Botanical Dye Studio #03: Mordant for Cellulose Fibers

Tips & Tricks from our Botanical Dye Studio – Mordant for Cellulose Fibers

As you already learned in our last article on mordants for protein fibers , dyeing with botanical dyes requires some kind of fixative. In technical terms, this magic ingredient is called mordant. Animal and plant fibers are morded differently to make the colors more durable. For cellulose fibers, alum alone is not sufficient as a fixative, and more steps are required. So far, we've achieved good results with a tannin-soda-alum mixture. This recipe is widely used in the international botanical dye community, so we're introducing it to you now.

Mordant for cellulose fibers

Gall apple powder (tannin) 12% WOF, soda 2% WOF, alum 15% WOF
WOF = weight of fiber, the dry weight of your fabric
Method: Pot/bucket + hot water

Step 1: Gallnut powder/ tannin

1. After washing, weigh your dry fabric. To determine the correct amount of gallnut powder, you'll need 12% of your fabric's dry weight. For 100g of fabric, that's 12g of gallnut powder.
2. Fill your pot or bucket with hot water (48-60 degrees Celsius). Stir the gallnut powder with the hot water before adding it to your bucket. Caution: The water must not boil, as this will destroy the tannins.
3. Now place your wet fabric into the stain bath. Let it sit there for 1-2 hours. Stir occasionally to ensure the stain is evenly distributed over the fabric.
4. After the exposure time, you can remove the fabrics from the tannin bath and rinse them carefully. You can either hang them up to dry or place them directly into the next pickling bath.

Step 2: Soda & Alum

1. Weigh out 2% WOF soda and 15% WOF alum in two separate containers. For 100g of fabric, this is 2g of soda and 15g of alum. Dissolve both mordants by adding hot water to the respective mordant powder in the container.
2. Fill your second pot or bucket with hot water (48-60 degrees Celsius). First, add the soda and stir well.
3. Now add your alum mixture. Do this carefully; the chemical reaction may cause it to bubble.
4. Now place your wet fabric into the mordant bath. Let it sit for another 1-2 hours, stirring occasionally to ensure the mordant is evenly distributed throughout the fabric. For even more intense colors, you can leave the fabric in the mordant overnight. When dyeing with botanical dyes, the motto really is: the longer, the better.
5. Voilà, the dye is complete. After the soaking time, you can remove the fabrics from the dye bath, rinse them a bit, and let them dry. Remember to label the fabrics with your dyeing method before putting them away for later. Trying multiple dyes at once can make it difficult to keep track. Of course, you can also start dyeing right after rinsing. That's the most fun!

I hope I was able to give you some useful basic tips. If you have any questions, feel free to email me or message me on Instagram.