The first batch of indigo was a small trial batch on 15L because I heard so much about the difficulties with indigo and that it was supposedly a lot trickier than e.g. madder and onion skin. As a low volume trial, I only dyed some swatches and some left over yarn that I had lying around. In my previous entry I covered the basics of indigo dyeing, look it up here if you’re interested.
From the left it’s wool, silk, wool, wool, store bought yellow wool and grey wool. Everything turned out pretty uneven but it’s not realistic to expect perfect result on the first attempt. Besides, it’s indigo, you can always re-dye it for a more evenly dyed fibre.
Considering the instructions for indigo batches I always use Sandström and Sisefsky (1970) for this purpose. Since I don’t know the exact chemistry behind this process (!) I use a linear model to keep the same ratio in each batch. That is, I just multiply or divide the value in the existing instructions to fit the fixed variable. The fixed variable differs from time to time, sometimes I have a finite amount of indigo, sometimes I have a certain amount of yarn I want to dye and sometimes there is a volume limit on the cauldron I am using. This makes me re-calculate everything before dyeing but that’s not a bad thing because I like to have time to think things through, which is something that I am forced to do in such cases.
As you can see, I try to write down the date, mark the fixed variable and then write down the other amounts used so that I would be able to re-do the exact same thing if needed. In that way, it’s easier to say that a certain hue can be made or if I would need to dye some more fabric or yarn in a similar hue.
Concerning the chemistry of the dyeing process, I aim to get a better understanding of the chemistry in time but this is a work in progress. If I am able to do that I think that it is possible to do several process optimisations, which would result in the usage of less material and heat but still having good water and light fastness in the dyed material. Using a linear model is often a very simplified solution, many chemical processes are not well represented by a linear model and it is possible that it’s the same case with the indigo dyeing process. I’ll get back to you if I find anything worth sharing.
The larger piece of wool fabric that you see to the left in the first picture was later on used as a lining for a 14th century womens hood, which is a comfortable use of an uneven dyed fabric since most of it won’t be seen anyway. Tablet-woven edges done using yarn in the same light blue hue from the same batch, just to keep up with the latest reenactment fashion ☆
My hood is made from leftovers so it’s a little lacking at some points but if you want an excellent tutorial for this hood you should check out Katafalks tutorial here.
I still haven’t done anything with most of the yarn since I don’t have any reenactment related ideas, suggestions are welcome. Worst case scenario, it’ll be used for modern knitting.
Smaller batches are always useful for learning and also very easy to handle so I’d definitely recommend it as a good starting point. Developing a habit of writing things down will also make it easier to backtrack your work, to learn from it and to know what kind of colour you will get from a specific setup. Notes are a superior tool in order to communicate methods and results to others; also, you don’t need to remember everything if you have it written down. Overall, information exchange and feedback is fundamental for improvement and to avoid having everyone repeating the same mistakes.
Combine this with a sample set of each batch and you will be on your way to greatness. Now get a fancy notebook and get going.
This is a short instruction of how to do an indigo dye; it is recommended that you look up further literature if you plan to do an indigo dye. If you understand Swedish, Sandström and Sisefsky (1981) is greatly recommended when it comes to plant dyeing.
As a chemist, I recommend the general use of glass wares because glass as a material is inert and will generally not be permanently stained or otherwise affected by chemical reactions. This goes ESPECIALLY for handling acids and bases. For the dyeing pot it’s stainless steel or enamelled pots, I myself use stainless steel and a smaller enamelled pot when the occasion calls for it. Iron and copper pots are also usable but will affect the outcome. Avoid aluminium.
I don’t know if this is necessary but I’ll write it anyway; NEVER use any equipment once used for dyeing in cooking. Some simpler things like alum might be easy to wash away but I’m lazy and don’t like meticulous cleaning so I use completely separate sets for everything, measuring and stirring included. I also greatly recommend taking notes on what you’re doing as well as pictures. Combine these two and you will have what is commonly known as a laboratory report. In that way, you don’t have to remember everything you did, for long and how it looked. The human mind is keen on forgetting things very quickly, especially if the process was successful. Writing things down will make it easier to share information or to successfully repeat the process. This is something I myself struggle with as I often wish I would take more informative notes of what I’m doing and why.
