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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.

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 spectroscopy and SEM-EDX analysis, together with a careful observa- tion 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