The study investigates the detection of standardisation and serial production in medieval masonry from the 11th to 13th centuries, a period with limited documentary evidence concerning the organisation of building work. Various studies have addressed aspects related to serialisation through visual, metric, metrological or statistical analyses, although they have generally been limited to individual buildings, regional contexts or specific categories of evidence. To date, however, no method has been identified that integrates these procedures and is specifically designed to detect, spatially represent and compare different degrees of serialisation. This requires an exhaustive study of stone layouts using a reproducible system that combines the quantitative processing and spatial interpretation of the results.This paper presents such a methodology, combining photogrammetry, GIS analysis and conversion to historical units of measurement to identify modular patterns and forms of workshop organisation. Several monuments were analysed, including the Monastery of Las Huelgas Reales in Burgos and the Basilica of St Mary Magdalene in Vézelay.The method comprises two complementary phases: first, an automated metrological analysis based on the classification of course heights and ashlar dimensions expressed in historical inches, allowing the detection of modules and alternations; and second, a spatial analysis of the distribution of these classes using colour-coded elevations to reveal dimensional tendencies and construction sequences. This approach integrates statistical objectivity with interpretative assessment, enabling the identification of intermediate degrees of standardisation that would otherwise remain undetected through exclusively statistical analyses or direct visual observation.The results show that the processes of serialisation and standardisation did not develop in a linear manner or involve the progressive replacement of craft practices by uniform systems. At Las Huelgas Reales, despite the apparent visual homogeneity of the masonry, the analysis reveals differences both between the faces of the same wall and among successive bays, suggesting different construction phases or the participation of independent yet coordinated workshops. At Vézelay, the analysis indicates a gradual increase in the organisation of the building process; however, serialisation and standardisation were only detected in the later phases, and their application varied according to the available resources, the requirements of the building work and the elements constructed. Overall, the findings show that standardisation in medieval construction was a selective, adaptive and heterogeneous process. The methodology developed provides a transferable analytical framework for the research and conservation of historic masonry.
Proteinaceous adhesives of animal origin constitute fundamental binding media in polychrome cultural heritage, requiring precise species identification to inform conservation strategies. This study developed an innovative analytical platform integrating trypsin-immobilized hydrogels for in situ enzymatic digestion with mass spectrometry and multivariate chemometrics, enabling minimally invasive characterization of collagen-based adhesives. Our dual analytical framework employs principal component analysis (PCA) to establish species-specific peptide fingerprints from unaged samples, while partial least squares discriminant analysis (PLS-DA) enables classification of aged adhesives. Validation studies using commercial animal collagens (from two different manufacturers) and mock mural samples subjected to controlled UV aging demonstrated the method's robustness. The PLS-DA model maintained 91.7% classification accuracy even after 336 h of accelerated aging, when traditional infrared protein signatures became undetectable. Microscopic examination and colorimetric analysis confirmed the absence of visible damage to pigment layers. By centering on an adaptive chemometric strategy rather than instrumental refinement alone, this approach offers a reliable, conservation-compatible pathway for protein binder identification in multilayered polychrome artworks, balancing high taxonomic precision with uncompromised material integrity. (c) 2026 Elsevier Masson SAS. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Volatile organic compounds emitted by materials used in museum display cases pose risks to the preservation of cultural heritage objects. Traditional assessment methods, such as the Oddy test, present limitations including subjectivity and lack of chemical specificity.To strengthen the Oddy test as a reference method for assessing emissions from display case materials, two complementary variants have been integrated: a cellulose-based modification, already employed to broaden the test’s sensitivity to the degradation of organic materials, and an IR-assisted approach, which enables the identification of corrosion products and thereby enhances both the interpretation of test results and the overall assessment of materials. The multimodal Oddy test approach has been supported by chromatographic techniques (µCTE-TD-GC–MS and SPME-GC–MS) on a common set of showcase materials.This integrated methodology revealed differences in material emissions and identified compounds potentially harmful to metals and organic substrates. Our findings demonstrate the advantages of combining complementary analytical methods to enhance the evaluation of material suitability for museum environments. This work supports the development of more robust, sensitive, and practical protocols for selecting safer materials, thereby contributing to improved preventive conservation strategies.
Vinegar Syndrome (VS) is the typical chemical decay process resulting from the hydrolytic deacetylation of the cellulose acetate polymer, which leads to the emission of acetic acid. In archives storing cellulose acetate motion picture films, acetic acid detection strips are widely used to monitor VS progression; however, the interpretation of their colour changes remains qualitative and subjective, potentially leading to errors in the estimation of acetic acid concentrations and, consequently, of the VS stage. This study proposes an objective and quantitative method to assess strip colour changes and relate them to the acetic acid concentrations released by films affected by VS. The two types of detection strips most widely used in film archives worldwide were investigated. In laboratory experiments, strip colour was measured by spectrophotocolorimetry before and after exposure to known acetic acid concentrations, using the hue angle value as the metric. The same approach was then applied at two national film archives to test its feasibility. In the case studies, strip colour was interpreted together with metadata relating to the inspected film reels in order to explore which intrinsic and extrinsic factors may influence VS progression. The laboratory results demonstrate a sigmoidal relationship between hue angle values and acetic acid concentrations for both strip types, while revealing differences in their sensitivity, particularly in the autocatalytic concentration range of VS. The case-study results suggest that reel-specific manufacturing features and environmental and use history may influence single-reel VS progression more strongly than the current storage environment. The proposed method can be routinely implemented by archival staff in less than five minutes per film reel, including both strip colorimetric measurements and transcription of the resulting parameters into a database. This allows the creation of a traceable record of this information over time, which can be integrated with other routinely collected data.
Iris flowers have been used for their dying properties at least since the Middle Ages and for centuries later in Europe. In particular, as regards the Iris germanica species, the colours that can be obtained from the petals are violet (the pure juice), dark blue (upon addition of alum) and green (upon alkalisation). The ancient technical treatises are rich with recipes describing the preparation of these dyes.Nevertheless, the dyes of Iris germanica have rarely, if ever, been identified on paintings. This could be due to a lack of diagnostic information, useful for the selective identification of these dyes. In fact, normally the identification of organic colourants throughout non-invasive methods is complex and generally harder than for inorganic colourants. In this study, non-invasive spectroscopic techniques, such as UV–visible diffuse reflectance spectrophotometry with optical fibres (FORS), FT-IR spectrophotometry in reflectance mode and Fibre Optic Molecular Fluorescence (FOMF), as well as micro-invasive techniques such as Surface Enhanced Raman Spectroscopy (SERS) and FT-IR spectrophotometry in transmittance mode, have been used to characterise the dyes extracted from the petals of Iris germanica. In the end, the methods exploited in this work have been built to move from laboratory-based information retrieved through non-invasive and micro-invasive techniques, to the in-situ study of manuscripts in which we identified selectively the dyes and, in particular, the iris green cited by the ancient technical treatises. Moreover, the combined application of these techniques could allow to identify its presence even in cases when the dye is mixed with verdigris or superimposed on it.
