What de fek Mordant?
When I first started dyeing, my wonderful mentor/spirit guide/local apiarist Mike gathered a bunch of his friends. Everyone was talking what I felt was cool gibberish. Mordant would turn out to be the most important of all the gobbledygook.
Mordant stems from the french word mordire which means to bite. In my brain, I imagine little tiny dye bugs trying to latch onto the fibres and being bounced off. Like a daddy-long legs that can't pierce through human skin even if he tries really really hard.
The mordant is a layer between naked fibre and dye that acts as the sticky gooey stuff of life. Not that kind of sticky gooey stuff of life! A family friendly G rated version. To be an effective mordant, there must be a chemical reaction in order to change the molecular bond between fibre and dye.
If you go back to high school science you might remember that two negatively charged battery ends will repel each other, whereas a sandwich of negative-positive-negative is as good as bread-pbj-bread. The mordant acts as the positive in the sandwich, where a fabric and dye which are both are the negatives.
For this sandwich to work, the fabric and the dye need to be PLANT based and the mordant must be PROTEIN based.
Plant or Protein?
Plant based fibres and dyes are ones that come from plants. Now THAT is some science.
Here's a lil list of PLANT:
- Cotton - fibre
- Linen - fibre
- Bark - dyestuff
- Berries - dyestuff
- Ramie - fibre
Here is a list of PROTEIN:
- Silk - fibre
- Wool - fibre
- Beetles - dyestuff
- Blood (I guess) - creepy dyestuff
You must must must mordant a plant fibre if you intend on dyeing it with a plant dye (which is pretty much the only kind of dyeing I do, so buckle up).
Kinds of Mordants
Here is where my knowledge is stretched a little thin. I understand the concept, but not so much the chemistry of a lot of these mordants so if you want to try out your own concoction please research it first! This post is the most in-depth review of readily available mordants I have found lately!
My favourite mordant to use is soy milk (actually a binding agent, as no chemical reaction occurs).
I don't love using powdered chemical compounds as mordants as they are dangerous to breathe in, especially when heated and steamed out of the pot. They are, however, very handy when you don't have a week to wait for soy milk to do its stinky thing. I always only ever dye outdoors on a gas heater, in order to avoid breathing in any nasties.
I've also used Alum Acetate. I hate maths, so Abigail Booth's book really helped me here. Use 5% alum acetate for the weight of dry fabric in grams.
Once you have weighed and figured out how many tbsp of Alum to add to the whole pot, dissolve the alum in a little bit of warm water. Then chuck the fabric, enough water to fully cover it, and the dissolved solution, into a pot and bring to a rolling boil for around an hour. You can either add the dyestuff directly into this mordanted pot, or rinse it out and save it for dyeing later! Perfect!
Soy Milk Mordant (but not really mordanting)
*As there is no chemical reaction involved, soy milk is not actually a mordant but a binding agent. But don't say that to her face. Treat this step with the same respect and care as all pre-treatments for the best colour results.
Soy milk is the stinkiest and bestest binding agent for natural dyeing I have used so far. I love using her because it is an exciting transformation, watching the mixture ferment and seperate. Also because I don't feel guilty dumping the old soy/water mix into the garden at the end of the week. The main downside is she gets pretty ponky. My recipe for mordanting with soy is:
- 1:5 soy to water ratio. Enough liquid to soak and cover material completely.
- Leave in a container with a removable lid for about 24 hours. Make sure if you are screwing a lid on/popping it down not to fully seal her. If you have watched ANY Brad Leone's It's Alive you would know that a fermenting baby in a sealed container is an explosive disaster waiting to happen.
- Rinse fabric so no solids remain. I like to do this in the leftover soy mixture. No need to waste fresh water, especially when curing the fabric with soy protein is the whole point.
- Hang out to dry for 1-5 days. Apparently the longer you cure it the better it gets but sometimes I can't wait and use it still damp. It doesn't work as well. I am just impatient.
Iron Mordant and Saddener
The iron I'm talking about here is the chemical Fe, not the steamy triangle that cancels wrinkles! Please don't mix a household iron with water and vinegar and expect anything other than a broken laundry appliance!
Iron is a most wonderful part of the dyeing experiment. As the iron thats bonded with the fabric and dyes is oxidised, the colour deepens and darkens. In my experience the saddening has turned bright pinks and yellows into a greys, purples, and browns.
It is so easy to make an effective iron mordant mix! If you don't want to wait, it's easy to pick up Iron Sulphate from Bunnings and such in the gardening section. Check which plants like Fe, and if you have any in your garden, make sure to pour the leftover iron water on them!
My recipe for making an Iron Mordant is:
- Find rusty metal. I rummage the garage for old rusted nuts and bolts. While foraging for native dyestuff I found a metre long rusted piece of metal which I bent down and made a mixture with. Anything with rusty bits will do.
- Dedicate a jar to the iron mordant. This jar will never live a different life. Once chosen, this jar will forever be home to iron mordant mixtures. It will never be food-safe again, and the stains are insane. Be wise and DO NOT use your mum's fancy crystal!
- 1:3 Vinegar to Water ratio. Enough to fully submerge the rusty goods.
- Put a lid on it. Loosely. Set aside for a week or so and there you have it!
I love to check on the jar every day to see the huge change in the first week. The first few days the water slowly gets yellow, but around the third day there is so much action! A slick rainbow skin forms on the top, with a bunch of bubbles, and a strong metallic smell.
Mordanting with Iron
Mordanting with iron before you dye is definitely an option, however it is tricky to control the colour shift. In order to have more creative control, I use Iron straight after I finish a dye bath. This is what I refer to as saddening.
Saddening with Iron
Saddening refers to darkening the dye colour. As an example, avocado pinks sadden from pink to purple to grey. The more concentrated the iron is, and the longer you dunk the fabric, the darker the fabric will get.
pour a good plonk of my homemade iron mordant mixture straight into the dye bath. Most of the time I will dye two pieces of fabric, and iron sadden one. This way I can put them side-by-side and really take in the impact of the iron saddener.