Prepping Your Own Fibers: Scouring and Mordanting

I know, you just want to get dyeing don't you? But these steps are crucial to getting the best, brightest, and most even color transfer into the fibers. They take some time but you prep fibers ahead and then store them until you need them–some even believe this 'curing' time boost the colors as well! Just make sure to wet them out before adding it to the dye pot to help with color evenness.

You may ask why the different process for Cellulose and Protein fibers. This is because the structure of the fibers are different so they take color different and therefore need a different prep process to perform to their best abilities.

Also, you should invest in a kitchen scale!

There are many recipes and methods for these processes and the recipes and instructions I have shared here are by no means the only ways to go, but they are what I consistently use in my studio and I have been very satisfied with my results. . Original recipes are sourced from the book The Art and Science of Natural Dyes by Catherine Ellis and Joy Boutrup and and the Botanical Colors 'How-to' section.

Scouring

This step is basically a deep washing of the fibers, to remove any dirt or oils left over from the fields, animals, or milling process to get them to the material state they are in now: cloth, yarn, roving, fleece.

Cellulose Fibers -

Cotton, Linen, anything plant based

Weigh your dry fiber to find weight of fiber (w.o.f.)
Fill a stainless steel pot with warm tap water and add a PH neutral soap at 1% w.o.f., like Dawn, Scour Power, or Synthrapol, and Soda Ash at 1% w.o.f. (if you don't have soda ash skip it!)
Add fibers to the bath and immerse completely.
Increase temp to a low low LOW boil. Maintain for 1-2 hours, moving the fibers around periodically and adding water when needed.
Cool fibers in bath (unless you are going straight to mordanting)
Rinse, rinse, rinse.

Protein Fibers -

Wool, Silk, anything produced by an animal

Weigh your dry fiber to find weight of fiber (w.o.f.)
Fill a stainless steel pot with warm tap water and add a PH neutral soap at 1% w.o.f., like Dawn, Scour Power, or Synthrapol.
Add fibers to the bath and immerse completely.
Increase temp to below a boil, not too high or wool will felt and silk will be damaged. Maintain for 1 hour, moving the fibers around periodically and adding water when needed. Be gentle to avoid felting.
Cool fibers in bath (unless you are going straight to mordanting)
Rinse, rinse, rinse carefully.

Mordanting

Derived from the Latin word morderé, meaning to bite. In natural dyeing fibers must be treated with a metallic salt bath (the mordant) which 'bites' onto the fibers and then in turn bites onto the pigments in the dye bath. Many plants will not transfer their color if no mordant is used so its important. It is really what takes the color on the fiber from a stain to a dye - making it more color and lightfast.

Health tip: When working with Alum wear a mask and gloves. The dry particles can cause irritation to your lungs and in general can irritate the skin. Alum does naturally occur in the body but you don't need the extra that would seep into your skin! Just wear the gloves ok?

Eco tip: Mordant baths can be saved and reused. When using next just add 50% of the necessary alum to mordant the fibers. I have heard a mordant bath can be recharged indefinitely but I toss it when there starts to be little alum floaties in the water. Your call here!

Cellulose Fibers -

Cotton, Linen, anything plant based

With noted weight of fiber (w.o.f.) from before or weigh the dried and scoured fiber.
Fill stainless steel pot with warm tap water. Weigh out Alum Acetate at 8% w.o.f.. Dissolve in cold tap water and stir, it will get sticky but keep stirring until the clumps are all broken up. Add to pot. *Note if you use HOT tap water you do not need to heat the mordant solution.
Immerse wet fibers in bath completely and slowly increase temp to just below a simmer and maintain temp for 1 - 2 hours periodically moving the fibers in bath. This can also be left overnight.
Wearing gloves (too much alum isn't good for your skin) squeeze out excess mordant and proceed to a calcium carbonate/chalk bath.
Mix Calcium Carbonate, used at 5% w.o.f., with boiling water and then add to a bucket or pot.
Immerse fibers treated with Alum Acetate into chalk bath and leave for 30 minutes.
Rinse and dry for storage, rinse again before use. Or rinse really well and go straight into dyeing.
Dry or use immediately for dyeing.

Protein Fibers -

Wool, Silk, anything produced by an animal

With noted weight of fiber (w.o.f.) from before or weigh the dried and scoured fiber.
Fill stainless steel pot with warm tap water and added Potassium Alum Sulfate (often just called Alum) at 15% w.o.f.. Stir until Alum is completely dissolved.
Immerse wet fibers in bath completely and slowly increase temp to just below a simmer and maintain temp for one hour. Periodically gently move fibers in bath.
Cool in pot.
Wearing gloves (too much alum isn't good for your skin) squeeze out excess mordant and rinse off any unattached mordant.
Dry or use immediately for dyeing.
Eco tip: This process can also be done by heating up the water to below simmer and then turning the heat off and allowing the fibers to sit for at least 24 hours.