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• ATR-FTIR spectroscopy is used to assess the condition of historical silk samples. • Evaluating the conditions of historical textiles guides conservation and preventive measures. • Differentiation between original and later interventions is also possible. • Visual, bivariate and multivariate methods are used to evaluate the data. • Spectral evaluation reveals deterioration markers, explained according to literature. Understanding the conservation condition of historical silk yarn allows to define appropriate storage, care and display of historical silk collections. This paper discusses the characterisation of silk fabrics from a collection of traditional Japanese samurai armours which date back from the 16th to the 20th century (Morigi Collection, Museo delle Culture, Lugano, Switzerland). An analytical protocol to assess silk fabrics conditions was defined, based on microinvasive ATR-FTIR spectroscopy. In particular, the amide I and II region was studied in order to extrapolate the conformational information about silk proteins. According to literature, this kind of information can be related to different degradation stages. A linear correlation was found between the amide I and the amide II shifts, allowing to assess the silk fibre condition. Along with this bivariate approach based on intensity ratios, a multivariate approach based on Principal Component Analysis was also applied to ATR-FTIR spectra. This allowed to group together silks with the same state of preservation. The findings of this research offer a valuable method to researchers and conservators to identify the most damaged textiles; the differentiation between original and restoration materials was also possible in some cases. [ABSTRACT FROM AUTHOR]

To correctly manage a collection of historical silks, it is important to detect if the yarn has been originally subjected to degumming. This process is generally applied to eliminate sericin; the obtained fiber is named soft silk, in contrast with hard silk which is unprocessed. The distinction between hard and soft silk gives both historical information and useful indications for informed conservation. With this aim, 32 samples of silk textiles from traditional Japanese samurai armors (15th–20th century) were characterized in a non-invasive way. ATR-FTIR spectroscopy has been previously used to detect hard silk, but data interpretation is challenging. To overcome this difficulty, an innovative analytical protocol based on external reflection FTIR (ER-FTIR) spectroscopy was employed, coupled with spectral deconvolution and multivariate data analysis. The ER-FTIR technique is rapid, portable, and widely employed in the cultural heritage field, but rarely applied to the study of textiles. The ER-FTIR band assignment for silk was discussed for the first time. Then, the evaluation of the OH stretching signals allowed for a reliable distinction between hard and soft silk. Such an innovative point of view, which exploits a "weakness" of FTIR spectroscopy—the strong absorption from water molecules—to indirectly obtain the results, can have industrial applications too. [ABSTRACT FROM AUTHOR]

This paper presents the limitations and potential of ATR-FTIR spectroscopy applied to the study of cellulosic textile collections The technique helps to differentiate natural fibres according to the content of lignin, pectin, hemicellulose, and wax, although some problematic issues should be considered. The spectral differences derived from the environmental humidity uptake and the plant composition are reviewed and discussed in the light of new experimental data. Diagnostic bands are proposed that can discriminate between different fibres from different plants. The contribution of ageing is also considered, demonstrating that sometimes aged fibres cannot be reliably recognised. In contrast, the potential of ATR-FTIR spectroscopy to discriminate between natural and modified fibres is discussed and proven. The best results were obtained when microinvasive ATR-FTIR spectroscopy was coupled with SEM observations. The proposed protocol was tested on microsamples of various cellulosic materials from traditional Japanese samurai armours dating from the 16th to the 20th centuries (Morigi Collection, Museo delle Culture, Lugano, Switzerland). The results facilitated a complete characterisation of the materials and demonstrated that the protocol can be used to study a wide variety of cellulosic materials, including both natural and man-modified fibres, and paper. [ABSTRACT FROM AUTHOR]

In the framework of an extensive survey campaign on a collection of Japanese samurai armors, metallic threads from different parts of the traditional equipment were studied by several analytical techniques. The collection of armors belongs to Museo delle Culture (Lugano, Switzerland) and it is composed of ten elements, which date back from the 15th to 20th century. Metallic threads under study come from six of ten elements of the collection and represent a complex and unique multimaterial, which shows specific characteristics in Japanese tradition (kinran). The multianalytical approach based on ATR-FTIR (Attenuated Total Reflection-Fourier Transform Infrared) spectroscopy and SEM-EDX (Scanning Electron Microscopy, Energy Dispersive X-Ray) analysis, together with a careful observation with optical and digital microscopy, permitted to obtain a complete characterization of materials, which have shown a great variability in metal foils and in organic adhesives (urushi, animal glue, starch). Gold and silver turned out to be not so largely used as scholars thought, while aluminum showed a great diffusion. Within the collection of analyzed armors, the obtained results allowed us for the first time to get a complete comprehension of materials and techniques used by Japanese craftsmen, and to observe differences in the quality of the materials and in manufacture technology over the centuries. [ABSTRACT FROM AUTHOR]

• First characterisation of pigments used in coloured Japanese photographs. • Non-invasive infrared analysis identified various pigments used to colour the photos. • Western pigments, traditional Japanese dyes, and aniline colours were identified. • Use of a beeswax-based varnish on the photos surface was revealed. This paper describes the first systematic analysis of 19th century Japanese coloured photographs. This unique Japanese technique followed the diffusion of photography taken up by Westerners. The photos were coloured by the painters of the School of Yokohama from ukiyo-e prints ateliers and were sold to travellers returning home as a souvenir from Japan. Although there are several museum collections throughout the Western world, this artistic technique has never been thoroughly investigated, due above all to the fragility of the artworks. In this study 22 photographs and a photo album cover from the Museum of Cultures (Lugano, Switzerland) were analysed by non-invasive infrared spectroscopy in order to identify the painting materials. A preliminary survey was carried out on reference pigments used in Japan in the 19th century, some of which are the same as those used in Western Europe, but many are particular to the Japanese school of arts. The reference pigments were analysed after extraction procedures taken from traditional recipes. Modern pigments such as "aniline colours" were also considered. The results provided insights into the painting materials, for example identifying Prussian blue, gofun, yamahaji , enju , shio , and rhodamine. The data confirmed the use of albumen paper and detected the application of a beeswax-based varnish for conservation purposes. [ABSTRACT FROM AUTHOR]