Curly Dock Mordant

Dock or sorrel are useful plants for mordanting – this was a fact that I’d gotten from reading and made a mental note of. I couldn’t remember where I read it, so I decided to just go ahead and try it. I picked curly (or curled) dock (Rumex crispus) in the roadside around July-August. Curly dock is a tall plant with a reddish seedhead.

The seeds of curly dock.

Curly dock can be distinguished from other related species from the fact that its seeds are enclosed by three petals that have a growth on the outside that looks like a seed but is not.

Enclosed seeds of curly dock.

I used about 100 g of stalks with flowers for a test skein of about 12 g of wool. I boiled the curled dock the first day and let it cool off. The next day, I heated the yarn in the sorrel bath to just under boiling, then let the yarn cool off in the sorrel bath (for a couple of days in the end, because I had other fish to fry). After the sorrel mordanting in the dark red sorrel soup, the yarn was coral red.

The concoction of curly dock, and yarn treated with it.

Finally to the dyeing part of the experiment. I dyed my sorrel mordanted yarn plus two other 12-g test skeins (one unmordanted and one mordanted with 10% alum, my standard mordant) with madder. The dye bath was 40 g of madder root in rainwater, and you can see the result below. As expected, the alum mordanted wool is an intense madder red, but the unmordanted and sorrel mordanted wools are the exact same shade of orange (and a nice orange I think). But I’m going to call this a failure, since the sorrel mordant didn’t make a difference from no mordant.

Alum treatment gives the usual madder red – no mordant or treatment with curly dock both give orange.

So what went wrong? In the end, I realized that I read about sorrel mordant in India Flint’s “Eco Colour”, the exact information she gives is:

“Dry and grind the roots and mix with water to make a tannin-rich soaking solution. The leaves of this genus are also rich in oxalic acid. Even the dried seeds have mordant qualities.”

This doesn’t completely solve my mystery, though. The roots contain tannin, which only works as a mordant on plant fibers, not wool. But I used the flower stands with leaves, which (like rhubarb leaves) contain oxalic acid, which should work as a mordant on wool. Maybe the amount was just too low? I have to try tris again next year.

Saxon Blue

Ever since I first read about Saxon blue, produced by reaction indigo with concentrated sulfuric acid, I’ve really wanted to try it.

The lawyer Johann Christian Barth is credited with inventing the Saxon blue reaction in 1743. He treated natural indigo with sulfuric acid, then known as “oil of vitriol”. According to de Keijzer, the dye was in use in England by 1748, and Jenny Balfour-Paul writes in her book “Indigo” that the dye “can be seen in some oriental carpets, most characteristically those made in Turkey during the second half of the nineteenth century, and also in late eighteenth century Kashmir shawls”. The dye was relatively popular, even though its light- and wash-fastness is not as good as that of indigo itself.

Balfour-Paul calls the color “bright turquoisy blue” while de Kaizer mentions “bluish-green” shades.

The story about this caught my interest because it seems to be a midway point between truly natural dyes, and the synthetic dyes that came after Perkin’s discovery of mauveine in 1856. If made from natural indigo, Saxon blue is not really a synthetic dye. But it’s not fully natural, either, and the process that it was used in clearly seems to fit better into what we think of as an industrial process.

The problem for trying this at home is that you need to use concentrated sulfuric acid in order to produce Saxon blue. This is not something you can just go out and buy, and there’s a good reason for that. It’s a quite dangerous acid that reacts with carbohydrates like bread in a way that makes it look like the bread is on fire.

But now, the perfect opportunity came up, the exam project for teaching chemistry that  I’m working on right now. So here’s my little experiment with Saxon blue. I tried this in a chemistry lab, inside a fume hood, wearing lab coat and safety goggles. DO NOT TRY THIS AT HOME!!

I mixed 0.5 g of indigo powder with 5 mL of concentrated sulfuric acid, and then heated it over a simmering water bath for about 10 minutes (left photo below).

