Sunday, 28 September 2008

getting blue!

On the tray is all the woad cut at Helen's on September 4th, about 450g. Several plants had grown better than mine, that is, they had bulked out though were still not as fully grown as expected. Others were middling, like mine, with a few well and truly eaten! But only three caterpillars emerged during the wash!

The four pots from my front garden yielded a further 50g, so in all I had about half a kilo. About half I'd been hoping for – but quite acceptable considering August's lousy weather. The left hand pile is good wholesome leaves, the top those that were fairly battered, bruised, part-eaten and part-rotting (bad bits later cut out). Can't quite remember what the right hand pile is – possibly small and slightly battered leaves.

While washing my leaves I felt they were more blue-green than Helen's, so compared them. One-all I think, if mine are bluer but hers grew better. I'll come back to the growing stuff later.

Half a kilo of chopped leaves - including stalks. I reckon stalks must contain some indigo too, and having so few leaves/weight I couldn't afford to be discriminatory.

Whisking time is telling time... when the alchemy works or doesn't. In my case I was leaping with joy to see so much blue pigment (indigotin) in the foam, and appearing so quickly! I was expecting the foam to turn 'back to green' within 10-20 minutes of whisking, but all I was getting was more and more foam, and blue. The bucket was less than two-thirds full of liquid - top third all foam! I tried scooping it off and re-whisking, I tried mixing the foam back into the liquid, I tried giving it a break for some minutes. But still foam came up good and blue. In the back of my mind was a vague memory from one or more of the various indigo workshops I've been on, where a similar stage in vat-making required stirring to introduce oxygen - and being told soon after that it had worked and I could stop stirring. And so an hour later I convinced myself that I surely had whisked enough, there certainly was blue there (and everywhere!), and I could move on to the next stage - bottling. The memory of stirring at an indigo workshop remains vague and, in the light of day (I stopped whisking around 1 am!), not making sense. Either I was confusing the process with another, or we were processing woad (or other) leaves to make indigotin without me realising. Anyway, whatever it was, it helped me at that time - I had started to think about what I was doing, the process that was happening, instead of just following instructions!

This yellowy-green is the colour of the liquid going into the jars.

Total of seventeen jars. At this stage I deviated from the instructions, which called for periods of settling and siphoning off of the top liquid, followed by a consolidation of all bottom liquids into one container, with the top liquid being diluted with water and siphoned. Each time I pulled off the top liquid it was greenish, making me suspect there was 'blue' in there too. I saved all siphoned liquid, letting that too settle before re-siphoning. In all, I had three separate siphoning stages. After a few days of settling, some jars were showing a central body of amber liquid, surrounded by greener tinted liquid and a strong blue bottom layer (see previous post). It demonstrated to me that my earlier instinct was right, that the top greenish liquid had contained some blue pigment, and a longer settling time was all that was needed.

All liquid from the last siphoning went into the bucket, and a few days later when its top liquid was siphoned off it revealed yet another bottom layer of blue!

Although it obviously wasn't traditional to use filter papers, I did think it was perhaps the modern take on a traditional filtering technique - and had read it would yield more indigotin. I also thought it might yield more if I didn't repeatedly 'water down and re-siphon' the liquid, as early on the top liquid had proved to also contain blue pigment. So I started filtering undiluted liquid - some greener, some bluer. My instinct paid off again - see how golden it came out (in a beer glass from a Bodmin Beer Festival, and looks good enough to drink!).

Filtering started at a rate of about two drops a second. By the end it was one drop a minute, which is why by then four filters were on the go! But slowness wasn't the imminent problem. Soon after starting the filtering, I was wondering how to get the pigment off the paper at the end. The more I thought about it the more I wished I hadn't started down this route. Perhaps an upside is that it made me concentrate on related chemical processes to look for a solution. There may be one but far too long-winded to take seriously, though I might check it out sometime.

Two dried filter papers with skims of pigment over some, and a crust in parts. The crust cracked up like dried mud. If it had been thicker it might have picked off cleanly, but for me it took some paper fibres with it. The very thin layers I scored lightly with a scalpel before brushing the fine powder away. But some paper fibres went too. Pigment and fibres weighed in at two grams.

Four filter papers, as much pigment as possible removed. Took about a day. Now, had I followed instructions to consolidate the bottom liquid more and dilute it down with water, this end result might have been different. Probably I'd have had just one filter paper, so the pigment on it would have been thicker and more easily removable. Possibly it would have not seeped so far into the paper had the pigment been suspended in water instead of the remnant alkaline solution. Possibly... probably...

One thing is for sure though: a lot of pigment remains on the paper. This macro-shot shows how much is wasted. Criminal considering time and effort - mine, Helen's and nature's. I won't be using filter paper again.

With thanks to Teresinha Roberts, Helen (in North Wales) Melvin, and Ian Howard for various processing instructions, guidance and encouragement; to Ian Howard, Isabella Whitworth, Vivien Prideaux, and Abi Evans for past indigo workshops which helped develop my understanding of the indigo-making process; and to Ian who supplied the seed I grew. And not forgetting members of the Natural Dyers list. Special thanks go to my good friend Helen (in North Cornwall) for patiently growing, watering and de-slugging my woad plants over the last few months.


Helen said...

Fantastic! What an interesting post. I am intrigued you had so much blue foam. I ran a Dyeing the Blues workshop in Augsut and for the first time I had a mountain of blue foam whenI used the fresh woad leaves. Even when I added thiourea dioxide the foam did not disapear. I am not sure what causes this but it seems to be peculiar to the woads. I have tried filtering some of my indogitin and like you had a real problen with the indigotin sticking to filter paper. Would cloth filters be better I wonder?
What does intrigue me is why you wanted to extract your indigotin rather than use the bath there and then as it strikes me it is a much harder process. You can also I am told freeze the liquid and use later but I suppose that would not be so energy efficient. Any way Congratulations lovely post!

Robin Paris said...

Hi Helen (in N Wales) - easy. Firstly, being the first time for me I wanted to see what was there, to be able to measure it - a yardstick for the growing stage. And also for knowing later what depth of blue can be achieved per x grams. A start that is not trying to be too clever all at once, in case something doesn't work out.

But also, possibly the major point, because I don't have the batiks ready for dyeing!

To be honest, as the stuff was filtering through, I did think I can see why you promote going straight into vat stage. When I'm more confident I'll be doing this!

Stephie said...

Hi Robin, just to say that I really enjoyed this post too! Thank you for sharing.