Fiber Preparation and Mordanting - #NDEP Instructions
Fiber Preparation and Mordanting
Mordanting prepares the fibers to bond with natural dyes. We recommend using aluminum potassium sulfate (alum) as a mordant as it is considered non-toxic and you can obtain the full spectrum of colors using only alum along with a few color changers and additions to the dye pot. Scour your fibers using the procedure below if they are dirty or feel oily. We recommend that you scour all cellulose as it contains waxes that may impede the takeup of mordant and dyes.
- Weigh the dry fiber and record the weight. This is the weight of fiber, or wof.
- SCOURING WOOL or PROTEIN FIBERS: Scour fiber using 5% Orvus paste on wof. For very greasy wool or mohair, add 0.5% soda ash to the scouring water. Bring the temperature to 200°F (for wool and alpaca) or 180°F for silk. Hold at this temperature for 30-45 minutes, then rinse fiber in very hot water, spin out excess water and proceed to mordanting.
- MORDANTING WOOL or PROTEIN FIBERS: Mordant the fiber with 15-20% aluminum potassium sulfate (alum). Cream of Tartar at 6% is optional and will brighten red and yellow dye colors as well as keep wool soft. Bring to 200°F and hold for 45 minutes. Spin out excess water. Once the fiber is cool, rinse carefully and extract excess water.
- SCOURING CELLULOSE FIBERS: Scour fiber using 5.5% cellulose scour and 2% soda ash. Bring the temperature to 180° Hold at this temperature for 30-45 minutes, then rinse fiber in hot water, spin out excess water and proceed to mordanting.
- MORDANTING CELLULOSE FIBERS: Mordant the fiber with 5%-10% aluminum acetate at 100°F (you can use very hot tap water). Hold at this temperature for 45 minutes. Remove goods and air or machine dry them. Then prepare a bath of 5% calcium carbonate in enough room temperature water to easily hold the goods. Immerse the fabric or yarn in this bath for 30 minutes, then proceed to dyeing.
How much extract to use
These formulas use the percentage method of weighing the dyestuffs. For example to weigh out a medium shade of red for Madder, multiply the weight of your dry fiber (weight of goods) by the percentage. So if my fiber weighs 250 grams, I would weigh out 7.5 grams of madder powder (3%) and dissolve it in boiling water.
| Name of Extract | Light | Medium | Dark | Notes |
|---|---|---|---|---|
| Cutch | 2-6% | 7-14% | 15-20% | Cutch loves oxygen. For deepest shades, mix and let sit overnight and then let goods simmer for 2 hours. Soda Ash at 1% and/or 1% concentrated hydrogen peroxide will redden and deepen the color if it is golden brown. |
| Fustic Liquid Extract | 1-2% | 4% | 5-10% | |
| Lac | 1-3% | 4-6% | 7-10% | Use 3% citric acid dissolved with the lac powder, let sit and strain off the clear red lac liquid, leaving the fine sediment behind |
| Logwood Purple | 0.25-0.5% | 0.75-1.5% | 1.75-2.5% | |
| Madder | 0.5-2% | 3% | 4-8% | Calcium carbonate@1% brings out the deep red color of madder |
|
Myrobalan
|
3%
|
4-6%
|
10-12%
|
|
|
Pomegranate
|
1-3%
|
4-6%
|
7-10%
|
|
| Quebracho Rojo | 1-2% | 3-6% | 7-15% | |
| Quebracho Moreno | 1-2% | 3-6% | 7-15% | |
| Himalayan Rhubarb | 1-2% | 3-6% | 7-10% | Stir well to dissolve powder fully. |
| Walnut Hull Powder | 5-10% | 11-50% | 50%-100% | This is a powdered raw dye, not an extract and a larger percentage of dye material is used. At the highest percentages, it is possible to reuse the sediment and get additional lighter colored dye baths. |
| Weld | 0.25-0.75% | 1-2% | 3% | Calcium carbonate@1% brings out the bright yellow color of weld |
DISSOLVING DYES
Make a paste using warm water and wet out the powder. Gradually add boiling water, stirring to dissolve. Some of the dyes will get quite sticky (cutch and Quebracho) during this process. You can let both of these dyes sit for several hours or overnight and they should then be dissolved.
ADD DYES and FIBER TO THE DYE POT
Measure out the amount of water according to the ratio below. Add dissolved dyes and stir well. Add wetted out mordanted fiber. At this point, the fiber, dye and water are all in the dye pot at room temperature. Begin heating the water and bring to about 90°F, rotating the goods regularly but carefully if you have wool yarns. Too much agitation may cause felting or shrinkage. Hold at this warm temperature for 30 minutes, and bring the temperature up gradually to 180°F, rotating regularly. Hold at 180°F for 30-45 minutes rotating regularly.
LETTING DYES COOL IN THE DYE POT
This is largely a preference for dyers and is based on the fact that some dyes will continue to strike during cool down, but other dyes may shift color a bit during this process. You may want to experiment to see if you get deeper color with a dye pot cool down. Otherwise remove the goods, extract the excess hot dye water and begin the rinse process.
RINSING
Using the same temperature water as your fibers, rinse the dyed goods once or twice to remove excess dye, then wash gently in a neutral liquid soap. Dry away from direct sunlight.
DISPOSING OF DYES
Any exhaust baths with dye left in them may be used to dye additional materials but these exhaust colors may be difficult to reproduce. I often have extra small skeins of wool yarn that are mordanted and throw those into the exhaust baths. Dispose of the used dye baths in accordance with your local municipal guidelines. Most utilities require that the temperature is cool and the pH of the dyebath is neutral. You can adjust pH with either white vinegar or soda ash.