Then I diluted the indigo into water, and put in alum mordanted wool. I heated the wool in the dye bath for about 40 minutes (right photo below). Even after diluting, the solution was very acidic (pH 1).

Dyeing in the chemistry lab.

This is how the skein of wool turned out after rinsing out the excess color (there was a lot). A very clear blue, that’s actually very similar to the shade of blue you would get with indigo used as a vat dye.

Saxon blue wool.

But the chemistry behind this blue is different from the usual indigo chemistry. The reaction between indigo and sulfuric acid produces a compound called indigo carmine (this is what is called Saxon blue). Indigo carmine is an acid dye, not a vat dye. That means that it will bond to aluminum that was attached to the wool during alum mordanting.

Notice the cotton thread tied around my Saxon blue wool skein below. It’s only slightly blue-tinged. Alum does not react well with cotton, so there were only very few sites on that thread where indigo carmine could bond.

Now compare with the blue on the pile of cotton in the back. It just happened that I used the very same cotton thread for tying around clothes that I shibori dyed with indigo using the usual method. Notice how parts of the thread in the back are quite dark blue. They were exposed to the indigo vat, and the color took well, because indigo can deposit directly on cotton (there are also white parts, but they were just not exposed).

Saxon blue does not dye cotton well at all – for that, you need an indigo vat.

It was fun to try dyeing with Saxon blue (indigo carmine), but I don’t really see myself repeating the experiment for the purpose of actually dyeing wool. The fact that the light-fastness is low and the process uses concentrated sulfuric acid means that the comparison with indigo itself does not fall out in Saxon blue’s favor.

But if you are wondering what Saxon blue is up to these days, check your candy wrapper. It shouldn’t be difficult at all to find yourself some candies containing FD&C Blue #2 in the US, and E132 in the EU. That’s indigo carmine, or Saxon blue. The stuff in food does not come from natural indigo, it’s synthetic.

If you have appetite for some more dyes, you can also look for natural red 4 (US) or E120 (EU). It may also be written as carmine. Around here, it’s known as cochineal. In this case, the coloring in food does actually come from the natural source. Some people find this disgusting, but having ground the lice so many times for dyeing, I actually find it quite unoffensive.

Green Matrix

Green is a difficult color to achieve with natural dyes. One might initially think that it was easy, given that green is the predominant color in nature. That’s not the case, since the green color of plants comes from chlorophyll, which doesn’t work as a natural dye (since it’s soluble in fat, not in water).

Since I had nice results with indigo overdyeing to get tones of purple, I repeated the process to get green. First, I mordanted my yarn with 10% alum. Then, I dyed it different shades of yellow:

  • a 1:1 bath of weld, gave a strong yellow
  • reused the bath above, gave a less strong yellow. Seen at the lower right in the picture above
  • a 2:1 bath of dry mugwort (so twice the amount of plant than wool) that I collected last summer. Gave a yellow-beige seen in the lower middle of the photo


Then, I overdyed the different yellows with dark, medium, and light indigo. The 3 blue skeins in the left side of the photo are dyed with indigo on white yarn, just to show the shade of indigo. The next 3 green skeins are indigo on mugwort. The lighter indigo overdyes give dusty shades of green, while the darkest one gives an intense teal. Really worth remembering that such a dull beige can be turned into such nice shades of green.

The next 3 green skeins are indigo on less intense weld, while the last 3 skeins to the right are indigo on intense weld. Generally, indigo on weld gives clear, almost too clear shades of green. The indigo overdye on intense weld really gives an electric shade of green. The Robin Hood kind of green, which used to be known as Lincoln green.

Old Polypore

Dyer’s polypore is one of the very good dye mushrooms found here in Denmark (and many other places, including the rest of Europe and North America). It grows on dead wood, or parasitically on the roots of living trees. It grows in the same spot year after year, and grows a new fruiting body every year. That means you will often find dried-up mushrooms from the previous year close to the fresh growth of the year.

