In 2021 I decided I was going to do a whole series of natural dye experiments, not focusing so much on colour as focusing on the tannins and mordant stage of cellulose dyeing and what it did to the colour. It’s not the most exciting step, but definitely the most important as it’ll affect the colour, not only in the immediate, but in the long term as well. There’s a lot of posts and information about how to do it, but not a lot of information I could find about how the different tannins themselves affect the final colours. I decided to do a small series myself.
This is really just scratching the surface. I selected a handful of colours and mordants, but there is such a huge world of variation, that it felt a bit like a drop in the bucket. It did give me a really good foundation going forward, and gave me a lot of confidence in choices I could make in the future. It also gave me a ton of practice just with the tannin and mordant steps with cellulose, which I felt still very new at in 2021.
Writing this now almost three years later is a bit wild. I was freshly pregnant when I was doing these (although I didn’t know it yet), but I knew this was likely the last chance I’d have the time to do it in the upcoming years. I made a ton of notes at the time, knowing I’d want to expand on them and write down my thoughts later. I didn’t realize how much later, but I’m always glad when I come back to things some time later to find my detailed notes.
I’ll be posting these as a series to really examine all the colours and what the bases did to them. So here we go, first up, the tannins and mordants.
These samples, all 4×5″ (with the untreated white on top for reference) are just tannin and mordants. From left to right they are gallnut, sumac, cutch, myrobalan, and a tannin blend (from Maiwa in Vancouver). The top row was treated with aluminum acetate with a chalk afterbath to help it set, and the bottom with potassium aluminium sulfate (alum) and soda ash.
The concentrations I varied per tannin and mordant, based on my personal prior experience, along with suggestions from natural dye sources. What I used was:
- Gallnut: 15% WOF
Sumac: 10% WOF
Cutch: 10% WOF
Myrobalan: 20% WOF
Tannin blend: 15% WOF
For the mordants I used these concentrations:
- Aluminum acetate: 8% (with a chalk afterbath of approx 10g/L of calcium carbonate)
Potassium aluminium sulfate 15% with 1.5% soda ash
I followed my standard method for mordanting – tannin baths are done in tap hot water (about 60-65C) and then allowed to sit, cooling slowly for 24 hours. They then get wrung out gently (very gently, in order to not remove the tannin, which hasn’t yet bound to the fibre, because we need the alum for that), and put in the mordant baths.
The mordant baths are similar – tap hot water, which is allowed to cool, although I generally only soak those about 2-5 hours, depending on when I get to them to wring them out.
You quickly see the differences in how the mordant affects the tannins. The top row (aluminum acetate) does not leave quite as strong of a colour from the tannin, but certainly with the tannin blend, it doesn’t alter the base colour as much either. The alum leaves a stronger base colour, but does alter it very slightly to a very, very, very slight brown hue.
I was baffled as to how I was going to keep all these samples separate while the dyeing, but a friend suggested I use little embroidered keys, and it worked like a charm and I was able to divide them up and start dyeing.