Harvesting with Color

This book is for the gatherer, the gardener, and the dye maker all rolled up into one. Harvesting Color: How to Find Plants and Make Natural Dyes was written by Rebecca Burgess, and published by Artisan (New York, 2011). It is filled with information about the basics of dyeing fiber, and obtaining dyestuff either through growing or gathering it yourself.

Part One  provides information for getting started, including materials, tools of the trade, and master dye recipes. Part Two walks through the seasons showing plant material the can be gathered through the four seasons of summer, fall, winter, and spring. Pictures of plant material are frequently juxtaposed with pictures of dyed wool or fabric in stunning colors. The Appendix provides an extensive resource guide, including these West Coast sources for scouring agents, mordants, and dyes:

• Washington:
• Botanical Colors: http://botanicalcolors.com
• Earthues: www.earthues.com
• British Columbia:
• Maiwa: www.maiwa.com

This book is full of inspirational ideas, recipes, and examples. I appreciated Burgess's emphasis on finding and growing dye sources locally, and her environmental concerns about the dyeing and clothing industries.  

Knowing the Spring

After weeks (or was it months) of rain storms here in the San Francisco Bay Areas, we finally had a break in the storm pattern. The temperature soared to the mid-seventies. Everyone erupted from their homes to squint in wonder at the sunny skies.  In the East Bay, my aunt and I met for lunch and walked to the restaurant, enjoying the signs of spring all around us. Lawns and the surrounding hills were green from all the rain. Flower gardens were perking up.

Knowing the Spring at Bishop Lake

Meanwhile out in San Ramon, Bishop Lake is attracting the spring flocks of geese, ducks, swans and herons (some local, others migratory). They are seeking food, mates and a safe place to roost. The landscape is green and the architectural plantings from the fall are now deeply rooted and perking up with the sun. Flowering trees are putting on their show of white, pink or yellow blooms. Ceanothus is blooming  along the roads and highways in deep blue. It's a time for Knowing the Spring wherever you are in the Bay Area,

Mordants and Fixatives

Mordants and fixatives help bond dye to fiber, and improve the color-fastness of the dye. Without mordants, most natural plant dyes fade quickly. We touched on mordants and fixatives a bit in Tooling Up to Dye and Equipment for Dyeing with Plants, now I'd like to reinforce some of these ideas.

Techniques for mordanting protein-based and plant-based fibers differ. Protein-based fiber requires metal mordants in order for dye to chemically bond to the fiber. Protein-based fabric includes wool, angora, silk and so forth. Metal mordants include iron, copper, chrome, tin, and alum (often used with cream of tarter as a brightener). Some of the metal mordants are toxic, so must be handled and disposed of carefully.

Metal mordants for protein-based fibers

Plant-based fiber can use mordants such as tannins, soda, salt, vinegar, and ammonia, as well as the metal alum. Tannins are often naturally-occurring in plant dye source, such as in black walnut hulls, sumac, and oak galls. Most of these mordants can be purchased at the grocery store, others, like dried, ground oak galls can be found at specialty stores. So far I have only dyed with plant-based fabric, so I'm focusing on their mordants. They are not toxic like metal-based mordants but some can be caustic so should still be used with care.

Mordants for plant-based fibers

Weigh the Fabric

In either case, you need know the weight of your fabric, so you can calculate the quantity of mordant to use. In my case, I'm dyeing white cotton dish towels, which weigh about 77 grams (2.25 ounces) each. Recipes frequently state the mordant ingredient as a percentage (% WOF, or weight of fabric). For example, if the recipe calls for 100% WOF, and you are processing 100 grams of fabric, you need 100 grams of alum for the mordant. If the recipe calls for 50% WOF, you would need 50 grams of alum to mordant your 100 grams of fabric. 

Weight of Fabric * (% WOF) = Weight of Mordant 

100 grams fabric * (100% of 100g) = 100 grams of alum

100 grams fabric * (50% of 100g) = 50 grams of alum

Wash and Scour the Fabric

Always wash the fabric to prepare it for dyeing. Even sparkling white cotton fabric may have a coating applied, which could prevent dye from bonding with the fiber. Some books recommend that you "scour" the fabric before you wash it to remove any wax, finish, or sizing. Sasha Duerr, in The Handbook of Natural Plant Dyes, recommends using a mixture of 2 tablespoons neutral detergent (like Dawn dish washing detergent) plus 1 tablespoon washing soda (like Borax, soda wash, or soda crystals) to remove these impurities. Simmer the fabric in the mixture for about an hour, then rinse, wash, and air dry.

