Friday, May 2, 2014


I was eager to try and achieve a gradation of solids in Wednesday's indigo vat, but the results weren't quite what I intended.  In indigo dyeing, different shades are produced by multiple dips of the fabric in the dye bath.  After each dip, the fabric is aerated so that the indigo can oxygenate and, in the process of doing so, bind to the fabric.  I decided to dye four fat quarters in a sequence of 2, 4, 6, and 8 dips--i.e., I stopped dyeing the first piece after two dips, the second after four, and so on.

I had high hopes after I pulled the second piece and hung it up to dry next to the first:

As the second piece dried, however, it became lighter and lighter.  In the end, it was practically the same shade as the first piece, even though it went through two extra dipping cycles.  I spent much of the next four rounds of dipping wondering whether what I was doing would make any difference at all.  What in the world had gone wrong?

Four possibilities occurred to me:

1)  My dye vat was over-reduced at the outset.  Indeed, in my lab notebook notes on my dye bath, I wondered at the outset if the vat was too yellow.  I read online, in an article by Michele Wipplinger, that dark indigo cannot be attained in an over-reduced vat.

2)  I needed to add more stock solution after the first couple of rounds of dipping.  In the instructions from last fall's workshop, Akemi Nakano Cohn suggests adding a little more dye stock after the first two or three dips.  I thought the vat still looked plenty strong and had plenty of indigo left, but maybe I was wrong?

3)  Maybe the vat needed sharpening with thiox by the mid-afternoon?  Again, I thought the bath looked good, but maybe it was oxidated.

4)  Should I have kept the vat warm?  The day was so sunny that I didn't bother with a heat source, but perhaps I needed to be more rigorous about maintaining a high temperature.

I think the first possibility was the most likely.  Why?  Note the following photo, which shows the full sequence of four fabrics:

After six dips (third from the left), the fabric was just marginally darker, but the 8-dip piece came out a deep, rich blue.  Explanations 2-4 don't explain that result, so I'm guessing that as the afternoon proceeded, more oxygen got into the dye bath, to the point that the darker shade became possible. 

I'm just a complete tyro, however, so if you're a real indigo dyer, I'd love to have your thoughts and comments.

1 comment:

  1. sorry, I can't help you with what went wrong. But on the bright side, they are all a lovely shade, and you did get some nice contrast with the last piece