The acidity of historic paper, a property crucial for its preservation, is thought to mainly depend on the type of sizing. However, this research shows that during its degradation, paper acidity increases mainly due to the formation of non-volatile carboxylic acids, which accelerate acid-catalysed hydrolysis. Whether and how this accumulation depends on paper composition has not been studied systematically so far. A collection of 89 European paper samples, dated between 1844 and 1990 was analysed for organic acids content and other conservation-relevant properties. Oxalic acid was the acid determined in the highest concentrations and with the strongest influence on paper pH. Multivariate data analysis revealed correlations between lignin content and oxalic and formic acid contents, highlighting the dominant influence of lignin on acid production. The results also indicate that the content of oxalic acid in paper increases by approximately 0.01 mmol/g per year, resulting in a decrease of pH at 0.008 per year (assuming other variables remain constant). To assist in paper conservation, a portable, non-invasive Raman spectroscopic method was developed to determine the lignin content of historic paper, using partial least squares regression. The research results are significant as they demonstrate the dominant impact of oxalic acid on acidic paper conservation.

In contrast to its European counterpart, Islamic papermaking is still little researched, especially in scientific and conservation contexts. This study presents the first in‐depth material analysis of a unique collection of Islamic‐African amulets and talismans from the nineteenth and twentieth centuries, held at the Slovene Ethnographic Museum. This research employed a multi‐analytical approach that included pH measurements, analysis of fibrous materials, iodine test for the presence of starch, hyperspectral imaging (HSI), FTIR‐ATR, Raman spectroscopy, laser‐induced fluorescence (LIF), and laser‐induced breakdown spectroscopy (LIBS), as well as cultural interpretations. Twelve selected manuscripts were examined to characterize paper, inks, dyes, and calligraphic features. The results showed the use of iron gall inks, plant‐based dyes, and mixed paper fibers (straw and softwood pulp), suggesting a mixture of local and imported materials from the colonial period. The calligraphic and decorative styles reflect a synthesis of orthodox Qur’an and local West African Sufi traditions, often incorporating protective texts, magic squares, and regional variants of Kufic script. The findings shed light on technological aspects of Islamic manuscript production in West Africa and support the informed conservation, display, and interpretation of these culturally and spiritually significant objects. This research sets a precedent for comparative heritage studies and enhances the understanding of Islamic material culture in African contexts.

In the 19th century, the weighting of silk with metal salts, such as tin, was a common practice to enhance certain properties of silk fabrics and compensate for the weight loss incurred during the degumming process. This technique induces both physical and chemical modifications to the fibres, contributing to their long-term degradation, which requires thorough investigation. This study aims to examine the structural changes in silk fibres caused by the accumulation of metal salts from the tin-weighting process, using mock-up samples prepared through successive loading with weighting agents using a traditional tin-phosphate treatment method. Unweighted and tin-weighted silk samples were compared using scanning electron (SEM) micrographs, which presented the dispersed nanoparticles on the fibres, while through energy-dispersive X-ray spectroscopy (EDS) elemental mapping, the presence and uniform distribution of the weighting agents were confirmed. Fourier-transform infrared spectroscopy (FTIR) analysis revealed structural changes in tin-weighted silk samples compared to untreated ones, including shifts in amide bands, altered water/hydroxyl and skeletal stretching regions, and increased skeletal band intensities suggesting modifications in hydrogen bonding, β-sheet content, and structural disorder without significantly impacting the overall crystallinity index. X-ray diffraction (XRD) analysis of both pristine and tin-weighted silk samples revealed significant alterations, predominantly in the amorphous regions of the silk upon weighting. These structural changes were further examined using small-angle X-ray scattering (SAXS) and small- and wide-angle X-ray scattering (SWAXS), which provided detailed insights into modifications occurring at the nanometre scale. The analyses suggested disruptions in β-sheet crystals and intermolecular packing, especially in the amorphous regions, with increasing amounts of tin-weighting. Contact angle analysis (CA) revealed that the tin-phosphate-weighting process significantly impacted silk surface properties, transforming it from moderately hydrophobic to highly hydrophilic. These changes indicate that the incorporation of tin-phosphate nanoparticles on and within silk fibres could restrict the flexibility of polymer chains, impacting the physical properties and potentially the degradation behaviour of silk textiles. By studying these structural changes, we aim to deepen our understanding of how tin-weighting impacts silk fibre structure, contributing valuable insights into the longevity, conservation, and preservation strategies of silk textiles in the context of cultural heritage.