I’ve often found myself standing in a forest with a bunch of dry polypores from the year before, thinking that it was really too bad that they were wasted. So I decided to collect some, to test if they still contain any dye.


I tried a single mushroom, weighing 24 g (it obviously would have weighed much more when it was fresh). I chopped it mushroom in small bits, and that partially powdered it.

I tried the dye bath on a 10 g test skein alum mordanted wool, and it turned a nice yellow-brown. So I used the bath a second time, and got a lighter shade. The old, dry mushroom clearly has a smaller dye potential than the fresh ones, but it does contain dye, so there’s no reason to leave it behind in the forest.




Fructose Indigo Vat


Quite a while ago, I knit this little pincushion, the physical evidence of my experiments with an organic indigo vat. It’s knit in Fenris 100% wool, 450 m/100 g.

The pattern is free, Peerie Pin Cushion by Ellen Kapusniak. You’re supposed to sew it together, but I, of course, grafted it closed.

I normally use a chemical vat with sodium dithionite as the reducing agent, which reliably works for me without crocking or anything of the sort. But it stinks, and I don’t like mixing the chemicals in the same house as my children.

Another problem I’ve experienced with this relatively harsh reducing agent is that the color doesn’t deepen with successive dips. This is a known problem with this type of vat. It is just as efficient at depositing indigo on your fiber as it is at stripping it back off.

And then, I was also inspired by my visit to the natural dyer Kenichi Utsuki at Aizenkobo to try the real thing myself. He holds nothing but contempt for indigo dyeing that, although it uses natural indigo, uses an artificial, chemical vat for the dyeing process. According to him, the complexity of the final result depends on the slow build-up of layer after layer of color – as does the light-fastness.

I tried using a fructose vat, using the ratio found in Maiwa’s instructions (there’s also instructions for the same type of vat here). Here, one uses the fructose as a reducing agent, since fructose is a reducing sugar. It’s not nearly as potent as the dithionite.

The instructions say 1 part indigo, 2 parts lime, 3 parts fructose. Or at least I thought I used their instructions – they say 20 g of indigo, but I decided that I would try with 5 g. That gave very little blue on my yarn, but lots of blue was left at the bottom of the vat. You can almost see how weak the color is here:


I was later advised by the knowledgeable dyers of Ravelry that the fructose vat doesn’t scale. You have to use at least 20 g of indigo, and that should give you a living vat that you can feed more fructose and base and keep using for months.

I tried scaling it up, but the results I got were not what I had imagined. Sure, I dyed yarn blue, but the amount of color I got out of the vat still just didn’t correlate with how much indigo I put in. There was still a lot of blue sludge at the bottom of my vat.

I would love to run this vat much longer and get a continuous process going, in order to transform more of the indigo at the bottom. The vat has to become a living thing, and you have to dip and redip and so on!

I want to try this type of vat again because it is much more people and eco-friendly, and it is much closer to traditional methods of indigo dyeing than the chemical vat is.




Jars of Lichens

Lichen dyeing is a slow discipline – the slowness only surpassed by the pace that the lichens themselves grow at…

I started two jars of lichens late in February, one with Evernia prunastri (left) and one with Ramalina fastigiata – at least, I’m fairly sure that’s what it is (right).


It’s important to mention how I gathered these lichens: the Ramalina fastigiata is all windfall from a single tree that used to grow in the playground near our house. Every time I walked under it, I found at least one bit of fallen lichen, and often, I filled both pockets. But then, the other day, I walked by only to find that the tree had been cut down! Along with every other tree nearby!! I hope some city planners somewhere are hanging their heads in shame. That place is not fit for humans anymore. Or any other species for that matter.

Most of the Evernia prunastri is also windfall, but some was picked during trips to several different forest where it grows so thick that most trees are completely covered with it, and in that case, picking off small bits is OK.

