Hey look at me! I’m writing a post and I finished doing something for myself! The baby is asleep (I had a girl, her name is Anaïs). Hurrah!
I receive quite a few emails about using our Australian native indigo Indigofera Australis for dyeing. Up until now I’ve been referring inquiries to Robyn Heywood’s great tutorial on the Turkey Red Journal using yarn. I recommend checking it out, especially as Robyn shows the other colours that can be obtained from this pretty Australian native (I’ll do another tutorial on that at some point!). The images are small however, there are none for the direct method and it’s a little hard to see the process of how the colour in the vat develops as you soak the leaves and the colour change you are looking for when you add the washing soda so I’ve done a tutorial which hopefully makes that a little clearer!
I live in the foothills of the Dandenong Ranges, literally on the side of the mountain, our property faces south west with a view looking out over Melbourne towards the bay and Williamstown in the distance, it’s a lovely part of the world. Although we are very exposed to the extremes of weather, particularly in Summer when it gets incredibly dry and seriously hot. Our thin layer of heavy clay “soil” (which barely covers the millions of shovel breaking rhyodacite boulders) bakes to resemble almost solid rock. It’s not great for growing the sensitive and needy plants that I am partial to. It is excellent conditions for growing native indigo to dye with however!
You can buy native indigo at most good nurseries. It grows quickly and is lovely in early Spring with abundant purple pea flowers. It looks best planted en masse. When you are harvesting the plant for dyeing look for leaves that are dark green with a blueish hue as these will contain more indigo pigment. Hopefully you can see the difference between the newer greener growth and the older blue/green leaves in the photo above. I’ve picked these ones when they were flowering, I haven’t had any trouble using indigo picked at other times of the year but again I seem live in an area conducive to growing indigo for dyeing.
So, this is how I do it.
Pack a jar with leaves. Small branches, flowers and other bits you can’t be bothered removing are fine too. I picked off most of the flowers (which are useless for normal dyeing as far as I can tell, happy to be corrected on that!) Fill the jar with hot tap water – not boiling. The jar I’ve used holds about 500ml. You can see here how the leaves are still quite green, the water is still fairly clear although with a slight aqua hue.
I added a length of silk in the jar with the leaves and water to show you the first method of dyeing with native indigo, the direct method or fresh leaf dyeing. I added the silk after filling with the hot water, you can see how the silk after about an hour has started to turn blue. How long it takes for this to happen will vary. I kept my jar warm on our ducted heating vent and left the silk in there for a day, pulling it out occasionally, stretching it out and then putting it back in.
Here you can see the dyed silk once it has dried, the shade of blue has a greyish hue. I could have left the fabric in for longer for more dips and a darker shade but I want to use the indigo for another method (see below).
The leaves in the jar are no longer bright green and the water is a red/brown with hints of blue, this is a good sign!
Here you can see the slick of bronze/blue indigo on the surface. This is after four days. If you don’t see these kinds of signs after a few days it might mean there isn’t much indigo in your leaves. You can leave it for a bit longer or use your leaves for a normal dye bath (will explain in another tutorial).
Now we can move onto the second method of dyeing with native indigo – chemical reduction.
Pour out the liquid from the jar into another bigger jar. I partially fill the smaller jar a couple of times, replace the lid and shake it to rinse the leaves thoroughly and then add that liquid into the bigger jar. I end up with about a litre. The liquid is now a dark red/brown with blueish froth. I have a few big old 2 litre French Arc wire lever type jars which are great for this, you don’t need to use a glass jar, it’s just easier to see what’s going on.
Now is the time to alter the pH of the “vat” to make it sufficiently alkaline. You’re after a pH of 9-10, any higher than that and you can damage your protein fibre (if using silk/wool, you can go a little higher for cotton/linen). Too low and the indigo won’t reduce properly. You can test this with some pH strips or a swimming pool/fish tank pH testing kit. I’m a bit of a hack and don’t bother with that (although I probably should!), I know my tap water has a starting pH of about 8 – 8.5, the fermentation of the leaves then makes the vat slightly acidic, to bring my vat (which is approx a litre) back to the right pH I add about 2 tbsp of washing soda.
