Japanese Indigo

These skeins of yarn (commercial spun, not my spinning) are all dyed with indigo from Japanese Indigo plants (Persicaria Tinctorium) grown at home, on the front room windowsill and in the greenhouse.

The yarns in the top row are a Traub worstead spun wool, in the bottom row spun flamme silk from Gaddum & Gaddum Ltd. (I intend to use these yarns in weaving scarves).

And this is what the plants look like, they are the straggly green leaved plants. The dark leaves belong to basil "Purple Ruffles" and the stoneware pot at the left side of the picture holds a Pelagonium with nutmeg scented leaves.
The seeds arrived in the post last winter from one of my friends in the Online Guild of Weavers Spinners and Dyers, along with instructions for different ways of making dyebaths and some samples from my friend's dyeing.

Following my instructions I found a large Kilner jar, filled it with leaves, covered them with water and left the jar to stand for a few days. The "few days" turned into a week, and the leaves had started to ferment. Gas bubbles pushed the leaves up the jar and it overflowed (note: next time leave a couple of inches empty at top of jar). The liquid at the bottom of the jar looked yellow, and it began to smell like rotting brassicas (i.e. cabbage, another plant in the brassica family).

Even before the dyeing process was begun, it was clear that these leaves contained blue pigment, see what has happened where this leaf is damaged...


Before the dyeing session I also had to prepare the yarns. The wool came in an 100g skein, from which I wound smaller skeins (not weighed, but 12 skeins of differing lengths), and the silk came on a large cone. When the skeins were wound, and loosely tied at least 5 or 6 times per skein, I put them into pans of warm water with detergent and heated them gently for about 20-30 mins. to make sure they were well scoured of any substance (especially lanolin in the wool, seracin in the silk) that might impede dye take-up. After the detergent and anything else was rinsed out, I left them in bowls of water to wait for dyeing.

The dyebath was prepared by warming the jar in a bain marie, created by resting the Kilner jar on the stainless steel basket from my pressure cooker, turned upside down in a 20 litre stainless steel dye bucket.

The instructions said to raise the temperature slowly to 71 degrees centigrade. I actually stopped heating it at 68 degrees. Then, I stained the liquid from the leaves with a nylon sieve that I reserve for dyeing use, poured the liquid into my bucket, and whisked for 20 mins with a slotted stainless steel spoon. At the end of this time the bubbles looked blue.

Why whisk? To introduce air into the liquid and oxidise it (i.e. introduce oxygen). There's a good article about using Indigo in Shibori dyeing in the latest Journal. Author Jane Callender explains how the oxidisation causes two indoxyl molecules (which are unstable) to combine and form the blue pigment indigotin.

The next stage was to add an alkali liquid to the dyebath to adjust the pH level. I was going to use "washing soda", but my dyeing instructions did not tell me how to make the liquid.

I recalled that I have a little booklet from Helen Melvin: "The Colour of Sea & Sky: The Art of Dyeing Indigo". I ran to find it, confident that she would have explained this - and there it was, p.9. 4 tablespoons Soda Ash into a litre of very hot water. Thank you Helen! It was like having a friend on hand when I needed you.

The dyebath was returned to the electric hob and warmed up to 50 degrees, and then half a spoon of "spectralite" sprinkled on the surface. This is a reducing agent (reduction is the removal of oxygen). Jane Callender says " a reducing agent... removes or 'digests' some oxygen from the indigo [and] causes it to change to leuco-indigo". The change is visible to the eye, as the dyebath gains a yellow tone, which took my dyebath from very blue to a deep moss green. Good! Just as my instructions said it should... so, time to add a couple of small wet skeins, and leave them 10-15 mins for the dyebath liquid to penetrate. Helen makes the point that leaving material in an indigo dyebath longer does not give a deeper colour. Deeper colours are produced by re-dipping... I remember reading about this before in Jenny Balfour Paul's book "Indigo" which is a wide ranging account of the historical and worldwide traditions of indigo dyeing.


After several skeins had been dyed, the reduced bath became more yellow, and this very yellow looking bath below was the one that actually gave the deepest shades of blue.

I used almost all the bowls and buckets I could find. I had one bowl with wet skeins of wool ready to dye, another with wet silk ready to dye. I had a bowl to rest my sieve on to put yarn in when it was immediately out of the dyebath...

oh, better interupt here. When the yarn is lifted out of a dyebath, like that one pictured above, it looks yellow. The blue colour forms as the pigment oxidises - or takes up oxygen from the air. Magic to watch!

...back to buckets etc, see below, a bowl to rinse the yarn after it has oxidised and turned blue, then a bucket to soak it a while in a strong saline (salt water) solution. A bowl to leave the saline soaked yarns until I get a moment to rinse them. The rinse and the soak in saline are essential to remove excess pigment and fix the colour so it won't rub off the yarn later.