Evernia prunastri, also known as oakmoss, ragged hoary lichen, and stag’s horn lichen, is a well known dye lichen, and is also a component of many perfumes (makes sense, its scent is wonderful, but that’s the case with all lichens I’ve met up close). I put 25 g of this in one jar.

Ramalina fastigiata is not specifically mentioned in the lichen chapter of “Vegetable Dyes” by Ethel M. Mairet, a remarkably useful book from 1916 that you can read for free at the Gutenberg project. Nor does “Lichen Dyes, The New Source Book” by Karen Diadick Casselman, but both books mention unspecified/other Ramalina species as sources of red/pink using the ammonia method (and Casselman also indicates that yellow can be obtained with boiling water method). I put 20 g of Ramalina fastigiata in a jar.

After adding lichen to a jar, it should be filled with 1% ammonia so it covers. I buy the ordinary kind at a supermarket. It is 8%, so I simply make a diltion to 1%.

And then comes the tedious part!

Let the lichens steep in ammonia for weeks and weeks, take the caps off every day to let in air, and shake the jars well and often to ensure aeration. Casselman warns again and again that the color will not develop properly without good aeration.

I was diligent in my vat-shaking until early April, at which point I decided to try out the dyes.

From each jar, I took the amount of liquid that is equivalent to 5 g of lichen. From the Ramalina jar, which had 2o g of lichen, that was 1/4 of the liquid or about 100 ml. From the Evernia jar that contained 25 g of lichen, 1/5 of the liquid.

I diluted them to cover the yarn and placed them in a double boiler system with glass jars inside a pot of water. I remember reading about this somewhere, but I don’t remember who the brilliant person is…

But it’s very clever for these small dye baths AND also very good because the pH is above 10 even after dilution, so you have to heat very gently to not damage the wool:


I gently heated the pot for about an hour, then took out the skeins of wool instead of leaving them in the dye bath until next day as I usually do. I did it differently because I thought the high pH over so many hours would ruin the wool.

This first dyeing attempt gave a couple of skeins of medium pink shades that are quite pleasing, I think! The Evernia-dyed skein (on top) has a slightly browner tone of pink than the Ramalina-dyed one (bottom) which is truly baby pink


After that, I let the jars continue until late June, but I’m afraid the vat-shaking was much less diligent!

But on June 21st, I decided to finish the experiment.

I filtered the rest of the liquid in each jar, then measured the pH, it was 10-11 (as expected). I split the dye liquid from each jar in two, left one of them as it was, and neutralized the other one. I used about 1 part 37% acetic acid to 5-8 parts dye. This is just what we happened to have in the house, HCl would work too. If you want to try this at home, wear goggles and lock children and pets in another room.

Then I used the same double boiler setup as first time, taking out the wool at high pH after an hour, and leaving the skeins in neutral jars until the next day. And the result:


From right to left, it’s:

1: The Evernia-dyed skein from April

2: The Ramalina-dyed ditto

3: Evernia high pH, June

4: Ramalina high pH, June

5: Evernia neutral pH, June

6: Ramalina neutral pH, June

So actually skeins 3 and 4 are just a repeat of 1 and 2 but a couple of months later. I’m really not sure why the color was better in April than in June. Because I stopped shaking the jars as much? Or does it influence the result that I used alun mordanted skeins in April but unmordanted wool in June? It shouldn’t, since lichen dyes are substantial, but one never knows.

The neutralized dye baths yielded more color, but the color is towards tan tones rather than a real pink. Nice colors, but I’ve gotten similar colors from avocado with less effort!


Mordant 10% alun on some skeins, none on the others (it’s what I had around)

Water Tap

Yarn Supersoft 575 m/100 g

Yarn:Dyestuff ratio 2:1 and similar ratios

Conclusion Lovely baby pink plus more saturated orange-pinks

Possible improvements I’d like to get more intense color with this method, and I imagine using more lichen could do the trick. But the shaking of the jars is probably just important to optimize!

