Historical Textiles

Covering, protecting, and adorning the body count among the most fundamental of human concerns, at once conveying aspects of an individual's persona while also situating a person within a given social context. Wearable adornment encompasses materials fashioned by human hands (like fabric, metalwork, or even animal bones) and modifications to the body itself (such as tattoos, cosmetics, or hairstyles), which beautify the body while simultaneously conveying social, political, and protective functions and meanings. The wearable is thus the most representational and at the same time most intimate product of material culture. This conference seeks to expand our current understanding of the wearable in the Middle Ages. Current scholarship on the topic in Byzantine, western medieval, Eurasian art, as well as Islamic traditions tends to encompass clothing and jewelry, and is frequently medium-specific, with minimal regard to the interrelatedness of different aspects of appearance. On the one hand, work on medieval textiles has tended to approach questions of identity, consumption, and appearance by comparing textual sources and visual depictions with surviving textiles. The study of medieval jewelry, on the other hand, largely focuses on the classification and attribution of precious metal pieces from excavations and museum collections, as scholars make sense of pieces long removed from the bodies they once adorned. Tattoos, prosthetics, cosmetics and headgear are almost entirely absent in our understandings of medieval dress practices. This separation was not always so, however, and indeed nineteenth-century art historians such as Gottfried Semper integrated all aspects of bodily adornment in their considerations of the nature of ornamentation and surface decoration.

The colorant behaviour of cochineal and kermes insect dyes in 141 experimentally-dyed and 28 artificially-aged samples of silk and wool was investigated using ultra-high performance liquid chromatography coupled to photodiode array detector (UHPLC-PDA), liquid chromatography electrospray ionisation mass spectrometry (LC-ESI-MS) and image scanning electron microscopy – energy dispersive X-ray spectroscopy (SEM-EDX). Partial-least squares discriminant analysis (PLS-DA) was then used to model the acquired UHPLC-PDA data and assess the possibility of discriminating cochineal insect species, as well as their correspondent dyed and aged reference fibres. The resulting models helped to characterize a set of 117 red samples from 95 historical textiles, in which UHPLC-PDA analyses have reported the presence of cochineal and kermes insect dyes.

Analytical investigation of the experimentally-dyed and artificially-aged fibres has demonstrated that the ratio of compounds in the insects dye composition can change, depending on the dyeing conditions applied and the type of fibres used. Similarities were observed when comparing the UHPLC-MS and SEM-EDX results from the dyed and aged references with the historical samples. This was verified with PLS-DA models of the chromatographic data, facilitating the classification of the cochineal species present in the historical samples. The majority of these samples were identified to contain American cochineal, which is in agreement with historical and dye identification literature that describe the impact of this dyestuff into European and Asian dyeing practices, after the Iberian Expansion in the 16th century.

The analytical results emphasize the importance of using statistical data interpretation for the discrimination of cochineal dyes, besides qualitative and quantitative evaluation of chromatograms. Hence, the combination of UHPLC-PDA with a statistical classification method, such as PLS-DA, has been demonstrated to be an advisable approach in future investigations to assess closely related species of natural dyes in historical textile samples. This is particularly important when aiming to achieve more accurate interpretations about the history of works of art, or the application of natural dyes in old textile production.

Široce koncipovaná metodika reflektuje přesné vymezení sledované problematiky a přehled dosavadního bádání s důrazem na středoevropské prostředí. Představuje možnou druhovou skladbu dochovaných souborů, uvedení do problematiky základního znalectví textilních technik a materiálů včetně těch tkalcovských a vyšívacích. Dále uvádí umělecko-řemeslný přehled a souvislosti, přehled degradativních vlivů a způsoby jejich prevence, evidenci a způsob vedení dokumentačního popisu. Důraz je kladen na praktičnost a přehlednost textu s přihlédnutím k využití metodologických postupů v přímé terénní praxi (církevní a památkové objekty, církevní praxe a výstavní/prezentační expozice aj.).

Up until the end of the medieval period, the most extravagant, brilliant and enduring crimson red fabrics were dyed with valuable insect dyes: kermes, lac dye and Polish and Armenian cochineal. Symbols of hierarchy and power, crimson textiles were very difficult to obtain, owing to the complex and costly dyeing processes involved and to the scarcity of insects. These were collected in certain parts of Europe and Asia, and traded through well-established commercial routes to reach the main European cloth-producing centres. With the Iberian Expansion in the 16th century, the Spanish began exporting American cochineal from Mexico. Richer in red colorant than other insect dyes, it achieved great success among textile manufacturers, bringing enormous financial profit to the Spanish Empire 1. Publications over the last century have affirmed that as soon as the American insect started appearing in Europe, it rapidly penetrated textile workshops and fashion, replacing other local insect sources 2. A multidisciplinary study-combining history, textile objects from museum collections, and chemistry-was developed to explore the impact of American cochineal in European centres of textile production, in relation to traditional dyes 3. After a comprehensive revision of historical sources, chemical investigation was undertaken to determine the red colorants used in luxurious European historical textile objects, dating from the 15th to 17th centuries. Since analytical limitations verified in previous works compromised the chemical characterization of cochineal dyes 4 , a new methodology comprising UHPLC (ultra high-performance liquid chromatography) and multivariate statistical analysis was carried out to obtain precise knowledge of the dyes present in the historical textiles 5. The successful results of this approach offer more accurate information about the historical context of the dyed textiles, and thus, more conclusive interpretations about the history of the trade and consumption of insect dyes used in European textiles and clothing, during the Late Medieval and Early Modern periods.