It was all great fun and I was happily "singing the blues" to myself throughout this wonderful dye session.

References:
(article)Indigo and the Tightening Thread, Jane Callender, in The Journal for Weavers, Spinners and Dyers, 231, Autumn 2009;
The Colour of Sea & Sky: The Art of Indigo Dyeing, Helen Melvin, copyright 2007, self-published;
Indigo, Jenny Balfour Paul, 2nd edition pub. Archetype Publications Ltd. 2006, ISBN 1-904982-15-8

Logwood

I used the traditional dye Logwood for the first time recently. Historically this dye was very important, especially as a source of navy blue (obtained with potassium bichrome mordant) from 1800 onwards, but I find when I talk to people who aren't dyers that while they have heard of woad, indigo and madder, this and many other natural dyes have slipped out of general knowledge. Jill Goodwin in A Dyers Manual says Logwood, from the south american native tree Haematoxylon campecianum was known in England from the time of Queen Elizabeth I, but its use was prohibited by law until 1661, as dyers needed to learn to how use mordants to make this dye lasting. The chips of logwood sold as dyestuff come from the heartwood of the tree, which is cut down when about 10 years old. Rita Adrosko in Natural Dyes and Home Dyeing and Rita Buchanan in A Dyers Garden both recommend soaking the logwood chips for at least a few days as fermentation that occurs when the logwood is soaked leads to better results. Rita Buchanan says the choice of mordant is important because logwood does not last long when alum or tannins are used, and best results are obtained when using chrome or iron.

I wish I'd read these books before I did this work with logwood, as I've used only alum mordant and also hadn't seen that Jill Goodwin recommends the dyer to stop heating the dyebath when the wool is added for best, clearest colour.

Here are the results of my experiment, the wool my usual superwashed merino, the mordant my usual pre-mordant of 10% alum (potassium aluminium sulphate) and 8% cream of tartar (potassium hydrogen tartrate). Progressively lighter shades were obtained from the same dyebath, until I ran out of wool.




The next photo shows how one of those magical dyebath transformations has occured - see how the colour of the dyebath the wool went into, and the first colour shown by the wool in the dyebath, was most definitely orange.

Traditional Natural Dyes

Attending a workshop on natural dyes gave me confidence to have a go at dyeing by myself. It turned out to be a simple process.

You start with undyed fibre or yarn, treat it by heating up with a mordant to improve dye take-up and lightfastness. Next, you heat up plant material to extract dye, and add the fibre or yarn. Different results with the same plant material are obtained by different using mordants, different fibre, different length of dyeing time and possible combining dyestuffs or dyeing the same fibre with two or more different dyes.


These are yarns I dyed last year, using traditional natural dyes purchased from a supplier of dyestuffs. I was impressed to discover what strong colours can be obtained from simmering plant material with wool. I hadn't been aware of natural dyes before I got Jenny Dean's book, and then had a go at dyeing for myself. I didn't expect these bright shades.


Left to right, the dyestuffs are: onion, weld, logwood, tumeric, madder and indigo.

Here's a group of shades from madder:








Blues from Logwood and indigo:













and a group of yellows, two skeins dyed with weld, and on the right, a skein dyed with buddleia flowers from the garden.












Encouraged by these results, I then decided to see what dye plants I could grow in the garden. Here are the results of using my own Dyer's Chamomile:

The wool (superwashed merino combed tops) was pre-mordanted by simmering for an hour with 10% alum (potassium aluminium sulphate) and 8% cream of tartar (potassium hydrogen tartrate). This percentage is calculated in relation to the weight of wool, e.g. with 100g wool, I use 10g alum and 8 of cream of tartar.

I picked a bowl full of flowers from the garden (do you remember the picture of my dye garden? there's no shortage of these flowers) and simmered them for one hour. Then I removed the flowers from the bowl and added the wool.

The sample to the left had a pinch of tin (stannous chloride) added at the end of the dyeing time, and was given another 10 minutes dyeing time. The green sample on the right was given a pinch of iron (ferrous sulphate) as after-mordant and also given just 10 minutes extra.

Now here's something I love about playing with the chemistry of natural dyes. One moment there is a pan containing pale yellow wool in a clear yellow water, add that pinch of tin and there is suddenly a swirling cloudy, orange developing and spreading in the pan. It happens fast! The wool is now orange.

Likewise, the pinch of iron. As it drops into the water and starts to dissolve, a deep green appears and spreads through the pan. Dramatic change! The wool takes the colour almost immediately, but a few extra minutes simmering gives stronger colouration.