Stir in the washing soda and then pour the contents of the jar into another jar a couple of times. If you watch whilst you are pouring you will see the liquid will change from dark red/brown to dark green with blue froth as you can see below. The vat also has a slightly “inky” smell, it reminds me of the smell of a blue ball point pen
Now we are ready to reduce the vat. Which means to make the hydrophobic indigo pigment soluble so it can “stick” to the fabric.
For the purposes of this tutorial I am using sodium hydrosulphite or hydros, because it’s fairly fail safe, easy and quick (I have a 5 year old and a 5 month old, any other vat and you wouldn’t be getting this tutorial for several years). I use Stabilised Hydros which is 50% sodium dithionite, you can buy it from Kraft Kolour, excellent suppliers of dye stuffs and fibres BTW. They also have 25% strength hydros which can be posted if you don’t live locally. You used to be able to buy it from the supermarket as Dylon Colour Run Remover, but it appears that they no longer use it in their formulation, or at least it’s not listed as an ingredient.
NB: I sometimes have a mild allergic, hay fever-like reaction when using hydros, it gives me itchy eyes and an irritated throat (I have the same reaction to some wines). This is because hydros is a sulphur based reducing agent, if you have asthma and/or are allergic to sulphites please take extra care if you choose to use it. Regardless it is necessary to wear waterproof gloves to protect your skin from the alkaline vat and it’s preferable to work outside or in a well ventilated area (I also use a mask). Always add the hydros carefully to the vat and never allow your container of hydros to get wet because it can combust! That said, when used with care hydros is safe. If concerned however you can use a natural fermentation vat, I’ll have to do a tutorial for that too!
To my one litre vat I add approx 1 tbsp (10 – 15 grams) of hydros. To keep my vat warm I stand the jar in a pot of hot tap water, this keeps it at about 40 – 50 degrees. For the purposes of taking clear photos I’m moving the jar to the bench to photograph and then returning it to the sink.
From this point onwards it’s important not to introduce air into the vat, introduce your fibre slowly and if you need to stir or move the fibre, do it gently.
Here I’m testing the vat with a strip of fabric to illustrate what it looks like when the vat isn’t ready, the fabric should come out initially a clear yellow (which it isn’t) and the pigment sticks to the fabric in clumps which means it hasn’t fully reduced.
The vat is starting to reduce, notice the ‘indigo flower’ starting to form on the top.
The indigo flower is getting darker and the vat is starting to turn yellowish, almost ready.
Anaïs woke up from her nap and I didn’t take a photo of the vat before I did the first dip with the fabric or many whilst I was doing it. Below is a phone photo I took afterwards which shows the typical bronze sheen and indigo flower of the reduced vat.
This is the fabric submerged in the vat. You can see that the fabric is yellow, when it’s removed from the vat it slowly turns from yellow to green and then blue. I allow about 10 mins between dips. I should have taken a photo of the fabric while it was oxidising, sorry, I blame the baby.
The two dyed pieces of silk. The smaller grey blue piece dyed using the direct method and the brighter more typical “indigo blue” of the silk dyed using the chemically reduced vat. I got a bit excited and over-estimated the amount of pigment for the amount of leaves and used a much bigger piece of fabric than I normally would for a vat of this size, that coupled with dyeing the other piece of silk first resulted in a lighter shade of blue. A much darker blue would have been obtained using a separate vat for each method and doing more dips. I only did three, after which there were children that needed to be fed, changed, attended to, kept alive and happy etc.
When you’ve finished dying and the vat is exhausted (it no longer dyes blue). You can neutralise the pH with some vinegar and aerate it by whisking, it’s then safe to pour down the drain.
I hope I’ve covered everything, let me know if not!