If you have found yourself here, you are likely on your own journey with natural dyeing. Natural dyeing is the practice of dyeing fibers with natural ingredients, such as roots, bark, flowers, leaves, and food scraps. Necessary to natural dyes is a way to ensure the dyes will bind with the fiber and last. This is referred to mordanting. Over the years of teaching natural dyes, I have found mordanting to be the step that scares people away. It can be conquered, however. In this blog, I will go over several different ways to mordant your fiber and go into detail on one method that I believe is the easiest for new dyers. All of these methods are for cellulose fibers – cotton, linen, hemp, and bamboo.
What is Mordanting?
Mordanting is the process of treating fabric so natural dyes will create a lasting bond with the fabric. To mordant fibers, we use a metallic salt that naturally occurs in minerals – most often aluminum. For cellulose fibers, aluminum acetate is frequently used, however other forms can be used, such as aluminum sulfate. There are many ways to mordant your fiber, so in this blog, I will share the most beginner-friendly way to mordant. This is the technique of aluminum acetate followed by calcium carbonate. This technique is simple while also producing satisfactory, lasting colors.
How to Mordant
There are several different ways to mordant cellulose fabric. Here are a few I have used:
- Aluminum acetate + wheat bran or calcium carbonate
- Tannin + Aluminum Acetate
- Tannin + Soda Ash & Aluminum Sulfate
Here, I will walk through the process of dyeing with aluminum acetate + calcium carbonate. These directions assume you have already scoured your fabric. I know it can be confusing to keep track of all the steps in dyeing, especially when you are first starting. I made myself a simple step-by-step when I first began dyeing as a reference whenever I became lost. You can access this guide for free below.
Steps to Mordant Fabric:
- 1. Start by wetting out your fabric in warm water. Simply put, just soak your fabric in warm water.
- 2. Make your mordant bath. The mordant bath does not need to be heated. However, you need to use hot tap water. Fill a large bucket or tub with hot tap water. You want enough water so that your fabric will be fully submerged and able to move.
- 3. Measure your aluminum acetate. This powder is very fine and plumes into the air. Wear a mask so you are not breathing in powders. Add the aluminum acetate to a cup of hot tap water and stir to dissolve.
- 4. Add the cup to the larger container of hot water and stir.
- 5. Add your already wet and scoured fabric to this mixture and submerge. Stir around to make sure your fabric is not creased or folded. I use a large storage bin for this. I generally mordant large quantities of fabric at one time and then put it away until I am ready to dye, so you may not need something so large. Use whatever size works for how much fabric you have.
- 6. Keep your fabric in the mordant mixture for 2-24 hours, stirring occasionally. I prefer to leave mine for 12-24 hours. Once it is time to remove, squeeze the excess water off your fabric into the bucket. You can reuse this mixture by adding more aluminum acetate at half the strength of your original mixture.
- 7. Make the calcium carbonate bath. To make this bath, use the ratio from the Beginner’s Guide to Natural Dyeing. Similar to the aluminum acetate bath, fill a pot or tub with hot water. Measure out the calcium carbonate and add it to a cup of hot water for dissolving. Stir to dissolve and add this to your pot of water.
- 8. Add the still-wet fabric to the calcium carbonate bath. Keep the fabric in this bath, stirring occasionally, for 5 minutes. Remove the fabric, squeeze out the excess, and rinse. Proceed to dyeing or dry and save for later.
Mordanting may not be the most exciting part of dyeing, but it is essential. Once you start dyeing, you will see spots that may not have dyed as well as you like. This is either because of poor scouring, poor mordanting, or the fabric was not wetted out. If you are careful with these steps you will have more even dyes. With all that being said, if your fabric is blotchy after dyeing, you can start again and fix it. I always save any dye projects that are not up to my standards. Once I have a large pile of fabric, I mordant these again and re-dye. So don’t worry or stress too much about this part. It takes time and practice, but each time you dye, your results will be better than the last time.
Resources for Natural Dye Beginners
Here a few of the resources we have available to help guide you as you explore natural dyes.