An indigo dye needs several chemicals and materials, e.g. table salt aka sodium chloride (NaCl), ammonia (NH3), 25wt% sodium lye aka sodium hydroxide (NaOH), sodium dithionite (Na2S2O4), denatured alcohol (I use T-sprit), indigo. In order to do this as safely as possible it is recommended to read up on every chemical BEFORE dyeing as well as reading the instructions thoroughly! Use the (Material) Safety Data Sheet, something that was mentioned earlier in this post, for each substance if you’re uncertain. If you feel comfortable with all of the chemicals above, how to store them and what to do in case of a spill or other accident, then go ahead.
It would be good to quickly mention the weight percentage of the sodium hydroxide; it’s supposed to be 25wt%, which means that if you want to have a stock solution of 500 gram (approximately 0.5 L since the density of water is 1000 gram/L) then you need 75% of it to be water and 25% of it to be sodium hydroxide. This is easily done by measuring 0.75×500=375 gram of water and then add 0.25×500=125 gram of sodium hydroxide. Keep in mind that this is a exothermic process (gives off energy, in this case heat) and that sodium hydroxide is a base so take care when doing this. If you’re uncertain about what I’m talking about, please read up on some elementary chemistry; it should be covered in most high school chemistry literature. If not, my literature recommendation on basic chemistry is Chemical principles by Atkins and Jones (2013).
In indigo dyeing, there is the preparing of the vat (where the indigo is) and the dye bath (where the vat and fibres are added and the actual dyeing takes place), so look at the instructions for both of these to make sure you have enough material for each step.The indigo vat can be done indoors for several reasons, mainly because of the lack of ammonia. The use of ammonia in the dye bath makes it unsuitable to do indoors unless you have a fume hood or equally efficient ventilation (a kitchen fan is usually not up to standard). Stay outdoors for the dye bath! Plan ahead.
Material: Glass jar with a tight shutting lid that holds the total fluid volume of the vat (in this case around 190 ml)
Something to stir the indigo vat with (it will be stained if not glass or stainless steel)
Pot that can be filled with enough water to cover the glass jar
10 g indigo powder
Denatured alcohol (I use T-sprit)
165 ml 50°C water
16 ml NaOH 25wt%
10 g Na2S2O4
Put the indigo in the glass jar and add a small amount (10-15 ml) of denatured alcohol, enough so that you can stir the indigo.
Add 165 ml of 50°C water, stir.
Gently add the Na2S2O4 and stir.
Screw the lid tight shut and immerse the glass jar holding the vat in a 50°C water bath for 1 hour. Put a cork coaster or something similar under the jar to avoid it being in direct contact with the heating source and as such avoid having an uneven temperature in the vat.
Done. The vat will be green-brown in colour.
And there you go. Now you have a vat! You don’t need to use all of the vat at the same time, you can save some for another time. Just make sure to save it in a tightly shut glass jar with a minimum of air in it. Write the amount of indigo and the date on the vat so you know what’s in it and how old it is.
In order to have different shades of blue you can always use more or less indigo, 10 gram would give a somewhat lighter blue.
A pot/cauldron that can take 16 L of water PLUS additional fabric and/or yarn without being crammed
A stick or something to stir with that is long enough so that you can comfortably stir the pot at the bottom without dipping your hand in the bath
Thick, long protective gloves
About 1000-2000 gram of fibre depending on the wanted colour depth and intensity
(Graduated measure cylinder (mätglas) is not necessary but really good to measure ammonia and sodium hydroxide in)
Dye bath: 16 L water
70 ml ammonia
30 g sodium dithionite
200 g table salt
200 ml vat
Heat the water to 50°C, make sure you have attained a stable temperature as the temperature greatly affects the outcome (deviation at most +/- 5°C).
Add the ammonia (avoid the vapours as much as possible). From now on only use protective gloves when handling anything containing liquid from the bath.
Add the sodium dithionite. After this you should avoid adding air/oxygen in the bath. Stir gently.
Add table salt and wait until the salt is dissolved in the dye bath. If not properly dissolved, the salt will gather at the bottom of the pot and leave dark stains on the fibre that comes in contact with it. To stir the bath in order to more quickly dissolve the salt is fine, just do it carefully in order to avoid stirring down unnecessary amounts of oxygen.
Gently add vat. The surface of the dye bath should have an oily look to it.
Prepare an appropriate amount of fibre (100-500 g) by immersing it in lukewarm water (about 30-40°C) for about 5-10 minutes before dyeing so that it won’t float to the surface when it’s dipped in the dye bath and to avoid dry spots.
Remove the wet fibres from the lukewarm water and remove excess water from fibres by gently squeezing it.
