A few Christmases ago, my lovely wife gave me a mysterious gift; a small white sack with the letters C.H. on it, containing strange deep blue chalky rocks.
From Cloth House (the C.H. was a clue) these rocks are Indigo dye. These little dye cakes opened a whole new world of dyeing to me. I had toyed with synthetic dyes in the past but I can't believe it had taken so long for me to try Indigo dyeing.
There is something special about the Indigo dyeing process. I'm not saying it is the best way to dye textiles, far from it. Decades of research into dyes and dyeing I'm sure has created a range of superior synthetic dyes both in terms of ease of use as well as richness of colours. But I like the way indigo dyeing sends me back to some undefined time in the past. The process feels traditional, manual and the quality variable, but in a good way. I would describe the results as 'individual' rather than 'unreliable'.
So if you haven't worked it out by now, for me, indigo dyeing macrame is as much to enjoy the process as it is for the results. I have an indigo day every few months and I really enjoy myself.
What is Indigo
Indigo is widely used all over the world as a natural deep blue dye. It is the blue in Denim, used in Japanese textile arts such as Shibori, and from my years living in Thailand Indigo dyed workwear (Ho Mon) was ubiquitous, I assume in part due to the availability of indigo dyed fabrics from traditional tribal craftspeople.
The natural indigo dye is made from the soaked, fermented, 'stomped' and dried leaves of an Indigo shrub (e.g. Indigofera tinctoria). You might also want to check out the fabulous Indigo Works and their Indigo Garden Workshops, promoting natural dyeing techniques for a closer look at growing and dyeing with indigo.
What you need for Indigo dyeing macrame
My wife bought my indigo from Cloth House and they have a few more advanced recipes as well on their website, so it's worth a visit if you are looking for alternatives. You can also buy Indigo cake from George Weil and other reputable craft and textile suppliers. But I would recommend buying natural rather than synthetic indigo to support the roots of this traditional craft as much as possible.
As well as the indigo cake itself you also need a reducing agent (I used Thiourea dioxide) an alkali (sodium carbonate or soda ash), some acid (vinegar), and some indicator paper to measure the pH.
Equipment is simple: a jar for making up the concentrate and then a larger vat for the dying solution. Plenty of PPE for your hands and your furniture to avoid staining and somewhere well ventilated to work and hang the dyed cords/fabric. You also need some way to grind up the indigo to make up a solution. A mortar and pestle is ideal if you have one, but using a rolling pin to crush the cake wrapped in cloth is a serviceable albeit messier alternative.
Recipe for Indigo Dyeing
I used this recipe: https://www.georgeweil.com/blog/dyeing-with-indigo/ by Allison Holland at George Weil. I'm sure Allison has forgotten more about indigo dyeing than I will ever know so I unreservedly recommend her blog posts and the George Weil site in general. I don't intend to cut and paste her recipe here, so if you want to try indigo dyeing for yourself, please visit her blog and trust her advice.
In a former life, in my 20s, I was an organic chemist. So the secret to indigo dyeing, reduction and oxidation are familiar reactions to me, but still magical to watch when there is a colour change. In essence the indigo in its reduced state is soluble in an alkali.
In this state the solution is not blue but green due to impurities, the reduced indigo is actually colourless. Once the cord or fabric has been soaked in and then lifted out of the indigo solution, it is initially stained with the yellow/green colour which within seconds transforms in front of your eyes to the well known deep blue as the indigo oxidises in the air.
This colour is locked in by soaking the oxidised dyed cord in an acidic bath where the blue indigo is now bound to the fabric, insoluble and so colour fast.
What do I dye
In the course of my craft I try to be as sustainable as possible, both in sourcing local, recycled and/or natural materials for my pieces and kits, but also to reduce waste by reusing packaging and minimising the amount of wasted cord. This has become a bit of an obsession for me that I will explore in later blog posts, but briefly, when creating and refining a design I will start by using too much cord and reduce this incrementally to the correct lengths after I have produced a few pieces. This cautious approach is easy to understand by anyone who has run out of cord half way thought a piece. I also discussed in my last post about how difficult it is to correctly predict how much cord you will need. So in the end I invariably have some left over cord that I trim away from my completed piece. This cord is usually a meter long or less, which is too short to create most of my patterned designs like plant hangers or wall hangings. So I usually sort the left over cords by length and then make small pieces to sell off or give away.
