Citizen science project: dyeing wool with 19th century recipes

20 May 2022

The library of the Textile Museum has a fantastic collection of old dyeing recipe books. For the 'To Dye For' exhibition, we want to look at and study these books in greater detail. But how do you do that?

The recipes from the books are very diverse. Some only supply a list of measurements and ingredients. Others contain page-long descriptions full of detail. However, even then questions remain: How can you understand a historical recipe when there are details omitted because during the time it was written they were assumed to be common knowledge? For example, what kind of water was used? At which temperature was the wool dyed? We were very grateful for the help of scientists Jenny Boulboulle, Natalia Ortegasaez, Art Proaño Gaibor and Ernst Homburg.

The best way to understand a historical recipe is to try it for yourself. Led by the more experienced dyers of the project, we organised workshops to put the recipes to the test. But first we needed to choose appropriate recipes. After looking through various recipe books, we found several recipes with ingredients that are easy to acquire and do not contain many harmful substances. The group chose four recipes for the colours black, red, blue and yellow.

It was then time to put together a grocery list of all the ingredients we would need. We also ordered a beautiful woollen cloth that closely resembled the dyed samples we saw in the recipe books.

Photo: The original recipe as seen in the recipe book from Pollet


Workshop preparations

In each of the four workshops, we test one dyeing recipe. The goal of these workshops is to get together with hobby dyers to discover how these recipes work and to experience what it's like to follow them. Librarian of the Textile Museum, Jantiene van Elk talks about the Citizen Science project and about the recipe books. Intern Semma Raadschelders talks about the chosen recipe, a recipe for the colour blue. Most blue recipes use either logwood or indigo. Indigo is more colourfast, but the dyeing process is lengthier and more involved. Because of this, the logwood recipe was chosen. These recipes are often referred to as false/fake blue since logwood loses its colour over time and is very sensitive to acidity. Indigo blue is seen as superior since the colour stays vibrant for a long time. The dyed sample accompanying the recipe also looks brown, rather than blue.


Testing in advance

To prepare for the workshop, Semma Raadschelders tested the recipe in advance. "My first attempt turned out brown rather than blue, so I tried again. Thankfully, the second time went better. Most participants of the workshops have worked with natural dyes before, so they can count on their own knowledge and experience. My experiments the week before will allow me to provide guidance to those participants with less experience."

Before the workshop, we come up with several things we'd like to experiment with. For example, we expect the composition of the water to impact the colour. We arranged a jerrycan of rainwater for participants who'd like to experiment with this. We leave as much as possible to the participants, hoping that differences in colour will arise naturally. Everyone interprets the recipe for themselves, weighs out their ingredients and must think about the timing.


Time for dyeing!

Finally, it's time to start dyeing. Two participants dye using rainwater, and the rest uses regular tap water. The total time of the recipe is about four hours. To speed up the process a bit, participants can use pre-soaked shavings of logwood and already mordanted pieces of cloth. Prior experimentation showed the colour took best on mordanted wool. Most participants choose to dye two pieces of woollen cloth, one unmordanted and one mordanted, they also throw in a small piece of unspun wool.


Photos: Workshop dyeing blue


What causes the difference in colour?

The ambience is great! Participants are enthusiastic and full of ideas. Before a new ingredient is added, small pieces of cloth are removed from the dye bath, to showcase the build-up of colour. Everyone is following the same exact recipe, but differences in dye baths arise quickly. We start to speculate about the causes. Does the rainwater have a lower pH? Does the logwood respond to the chalk in our tap water? Could the material of the pot influence the colour?

The recipe turns out to be a challenging one. We only know the recipe is supposed to result in a 'dark blue', but exactly what shade cannot be determined from the faded sample in the old recipe book. The results vary from brown to purple, to a blue so dark, that it appears black!


Showcased at the exhibition

We ask participants to write down their methods and experiences on a sample card ('Staalkaart'). On this card, participants can describe their process and attach a couple of samples. These cards are on display during the 'To Dye For' exhibition in the green room. The exhibition is on display until October 2nd 2022.

Photos: Sample cards made by participants


Unsolved mysteries

The workshop has provided some insight. For example, cream of tartar and sumac will turn logwood yellow if added too much and rainwater has a big impact on the final colour. But there are just as many new questions as answers: Why does the rainwater have this effect? What colour was the recipe intended to dye? This group is inspired to learn more about the ancient craft of natural dyeing.



Are you curious about the old recipe books or do you want to test one of the recipes? As a part of this project, all manuscripts have been transcribed. They will be available on our website soon. The recipes used for the four workshops are already available here: recipe yellow, recipe black, recipe red and recipe blue.