Monday, 27 August 2007

indigo and organic cotton 2

There were three specific trials I'd planned for on my indigo dyeing day with Isabella Whitworth: (1) a four-stage series of dips (on prima) to get an idea of how colour builds up with successive dips; (2) comparative dips with the organic cottons (and prima) either scoured first in boiling water with soda ash or by washing in hand-hot water with soda ash; and (3) dipping a large sarong size piece of prima (1.75 x 1 metre) to get an idea of required vat size and other difficulties when working large.

My earlier teachers (Abi Evans, Vivien Prideaux) had already advised that for deeper blues multiple five-minute dips with airing/re-oxygenating time in between gave greater fastness than a single longer dip. Although there seems marginal difference between individual stages the change between first and fourth is striking. Another time I'd like to test hues achievable with up to twenty dips. Quick calculation... requiring 200 individual dips! Taking over 16 hours! I had been pondering various home-made time-saving devices for multiple-piece dipping before the day at Isabella's – definitely one would have come to fruition before 20-stage testing!

The "sarong" wasn't a complete success – although the vastness of blue is gorgeous! But parts have uneven colour – aka bad dyeing! Possibly just in the third stage when I was chinwagging more than concentrating on dyeing and simply didn't open the cloth up enough. Less liquid in the vat by the third dip might also be responsible, not giving the cloth the room it needed. However, the marks are those of cloth not being exposed to dye. Strangely we both commented on brighter lighter patches showing as the cloth hung drying/airing against the light. But they seemed to disappear, perhaps as excess but unfixable excess dye ran down the cloth, obliterating the patches.

With Abi I had learned to lower cloth in to the vat in sheet fashion and similarly remove; with Vivien I'd learned to squeeze out water and lower in in clenched fist, opening the cloth up under the surface, and re-squeezing below the surface before removal. Both methods have the same intention (to prevent air getting into the vat) but the squeezed method would be difficult with waxed cloth to avoid cracking. Hence I need a vat big enough to lower "sheets" in and a high enough ceiling to allow for this – maybe standing on a ladder? Or another device to assist dipping large pieces...

The organic cotton tests were both successful and not successful. One intention was to discover whether each fabric needed boiling to remove starches and other residues from processing, or whether a wash in hot water would suffice. They were boiled for about five minutes each. Soda ash was used with both - alternative trials for another time could be to boil or wash without but testing that would come later. The ideal is to use a fabric that requires the least energy and resources input before dyeing (and waxing), though this could be a false saving if the cotton went through more unecological processes before purchase. I believe an advantage with certified organic cottons is that the processes used have been audited and theoretically are traceable. And certainly the worst offenders have been eliminated. I'll be investigating this later on.

The boiled cloths had a second dip to deepen colour. I was surprised to see the intensity of colour was nearly even over all except the voile, which is darker. They were the first dyeings of the day, and the first few cloths came out with dark almost black streaks in one corner, which haven't washed out. I assume it was indigo transferring from my gloves – I hadn't washed them since the Prideaux workshop (note to myself: haven't washed them since the Whitworth day either so do it while remembered!).

The warm-wash cloths came last, partly because they were still drying and needed to be dry before waxing on the cloth name and process. I was also nearly out of time if I was to catch the bus to Launceston, and so the cloths went in two or three at a time with less eye on the clock. No time for a second dip, they possibly also suffered from a short airing before being dumped in my bucket along with the rest of the wet work. So it isn't possible to do a fair comparison between processes. Instead I'll have to do it with dip-dyeing in Procion.

Of the warm-wash cloths the dye is very patchy on the Bishopston handloom – but I really like the effect! Probably any experienced indigoer will groan embarrassedly at my delight in accidental effect but it has something of a stonewashed look. It hasn't occurred on the boiled version but as already mentioned, the stonewash effect was most likely down to bad practice and not cotton quality (no problems dye-painting with Procion). However, close up the boiled Fabrics Ltd handloom gives a hint of stonewash effect and its warm-wash version also looks stonewashed, so perhaps there is something in it. On the other hand all the other warm-wash cottons have a degree of stonewash (even the prima), which perhaps would have been evened out by a second dyeing. Though the boiled white (but surprisingly not natural) percale also has a suggestion of stonewash. And so frustratingly, I can't really draw conclusions one way or another on washing or boiling or my dyeing ability. Except that the four dip test on prima shows no stonewash.

And then there's the boiled powerloom. Even after two dips the colour doesn't seem happy on the cloth. It's a bit greyish and uneven, not worthy even of being named stonewash. On the warm-wash version the dye is intense along (presumed) creases and blotchy in between, pretty much as already seen with handpainting Procion on cool-soak version. Powerloom needs some serious de-scouring... of what? With what?

Conclusion? Other than powerloom I think all boiled versions would dye evenly enough with further dips and more practice on my part. But I'll wait until after dip-dyeing with Procions before being too deductive.

pics show: (1) four dip comparisons; (2) boiled wash and two dip results; (3)warm-wash, single dip results; (4) handloom comparisons - left, boiled, two dip handloom; right, warm-wash, single dip with stonewash look. The odd dark spots are dew from the grass.

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