An Earthball Study

Earthballs contain a yellow-brown dye, but also a large and annoying amount of tiny, black spores. So I set out to find out if the spores contain any dye or if they could just be discarded.


Common earthball, Scleroderma citrinum.

A couple of years ago, I dyed a lot of yarn with earthballs. The color turned out a nice yellowish brown, but the yarn was simply full of spores that continued to drizzle out, both when winding the yarn into skeins and when knitting with it.

The drizzling pores were obviously annoying, but I also started wondering if the spores are even safe to breathe? It’s usually said that earthballs are “moderately toxic”.

In their book “Färgsvampar & svampfärgning” (Dye mushrooms and dyeing),  Lundmark & Marklund label earthballs “good” dye mushrooms, so it would be a pity to give up on earthballs just because of the spore problem. Lundmark & Marklund mention that earthballs contain the dyes badion A, norbadion A, and sclerocitrin.

Sclerocitrin is also described in the research paper “Unusual Pulvinic Acid Dimers from the Common Fungi Scleroderma citrinum (Common Earthball) and Chalciporous piperatus (Peppery Bolete), Angewandte Chemie International Edition, 2004, 43, 1883-1886 by Winner et al. They show that the “brilliant yellow” dye sclerocitrin is found in “remarkable amounts” in earthballs. As the title says, sclerocitrin is also found in peppery boletes. I haven’t looked for it, but a mental note has been made.

Earthballs have a dark or black spore mass inside, surrounded by a relatively thin outer wall. I decided on a small experiment in order to see if the spores contain any dye. If not, it would make sense to just leave them in the forest.

Halved earthballs with grey and black spores inside.

I used as small amount of earthballs for my experiment, gathered during the fall of 2016 and dried until use (2016 was not a good mushroom year, so not many earthballs were to be found).

Separating the spore mass from the mushroom’s outer wall was incredibly difficult. The parts were completely stuck together in the dry mushrooms, but in the end, I had 23 g of out walls and 10-11 g of spores. I soaked both overnight, the outer walls simply by adding water. The spores were stuck together in stone hard lumps that I separated by grinding them in my mortar. The spores repel water, I solved that by wetting them in denatured alcohol, then adding water.

The next day, I boiled the two dye baths and filtered the spore bath through a coffee filter. It took very long for the liquid to run through, that’s always the case when filtering a solution with many tiny particles. I then dyed a 10-gram alum mordanted test skein (Fenris 100% wool) in each bath, and got the result below – almost the same color from the two.

The top skein of yarn in the picture is dyed with the outer walls, the bottom one with the pores. I had hoped to find that the pores didn’t dye, but clearly that’s not the case. In principle, it’s not surprising, though, to find that sclerocitrin and the other pigments are distributed throughout the mushroom. The dark color of the spores is not caused by a pigment that acts as a dye.

In conclusion, all parts of the earthball contains dye, and discarding the pores would mean discarding a lot of good dye. So the best method for earthball dyeing would be using the entire mushroom, wetting the spores with alcohol, and then investing the time required to filter the entire dye bath before any wool is added.

Yarn dyed with different parts of earthballs. The top skein is dyed with the outer walls only, the bottom skein with pores only.

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Seasonal Color Variation

An experiment with yellow to green tones of birch leaves over the summer. I didn’t see any difference, but most experiments do have different outcomes than expected.


A fresh new year calls for a new, big series of dye experiments, but I’m going to begin with an old one that was going on for so long that I never wrote about it.

“Yellow can be many things, so for each plant, I will  specify the particular yellow it gives. There will always be differences, the tone being more green earlier in the year.”

This is what Ester Nielsen writes in her introduction to natural sources of yellow in her book “Farvning med planter” (Dyeing with plants). This Danish book, published 1972, is full of useful information, but such a claim as this is just begging to be tested. I decided to use birch leaves for the test.

Birch leaves. It’s impossible to tell from the outside that they contain a good, warm yellow color.

To test the claim that colors are greener early in the growing season, tending towards yellow later, I made two 10 g test skeins of supersoft wool. I dyed each of them with 40 g of fresh birch leaves, since Ester Nielsen recommends 4 times the weight of fiber in fresh plants (twice the weight of fiber if using dried plants). I picked the first portion of leaves on May 11th, the second on July 4th.

The picture below shows the result. The skein in front is dyed with the leaves from May, the back one with thw leaves from July. They’re almost the same color, so my little experiment didn’t back up Nielsen’s claim…

Wool dyed with fresh birch leaves. The front skein is dyed with leaves picked in May, the back one with leaves picked in July.

