Dye Project: Preparing your Fabric (Scour, Mordant, Brighten or Sadden)

I like to have a batch of prepared cotton fabric on hand, so that I am ready to dye when I come across an interesting dye source. The process involves scouring the fabric to remove impurities, mordanting fabric so the dye bonds with it, and brightening the fabric to intensify color and improve staying power. (You could sadden the fabric instead to subdue the color).

I've covered all these processes in previous posts, but am summarizing the basic steps here. You can follow the links to the original posts for details. These are my standard processes, but I deviate frequently to try new things! 

These instructions are for plant-based fabrics, typically in one pound batches. For safety:

• Wear a face mask when measuring and working with powders, so you don't inhale small particles.
• Wear gloves when working with soda ash, which is caustic!
• Work outside or in a well ventilated space.
• Do not use your dye pots, buckets, or utensils for food preparation.

Prepared fabric - hanging to dry

Scouring (Soaking Method, Textile Detergent + Soda Ash)

Purpose: Scour fabric to remove impurities that may compromise dye results. These instructions are for the soaking method, which is to soak the fabric overnight in boiling water and scouring agents. Use textile detergent (such as Synthrapol or Professional Textile Detergent) and soda ash for the scouring agents.

The basic process for this step:

1. Prewash the fabric in the washing machine, using textile detergent. 
2. Soak the fabric overnight in boiled water and scouring agents. 
3. Rinse the fabric in cold water, then wash in the washing machine.

For scouring a pound of fabric:

• 1 teaspoon textile detergent 
• 4 teaspoons soda ash (caustic, so use gloves)

Scouring - the brown indicates impurities are being removed from the fiber

Scour the fabric:

1. Pre-wash the fabric in the washing machine using 1 teaspoon of textile detergent. You can hang to dry and use later, or use the damp fabric in the next steps.
2. In a large bucket, add textile detergent and soda ash to three gallons of boiling water and stir to mix.
3. Add fabric to the bucket and soak overnight. Stir periodically to rotate the fabric. After about half an hour, the water starts turning brown with impurities.
4. The next day, rinse the fabric in cold water, and squeeze out excess water. Wash the fabric in the washing machine (cold water, no detergent). Optionally add an extra rinse cycle.
5. At this point you can immerse the wet fabric into your mordant, brightener, or dye bath; or you can air-dry the fabric and store it until needed. Label it so you know how it was scoured. 

Details: Scouring Fabric (Soaking Method)

Mordanting (Oak Gall Extract)

Purpose: Mordants help bind dye to fiber and improve color fastness. I like to use ground oak gallnut extract as a mordant for cotton fabric. Gallnut is a clear tannin and made from ground oak galls. The mordant works best if the tannin bath temperature does not exceed 180 degrees F (or 82 degrees C). You can skip this process if the dye material is rich in tannins, such as walnut, onion skins, indigo, and rhubarb. 

The basic process for this step:

1. Simmer the gallnut in water.
2. Add fabric and soak.
3. Rinse the fabric in cold water.

Maiwa recommends the following Weight of Fabric % for gallnut:

• 12% WOF for Gallnut powder
• 6-8% WOF for Gallnut Extract

For just over a pound of fabric, use:

• 3 tablespoons powdered oak gall extract
• 2-4 gallons of water

Mordanting - soaking the pre-washed and scoured fabric in oak gall extract

Mordant the scoured fabric:

1. (Optional) Presoak the scoured fabric in water for about 30 minutes, if it is not already wet. This helps ensure even distribution of the tannin solution.
2. Stir the gallnut extract into a pot of water to dissolve.
3. Bring the tannin solution to a simmer and then simmer for 30-60 minutes, making sure to not exceed 180 degrees F (or 82 degrees C).
4. Remove the tannin pot from the heat and let cool.
5. Add the scoured fabric to the tannin pot.
6. Steep the fabric in the tannin solution for 8-24 hours.
7. The next day, rinse the fabric thoroughly in cold water, and squeeze out excess water. Wash the fabric in the washing machine (cold water, no detergent). Optionally add an extra rinse cycle.
8. At this point, you can immerse the wet fabric into your brightener or dye bath, or you can air-dry the fabric and store until needed. Label it so you know how it was scoured and mordanted.

Details: Mordanting Fabric (Oak Gall Extract)

Brightening (Alum + Soda Ash)

Purpose: Use a combination of alum and soda ash to mordant and brighten fabric. Even if the fabric was previously mordanted with oak gallnut, you may want to mordant fabric multiple times in different ways to intensify the color or improve colorfastness.

