Month: February 2022

Let’s talk plants: Madder

/ Jazmin / Leave a comment

I’ve talked about dyeing with madder more than a few times. I’ve written up documentation about some of my early madder experiments. I don’t think anyone would be surprised to know that I am really rather fond of playing with madder. So let’s do a little bit of a wander down the botanical path with the plant.

NB. I am a terrible gardener. I managed to kill a mint plant, that’s the level of terrible we are talking here. I do not grow my own. I let professionals (or awesome friends) do that for me and reap the bounty of their labours with gratitude (and/or payment.)

Franz Eugen Köhler, Köhler’s Medizinal-Pflanzen, Public domain, via Wikimedia Commons

Right, we’re talking about Madder. Most commonly, when the word madder is tossed around in the dye world, folks are meaning the dried and ground roots of Rubia tinctorum. Also referred to as common madder or European madder. It is, however, not the only madder plant out there that has dyestuff for us! It’s not even the only madder plant we can buy. The other one that’s easy to find at the dye supplier is Rubia cordifolia. Also referred to as Indian madder, or munjeet. But yet again that’s not the only other madder out there, there’s more! Wild madder, Rubia peregrina and Japanese madder, Rubia akane and there are others in the Rubia family.. but the first two are the most commonly used.

R. tinctorum is a perennial that was cultivated throughout Europe and the Middle East, with the highest quality coming from Turkey, Holland and France. It is native to western and central Asia and naturalized itself in central and southern Europe. Munjeet (R. cordifolia) comes from moutainous regions of Asia, from the Himalayas to Japan and also in tropical Africa. Wild madder (R. peregrina) is a native of Europe, Turkey and North Africa as well as the coastal regions of southern England and some bits of Wales and Ireland. The roots of wild madder are smaller than that of madder, requiring more dye stuff to gain a strong colour than one would require from madder, although that can be mitigated by waiting longer to harvest the wild madder roots (five years, rather than three for R. tinctorum)

Madder dyed wool

All of the various versions of madder have been used since antiquity, with evidence in extant items from Mohenjo-Daro in the Indus vally (approx 3000 BCE) and mentions in Pliny the Elder’s Naturalis Historia and recipes using madder are found in the Papyrus Graecus Holmiensis (approx 4th century) Assumptions about which madder was being used are usually based on geography. The East was more likely to be using R. cordifolia, the West more likely to be using R. tinctorum or R. peregrina. Local traditions using local plants, as the Rubia plant family is happy to grow in so very many different places.

All of them contain similar dye molecules, although different plant species have them in different combinations and concentrations. This chart from “The Colourful Past” by Judith H. Hofenk de Graaff is an excellent summary of who has what, with some extra plants that also contain anthraquinones.

Forgive me for being the kind of person who casually drops words like ‘anthraquinones’ in conversation, but in a nutshell.. those are the dye molecules that provide the red colour. For the curious, these are their structures (why this graphic is missing alizarin, I have no idea but it’s below):

Mohd Yusuf et al., “Eco-Dyeing of Wool Using Aqueous Extract of the Roots of Indian Madder (Rubia Cordifolia) as Natural Dye,” Journal of Natural Fibers 10 (March 13, 2013): 14–18.
George B. Kauffman, ed., Coordination Chemistry: A Century of Progress, vol. 565, ACS Symposium Series (Washington, DC: American Chemical Society, 1994), accessed February 18, 2021, https://pubs.acs.org/doi/book/10.1021/bk-1994-0565.

Phew, okay.. still with me after the brief foray into chemistry? (If you’re interested, the handout for my class on dye molecules can be found here. If you have a virtual event you’d like me to teach it at, just ping me.)

At the end of the day, if you have madder, munjeet or wild madder, you’re getting a dose of very similar dye molecules and just enjoy the ride. All of them function pretty similarly, and the reds are just so much fun to work with. I have an experiment in progress comparing R. tinctorum with R. cordifolia, through a collection of exhaust baths, so look for that coming soon!

Bibliography:

Hofenk de Graaff, Judith H., Wilma G. Th Roelofs, and Maarten R. van Bommel. The Colourful Past: Origins, Chemistry and Identification of Natural Dyestuffs. London: Archetype Publ, 2004.

