Madder & Chalk

Most sources agree that you need chalk to unlock the true reds of madder. I’ve always had a difficult time reconciling that with my own results, so experiments were called for.

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I spent the past summer with a lot of experimental dyeing, and one of my themes was how chalk affects madder red.

Earlier in the year, I had experimented to see if I could remove the yellow tones from madder by soaking the madder in hot or cold water and discarding that water before dyeing (extraction) but according to my experiments, that’s not possible.

So the problem remained: sometimes I get a nice saturated red, other times a less saturated, more orange tone, although I use the same dyeing method.

My earlier experiments didn’t show a large difference between reds from rain water and tap water. The red with rain water is only slightly better than the one with tap water, but that is because the tap water is soft here.

But I have heard from several other Danish dyers that they have hard tap water, and that destroys the madder reds for them. I’ve also seen that myself where I used to live before, in a place with hard water.

This observation is quite consistent – but – is directly contradicted by a large body of work by many different authors, of mostly English-language dyeing books. Here’s a small selection from different authors:

“Chalk or slaked lime is added, particularly in areas with soft water.” John & Margaret Cannon: Dye Plants and Dyeing, p. 76.

“Add a tablespoon of ground limestone or chalk dust.” Rita Buchanan: A Dyer’ Garden, p. 52.

“If the water is deficient in lime, brighter shades are got by adding a little ground chalk to the dye bath.” Ethel Mairet: Vegetable Dyes, p. 42.

“Powdered chalk or limewater should be added to the dye-bath if the madder is ‘acid’.” Quote from Hellot’s “Art de la teinture des laines et étoffes de laine” in Dominique Cardon: Natural Dyes, p. 113.

I could go on like this. Source after source points out that chalk should be added. Some say if there is not “enough” or ir if the madder is “acid”, others just always add it.

It’s not clear where the idea comes from, but it seems to have been in circulation for a very long time. Hellot, quoted by Cardon, published his “Art de la tenture” in 1750, and it has been a very influential book.

The plant it’s all about – madder, Rubia tinctorium. Here a second-year plant growing in my dye garden in the middle of the summer.

In order to understand the effect of madder and chalk, I carried out a series of dyeing experiments on wool.

In all experiments, the proportion of madder to wool was 1:1, and I dyed at approx. 55 degrees C. I let the madder soak in water overnight, then dyed in that dye bath. During dyeing, I held the temperature for an hour, then let the yarn cool off in the bath until the next day.

First, I wanted to find out if it is chalk in tap water that affects the madder color, or something else. And by “something else”, I mostly mean iron, which may be present in tap water, and can affect colors a lot, when present even in small amounts.

For comparison, I began by dyeing a skein in tap water.

Then, I added chalk (from a garden center) in the amount of 4 g/L. That corresponds to about 2 Tsp in 10 L of water, giving a very slightly elevated pH of 7-8 instead of plain 7. The amount was just a guess, at that point in my experiments, I didn’t have a good idea of how much to use. I tried adding that amount both to tap and rain water.

Finally, I tried quicklime, which is a very strong base. So I neutralized it with a strong acid, since base destroys wool.

The results from that first round are below. On the left, yarn dyed in tap water, a paler red, the usual shade with tap water. When I add chalk to tap water, the color darkens slightly, just slightly. With rain water and chalk, the color is a bit lighter that with tap water alone, but very similar. So the conclusion so far is that chalk is the component in tap water that affects the color, not something else like iron.

But to be more sure, and having read that chalk for the garden can contain iron, I also tested quicklime. Calcium in tap water and in chalk for the garden is CaCO3 (calcium carbonate). Quicklime, on the other hand, is Ca(OH)2 (calcium hydroxide), a strong base. It was impossible to measure accurately, so I just took some of the chalky water in my bucket of quicklime and added it to demineralized water. This way, no other metals or minerals are present. I then neutralized the quicklime with a strong acid (I don’t remember which one).

The result of the quicklime experiment is seen at right. A very dusty pale red. So my conclusion so far is that yes, chalk has an effect, which is to make madder red paler and dustier, not more intense red. And yes, the component of tap water to affect the color is chalk. And the more of it (the harder the water), the larger the effect.

Madder dyeing in tap water, tap water with added chalk, rain water with added chalk, and demineralized water with neutralized quicklime.

