Friday, 16 September 2016

An Attempt at Making a Fresh Indigo Leaf Ferrous Vat for Batik Dyeing

My friend BG gave me a batik kit last Christmas. Trouble is, the instructions online say batik wax starts melting at less than 50 degrees Centigrade and the plant dyes I like using need a long simmer to fix their colours onto cloth. Recently, I read that a ferrous indigo vat works at 21 degrees and dyes cotton and linen really deep blues with short dips.  It is supposed to be quick to set up and stay active for a couple of weeks, no need to keep reheating the dye pot or rushing to dip more stuff in order to exhaust every particle of indigo within one session.  All in all, it sounded well worth trying to make a ferrous vat with some of the Japanese Indigo plants which are currently ready for harvest in the garden.

The instructions I found start with powdered indigo, which you first hydrate in a small amount of water.  To extract indigo from fresh leaves, I give them 24 hours to steep in hot tap water, with the pot surrounded by a sink full of hot water, which can be renewed a couple of times to keep the temperature up. After the contents of this pot had been poured through a colander and the wilted leaves wrung out, though I had a bucket full of promisingly blue
liquid, past experience of dyeing with Japanese Indigo Leaf vats deoxygenated with spectralite suggested there would be less in that bucket than the 20g of powdered indigo specified in the recipe.  Guessing, optimistically, that I might have as much as 15g of indigo, the 3:2:1 ratio meant
adding 45g calcium hydoxide and 30g of ferrous sulphate.  A further problem was temperature.  My bucket having only 15 litres capacity and being nearly full already, there was no chance of adding gallons of boiling water, so I poured the extracted indigo back into the pot and heated it to the usual working temperature of 50 degrees centigrade then returned it to the bucket.  Though the average ambient temperature in
Wales is considerably less than 21 degrees, I had had a rather wizard wheeze.  Grass cuttings generate a steady heat as they start to compost, so standing the bucket in a bag of freshly mown grass would keep it warm for quite a while, even if the nights got cold. Pouring in the dissolved iron and the lime, I stirred the mix, covered the bucket and let it stew for half an hour.  I bet you are thinking this hodge podge of approximations is
never going to work, because by this point, I had my doubts.  It was almost shocking to see that coppery film and bloom of bubbles showing deoxygenation was really happening, even though the pH was at the maximum my testing strips can indicate.  Past experiments have shown that keeping the vat at pH 9 works best, but at least I wasn't planning to put any wool or silk in there.

BG and I had previously melted some wax granules in an old saucepan and got out paint brushes and the Tjantjing thing for applying a batik resist.  First, we each tried designs on the back of old cotton shirts.  Keeping the wax temperature right turns out to be critical to success.  Too cool and it just sits on the surface of the fabric instead of penetrating through, too hot and it pours out of the Tjantjing into a puddle instead
of a line.  Brushing wax on using leaves for a template, you have to be quick and light handed, or the leaf gets welded on.  Next, we tried out designs on a thicker curtain fabric, 80% cotton and 20% linen.  The looser weave soaked up wax more readily, but by the end of the afternoon, I had despaired of ever keeping the wax temperature right without buying one of those electric heated pans.

When I slid the soaked cotton pieces into the ferrous indigo bucket, green sludge swirled up. Pulling them out after ten minutes, the cotton was coated with slime. Graham Keegan writes that immediate rinsing will not remove the indigo, so I plunged the cotton in a bucket of fresh water, hung it up and watched hopefully.  It did go blue, but not very blue, even after several dips.  The cotton/linen mix fabric
took up the indigo better, though I had secretly been hoping for a more dramatic, midnight blue result.  A few days later, I came back to the vat and found the green sediment had settled further down and it was still working well enough to dye cotton pale blue.  A week later, no heat was left in the grass cuttings and no indigo was fixing.  Trying to work out how to 'sharpen' the vat, which was not only cold, but possibly too
green, I stood the bucket in the sun and chucked in an unknown amount of iron in the form of an old jam jar of water with rusty nails.  This did get it blooming a bit, though it only dyed things pale blue.  Enough - I poured the lot down the drain, resolving to add less lime in future for a lower pH and to keep an eye out for a larger, narrower, deeper bucket.

My companion, The Entertainer, Elinor Gotland, arrived home while I was putting the pieces of dyed cotton and linen into boiling water. 
"Hiya, Beaut." She peered dubiously into the pot.  "Hope that's not our dinner.  Poor Cow, you've lost the plot, gone Up the Junction, stuck here at home."
I bridled.
"It's you who's had a dose of social realism, not me. While you've been off filming yet another Alfie remake in grubby old London, I have been practising the exotic Indonesian art of batik."
"Starring in your own domestic drama.  The Homeliness of the Wrong Resistance Dyer."
"What's wrong with my batik resist?"
"There's an awful lot of wax floating up.  Did you scrape off the cloth first?"
"Umm, no."
"Plenty of time for me to catch up with my enormous pile of fan mail before tea, then. Wax is a bugger to get rid of."
I concentrated on scooping off as much of the wax as possible to make Room At The Top of the water.  Fast as I wiped the ladle, cooling wax congealed back onto it. Beeswax everywhere with never A Taste Of Honey.  Despite clearing masses of the stuff, the boiled cloth still felt waxy.  A second pot of boiling water was needed.  Then I tried rinsing all the fabric with a bit of detergent, particularly the cotton pieces seemed to retain a greasy residue, long after the cotton and linen mix looked clean.

Eventually, I turned from the sink, wringing out the last cloth.
"I never realised this whole batik technique would be such a performance.  Thank goodness that wax has finally gone."
Elinor was busy slipping signed photos into envelopes.  She glanced up.
"Gone, is it?  What wax is not still lining those pots is probably settling about half way round your U bend."
Oh, Look Back in Anger, what a grim kitchen sink drama.  If anyone out there has some slightly more helpful advice than Elinor's, I'd be glad to hear it.  Unless I can formulate a better plan, I'm not sure I'd try a ferrous indigo vat or the batik technique again.  At least, not til time has mellowed the memory of this attempt.


  1. Has she been growing horns in her absence? She cant 'arf be a nasty piece of meat! Threaten her with a lamb shank Fran. I like the pale blue with the shell. I would consider it a success...even if she does not.


    1. Batik does open out endless pattern possibilities, but Elinor was right about the wax, damn her.

  2. I read somewhere that soy wax is easier to use - but I have no experience of my own about that. one of the reasons I don't do batik - is getting rid of the wax:( if I do clog up the sink - I'll never hear the end of that:)

  3. must have been made friday night Saturday morning a cracker of a kitchen sink drama Fran :-)

  4. must have been made friday night Saturday morning a cracker of a kitchen sink drama Fran :-)

  5. Got to ask yourself, What's it all about, Ali? :)

  6. How beautiful is that shell? :D I used batik on cotton many years ago and probably used the same wax as you. I scraped it off with a knife first, then ironed the fabric between brown paper to absorb the wax and then finally a hot water wash. The fabric was still stiff and a little waxy, even after all of that! It can be done though, so maybe try again?

    1. If I do, I shall have a Special Purpose, properly planned out. And a more predictable dye bath. Thanks :)