Dean, Jenny. Wild Color: The Complete Guide to Making and Using Natural Dyes. Rev. and Updated ed., 1st rev. U.S. ed. New York: Watson-Guptill, 2010.

Cannon, John, and Gretel Dalby-Quenet, eds. Dye Plants and Dyeing. Repr. London: Black, 2002.

Yusuf, Mohd, Mohammad Shahid, Shafat Khan, Mohd Khan, Shahid Salam, Faqeer Mohammad, and Mohd Khan. “Eco-Dyeing of Wool Using Aqueous Extract of the Roots of Indian Madder (Rubia Cordifolia) as Natural Dye.” Journal of Natural Fibers 10 (March 13, 2013): 14–18. https://doi.org/10.1080/15440478.2012.738026.

Kauffman, George B., ed. Coordination Chemistry: A Century of Progress. Vol. 565. ACS Symposium Series. Washington, DC: American Chemical Society, 1994. https://doi.org/10.1021/bk-1994-0565.

Water quality and your dye pot

/ Jazmin / 1 Comment

I’m in the depths of getting wool skeins dyed, and don’t have any of that ready to show to the world yet. Its a lot slower and more complicated to get from water sample to dyed wool when taking measurements at every step on the way, but it’ll be good in the end. Hopefully I can remember to stir the next batch more so they are less blotchy. <sigh> But I digress! There’s three main things I’m looking at in the water: pH, Total Dissolved Solids (TDS) and iron content (ppm). Let’s have a chat about each of those in turn and today we’re going to chat about pH. There’s a lot of complicated chemistry involved in water, and there’s quite a bit of interplay between all three (and temperature, and and and).. I mean, you can get a whole university degree in water, so know that we’re aiming for broad strokes here and big picture.

The pH Scale of Common Chemicals

The one that most people are familiar with on any level is pH, the measure of how acidic or basic something is. It’s measured by looking at the free hydrogen ions (H+) in the solution. (Inversely proportional, as a note: More hydrogen, lower pH.) It’s a scale that runs from 0-14, with acidic things down low and basic things up high. Pure water is the control, and it sits at 7.0. A few things people don’t realize (or remember from high school chemistry) is that the scale is logarithmic, which basically means that the distance (or number of hydrogen atoms) in going from 7 to 6, is not the same as the distance from 6 to 5. There’s 10 times as many in that second chunk. That’s trivia level content more than super relevant to anyone reading, but if you ever wanted to try and count hydrogen atoms.. well we can talk about new hobbies, hmm?

When reading the WHO Guidelines on drinking water (1) , a pH anywhere from 6.5 to 8 is considered acceptable. Pure water, remember, hangs out at 7 exactly, but there’s a lot of elements that affect the pH without making the water undrinkable. All of us who lived through the pollution filled 1970s and 1980s remember the screams about acid rain and how it was melting away everything, I think. Pollution can affect the pH of water, but by the same token, most ground water has absorbed enough minerals that it slides itself a little higher on the pH scale. (And you pay extra for all those minerals at the store when you buy spring water.. s’okay, they are generally what makes water taste better. Distilled water always tastes flat and weird.)

So clearly everything below 6.5 and above 8 is dangerous, right? Well, not so fast. Where it gets more complicated is that pH alone is not an indicator of safety. Common household vinegar has a pH of approximately 2.8, which is extremely low.. in the same range as stomach acid, but we think nothing of ingesting vinegar (ideally on a nice hot plate of fries.. mmmm.) It is a weak acid, a well diluted acid, generally sitting at about 5% strength. If it was full strength, it would be very dangerous indeed!

Further complicating matters is how pH and other measures interact. pH is extremely dependant on temperature (not much of a consideration for me, all of my samples were at room temperature), and the pH of water can determine its tendency to have picked up other ions. As the pH gets lower, the metals are more soluble.. they dissolve more easily in the water, so there tends to be more lead, copper, iron etc in water that tends towards the acid. We’ll talk more about metals in water when we have a better look at the iron testing that I did and how that affects the dye works.

Water chemistry is complicated and while I knew it was a big field to go poking into, it’s been a fast train into the depths. It’ll take a lot more digging to get myself out of these weeds.

References

  1. World Health Organization – pH in Drinking water (2007)
  2. Safewater.org TDS and pH (2017)
  3. Health Canada – Guidelines for Canadian Drinking Water Quality: Guideline Technical Document (2015)