Wash and scour fabric to remove impurities that prevent the dye from bonding to the fiber

Mordant the Fabric

Once you've scoured and washed your fabric, you're ready to mordant. The basic process for mordanting fiber is: 

1. Add the mordant to boiling water.
2. Add the fabric and simmer for about an hour.
3. Remove the pan from the heat and let the water cool. 
4. Remove the fabric and squeeze gently.
5. Use immediately, or air dry and label for future use.

Fabric simmering in a salt mordant bath

Following are a couple of mordant recipes for plant-based projects, condensed from Duerr's book. You can find alum and ground tannin through suppliers such as Amazon, MAIWA, and Dharma Trading Company.

Ingredients	Steps
Basic Tannin Mordant 113g fiber (4 ounces) 1 teaspoon (1 ounce) powdered oak galls	Soak fabric overnight in cool water. Dissolve oak gall powder in 4-6 gallons of water. Simmer tannin water for 30-60 minutes, then let cool. Move fabric from soaking water to tannin water and let steep for up to 24 hours. Remove fabric, rinse in lukewarm to cool water, then wash in a pH neutral soap, rinse thoroughly, and hang to dry.
Alum Mordant with Tannin-Treated Fiber 113g fiber (4 ounces) 20% WOF alum (4 teaspoons) 6% WOF washing soda (1.5 teaspoons)	Follow basic tannin recipe above to prepare fabric. Dissolve the alum and washing soda in a large pot that is half full of water. Add the tannin-treated fabric and add water to cover. Heat the solution to 82 degrees C. (180 degrees F.), turn off heat, and let fabric steep for 4-8 hours, stirring occasionally so the fiber absorbs mordant evenly. Remove the fabric and squeeze the mordant solution back into the pot (you can reuse it). Wash fabric in a pH-neutral soap, rinse thoroughly, and hang to dry.

Additives

Additives such as vinegar or ammonia can change the pH of the water, and the color of the dye. They can be added to the mordant, or to the dye. I haven't tried adding them to the mordant yet, but have added vinegar and ammonia to separate red cabbage dye batches. I was amazed to see the dye vats turn from from blue to dark blue/purple from the ammonia (base), and from blue to green from the vinegar (acid). It's always fun when art and science converge!

Additives can change the dye results

Search for Dyes: Pehr Löfling

This year we are revisiting our Linnaeus Apostles, who were sent out into the world from the University of Sweden, Uppsala in the 1700s to gather plant specimens, name and classify them using the binomial naming system, and identify plants that could help Sweden be self sufficient. We'll take a look at their efforts, through the lens of textiles and plant dyes, with writer Viveka Hansen, author of Textilia Linnaeana: Global 18th Century Textile Traditions & Trade, as our guide.

Pehr Loffling (1729-1756) spent two years in Portugal and Spain, and then six months in South America, including Venezuela. He died at the age of 27 in South America, due to disease caught during his travels. He was a botanist primarily, and not very interested in textiles, but he did record a few things about plant dyes during his travels.

Loffling described saffron (Crocus sativus) as producing a yellow dye
Illustration from Koehler's Medicinal Plants
(published before 1923 and public domain in the United States)

Loffling headed for Portugal in 1751 and spent two years searching the countryside of Portugal and Spain for plants. His letters to his sponsor, Eric Gustaf Lidbeck at Lund, and professor, Carl Linnaeus, describe the familiar dye plants, dyer's weld (Reseda luteola),  and buckthorn (Rhamnus tinctoria). He also mentions alder bark which produces brown dye, and saffron (Crocus sativus) which produces an expensive yellow dye.

His letters also indicate that he knew about the harvest of cochineal lice that lived on cactus and was used to create a red dye. The cochineal insects, Dactylopius coccus, were harvested on plantations in South America, dried in the sun, and then exported to Spain.

Loffling headed for South America in 1754.  His letters to his sponsor mention Indigo (Indigoferra) which produces blue dye, but he does not indicate whether the source was wild or cultivated. He also wrote about other exports from South America, including Dyer's broom (Genista tinctoria) used to produce a yellow dye, and Brazilwood (Caesalpinia gilliesii) used to produce shades of red, as well as yellow-wood, and sandalwood (Santalum album). Importing South American dye materials from Spain was very expensive, and Loffling recommended that Spanish-owned plantations in South America export to Spain.

Loffling was ill for most of his time in South America, but he reported that he had collected 550-600 distinct species during his travels. He succumbed to disease after six months in South America, and his plant collection was destroyed in a natural disaster. Sill his letters provide information and insight about the dye plants available in Portugal, Spain, and South America.

Learn More

Textilia Linnaeana: Global 18th Century Textile Traditions & Trade by Viveka Hansen, fifth volume in the Mundus Linnae Series, issued by the IK Foundation & Company (London 2017). See pages 61-64.