On the 1st July 2016, our TTT member Ana Serrano presented and discussed her PhD dissertation, with the title “The Red Road of the Iberian Expansion: Cochineal and the Global Dye Trade”, which aimed to explore the impact of American cochineal in the global trade, and its importance in the main European and Asian textile centres, between the 16th and the 18th centuries.
Of all natural reds, insect dyes have always been a valuable commodity for Europeans and Asians alike, as until the invention of synthetic dyes in the 19th century, they provided the most brilliant, rich and enduring shades of crimson red in dyed textiles. Symbols of power, status and hierarchy, these colours were very difficult to obtain owing to the complex and costly dyeing processes involved and to the scarcity of the insect dyes.
Until the end of the 15th century, the richest red fabrics were dyed with kermes (Kermes vermilio), lac dye (Kerria lacca) and Polish and Armenian cochineal (Porphyrophora polonica and Porphyrophora hamelii, respectively). These insect dyes were collected from plant roots and tree branches growing in certain parts of Europe and Asia, and they were traded between both continents, by way of major commercial routes, such as the Silk Road. Thus, they travelled great distances to reach the main textile industries, where they were used to colour fine and expensive cloths, meant for the wealthy elites.
Between the end of the 15th century and beginning of the 16th, the Portuguese and the Spanish expanded their empires to the Americas. This eventually led to the exploitation and export of local sources. For instance, while the Portuguese soon dedicated to the exploitation of brazilwood (Caesalpinia echinata), the Spanish came to establish a monopoly in American cochineal (Dactylopius coccus) that was of paramount value, ranking in price after silver and gold among exports to Spain.
Once in Europe and Asia, this dyestuff soon revealed to possess a much higher content of colorant than local insect dyes, as much fewer insects were required to achieve the same shades of red. This advantage was an imperative factor for its adoption in many workshops, thus leading to its progressive rise as a staple product of trade on a global scale, in the forthcoming centuries.
It has been often assumed that, as soon as the American insect started to appear in Europe and Asia, it was quickly adopted in textile workshops and fashion and, as a consequence, the other European and Asian insect dyes were soon forgotten. Moreover, there has been an overall idea that the trade and adoption of the new insect dye was generally widespread, and it occurred simultaneously in major international ports and textile industries.
Serrano developed a multidisciplinary PhD project - combining history, textile objects from museum collections, and chemistry - to explore American cochineal’s long-distance trade between the 16th and the 18th centuries, as well as its impact in European and Asian centres of textile production, in relation to traditional dyes.
For this, she undertook a comprehensive revision of historical publications and primary printed sources related to the trade and use of American cochineal as a red textile colorant, as well as of other Eurasian insect dyes. Since historical information is not always available in the literature, relevant evidence may also be found in the examination of historical textiles. Therefore, she intertwined interpretations based on the historiography with luxurious historical textile objects (dating from the 15th to 17th centuries), by following a pioneering chemical method to determine the presence of cochineal on their red colours.
Owing to method limitations in chemical analyses, difficulties have always been associated with the distinction of cochineal dyes in red-dyed historical textiles - particularly between American and Armenian cochineal. This often leads to inconclusive interpretations. Facing this problem, Serrano developed an ultra high-performance liquid chromatography (UHPLC) method to deliver more accurate chemical results. She then undertook dyeing experiments with cochineal dyes on silk and wool, according to old recipes; and she submitted the dyed fibres to artificial ageing. In this way, she was able to demonstrate that these historical reproductions can be chemically compared with historical textile objects. However, once both reproductions and historical samples were analysed with UHPLC, a great amount of chemical data was obtained. For this reason, the most suitable way to compare all these results was to use a multivariate statistical method (partial-least squares discriminant analysis - PLS-DA), which ultimately led to the identification of the cochineal species that were used to colour the historical textiles. Resulting in several papers in peer-reviewed journals, this approach has proven to be highly recommendable for future projects regarding the characterization of insect dyes in cultural heritage objects.
A Successful Outcome
By combining the results of this successful approach, the results for other colours in the examined historical textiles (where dyes like brazilwood, madder, safflower, weld or dyer’s broom were reported) and their contextualization with historical evidence, she brought assertive interpretations about the date and provenance of the investigated textiles. More importantly, she highlighted the importance of using these objects as reliable sources of evidence, to support historical documentation.
Ultimately, this has contributed to achieve an unparalleled view of the global circulation of American cochineal in the Early Modern world, as well as unique perspectives about its overall impact in European and Asian dyeing traditions and patterns of consumption of red dye sources. Indeed, it became clear that a gradual but clear adoption of this insect dye in Europe and in West Asia occurred, while local insect dyes kept a representative role in on-going practices, especially in East and Southeast Asia.
Based on the successful outcome of her research, Serrano is currently adapting her dissertation into a book.
Serrano's PhD project was funded by the Fundação para a Ciência e Tecnologia (FCT), Portugal (grant SFRH/BD/73409/2010) and it was undertaken in History, with specialization in Discoveries and the Portuguese Expansion. Her project was supervised by Dr. Jessica Hallett (CHAM, Faculdade de Ciências Sociais e Humanas da Universidade Nova de Lisboa e Universidade dos Açores) and Prof. Dr. Maarten van Bommel (Conservation and Restoration of Cultural Heritage, University of Amsterdam). She performed her chemical research at the facilities of the Department for Movable Heritage, Rijksdienst voor het Cultureel Erfgoed (Amsterdam).