To check for other possible differences, I tested the light-fastness of the two skeins. But again, no difference. The only thing worth noting in the light test shown below is a really good light-fastness of both yarns. The test took place over more than a month of summer.

Light test of wool dyed with birch leaves picked in May and July.

My conclusion: the time of harvest does not affect the color achieved with birch leaves. But that may only apply to birch leaves. It is possible that other plants to have a variation from yellow-green to yellow as the summer passes.

Vindauga Baby

The design theme from my Vindauga Blanket just stayed in my brain after I knit the first one, demanding to be knit in more variations! And when that design theme met with my experiments in 2-dimensional gradients (or matrices), the result was the Vindauga Baby Blanket, which I’ve finally managed to publish the pattern for.

You can buy the Vindauga Baby Blanket pattern on Ravelry. I’ve also dyed a small number of kits, you can find them at my Etsy shop. The colorways are purple-blue (dyed with cochineal and indigo – sold out), red-blue (dyed with madder and indigo) and green-blue (dyed with weld, mugwort, and indigo).

From a set of 9 skeins of matrix-dyed yarn (on the left) to the Vindauga baby blanket.

I’ve now written the pattern, had it test knit, and corrected over and over again. It’s finished, and now published in Danish and English. I’ll be the first to admit that actually finishing a pattern is not my favorite part of the process from idea to pattern. But if I don’t pull myself together at some point, then my ideas end up as just that – ideas in my head.

But dyeing the matrix mini skeins is a lot of fun. I’ve worked with these 2-dimensional gradients for some time now, but it’s still difficult to get them just exactly right!

First, I dye gradients of red, pink, or red with madder, cochineal, weld, tansy, or mugwort. I make 3 skeins of each. Then, I overdye with an indigo gradient, giving each of the 3 identical skeins a different indigo overdye. This may not sound difficult, but both steps are hard to control.

When dyeing with cochineal and madder, I find that the first bath always gives a more intense color than the second one. But sometimes, the second and third give about the same. It’s also difficult to control the exact shade of blue with indigo dyeing. One factor is how long you dip skeins in indigo, another factor is the number of dips. But the amount of available indigo in the vat also changes over time. Even after making many sets of matrix dyed skeins, it’s still a challenge!

indigo overdye
Yellow, red, and white skeins soaking on the left. On the right, similar skeins in an indigo bath. The temperature is 52 degrees, pH is 9-10. Everything is under control!

See projects on Ravelry:

Amazing Dyeing Failures 2

The topic of my last post was failures in dyeing, and here’s more. First, my most serious and most annoying failure as a natural dyer.

3: Organic Indigo Failure

A while back, I experimented a bit with an indigo vat with fructose, but my results were not very convincing, in the sense that the amount of blue I got out of the vat was completely underwhelming given the amount of indigo that went in. Mona of Thread Gently on the Earth suggested trying another type of indigo vat that uses madder and bran. So, using what Mona wrote and what her source of the information, Aurora Silk wrote, I tried the madder/bran vat, since I’m still very interested in a natural fermentation vat for indigo.

In the beginning of May, I mixed 34 g of indigo, 17 g of ground madder, 17 g of wheat bran, and 116 g of sodium carbonate. I used at pot with a well-fitting lid, and filled with water so there wasn’t much air in the pot. We had a very warm early summer this year, so I just put the pot outside the house, where it was 27C during the day. But nothing happened. I had suspected that, since the pot would cool off during the night.

My next setup consisted of a simple electric hot plate for cooking. After a bit of experimentation, i figured out that on the lowest setting, and switching it on for 15 minutes out of every 2 hours with an electric timer plug, I could keep the vat around 37C. After a couple of weeks, though, I was forced to admit that nothing much was going on there.

So I started a bit of wild experimentation. Could it be lack of reducing power? I added fructose and more base, but that didn’t get the vat started. I then transferred part of the vat to a large jar, and tried warming it on a water bath. The jar was full and had a tightly closed lid, and that did improve things. The color didn’t shift to yellow-green, it was still blue with just the slightest green tinge (you can see it on the spoon, top left image above), but the jar vat developed the coppery film of a working indigo jar. I dyed small skeins, and they came out a lovely dusty blue.

Indigo dyeing with a madder/bran vat with a sprinkle of fructose along the way. The vat became slightly green-tinged (top left), but did develop the coppery film that shows it’s working (top right). Bottom, a small skein of yarn dyed dusty blue in the indigo jar.

