
Safflower petals before washing
I recently took part in a two-day workshop in Amsterdam, dyeing historical reds on silk at the Rijksmuseum’s Department of Conservation and Restoration. The event was organised by the Cultural Heritage Agency of the Netherlands. Selection for the workshop was by application, and the organisers chose eight international participants known for the variety and extent of their expertise in natural dyeing, and / or their interests in historical dye recipes.
A range of 26 samples was produced using American cochineal, kermes, annatto, brazilwood, madder, safflower and lac. Participants worked in pairs dyeing different sets of dyes: my partner was Paula Hohti of Aalto University, Helsinki, where she is Assistant Professor of History of Art and Culture. We dyed three recipes in total: one for lac and two for safflower. Demineralised water was used throughout.
Lac Our lac recipe was adapted from Edelstein’s translation of the 1548 edition of The Plictho of Gioanventura Rosetti. We prepared and used an alum mordant on Day 1, in which the silk rested overnight. The stick lac we were to use had been extracted over the previous three days. On Day 2 we sieved the lac solution and heated it, adding 25% (to weight of dry fabric) cream of tartar. It was dyed for an hour.

Lac-dyed silk being lifted from the beaker to check for colour. On the right is the beaker containing yellow safflower dye and silk
Safflower We dyed two versions of safflower: yellow and red. Our recipes were adapted from various sources, including Macquer’s Art de la Teinture en Soie. To obtain yellow, safflower florets were washed once and drained, and then soaked again for 30 minutes. After sieving, the resulting extract was used to dye unmordanted silk.

First washing-out of the safflower florets for yellow dyeing
To obtain red, safflower florets were pre-washed for two weeks to remove all traces of the yellow extract – this process had been completed in advance of the workshop. We undertook a further sequence of washings until the yellow stopped running and the water was clear. The water was sieved out. Potash was added to obtain pH 10, and the florets squeezed by hand until they appeared pink and transparent and the liquor looked pinky red. This took about half an hour to achieve.
After sieving into a new beaker, unmordanted silk was added and the pH checked (it was around 7). We then added fermented beer (bierken) little by little, continually monitoring pH, until the pH dropped to a crucial pH 5. This threshold pH has a term ‘virer le bain‘ or ‘turn the bath’. We were required not to allow the pH to drop lower or it would damage the silk. The silk then rested in the dye for 10 minutes after which it was washed in Marseilles soap, and water.
Both safflower baths produced strong colours, with the pink having an especially bright ‘pop’. The colour is very light fugitive.

Safflower red (left), lac (centre) safflower yellow (right
Everyone, including the three organisers, gave short presentations on their work and research interests. I showed some samples of my orchil dyeing as well as a few pieces of my studio work in natural dyes. Many participants were involved in education, some of us were artists and dyers, others were textile researchers or art historians. These absorbing presentations illustrated what a privilege it was to attend the workshop.
The results of the workshop were recently published at the Spring Symposium of the Textiel Commissie.

Participants were able to take away a sample of each recipe dyed: a total of 26 samples
Participants took home a complete set of all the silks dyed. The organisers also retained a set, which will be catalogued and stored as historical reproductions on reference sheets, together with supporting information on the recipes and preparations. The sheets will eventually be published online through the Cultural Heritage Agency (RCE) website, for the benefit of other researchers.
Thanks With many thanks to organisers Drs. Ana Serrano, Jenny Boulboullé and Art Proaño Gaibor; to the Cultural Heritage Agency of the Netherlands; the Ateliergebouw of the Rijksmuseum; and to all fellow participants at the workshop for their unique and specialist contributions.
Links
Rijksmuseum Conservation and Research
Cultural Heritage Agency of the Netherlands
Paula Hohti has recently been awarded a European Research Council grant for a five year project Re-fashioning the Renaissance: Popular Groups, Fashion and the Material and Cultural Significance of Clothing in Europe 1550 – 1650