Some time ago I got a book in my mailbox about historical dyeing. The colourful past is an elaborate reference work about historical dye methods through the ages and analyzing them in a laboratory. In this book there is also an extant part about madder. The chemical analysis of madder is very interesting. I will not bore you with chromatograms and chemical structures, but this book shows me my dream job exists.
The book also contains historical recipes for dyeing, and I tried one for madder red. Interesting was the mordant combination of alum and tartaric acid. The mass-ratio for mordanting the cloth:alum:tartaric acid I used was 100:10:5. As always I nearly boiled the solution with the cloth for two hours while gently stirring occasionally. I let the solution cool with the cloth inside and let it stand overnight.
The dye bath had the mass-ratio of 1:1 for cloth and dyestuff (madder). I used rainwater instead of tap water, because previous experiments showed that this was good for getting reds out of madder. The madder was pre-soaked for two days and then it was brought to 65 degrees Celsius for several hours. The cloth was added and also gently stirred occasionally for two hours. The solution was cooled overnight. The cloth was rinsed the next morning and left to dry.
As you can see the red colour became very intense and dark with this procedure and I have the feeling I am getting close to unfolding the madder mystery!
De Graaff, J. H. H., Roelofs, W. G. T., Van Bommel, M. R., De Graaff, J. H. H., & Van Bommel, M. R. (2004). The Colourful Past. Abegg-Stiftung.