So it’s sort of working – but not amazingly so. I can only dye very small skeins in this jar, but I did a lot of troubleshooting which may bring me closer to running a fermentation vat properly and over a long time. For now, I do consider it a failure, since I got so little blue out of my 34 g of indigo, but I’m clearly not done with this. Maybe one needs to set up a larger vat, using an amount of indigo that makes abandoning the vat unthinkable.

4: Common Broom Failure

I have tried – and failed – to grow dyer’s greenweed (Genista tinctoria) a couple of times. The seeds need cold stratification, which I have tried to give them, but they never sprouted. Dyer’s greenweed is supposed to grow wild in my part of Denmark, and I have searched for it, but not found it.  Then in June, the landscape was dotted with yellow: it was common (or Scotch) broom (Cytisus scoparius). This plant is considered invasive in many places, but not in Denmark, where it occurs naturally. But it has been spreading in a new way for the past 30 years, so picking it is definitely fine, just keep in mind that the seeds are poisonous.

I studied my old flora a bit, and since both dyer’s greenweed and common broom belong to the legumes (family Fabaceae), I convinced myself that common broom would be worth a try in the dye pot. At that time (June), the flowers were already past their prime, but i picked some branches at the roadside.

Common broom is spreading, adding splashes of yellow to the roadside.

The result was not impressive – good old failure beige once again:

Wool dyed with common broom – hello beige…

I would have called it a failure and left it at that if I hadn’t come across an entry on common broom in John & Margaret Cannon’s excellent book “Dye Plants and Dyeing” (I recently bought a second hand copy). This book tells you that the part of the plant used for dyeing is young branches, picked in April or early May, not the flowering stalks picked in June as I did. The young branches should produce shades of yellow-green with alum and green with copper. I might try this again next year.

“Dye Plants and Dyeing” also mentions some confusion in the dye literature between common broom and dyer’s greenweed, since the latter is sometimes referred to as dyer’s broom. Not surprisingly, Cannon & Cannon (in a book published in association with The Royal Botanic Gardens, Kew) recommend that the dyer relies on scientific nomenclature for dye plants. Actually the same conclusion is reached by Catharine Ellis in her run-in with “broom”.

5: Reindeer Lichen Failure

During my summer holiday, I gathered some lichen of the Cladonia family, I believe it’s reindeer lichen (Cladonia portentosa). In “Lichen Dyes: The New Source Book”, Casselman lists this lichen as a boiling water method lichen that should give a “leaf green” color. So into the dye pot it went, with a test skein of unmordanted wool, since lichen dyes are substantive. The result is not what I hoped. Beige, despite the fact that I used a large amount of lichen relative to yarn:

Reindeer lichen (Cladonia portentosa) and yarn dyed with the lichen.

6: Cold Dyeing Failure

Mommy is a witch. Check out my cauldron, a dye pot with mushrooms and wool.

At some point, I tried dyeing with old polypores, in the usual hot dyeing process, and that actually gave me a good yellowish brown. Recently, when cleaning up outside, a big hoard of old polypores surfaced. I don’t have enough space to store dyestuffs inside, so they were outside and were damp and looked like they would spoil.

I had a thousand other projects going, so I wasn’t really ready to dye with them – so I decided to try a very lazy experiment: cold dyeing (which I normally never do because it seems to me that it doesn’t really work). The experiment amounted to throwing the polypores into a bucket with rainwater that was just standing there, then put in a small, 12 g test skein of alum mordanted wool, and then letting it stand there for about 3 weeks. You have probably already guessed that it produced a smelly skein of beige wool, which I cannot even find now (I think I overdyed it with indigo). So all I have to show for this experiment is my 6-year old Dagmar’s drawing showing that “Mommy is a witch”. I am taking it as a compliment.

PS: Just as I wrote this, light samples of both the cold dye and hot dye with old polypores surfaced on my desk. None of them have the light-fastness achieved with fresh polypores in a hot dye bath.

Amazing Dyeing Failures 1

Failure in natural dyeing is commonly defined as not getting the result you expected. Beige, off white, baby yellow and other tones of grime are all examples of colors I have made no attempt to acheive, and yet, I have a big pile of skeins just like that. But there’s actually a lot to be learned from failures. Some give new ideas of what to try next. Others just tell you what not to do. Below, I’ll describe some of my failures – actually, I’ve failed so many times that this will only be the first installment, more to follow.

Alle de mislykkede og uønskede farver. Efter billedet blev taget overfarvede jeg med indigo.
Skeins of failure. They were all overdyed with indigo after taking the photo.

