Ars purpuraria : Neue methodische Ansätze bei der Anwendung von Küpenverfahren in der Purpurfärberei

After providing a series of experiments with purple snails of the species
'Bolinus brandaris’ using different vats (soda, urine, yeast, sodium dithionite), not only the
achieved colour samples were compared with each other, but also the various vats on
criteria such as reliability and energy demand. The experiments were closely based on
written sources from antiquity (Aristotle, Pliny and Vitruvius) and the historically
documented woad/indigo vats. For modern circumstances, the sodium dithionite vat
would be considered as the optimal purple dyeing vat. However, it has no historical value,
since sodium dithionite has only been available around 100 years ago. The soda vat
elaborated by Boesken-Kanold and Haubrichs gave a satisfactory result with the used
molluscs. Also, the combination of long fermentation time and mechanical heating of the
vat led to increased energy consumption. In return, the urine vat showed its advantages
precisely in this respect using low room temperature and no additional heating source.
Yet, the odour was considerable. The yeast vat could not be performed successfully in
this series of experiments.
The imitation dyes, which had been reproduced according to the papyri 'Graecus
Holmiensis’ and 'Leidensis X’, could emphasize the potential and practicality of these
historical recipe collections. The results suggested that the antique dyeing workshops
would operate a large market, which was subject to more or less rapidly changing fashion
trends, with affordable products. Cheaper dyes from madder and alkanet roots, safflower,
woad/indigo, kermes, and lichens could mimic all sorts of purples effectively. Yet, the
substitutes faded quickly. And ultimately, the typical smell of true purple could not be
counterfeited.