Thursday, April 14, 2011


i have all sorts of natural dye projects half on the go, and felt a little bit like i was being held up by my zinc-lime indigo vat, which is waiting for a couple key ingredients - some more zinc to arrive in the mail, and for the weather to warm up a bit.  last week i took all the liquid out of the vat and heated it up pot by pot, then wrapped dear little vat up in an emergency blanket and some regular blankets.  and still, three days later, it was back down to 60 degrees.

so.....i decided to take a little pause and make myself a thiourea-dioxide vat - a quick easy vat that can be ready in about an hour.  i clamped up a bunch of fabric, and did some dipping:

you might wonder why i would even bother with a zinc-lime vat if it's possible to do a thiourea vat in just an hour.  and there's a couple good reasons.  once you get your zinc vat going (easier said than done) you can keep it going indefinitely with only a little bit of maintenance.  some people have vats that have been kept alive for years and years.  so your vat can be there, ready to dye whenever you are.  the thiourea vat only lasts for as long as you keep it hot (110-140 degrees).  you can heat it back up again, and add more reducing agent, but it's just not quite the same.

the other main reason, and for me the biggest, is that with the zinc-lime vat it's possible to build up much deeper shades of blue.  with the thiourea vat, even with multiple dippings, it's only really possible to achieve a relatively pale blue.  this is because the thiourea dioxide is actually a colour remover (it's what you would use in discharge printing).  so unless your vat is exactly balanced while you're using it, you may be stripping the colour off from the previous dip every time you dip.  with a zinc-lime vat it's possible to build up a range of blues, all the way to almost black.

the first image is for a project that i'll be pairing with a nice deep orange, so i would like the colour to be much darker, but the scarves in the second image will be layered with other colours, so the pale colour is actually fine.  and mostly, i'm happy to have done the vat, just to get the ball rolling a bit.  i'm hoping to finish up enough pieces to open up a small rubia weld shop next week......

1 comment:

  1. the zinc-lime vat process reminds me of a sourdough starter... we have one at home, sitting in the fridge, it's been alive for hmmmm, two years now.

    congratulations on the blog julie!