Carefully add the fibres to the dye bath. Avoid creating air pockets in the fibre that will add unnecessary oxygen to the bath or limiting the fibre access by having tangled fibres. Untangle everything and make sure that every part of the fibre is in contact with the dye bath and kept under the surface of the dye bath throughout the dyeing process.
Wait 5-10 minutes. The fibres will look yellow in the bath.
Remove the fibres slowly from bath, avoid dripping as oxidised droplets will add oxygen to your dye bath. The yellow-greenish look on the fibres will slowly turn blue when in contact with oxygen.
Let the fibre oxidise for about 20 minutes to see to what extent the fibre has been dyed.
If wanted, repeat step 8-11 up to a totalt of 4 times for deeper hues and shades.
Use appropriate tools when removing the fibres from the bath. Always wear protective gloves. Protective glasses can also be used if deemed necessary.
Rinse fibres thoroughly after dyeing. Sandberg and Sisefsky (1981) recommends an acidic after wash using acetic acid to increase the general rubbing fastness of the dye.
When dyeing loosely woven wool, it is possible that there will be a shrinkage because of the temperature of the bath. To avoid this, test the shrinkage of your fabric beforehand and add shrinkage allowance accordingly.
Some additional notes on indigo dyeing:
Don’t be in a rush. Take your time, read and think things through. Prepare it in several steps, do the calculations one day and then dye another day. It usually takes me half a day to do one batch of indigo dye and I usually do the calculations the day before.
Not happy with the first result? Then just redo it, an intense indigo dye can save the blotchiest of fabrics.
Make sure you always have some extra fibres for swatches so that you can check that the dye bath gives the colour you wanted. Just remember to wait 20 minutes so the swatches are properly oxidised and thus representative of the end result.
If you get a stain of indigo powder somewhere, just clean it up using a paper tissue with denatured alcohol. But if you get a stain of indigo vat somewhere then there is no helping you. Sorry. To avoid this, be careful and keep a clean working area and remove everything that you could not handle being stained. Wear working clothes, you will get stains on your clothes.
Concerning historical sources of indigo for the 10th century, it is the same dyestuff in both woad and indigo; indigotin. According to my understanding, it is at the moment not possible to distinguish the indigotin source in older fabrics and findings even though it is probable that the main source of indigotin in the Nordic countries during the 10th century is woad. As an example, the indigotin found in the Mammen grave is said to be either woad or indigo (Hägg, Inga et al., 1991). On a different note, madder is also found at Mammen even though there are no evidence of the cultivation of madder in Scandinavia at that time. The dyestuff, procedure and result is the same for both woad and indigo; the main difference right now is that indigo powder is a lot cheaper than woad powder which unfortunately makes a lot of difference for me. But then again, the rest of my reenactment gear is not on the level that the breaking point of its authenticity would be the origin of the dyestuff. But when it is, I’ll do something about it.
Currently, I think that the trickiest part with indigo dyeing is knowing when to stop. At some point, you will not have enough indigo and/or too much oxygen in the bath and that will make the dyeing uneven or without effect. But exactly where that point comes is something I’m currently trying to figure out. Experience is key.
Keep in mind that the above, numbers and all, is more what you’d call “guidelines” than actual rules.
Happy dyeing y’all.
Atkins, P.W., Jones, L. & Laverman, L. 2013, Chemical principles: the quest for insight, 6th, International edn, W.H. Freeman and Company, New York.
Last week I had the opportunity to do a quick visit to Stockholm and as such I naturally did what anyone would do, I spent the evening at The Swedish History Museum (Historiska Museet). Because, luckily enough, the museum had extended opening hours on a weekday that coincided (promise!) with my visit in Stockholm. As such, I spent the evening hours walking around in their exhibitions. It was a good time, I especially liked the iron age ceramics as well as the viking exhibition. I appreciated the opportunity to see source material in real life and especially some of these well debated findings; yes, I am thinking of the silver top that was presumably a part of a hat. There was a guided tour happening just at that display when I passed it so I didn’t have a good opportunity to photograph it, you can check it out here though.
When visiting museums I often think that “I don’t need to take pictures because there is a better picture of this somewhere else” but I have realised that I appreciate the pictures afterwards even though they might be shaky and out of focus. My photos are certainly not top quality but they kind of makes all the difference in the end on what I remember and what not. I’ll share some of the pictures I liked here because, as anyone with a pinterest account has discovered by now, there are a very finite number of pictures of available source material online so it’s nice to see something from a different angle for once. Remember though that they are taken through a glass window of the display with my cell phone and under less than perfect circumstances.
