Mordant

/ˈmôrdnt/

From the Latin mordere, "to bite".

What is Mordanting?

Mordanting is a process where a dye fixative is used to make a fiber receptive to dyes. There are many methods of mordanting, using different compounds and processes. Here I will be discussing pre-mordanting with Alum. There is as much to learn about mordanting alone, as there is dye plants. Please use this a springboard for your interest and do your own explorations into the subject.

WHY Mordant?

Mordanting is an integral part of the natural dying process, without mordanting dye will not be able to bind to the fiber. Most plants on their own will wash out, fade quickly and often not dye at all. Mordants are used not only to make dyes colorfast but to also enhance and change the color. Alum mordants are used to create clear and bright colors, but depending on the desired affects other mordants can be used to achieve a variation of color from a single dye.

Terms:

Cellulose Fibers - Fibers derived from plants, such as cotton bamboo hemp.

Protein Fibers - Fibers derived from animals, such as silk and wool.

WOF - Weight of Fiber

How to mordant?

You will need to mordant cellulose fibers:

• Bucket or dye bowl

• Cup for dissolving powder

• Hot water

• Fiber ( scoured )

• Scale for weighing fiber and alum

• Alum Acetate 10% WOF (get it here)

• Calcium Carb 5% WOF (get it here)

• Gloves

• Face Mask

• Stir stick/whisk/spoon

While alum is essentially non toxic, it is a caustic fine dust that can irritate your eyes, lungs and skin. Take care and avoid contact. It is also important to keep your tools seperated from your kitchen, and don’t use them interchangeably.

Weigh dry fiber and take note

Wet out fiber by allowing to soak in water for 10-30 min.

Fill dye pot or bucket with hot water (tap is fine, or 110* - 120* F)

Weigh 10% WOF alum acetate

Dissolve alum in boiled water, poor into bucket of water and stir well

wring out fabric and place in mordant bath, taking care to get out air bubbles and wrinkles. you want your fiber to be floating freely in the water.

let soak for 1 hr - 1 day.

in a separate bucket, dissolve calcium carb in boiling water. Remove fabric from mordant bath and place in calcium carb bath. Swoosh around and allow to sit 15-30 min. rinse lightly and head straight to dyeing, or dry and save for up to 6 months.

Mordanting protein fibers:

• Bucket or dye bowl

• Cup for dissolving powder

• Hot water for dissolving mordant, cold water for bath

• Fiber (most silk comes de-gummed and is already scoured)

• Scale for weighing fiber and alum

• Alum Sulfate 10% WOF (get it here)

• Gloves

• Face Mask

• Stir stick/whisk/spoon

This is a cold water method, it takes a little longer but less likely to damage silk fibers. If short on time, you may add 5% cream of tartar and very slowly heat the fibers to a simmer. from there allow to cool and proceed.

Weigh dry fiber and take note

Wet out fiber by allowing to soak in water for 10-30 min.

Fill dye pot or bucket with hot water (tap is fine, or 110* - 120* F)

Weigh 10% WOF alum sulfate

Dissolve alum in boiled water, poor into bucket of water and stir well

wring out fabric and place in mordant bath, taking care to get out air bubbles and wrinkles. you want your fiber to be floating freely in the water.

let soak for overnight, making sure the fabric remains under the solution, otherwise it will result in an uneven mordant affect.

wring out excess liquid and proceed to dyeing, or dry for later use.