After this first round of experiments, I started thinking that I had added too much chalk. It might just be that there was a good effect at a certain low amount, but that too much chalk added could ruin the color. Having searched through my entire dye library, I finally found the figure 1-2% mentioned by Mairet. Most books just give nonsensical directions such as “a spoonful per dye pot”.

In order not to miss the sweet spot, I tested addition of 0.2, 1, 5, and 10% chalk. The result below was not entirely what I had expected. There really is no difference between dyeing in pure rain water and adding up to 5% chalk. The color began changing very slightly at 10% added (becoming paler) but the difference is so small that the photo does not capture it.

Wool dyed with madder in rain water with no chalk added, and with 0.2, 1, 5, and 10% chalk added.

I couldn’t really decide if this was a good or bad result. Chalk in relevant amounts does not have an effect. It does not help unlock the good reds, but it also doesn’t do any harm.

But if all the English-language dyeing books are wrong, are the Danish dyers then right? Does the red color improve with less chalk? Below, a comparison of madder dyeing in rain water, tap water, and demineralized water. There is the usual difference between rain and tap water, the former giving the better red.

I took extra care with the yarn dyed in demineralized water. After mordanting, done in tap water as usual, I washed the yarn in rain water several times, and also cleaned the glassware for dyeing in rain water. That treatment gave the best red in the entire experiment, so I have to conclude that less chalk gives better red.

Dyeing with madder in rain water, tap water, and demineralized water. Tap water gives the least good red, demineralized water the best.

Below, I’ve shown all the colors in one picture so it’s easy to compare them.

All colors from the test together. All are 1:1 madder on wool, and cards grouped together were dyed simultaneously in glass jars over a water bath.

So my result is very clear – less chalk gives better reds. But one mystery does remain. Why do all dyeing books from the last 3 centuries state that madder gives better reds when chalk is added?

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Madder’s Family

Madder has several relatives that are also rich in useful reds. These plants are native here in Denmark, and have been used as red dyes a very long time back.

Believe it or not, the year is drawing to a close. So, I want to try to summarize all the many dyeing experiments I did over the year.

This summer, I searched for madder’s relatives, to find as many as possible. Madder, Rubia tinctoria, belongs to the madder family (Rubiaceae) in which you also find the bedstraws (the genus Galium).

Galium species do not contain as large amounts of red dye as cultivated madder does, but several of the species grow wild here in Denmark, and their historical use is well known.

Madder plant growing in my dye garden.

The first Galium species to present itself was cleavers (Galium aparine). It’s everywhere! Anybody who has ever walked outside surely know this plant. Or at least its seeds. They are extremely good at clinging to clothing and dog fur. The whole plant is covered with clingy hooks – the very same that cultivated madder has.

My attempt to dig up cleaver roots quickly came to an end. The roots have the thickness of sewing thread, so a lot of digging is required. But the roots are said to contain dye, so I’m keeping them on my list of maybes.

Cleavers up close. You can see the characteristic clingy hooks on the seeds. The very same that madder is covered with.

Lady’s bedstraw (Galium verum) is the plant mentioned by most natural dyeing books. I tried growing it in the garden this year, seeding it outside in the spring, but nothing grew.

Whenever you’re looking for a specific plant or mushroom, but haven’t found it yet, it’s simply invisible. But, once you find it, you start seeing it everywhere. The relationship between Lady’s bedstraw and myself developed exactly like that over the summer. Once I found it, it was everywhere! For example this coastal grassland:

Coastal grasslands with very sandy and infertile soil, perfect for Lady’s bedstraw. I took this picture in a region of Denmark called Mols.

 

Lady’s bedstraw truly thrives in the nutrient-poor, sandy soil, along with yarrow and St. John’s wort.

Lady’s bedstraw growing in a big cluster.

Unfortunately, several walks with a shovel only yielded a very small handful of Lady’s bedstraw roots – so little that my scale didn’t register. Like with cleavers, the roots are extremely fine, and they tangle up with roots of grass etc. In combination with stony, sandy soil, the digging job gets hard. To get your hands on a larger pile of these roots, I suspect you have to grow them in a well-prepared sandy soil without obstacles. Anyway, I tried dyeing with my small handful of roots, but it gave almost no color.

But then, on a forest walk, this plant turned up – hedge bedstraw (Galium mollugo):

Flowering hedge bedstraw photographed in July.

