The hidden history of woad blue: a path through technology and diffusion of “European indigo” in 18th-century technical literature (extended version)

Woad, the famous “European indigo” plant, still hides some unknowns in its long history. This study wants to contribute to a better understanding of woad’s diffusion and use in Italy throughout the 18th and first half of the 19th century, by analysing the technical-agricultural literature of this period. The research allowed to collect some information on the “geography” of Italian woad, on its processing techniques and on its relation to “rival” Indian indigo: concerning the “places” of Italian woad, the investigation showed that Italy still had some relevant woad-producing centres at the time, which in some cases reached out to European trade routes; as to woad’s processing, the special account of a small-scale dyer allowed to set up a comparison between large-scale and small-scale woad production, showing that both could still prove economically profitable; finally, the examined sources highlighted that woad was still acknowledged to have a significant dyeing function by Italian authors of that time