Dyeing with Indigo

If you missed last week's post on extracting indigo, you can click here to check it out. It's all about how I get the pigment out of the plants so I can make a vat to dye with.

Like everything else with indigo, dye vats come in all shapes, sizes, and chemistries! And chemistry is the name of the game here because indigo is not soluble in water. In order to make it soluble, we need to raise the pH above 10 (which is pretty high), and we need to take out all the oxygen from the liquid using a reduction agent.

 As I’ve said before, and I will say until my last breath, the magic of indigo never gets old! Here's the very first time I ever saw the magic happening live before my very eyes. This is Catherine Ellis, who taught a week-long workshop at Arrowmont School of Arts & Crafts in Gatlinburg, Tennessee. When she pulled that strip of cotton out of the vat and it turned from the yellow-ish green you see in the photo to full-on BLUE in about 60 seconds, I was like a giggly school girl.

You see, I actually really love magic! You know, the kind where they do amazing things on stage that we can’t believe. Yep, that kind of magic. I even had a magician at my 40th birthday party. And this was real live magic that I could do myself! Note: Yes, this is actually chemistry in action. But that doesn’t make it any less magical!

The first vat I learned to make is called a 1-2-3 vat made famous by Michel Garcia. He told us a funny story about this when I was participating in his Master Classes in Newburgh, Scotland.

Many years ago, when he was being filmed for a digital course (I believe it was on DVD at the time), he was chugging along showing his process, but wasn’t being very precise about the amounts he was using. This didn’t surprise any of us in the master class, because we witnessed this firsthand. He’d say, “Add a pinch of XYZ,” while grabbing a handful of the stuff. No measurements, just intuition and understanding built over decades of working with the stuff.

Quick side trip to share some images from my Scotland Trip. The first is the textile studio in Newburgh, which was a converted chapel, and the other is of me during my 65 mile hike around the east coast on my way to the master class. 

The textile studio was converted into an Airbnb after Covid hit. Which is a shame, but also a pretty cool place to stay!

This is me on my last day of hiking - it was a grueling 16 miler that I did with a stress fracture at the top of my left tibia. But that's a story for another day...

The image above is taken from a video tutorial on how to make an indigo vat. It's part of From Plant to Dye Pot: A Natural Dye Workshop for Rug Hookers and Wool CraftersIf you're interested in being the first to know when registration is open again, sign up for the wait list here.

So, back to the story… when the person recording kept asking him to say how much of each ingredient he was using, he just blurted out that the proportions are 1-2-3: 1 part indigo, 2 parts lime (calcium hydroxide, aka calx), 3 parts fructose. And the 1-2-3 vat was born!

In this particular recipe, the lime increases the pH, and the fructose reduces the liquid (takes the oxygen out). Here I am adding some indigo pigment to a bucket that's already got the lime and fructose dissolved.

It takes a little time for the vat to reduce (get all the oxygen out), but you'll know when it's done by the purplish-coppery sheen on top and when the liquid beneath the surface is a clear amber or yellowish green.

Once the indigo is reduced to liquid form, it attaches itself to the fibers that are immersed in the vat. When you take the fibers out, they appear yellowish or greenish. Then, as the fibers are exposed to the air, they turn blue before your very eyes! The magic of this never gets old! Here’s what’s happening: the oxygen is reattaching itself to the indigo molecules (called oxidation), and the indigo is turning back into its solid form right inside the fibers. This is what makes indigo such a colorfast dye. The indigo that’s turning into a solid inside the fibers is attaching itself permanently to them.


Seriously, how cool is that??? The series above shows how I go into the vat with a damp white cotton swatch. When it comes out, it's yellowish-green. To rinse off any particles that haven't fully attached, and help with the oxidation a bit, I dunk it in some cold water. In the end, it's forever blue!

Unlike other dyes that will give you deeper colors by adding more dye or keeping your fibers in the dye bath longer, with indigo, we build color over time by multiple dips into the vat.

This is a scrap piece that I was playing with to see what kinds of overlay designs I could create. The top, lightest color was in the vat for 1 minute. Each subsequent dip was also 1 minute. You can see the color build with each dunk in the vat.

Each time you go into the vat, you have to let it fully oxidize outside the vat before going back in. A general guideline is to stay out as long as you were in, up to about 6 minutes. So, if you have your piece in the vat for an hour, you still only need about 6 minutes for it to oxidize. That's only a guideline, and there are many exceptions - like when you're doing shibori - the Japanese term for what we call tie-dye. When you create areas of resist in your fibers, there are all sorts of nooks and crannies that it takes longer for the air to get to. Fortunately, you can also oxidize in water because good ole h2O contains oxygen! 

Also unlike a dye bath, the indigo vat can last weeks, months, or years, depending on how well you care for it. Indigo will eventually need to be added to the vat, but it's kind of like sourdough that everyone learned how to make during the pandemic. You can have a "mother" that's generations old!

Okay, that's all for this week. Until next time, I wish you abundant love and colors!