Monday, July 20, 2015

From the indigo vat: Solids

I'm always like to test the vat out by dyeing a range of solids:

From left to right, the six shades involved, respectively, 3, 4, 5, 8, 14, and 20(!) cycles of dipping and oxidizing. The 4- and 5-dip pieces were done separately from the rest of the lot, after I saw some final results and wanted to fill in a couple of gaps in the gradation.

The solids taught me a lot about the vat.  After the first half dozen dips or so, the fabrics didn't seem as if they were getting much darker, and at times I wondered if they were actually losing color.  Very frustrating!  But I kept going anyway, to see what would happen, especially after the vat reached a dark amber that made me think it just had to be working properly and adding more blue.  After I washed the final two pieces on the right, the true color underneath was significantly darker.  Somehow, the zinc-lime vat seems to leave a lot of unreduced indigo on the surface of the fabric, which later washes out and reveals some happy surprises.

At the same time, I was able to get to dark shades more quickly with last year's thiox vat.  The 20-dip piece on the far right isn't really any darker than a good dark blue that I got after about eight dips last summer.  In the workshop that I took last fall, Gasali Adeyemo says that he gets a dark blue in just 3-8 dips, which suggests that if I want really dark blues, I can be much braver about using a heck of a lot more indigo than most of the standard vat recipes suggest.  I tried to look up the maximum solubility of indigo in an alkaline environment, but no luck thus far in getting that particular chemical statistic.

I also can't honestly say that the blues from the zinc-lime vat are significantly different from the ones from last year's thiox vat.  Maybe the difference in tone from the Japanese fabrics in my collection comes from the indigo?  Or something else in the vat chemistry?  I wish I had some Japanese indigo that I could try, for purposes of comparison.  If anyone wants to bring me some natural indigo from Japan, derived from polygonum tinctorium, please feel free to do so!  Or if you want to grow it yourself and ferment it for me, I will happily try it out!

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