In order to support the museum and to get some decent pictures of the findings, I bought three booklets about their exhibitions and a bag with valkyries on it. Support your local museums!
I also happened to see some findings that I have replicas which is always fun! The findings were displayed in the museum but the since it was kind of troublesome to take pictures due to the lightning and display cases, I compare the replicas with pictures of the findings from the booklets instead. I really appreciate the effort people go through in creating replicas, especially when they look this good.
Note the differences in source material and replicas; I dare say we sure are fond of symmetry nowadays. I try to keep this in mind when working with reenactment, to not be bothered by asymmetry and ease up in our strive for perfection. Somehow, it’s more difficult than I would care to admit, especially when it comes to your own work.
There turned out to be a lot of viking items in this post but I enjoy the pre-christian designs and expressions. Not trying to be rude but I think there is a limited number of times that you can depict iconic bible moments and still keep it interesting. The amount of bible depictions in the source material for the medieval times and the 14th century clearly surpasses that number. On the other hand, this gives us some context so I guess it might be a good thing. Ah well.
Unfortunately enough, the textile department of the museum was closed at the time of my visit so I’ll have to revisit again at another time. But if nothing else, check out their database that I used to find information of all the above material; I’ll definitely keep this in mind in the future, extremely handy!
All in all, go visit The Swedish History Museum (Historiska Museet) in Stockholm if you have the opportunity to do so! They have a lot of nice things.
Sometimes some things just works out better than expected. Here is a comparison between some store bought fabrics and plant dyed yarn. These plant dyes were made during a Battle of Wisby workshop in 2013. The green yarn is birch leaves, the darker green is birch leaves with additional iron sulfate and the red one is madder.
I’ll try to dig up som old corpses, dyes and crafts that I have done over the years to start with. First out is my very first plant dyed yarn! It was 200 gram of a thick, bone white, single ply wool yarn from Marks & Kattens.
I like thick yarns to naalbind socks and mittens, because it’s quick work and becomes soft, though I have heard that socks made from thicker single plied yarn supposedly gets worn out more easily. I have a pair of socks in this yarn and this has yet not happened to me but maybe I just have baby soft feet incapable of causing harm (not true) or feet sweaty enough to full the wool instead. For example, I can show you how socks made from this yarn has turned into a nice felted sole (if you’re into that kind of thing). But then again, these are just event socks; which means I only use them 1-2 weeks a year so the non existent wear and tear of these socks is not representative of everyday use.
Findings of a single plied sock is yet to be found, I somehow have an idea of it mostly being 2-ply, 3-ply and 4-ply yarn but right now I can’t seem to find anything about this except this small picture on the sock from of the Coppergate findings. If anyone can help me out with a better source on this I would welcome it.
Back to the dye! Done in December 2014, it is the most unregulated and unknown dye I’ve done since it was made from leftovers from a tansy bath that I got from my excellent partner in reenactment crime, Anna (check out her blog!). As such, I have no idea of weight ratio or actually anything about what this was. It could be a mixture of plants for all I know. However, the dye was made with about 2 L of left over bath so I just diluted it with enough water so that the wool could move around and get a even spread of dye in bath. The pot in the picture is a 15 L pot so I’d say that I might have used a ratio of 1:4 of left over dye bath to water; I don’t know why I used such a small amount of water, I should’ve used more but who knows, maybe I was having a bad day…
In the case of dyeing, if your pot is 50L or less, I’d recommend to use as much water as possible. Even though it’s diluted it’s still the same amount of dye just less concentrated (if anyone remembers m [gram] / M [gram/mol] = n [mol] where n is the mole that represents the amount of substance, in this case the amount of dyestuff. Using the formula for concentration c [mol/m3]· V [m3] = n [mol] we can see that n is unchanged since an increase in volume would affect the concentration as well and as such leave the mole unchanged). A larger volume of water is beneficial for the diffusion of the dye bath so that the dye can spread itself evenly through the bath and uneven colouring can be avoided (Dumitrescu et al., 2008; Lewis and Rippon, 2013; Mehrparvar et al., 2016). If possible, I will make a separate blog post where I briefly elaborate further on relevant thermodynamics, diffusion and heat transport.
