on which black spots were generated, were closely observed, and investigated. First, X-ray fluorescence and micro-X-ray diffraction analyses were performed on a bronze artefact, from which the black spots were removed, to determine the composition of the artefact. Second, to investigate the composition of the black spots, fine structure analysis of the black spots on the fine fragments of the bronze artefacts was conducted using scanning and transmission electron microscopy, energy dispersive X-ray spectroscopy, and electron diffraction (ED) analysis. The results indicate that the black spots were partially composed of metallic copper and a fine particle mixture of Cu₂S and CuSO₄. These results imply that the transformation of copper sulfide to metallic copper may have played an important role in the initiation and propagation of black spots. In this study, ED analysis was performed on the microscopic area of the black spots; no amorphous phases were detected, and all observed phases were identified as crystalline materials. To determine the sources of gas-phase sulfur compounds that cause black spots, H₂S and carbonyl sulfide (COS) emissions from a spherical clay artefact (a cannon ball with gunpowder excavated from an underwater archaeological site) which was exhibited in the same showcase with the bronze artefacts were analysed via gas chromatography. The concentrations of H₂S and COS were 0.462 and 8.636 ppb, respectively; these are significantly higher than those in the lower troposphere. These results indicate that deterioration by black spots occurred because of H₂S and COS, which were emitted from the spherical clay artefact excavated from an underwater archaeological site in the exhibition case. In addition, it was confirmed that the inclusion of deoxygenating and dehumidifying agents (RP-AN) in the plastic bag in which the spherical clay artefact was inserted resulted in a significant decrease in the concentration of H₂S and COS.

One of the concerns of watercolor artworks on paper is the natural oxidation process of the paper, leading to the development of unsightly yellow-brown spots referred to as foxing. Historically, efforts to preserve watercolor pieces in museums, institutions, and private collections have relied on intricate and expensive techniques. Unfortunately, these methods are not practical for the broader community of artists and less affluent collectors. Furthermore, the introduction of foreign preservation materials, which can interact with the artwork's components, poses a risk to the original visual appeal. Consequently, watercolor art collections have lost some of their appeal compared to oil paintings on canvases. This study endeavors to offer an alternative, straightforward, and cost-efficient approach to safeguarding watercolor artworks created on high-quality watercolor paper, a type commonly used by typical watercolorists, making it a suitable candidate for this investigation. This approach also avoids introducing additional substances to the artwork. The protective technique involves the application of commercially available acrylic gesso to a fresh sheet of watercolor paper. This gesso-coated paper serves as a backing for framing and displaying the original watercolor artwork, without the need for any foreign preservation materials to be added to the artwork itself. To assess the effectiveness of this protection method, a comparison was made between the foxing tendencies of protected and unprotected paper artworks stored for a decade. These samples were subjected to various analytical techniques, including optical microscopy (OM), confocal laser scanning microscopy (CLSM), field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDX), X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and thermogravimetric analysis (TGA). The results revealed that, when compared to untreated samples, rarely any foxing spots were observed on any of the treated samples, and both the oxidation and degradation of cellulose fibers were diminished. Additionally, the analysis showed that the acrylic gesso comprised inorganic components such as calcium carbonate (CaCO₃), dolomite (CaMg(CO₃)₂), rutile (TiO₂), and organic acrylics. The carbonates created a mildly alkaline environment, neutralizing the acidity in the paper. The titanium dioxides exhibited biocidal and fungicidal properties due to their photocatalytic characteristics. The acrylic component bound and dispersed the inorganic constituents, and the coating formed a less impenetrable barrier layer as indicated by the scanning electron microscopy (SEM) results. In addition to significantly improving the resistance of the paper to foxing, the methods outlined in this study are highly cost-effective and readily accessible to artists and collectors. Importantly, they do not in