For this technique, you do not need to “cook” the fiber. You can start with hot tap water (between 120-and-140 degrees Fahrenheit, or 48-and-60 degrees Celsius), and let it cool naturally. It is not necessary to reheat the bath to maintain temperature.

The basic process for this step:

1. Mix alum and soda ash in hot water. 
2. Add fabric and soak. 
3. Rinse and air dry the fabric 

Maiwa recommends the following Weight of Fabric % for the brightener:

• 15% WOF for Alum
• 2% WOF for Soda Ash

For just over a pound of fabric, use:

• 1/4 cup of Alum (67.2 grams)
• 1 3/4 teaspoons Soda Ash (8.96 grams)
• 2-4 gallons of water (I typically use about 3 gallons)

Brightening - soak the scoured and mordanted fabric in
alum and soda ash for a second mordant.
Saddening - you could soak the fabric in
iron, or ferrous sulfate instead.

Brighten the scoured and mordanted fabric:

1. (Optional) Presoak the scoured and mordanted fabric for about 30 minutes, if it is not already wet. This helps ensure even distribution of the brightening solution.
2. Add the fabric to a bucket or pot. 
3. Dissolve alum in hot water and add to the pot. 
4. Dissolve washing soda in hot water and add to the pot. 
5. Fill the pot with enough hot tap water to cover the fiber. (If you are curious, you can check the temperature with the thermometer). Stir to mix.
6. Steep the fabric in the brightening solution for 1-2 hours, or overnight. Optionally you can cover the pot so that it stays warm longer. After soaking, you can: rinse and re-mordant, for example, at 10% alum; rinse and dye; or air dry to dye later. 
7. Squeeze out excess liquid. Soda ash is caustic so wear rubber gloves. 
8. Wash and rinse fabric thoroughly in the washing machine (cold water, no detergent), and hang to dry.
9. Store fabric until you are ready to dye. According to one source, the alum can weaken the fiber, so it is best to use the fabric within a month to prevent this. Label the fabric so you know how it was scoured, mordanted, and brightened.

Details: Brightening Fabric (Alum + Soda Ash)

Saddening (Iron, or Ferrous Sulfate)

Purpose: Use iron sulfate to mordant and sadden, or darken, fabric. Even if the fabric was previously mordanted with oak gallnut, you may want to mordant fabric multiple times in different ways to modify the color. I don't have any experience using ferrous sulfate to mordant prepared fabric, but have experience using it to change the color of dyed fabric. I am including steps for mordanting with iron here for future use.

Botanical Colors recommends maintaining water at 130 degrees Fahrenheit (or 55 degrees Celsius) for the iron bath. For my solar dyeing experiments, I used tepid water with no heating.

The basic process for this step:

1. Presoak the scoured and mordanted fabric. 
2. Mix ferrous sulfate with water and add fabric.
3. Bring to temperature and then soak. 
4. Rinse and air dry the fabric 

Maiwa recommends the following Weight of Fabric % to sadden the dye bath:

• 2-4% WOF for ferrous sulfate (wear a mask when working with powders)

For just over a pound of fabric, use:

• 1-2 teaspoon of ferrous sulfate (9.08-18.16 grams)
• 2-4 gallons of water (I typically use about 3 gallons)

Sadden the scoured and mordanted fabric:

1. Dissolve ferrous sulfate in a cup of water and add to the dye pot. 
2. Add the fabric to the pot. 
3. Fill the pot with enough water to cover the fabric. Stir to mix.
4. Heat the dye bath to 130 degrees Fahrenheit (or 55 degrees Celsius), stirring often. Hold the temperature for 30 minutes.
5. Remove the dye pot from the heat and let cool.
6. Squeeze out excess liquid. 
7. Wash and rinse thoroughly in the washing machine (cold water, no detergent), and hang to dry.
8. Store fabric until you are ready to dye. Label it so you know how it was scoured, mordanted, and saddened. You can also save the iron bath, and use it to shift fabric color after you have dyed it.

Details:

• Camellia Petals (Batch 2)
• Logwood Exhaust 2 (Alum + Iron)
• Cochineal Exhaust 2 (Alum + Iron)
• Coreopsis & Marigold (Solar + Iron + Exhausts 2 & 3)

Ready to Dye

Once you finish these processes, you are ready to dye. Having a stash of prepared fabric is like having money in the bank that is ready to fund of your creative process!

Prepared fabric that is labeled and ready to dye!