Mordant Monday: Middle Mordant Magic

In this week’s Mordant Monday, we discuss Middle Mordant. Middle Mordant is a technique that I learned about from The Art and Science of Natural Dyes. It’s considered to be a Japanese technique and is a simple way to create rich color on silk. Middle mordant uses room temperature dye baths and you can repeat the process until the fabric is the color you want. The purpose of middle mordant is to deepen the depth of shade and most of the examples I’ve seen use silk fabric and alum mordant. There are somewhat similar techniques that old dye books discuss, but these European methods usually mordant the fabric first, then immerse in dye, then back into mordant and dye again, usually using high temperatures. What I like about the European method is that they use phrases like “heave the fabric back into the bath, give it seven turns, or until done.” Middle mordant starts with unmordanted fabric that is immersed in a room temperature dye bath, then plunged into a room temperature mordant bath, briefly rinsed, then returned to the dye bath. You can dye additional pieces of silk fabric using this technique and gradually exhaust both the mordant and dye baths. The subsequent fabrics will be lighter and lighter, creating a beautiful gradation of shades.

Try it with leftover dye baths and see if you can coax additional colors onto fabric for other projects!

How to Middle Mordant

Step 1 – Weigh out and note the dry weight of your unmordanted, silk fabric (scoured if necessary). Then soak the silk fabric in water to wet out the fiber.

Step 2 – Prepare an alum bath (we used aluminum potassium sulfate), but aluminum sulfate will work equally well here. We used 20% on the dry weight of the fabric. Dissolve the aluminum sulfate in very hot water, then add to a container that is large enough to hold the fabric. Add enough room temperature water so the fabric can move easily. Also prepare a room temperature water bath for rinsing that is large enough to hold the fabric.

Step 3 – Prepare a dye bath (we used cochineal extract @3% wof). Dissolve the dye in very hot water or use a bath from raw dyestuffs and add to a container large enough so the fabric can move freely in the dye bath.

Step 4 – Take the wetted out silk fabric and immerse in the dye bath. Swish it around for 10-15 minutes. The fabric will look a little pale.

Unmordanted silk fabric is immersed in a 3% cochineal extract bath (this amount is considered enough to create a rich shade).

Step 5 – Remove the silk from the dye bath, gently squeeze out excess dye and immerse it in the mordant bath. Don’t rinse it or you’ll wash away the unattached dye. Swish it around for 10-15 minutes.

Step 6 – Remove from the mordant bath. Briefly rinse the fabric in water, then gently squeeze it and return it to the dye bath, swishing it around in the dye bath. You should start to see that the fabric becomes darker and richer colored.

The fabric is returned to the cochineal dye bath and starts to get darker and more saturated

Repeat Steps 4-6 until the fabric is the shade that you want, then rinse and hang to dry away from direct sunlight.

Comparison of middle mordanted cochineal. Top is after 1 dye and mordant dip, and bottom is after 3 dye and mordant dips.

Try Middle Mordanting and get great recipes from The Studio Formula Set!