Hedge bedstraw is also mentioned by different books as a dye plant, so I brought out the shovel once more. Again, it was difficult. The forest soil is obviously full of tree roots that make digging quite impossible. But I managed to get a couple of handfuls of roots, mainly because hedge bedstraw roots are not that thin. I dug up the roots on July 9th. The next day, after cleaning, the slightly dried roots weighed 30 g.

My pile of hedge bedstraw roots, with reds clearly showing under the out bark.

I soaked the roots in cold water overnight, then dyed my usual alum mordanted 12-gram skeins of Fernris to test the dye. I removed the overnight water because Jenny Dean does, but I should have concluded from my madder experiments that it is not necessary to do so. The water used to soak the roots overnight simply contains a small amount of dye, with the same properties as the dye you extract when you heat the roots in water (the small 6-gram skein laying across the others in the picture below was dyed with the discarded water).

Then, I dyed alum mordanted 12-gram skeins in a 1st and 2nd dyebath, in exactly the same way as if it had been madder: heating up to 60 degrees C, then leaving the yarn in the dyebath until the next day. The first bath gave a convincing red-orange, which would not have been a surprise had it been madder I was dyeing with. The dye is less abundant in hedge bedstraw than in madder, but the difference is actually smaller than anticipated. Here, I used 30 g of roots on 12 g of yarn, with madder, you would get this shade with less than 100% weight of fiber.

After the second bath, which also worked well, I was evidently feeling on top of things, and threw in a 50 g skein. There was not much dye left, but to extract everything that was there, I left the bath with yarn in a jar outside. That was in mid-July.

A couple of times, I heated the entire jar over a water bath to give the process a helping hand, but the rest of the time, it was just standing there. I turned over the yarn to get an even dye, and for a while, it also fermented. Both time and fermentation should help release the dye. Also, I imagine that a skein of yarn in the bath will soak up the dye as it is released, permitting more to come out (alizarin has a rather low solubility in water). In any case, my large skein stayed in the jar for 6 weeks, and turned out a pleasing coral color. And, the dye bath ran clear, so there was probably nothing left in the roots.

Dyeing with roots of hedge bedstraw (Galium mollugo). 1st bath (left), 2nd bath (middle), and the large skein on the right is fermentation of the 3rd bath. The small skein across was dyed in the water used to soak the roots overnight.

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Red Madder

Madder is one of the most ancient dyes, and one that is described in pretty much any book on natural dyeing. But every book seems to give a slightly different method for obtaining the sought-after madder red. There’s only one thing to do – experiment!

A bunch of madder dyed skeins. They’re all dyed in slightly different ways, so the colors have turned out differently.

Madder was one of the first natural dyestuffs I tried just when I began learning about natural dyeing, many years ago. I followed Jenny Dean’s “Colours from Nature”, the first book I bought back then (now, of course, I have a largish library on natural dyeing).

Dean gives a dyeing method for larger pieces of madder root, not powdered root. She rinses the root in cold water, then boiling water, and then adds the water for the actual dye bath. I tried her method for my first attempts with madder, but only got a series of tan/coral shades. Sometimes slightly more pink, sometimes more towards orange.

After my first attempts, I was ready to just give up. Coral was not exactly my favorite color, and I didn’t make any further attempts with natural dyes. That was until I happened to talk to some dyers at iron age and viking markets. One of them told me, that she always got good reds with madder by using destilled water.

After that, I happened to find a copy of a classic Danish dye book from 1972, “Dyeing with Plants” by Ester Nielsen. Nielsen steeps madder for 24 hours, and mentions nothing about changing the water at any point. Also, she mentions nothing about the type of water. Over time, I arrived at a variant of Nielsen’s method, using rainwater instead of distilled water because rainwater is free. I leave the madder to steep overnight in my dyepot, add alum mordanted wool, heat slowly to 55 C, and then wrap the pot in a blanket and leave it until the next day. So, yarn and madder in the pot together, and no changing the water.

I’ve achieved many clear reds with that method, but sometimes, the color has turned out more orange than red. That’s the case with the yarn for this hat:

Brisingamen hat in madder dyed yarn.

I do like orange, but it’s red you’re after with madder. Also, I’ve become increasingly confused the more I’ve read about madder dyeing, and I am not the only one. As mentioned, Dean uses a hot extraction (a soak in water that is discarded) whereas others, for example Ecotone Threads use a cold extraction.

