Our How To guides are intended to make the mordant dye process easy, from scouring your fibers to dyeing with an assortment of dyes. You can find other How To guides here.
What is Mordanting?
Mordanting is the most important process of preparing fibers to accept color. A mordant is a mineral salt that fixes with the fiber allowing natural dyes to bond to it. For us it is the most important step to improve light and washfastness. Using a mordant helps to ensure the most durable and long-lasting colors. With the exception of indigo (as a vat dye, it does not require a mordant), this is not an optional step. However, there are many different mordants you can use. Deciding which mordant to use comes down to the types of fibers you want to dye and how much time or energy you wish to spend. The table below explains the different mordants that we offer and the advantages and disadvantages of each one. The mordants we offer are generally accepted as non-toxic, and we encourage you to work in a well-ventilated area and to use gloves, dust mask and eye protection when weighing powders. Always supervise children when working with natural dyes, and keep all ingredients away from children and pets.
(Check out our Q & A: Round Up of Scouring + Mordanting 101 here.)
What kind of fibers are you dyeing?
Our How To guides are intended to make the mordant dye process easy, from scouring your fibers to dyeing with an assortment of dyes. You can find other How To guides here.
What is Mordanting?
Mordanting is the most important process of preparing fibers to accept color. A mordant is a mineral salt that fixes with the fiber allowing natural dyes to bond to it. For us it is the most important step to improve light and washfastness. Using a mordant helps to ensure the most durable and long-lasting colors. With the exception of indigo (as a vat dye, it does not require a mordant), this is not an optional step. However, there are many different mordants you can use. Deciding which mordant to use comes down to the types of fibers you want to dye and how much time or energy you wish to spend. The table below explains the different mordants that we offer and the advantages and disadvantages of each one. The mordants we offer are generally accepted as non-toxic, and we encourage you to work in a well-ventilated area and to use gloves, dust mask and eye protection when weighing powders. Always supervise children when working with natural dyes, and keep all ingredients away from children and pets.
(Check out our Q & A: Round Up of Scouring + Mordanting 101 here.)
What kind of fibers are you dyeing?
Different mordants can perform better on different kinds of fibers. We divide fibers into two categories. The first category is cellulose fibers. This category includes all plant-based fibers, such as cotton, linen, hemp, viscose, lyocell, bamboo and other similar fibers. The second category is protein or animal fibers. This category encompasses any fiber that comes from an animal, including wool, cashmere, alpaca, mohair and silk. If you are dyeing a blend of protein and cellulose fibers (such as wool/hemp, silk//bamboo, or silk/cotton), use mordants that can dye both types, as seen below. As a general rule, synthetic fibers such as nylon and polyester will not dye well with natural dyes.
We recommend aluminum sulfate (for protein fibers such as wool and silk), aluminum potassium sulfate (for protein fibers), and aluminum triformate (for either cellulose fibers such as cotton and linen or protein fibers). These three mordants are easy to use and deliver excellent results. If you are dyeing only cellulose fibers, aluminum acetate with calcium carbonate is an excellent mordant, and adding a tannin step before mordanting is recommended.
Which mordant should you use?
For basic mordanting, refer to this table. Once you are comfortable with these techniques, you can experiment with different mordants on different fibers and compare the results to find out what you prefer.
| Mordant | Fiber types | Features | Process notes | Detailed Instructions |
|---|---|---|---|---|
| Aluminum Acetate with wheat bran or with calcium carbonate afterbath | Cellulose fibers | Produces bright colors Does not require heat or energy | This mordant uses a multi-step process Aluminum acetate is a very fine powder and we recommend a high-quality dust mask when measuring. | See more. |
| Aluminum Potassium Sulfate | Protein fibers | Easy to use Produces bright, clear colors | Recommended to use heat/energy, or soak fibers in the mordant at room temperature for longer periods. | See more. |
| Aluminum Sulfate | Protein fibers | Easy to use Quick process | Recommended to use heat/energy, or soak fibers in the mordant at room temperature for longer periods. | See more. |
| Aluminum Triformate | Cellulose and protein fibers | Easy to use Does not require heat/energy | Longer process – this mordant delivers the best results with an overnight soak and we recommend rinsing before dyeing. You can reuse this mordant multiple times before recharging the mordant bucket. | See more. |
| Symplocos | Cellulose and protein fibers | Bio-based from dried leaves rather than mineral-based | Longer process and works best with heat and long soaking times. Requires multiple steps for cellulose fibers | See more. |
| Tannin and Aluminum Sulfate | Cellulose fibers | Most lightfast mordant for cellulose fibers | Tannin can alter dye colors slightly as it has a color of its own. You can also pretreat aluminum potassium sulfate with tannin as well. | See more. |
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Q & A: Round Up of Scouring + Mordanting 101
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