All in all, I’m pleased with my first results using these types of lichens and the ammonia method. But I do think there is a lot of room for improvement. I’ll probably start some new jars soon!

Avocado, Meet Blender

Remember these jars?


They had been fermenting for over a week, and the color of the liquid didn’t change over the last days, so I decided it was time to try them.

The front jar contains the pit and peel from 1 avocado and 1 Tsp salt, the other one the same with the addition of 1 Tsp ammonia. I combined the pit and peel in one dye bath because my earlier attempts didn’t yield different colors with them separated. And this time I blended the pit and peel, carefully and a bit at a time to not destroy the blender.

The much deeper red in the ammonia jar does translate into more color, a reddish brown, on the yarn (in front) than the jar without ammonia (in the back) which just gave the standard beige. Again beige.


No pink this time, maybe because I didn’t heat the avocado before fermentation?


Mordant 10% alun

Water Tap

Yarn Supersoft 575 m/100 g

Yarn:Dyestuff ratio 10 g yarn to one avocado

Conclusion Ammonia extracts more color

Possible improvements Boil before fermentation to get pink. Filter out blended avocado before dyeing

At this point, I think it’s fair to say that I have tried a lot of combinations with avocado fermentation of avocado pits, of the peels, and now blending them together and fermenting them with and without ammonia. I’ve achieved a range of colors from beige over pink into brown.

So I do think this concludes my experimentation with this for now. The only thing that remains to be seen is how light and wash fast this is over a longer time.

Dette er det – måske – sidste forsøg med avocado, for nu i hvert fald. Denne gang har jeg blendet skal og sten af avocado sammen og prøvet at fermentere dem i en uge med eller uden ammoniak. Sidstnævnte gav den kraftigste farve i glasset og også på ulden. Men ingen pink denne gang, kun beige og brun.


An Experiment in Cold Mordanting

Recently, I have wondered how much it is really necessary to heat wool when you mordant it. To the usual 80-90C? Or would 60C be enough? (Yes I wondered about that because I ruined some yarn, and I think I overheated it!)

So I turned to the knowledgeable people on Ravelry’s natural dyeing forum for help, and was told that you can cold mordant. No heating, just steep the wool in the usual alun solution without heating it. And for how long? Sea green and sapphire writes that it is enough to leave it overnight in a cold solution, and that “dyeing results are not compromised in any way by leaving out the heat”.

So it had to be tried! I took:

  • One 10 g test skein of wool, mordanted in my usual way: prepare a solution containing 10% alun. That means if you have 100 g of wool, put 10 g of alun in the pot. Dissolve the alun, add clean and completely wet wool, and heat it to about 90C for an hour. Then, I always just let it cool off in the solution until the next day
  • One 10 g test skein of wool, mordanted by leaving it in a cold 10% solution of alun for 24 hours.

Both skeins then went into the same dye bath in order to compare them directly. The dye bath consisted of 40 g of dried heather from last fall, I had wanted to try that for the longest time, to see if heather yellow is warm or cold. And the result:


I am not able to tell the skeins apart, so the conclusion is that cold mordanting us just as good as hot. I think this is great news, because it really saves electricity!

The heater’s yellow is a wonderful warm tone, so I will definitely collect more this fall. Next time I dye with heather, though, it should be boiled and the dye bath strained before the wool goes in. The heather twigs are very difficult to remove – they are like small hooks inserted in the yarn.


Mordant 10% alun hot or cold

Water Tap

Yarn Supersoft 575 m/100 g

Yarn:Dyestuff ratio dry 1:2

Conclusion Heating is not necessary for alun mordanting! 

Heather yellow is warm and wonderful

Possible improvements Remove heather twigs before adding yarn

De to nøgler garn ovenover er begge bejset med alun, men det ene uden nogen form for opvarmning. Det ser ud til at virke fuldstændig ens – en god nyhed, for det betyder en stor energibesparelse under naturfarvning. Nøglerne er farved med lyng fra sidste sensommer.