Madder contains many different dye compounds. According to “Handbook of Natural Colorants” by Berchtold & Mussak, more than 35 different anthraquinones have been detected in madder (anthraquinones are the type of molecules that alizarin, the important red in madder, also belongs to). The different dye compounds have slightly different colors, so the the point of (cold or hot) extraction would be to remove some of the yellow or brownish ones.

I decided to test, whether I could get rid of my orange reds by using an extraction method. For this test, I’ve used my usual 12-gram skeins of Fenris (100% wool) mordanted with 10% alum. In all the experiments, I used 12 grams of madder powder per skein, leaving the madder in the dyepot the entire time. A few writers say that the madder should be removed from the dyepot before fiber is added, but most agree to leave it in.

According to Liles’ “The Art and Craft of Natural Dyeing”, alizarin has a very low solubility in water, and that’s why the madder should stay in the pot. As alizarin in solution is taken up by the yarn, more will be released from the madder. In all cases, I dyed the yarn by heating yarn and madder to 55 degrees C keep it there for 1 hour, and then leave the yarn in the dyebath overnight.

In my little experiment, I tested the following, both with rainwater and tap water: steeping the madder overnight and dyeing in the same water, filtering out the madder and dyeing with it in new water, and finally pouring boiling water over the madder and then dyeing with it in new water.

Filtering a small amount of madder in an old fashioned coffee filter.

Results below:

1: Madder steeped overnight in rainwater, yarn dyed in the same water.

2: Madder steeped overnight in tap water, yarn dyed in the same water.

3: Madder steeped overnight in rainwater, filtered, run-off removed and yarn dyed in new rainwater.

4: Run-off from 3 (the liquid that ran through the filter).

5: Madder steeped overnight in tap water, filtered, run-off removed and yarn dyed in new tap water.

6: Run-off from 5 (the liquid that ran through the filter).

7: Poured boiling water over the madder, filtered immediately, yarn dyed in new rainwater.

8: Poured boiling water over the madder, filtered immediately, yarn dyed in new tap water.

9: Run-off from 7 (not repeated for 8, as it would be identical.

The madder dyed skeins – theme and variations.

Skein 1 is dyed with just one volume of rainwater, which is my usual method. Luckily, skein 1 is one of the good reds in my test. Skein 2 is the same method, but using tap water. Skein 1 is only a slightly bit redder than skein 2, so using rainwater instead of tap doesn’t seem to have the importance that I thought. I measure pH of both baths, and they were both neutral after steeping overnight.

Skein 3 and 5 are dyed with madder that was steeped overnight, and then filtered to remove the first volume of water. If it was true that steeping and removing the water would remove yellow and brown tones, then skein 1 and 3 (both dyed in rainwater) and skein 2 and 5 (both dyed in tap water) should be different, but they are not. My conclusion is, that cold extraction does not remove yellows and browns.

That conclusion also seems to be correct when you look at skein 4 (rainwater) and 6 (tap water), which are dyed with the run-off from 3 and 5. If the extraction removed yellows and browns, then skein 4 and 6 should have those colors, but they don’t. They are tan/coral, exactly the kinds of colors I normally get from second, third and later afterbaths. So this could mean that cold extraction just removes a small fraction of the overall color present in madder.

Finally, the hot extraction. Skein 7 (rain) and 8 (tap) are dyed in new volumes of water added to the madder after the hot extraction. They are weakly colored, and the shades are very similar to those of skein 4 and 6. So most of the color is just gone after the hot extraction, and has ended up in the run-off that was used to dye skein 9.

Skein 9 has a good, saturated red-orange color, which is not that surprising. Temperature is the only factor that more or less all authors agree on. The temperature mustn’t get too high, as that brings out orange or terracotta tones, exactly what I’m seeing here. If  the light fastness turns out to be good, then this is actually a very good method for dyeing orange.

It’s nice to observe that this little experiment fits with my very earliest observations with madder. Deans method gives skein 8, a pale tone that would definitely be disappointing if you are trying to dye red.

So, in summary, the conlusions of my little experiment are:

Reds obtained with rainwater and tap water are not very different, and rainwater gives a red that is only very slightly better than the red with tap water. This conclusion is for my tap water, and may be entirely different elsewhere.

Cold extraction is not efficient for removing yellows, and hot extraction removes almost all the color.

I usually keep the temperature around 55 degrees C, but I have never checked myself to see how sensitive the color is to temperature. And I haven’t even begun to look at pH and calcium. My next experiments will be on those factors.