1: Bark Failure

Several books on dyeing will tell you that different types of barks are good dyestuffs. For example, Jenny Dean’s “Wild Color” mentions these barks and the color they should produce on alum mordanted wool: alder (brown-green), barberry (yellow), ash (bright yellow-green), apple (warm yellow), oak and willow (beige), and finally elm, birch, cherry, pear, and plum (pink).

For a while, the theme of my walks was bark; in the end, I found enough of these three to try them as dyestuffs:

  1. Birch (Betula) – I’ve used birch leaves several times for a sunny yellow, but not the bark. Some trees were cut down near our house, and I jumped at the chance. The trees had been left in a big pile, which I obviously had to climb to get to the good parts, and since I was of course wearing clogs, I fell down from that big pile in the end. With 60 g of birch bark in my pockets.
  2. Another day I hear some men working outside, shredding logs. On their day off, I casually walked by and managed to peel a good amount of bark off. The logs turned out to be alder (Alnus), the kind with the tiny cones. 70 g of bark.
  3. Last one is some bark from a forest walk. I jumped over a big, big ditch to get this. I’m pretty sure it’s beech (Fagus). My daughter jumped it too, so I had to save her afterwards. 94 g of bark.
Dagmar tæt på at falde i grøften
Dagmar, seen moping, came close to falling into a large ditch.

I used Jenny Dean’s general dyeing method for bark. She says that “barks are best soaked for several days or even weeks in cold water before processing. Then simmer them for one hour. Never boil bark, as this will release too much tannin”. So that’s what I did – left the three types of bark to soak for a couple of weeks. That was long enough that they started fermenting, and I can tell you that it didn’t smell that good.

But when I simmered 10 g test skeins of alum mordanted wools in the three bark dye baths, the color in the end was pale beige. I didn’t even bother taking pictures (because when you’ve seen one skein of pale beige wool, you really have seen them all), but you can see one sticking out between the pale pink skeins in the left side of the first picture above.

I have seen other dyers experiment with bark (for example, at my wool group’s dyeing day) and also get pale beige or off white. So right now, I’m not even convinced that it would ever work, and I probably won’t try it again unless someone can tell me what went wrong (please comment below if you know or if you’ve had good results dyeing with bark).

2: Slimy/Moldy Avocado Failures

There are established procedures for dyeing with avocados, but I’ve been experimenting with slightly different ways of doing it. I suppose to make the procedure easier and better, but of course ending up making it messy and complicated.

According to Carol Lee, avocado pits should not be allowed to dry before use because they will become so hard that they are impossible to chop. Instead, they should be frozen until use. I wanted to find a way to dry them anyway because my freezer is small.

So I chopped the pits and skins and then left them to dry. This worked well on a couple of occasions, but most times it did not because they became completely overgrown with mold before they had time to dry. Moldy materials may still work as dyes, but I think it is generally unwise to handle them repeatedly around the house, since many molds produce toxins that may be inhaled. So I went back to freezing the skins and pits.

Avocado pits and skin turn red as they dry, so it’s not that surprising that the dye bath they produce is also red.

Another experiment was to ferment the pits and shells for a looong time to see if they yielded more color that way. I used my dry material, soaked overnight, but I suspect the results would have been the same had I used frozen dyestuff.

I usually ferment avocado pits and skins by heating them up once in brine, then just leaving them. Normally for a few weeks or a month, this time for six months. And the dye bath did develop a deep red, but it also became extremely slimy.

Despite the sliminess, I tried dyeing a small test skein in this dye bath, but it didn’t yield good color. My guess is that the slime prevented good contact between yarn and dye. But I’m not convinced that a long fermentation couldn’t yield good color. I’ve been adviced to put avocado pits and skins in jars, close the jars, heat them up, and then ferment. Such jars should not go slimy. I’ll try that next time.

Beige med lidt rødlige striber
Beige with a red streak, that’s the look of yarn dyed with avocado slime.





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.

Shibori ♥ Indigo

A while ago, I tried the classical combination of indigo and the Japanese technique shibori, for the first – and definitely not last – time. I dyed a handful of cotton t-shirts and shirts from local second-hand shops.

Traditionally, arashi shibori was made by tying fabric around a wooden pole. The patterns thus achieved are reminiscent of waves of a rough sea – “arashi” means storm.

I made my arashi shibori by wrapping the t-shirt around a piece of pvc pipe, folding the t-shirt vertically (1 and 2 below) before wrapping it. Then, I tied cotton string tightly and bundled the fabric towards the centre (3). It should fold as much as possibe, that’s what produces the pattern (4).