Anyhow, don’t let confusion get to you just because I used some different words, standardised units and chemical formulas; all of you probably can intuitively come to terms with the idea that more water is needed to give a good flow throughout the yarn and it’s not bad to apply some basic science or analysis in your everyday life. Who knows, it might come in handy later on (the real struggle here is for me to avoid being overly vague or incorrect because if I at some point am, the internet hellhounds will haunt me for the rest of my natural life). Sandström and Sisefsky’s (1975) recommendation on this is a 5 L bath per 100 gram wool which I’d say can be considered a guideline as good as any.
The pre-mordant used was alum, KAl(SO₄)₂·12H₂O but is also known by the name of aluminium potassium sulfate dodecahydrate, used with the generally recommended ratio of 20wt% mordant (Conradi-Engqvist, 1978; Kierstead, 1950; Sandberg and Sisefsky, 1970). Deviations from this recommendation is Vrande (1982) and Råbergh (1978) with 15wt% alum but instead they commonly uses additionally 10wt% tartar or uses post-mordants with a 5wt% of copper sulfate, CuSO4, or iron sulfate, FeSO4, respectively.
It is sometimes considered that older recipes and ratio for pre-, post-, and meta-mordants are overdoing it concerning the recommended amount of mordant; I have not yet done any further testing of different mordant ratios since I only have two pots for dyeing at the moment and as such, I currently consider myself lacking enough equipment to do any good mordant ratio variations. Nevertheless, I think I’d like to give it a go at some point. But yes, I’d be inclined to agree that less mordant can be used but it will affect both the colour and the fastness against water as well as light. Less mordant means less colour intensity and also less wash fastness and less resistance to light. That is, using an insufficient amount of mordant will cause most of the dyestuff to eventually be washed out. Using mordant attaches dyestuff to the fabric due to the complex coordination properties of metals (Lee and Kim, 2004; Uddin, 2014; Mehrparvar et al., 2016), e.g. you can get different hues as well as increased levels of fastness against water and light using mordant (Waheed and Alam, 2004; Burkinshaw and Kumar, 2009; Dumitrescu et al., 2008).So, again, it all depends on what you want. If you want a dyed material with a well defined colour that should be relatively unaffected by both sunlight and washing, it would be suitable to use mordants. Nevertheless, it is also good to use resources sparingly and using too much mordant of any kind is a waste, the question is; how much is too much? What’s the smallest amount that can be used and still get an effect?
Anyhow, enough mordant talk for now, I will have to get back to that subject later.
I don’t have any notes from this dyeing but I think the pre-mordant was done for 60 min at ~90°C and then leave the wool in the mordant bath until cooled. Then I let it hang for a day or two to dry before it was time for the tansy bath. Same procedure with the tansy bath, 60 min at~90°C, let the wool cool in the dye bath.
Despite not having any exact knowledge of what I was doing it turned out Very Nice.
Considering the colour intensity of the yarn, I could’ve probably used the bath for several more dyes but for I had no further dyes planned so I didn’t. The plot twist of this story is that the yarn was supposed to be for my friend in Stockholm but the package was lost or stolen from the letterbox during the christmas holidays. I mourned for a couple of months but I still have a small piece left that I took for reference.
Anyhow, this is so far the most tragic tale I have in the art of plant dyeing so stay tuned for happy excitement as we prod at the dyes of the past.
Conradi-Engqvist, Cecilia (1978). Spinna, växtfärga och forma av tråd: från naturfiber till textil. Spinna ull och lin och forma av tråd : med färg- och kompositionsövningar : studieplan. Stockholm: LT
Kierstead, S.P. 1950, Natural dyes, , United States.
Lee, Y. & Kim, H. (2004), Dyeing properties and colour fastness of cotton and silk fabrics dyed with Cassia tora L. extract, KOREAN FIBER SOCIETY, SEOUL.
Lewis, D.M., Rippon, J.A. & Ebook Central (e-book collection) 2013, The coloration of wool and other keratin fibres: edited by David M. Lewis, Department of Colour Science, University of Leeds, UK and John A. Rippon, CSIRO Materials Science and Engineering, Australia, Wiley, Chichester, West Sussex.
Mehrparvar, L., Safapour, S., Sadeghi-Kiakhani, M. & Gharanjig, K. 2016, “A cleaner and eco-benign process for wool dyeing with madder, Rubia tinctorum L., root natural dye”, International Journal of Environmental Science and Technology, vol. 13, no. 11, pp. 2569-2578.
Råbergh, Hilkka (1978). Färga garn och tyg: växtfärgning, syntetfärgning på bomull-batik, syntetfärgning på ull. Västerås: Ica bokförl.