Depending on the lengths of cord I have, these pieces might be small coasters, key fobs, feathers bookmarks, stars, or simply added as tassels to a larger piece. These small pieces are pretty in themselves, but can be enhanced with a bit of dip dyeing to produce pieces that are much more striking. So over time I store up some of these small pieces waiting for my next indigo day.
Today I have a stock of key fobs and feathers ready to dye. To get a variety of effects I have left some cords as rope and some I have unwound the rope and combed out the individual strands of cotton. I followed the recipe above to grind up some of the Indigo cake, make up the stock reduction with Thiourea dioxide and add to an alkaline solution in a dyeing vat. A few pieces I submerged completely into the vat and allowed to soak but most I dipped the tips of the feathers or bottom of the key fob tassel and allowed the dye to creep along the cord in a fairly random way. Lifting the feathers out, the cords are green but rapidly oxidise to a deep blue in air. Successive dipping until the blue colour was as deep as I wanted and then hung up to fully oxidise and dry a little. A little later I plunged all the pieces into an acidic bath (bucket of water with a few tablespoons of vinegar in), to fix the indigo dye on onto the cotton.
As I dip dye parts but not all of the cord there is quite a bit of uncertainty with the results as it wicks and creeps depending on how wet the cotton is or how it is hung. I love this, and I am always looking to create different effects.
These feathers have a raw, punky look to them. I cut the shapes roughly too to emphasis this effect. The dark blue surrounds and creeps in towards the white pure centre to corrupt it. I think this gives the impression of tension and stress.
This image shows what happens when you dye the 3 ply rope cord first and then unwind and finally comb out the individual cotton strands after the dyeing is complete. The 'white strips' are where the dye hasn't reached into the middle of the tightly wound rope.
This final example is where I have dipped cords for varying lengths of time to produce different shades of blue. The longer they are dipped, the darker the colour. Using these cords in shade order to make a table decoration here with darker cords on the left slowly fading to white on the right.
Indigo dyeing tips
I am no expert when it comes to indigo dyeing but here are a few tips from my limited experience.
Cover everything that might get splashed. It is well worth the extra few minutes it takes to tape plastic or paper over your worktop to avoid having to try and clean up dried indigo once it has stained your surfaces.
The thiourea solution is a bit pongy but not harmful so best to work outside or in a well ventilated room.
I ground the indigo cake in a mortar and pestle which is ideal if you have one, and a finer grind is better to produce a strong solution and avoid having unusable solid indigo bits in you vat.
The Thiourea dioxide reduces the oxygen contained in the dyeing vat and keeps it looking green. Try to keep the vat from absorbing too much oxygen from the air through stirring or dripping excess dye into it turning it blue again.
Keep and eye on the pH, particularly if your concentrate solution is blue rather than yellow or if there is still quite a bit of blue solid in suspension. Using the indicator paper keep the solution alkaline around pH 11, add more sodium carbonate if needed.
The more times you dip the deeper the blue colour and it also lightens a little on drying and fixing so I would go a little deeper than you want during the dipping.
Think about where you will place the dipped pieces to dry before you dip. Particularly if you are dyeing some areas and not others on the same piece. This is obvious of course, but you don't want to get caught holding a piece up, dripping dye with nowhere to hang it and not be able to put it down in case the dye runs where you don't want it too. You can tell I've done this, can't you?
Your Indigo day
So there you have it, that's my Indigo day. Have you tried using indigo, or other natural dyes like onion or avocado skin? I would love to hear about your experiences. Please share your results, and feel free to challenge what I have written based on your experiences, or offer tips of your own.
Please join the discussion and post a reply.
In future posts I will post more of my macrame journey as well as tips and tricks, including choosing cord types, making unwanted cords disappear and upcycling waste cords, so remember to register on this website and follow me on Instagram @ButOneString to get updates.