T-shirt (1) folded (2) tied (3) and done (4).

The direction that the pattern takes obviously comes from the direction of folding before wrapping. Next time, I’ll try diagonal folds. But all in all, the arashi pattern turned out great, here’s a closer look.

Detail of neatly folded t-shirt.

And a detail from a shirt where I didn’t fold the fabric neatly before wrapping – that actually makes the pattern more interesting.

Detail of randomly bundled shirt.

Itajime shibori is made by folding and clamping fabric. I tried the very simplest verision, clamping a quadratically folded t-shirt (1 and 2 below) between a couple of wood blocks using rubber bands (3).

T-shirt (1) folded (2) clamped (3) and done (4).

This fold gives a pattern that I find simple and attractive (4). And look at the wood blocks after an indigo bath. Maybe my next experiments will be dyeing wood using indigo.

The wood for clamping also took indigo blue nicely.

There’s a lot more to try with itajime shibori: other folds, clamping with other shapes instead of simple wood blocks. And there are many other types of shibori: kumo shibori and yanagi shibori to begin with. Many more experiments!

Late Summer Greens

This summer, I’ve dyed a nice pile of green wool using reed flowers and velvet pax – two dyestuffs that are a highlight of the dyer’s year. Reed flowers because they give such an electric green. You have to admit it’s a bit strange that these red flowers dye wool a wild green, but only if you get them into the dye pot absolutely fresh. If the flowers have opened or are not freshly picked, they will only give yellow. Velvet pax because its dusty greens are so lightfast. The two skeins in the back are dyed with velvet pax, the three in the front with reed flowers.

grøn green
Greens from reed flowers and velvet pax, the essence of late summer dyeing.

I’m becoming better at finding velvet pax. The first couple of years, I looked for it too late in the season. This year, I’ve found it growing several places, for example this archetypical plantation, where Dagmar is picking a big one. Just the kind of place that velvet pax likes to grow.

Dagmar picking velvet pax (with the arm that’s not broken).

Velvet pax can be found in August, and this year, everything was early, so it was there at the beginning of August. And the mushrooms were huge – I found some that were 25 cm across.

Characteristic brown tops of velvet pax, captured in a typical habitat.

Big, fat spiders are another joy of late summer. This one, which is possibly the fattest spider I’ve ever seen, lives outside our house. When I was sticking my camera right in its face, the neighbor’s big dogs started barking. Immediately, the spider lifted its front legs as if to attack. I chose to run away, so I only got a good shot from underneath the spider, where its pattern looks a bit like eyes. I think it’s a very light colored cross spider, since its body is pointy at the back. After reading that they can bite if provoked, I think my decision to flee was not a bad one.

My pet spider.

Summer is also the time of year to test light-fastness. I tested a handful of colors on the windowsill from early July to mid August, and their light-fastness was quite different.

  1. Old polypores, the two top ones warm baths and the lower one a cold bath that brewed outside for some weeks. None of these yellow browns are very light-fast.
  2. Velvet pax, the color didn’t change. I’ve seen this light-fastness in previous test, so it really is that good!
  3. Orange Cortinarius mushrooms, I don’t know which species. Not that light-fast
  4. A matrix of madder and indigo, showing that saturated colors are much more light-fast than pastels
  5. Sorrel root, not very light-fast
  6. Birch leaves. Surprisingly light-fast
  7. Weld. Surprised by the fact that it’s less light-fast than number 6…
  8. Henna on alpaca. I’d say this is a medium light-fastness
  9. Calendula flowers. Surprisingly light-fast
Light testing summer 2016.

I’ve also dyed with tansy, which doesn’t give green, but “just” yellow on alum mordanted wool (no pictures of that). But when I admired the flowers, I suddenly wanted to check if they really do stick to Fibonacci numbers.

The Fibonacci series begins with two ones, and then the next numbers are found by adding the two previous ones:

1, 1, 2, 3, 5, 8, 13, 21, 34, 55, etc.

The last time I thought about Fibonacci numbers were for calculating the numbers of my Vindauga blanket where rectangles obey the golden ratio, approximated by the ratio between neighboring numbers in the Fibonacci series, eg. 55/34 = 1.61.

Below is a close-up of a tansy flower. And as promised, the numbers of rows of tiny buds are Fibonacci numbers – 13 clockwise rows and 21 counter-clockwise.

Tansy flower obeying Fibonacci’s sequence.

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.