Dye Project: Multiple Lichens (Heat Extraction)

For this project, I'm dyeing with an unknown mix of multiple lichens that I harvested on our property in 2020 and kept in the freezer. Lichens are a composite of algae or cyanobacteria living among fungi species (with yeast being a possible third partner). They live together in a mutualistic relationship. Lichens can produce brilliant dyes in many shades, depending on the fiber or fabric and the dye method used. Dye methods include fermenting in ammonia, boiling in water, and photo-oxidizing. 

Lichen mixture from our property

Since the type or mix of lichens is unknown, I'm not sure what color to expect, if any. However, looking back at my research notes at the time, possible lichen types may include:

• Common greenshield lichen (Flavoparmelia caperata) - produces earthy tones ranging from lemon yellow, gold, and butterscotch to warm orange-brown, tan, and dark brown using the boiling method.

• Oakmoss lichen (Evernia prunastri) - produces yellow, tan, or bronze using the boiling method. 

The lichen may produce a nice earthy brown color, or may not produce any color at all. But, it will free up some freezer space!

Lichen is a composite organism of fungi and algae

Key Supplies

I'm using my usual dye equipment, including a convection burner, a non-reactive stainless steel dye pot, candy thermometer, strainer, cheese cloth, various plastic pails and containers for soaking and rinsing, a digital kitchen scale, stir stick, a mild pH-neutral soap (such as Synthropol or Professional Textile Detergent), rubber gloves, and a face mask. Additional supplies and equipment:

• Lichen: I collected the lichen from all over our yard about six and a half years ago and froze it. At the time we had many types of lichen in our landscape, so the collection is a hodge-podge.

• pH test strips: to test how acidic or alkaline the dye bath is.

• Fabric: 100% protein fibers like wool or silk (as with dyeing with mushrooms, protein fibers respond better than cellulose). I'm using a silk scarf and a silk/wool blend scarf from Dharma Trading, both of which have been scoured and mordanted with alum. For details, see Dye Project: Preparing Protein Fabric (Scour &  Mordant). Note that you do not need to mordant fabric or fiber when dyeing with lichen, since lichens produce light and colorfast dyes. 

• The silk scarf weighs 1 ounce or 28 grams.

• The silk/wool blend scarf weighs .7 ounces or 20 grams.

• pH Modifiers: Use modifiers to make the dye bath more acidic or alkaline, and change the color outcome. I plan to add some white vinegar as a modifier for this project (in addition to the alum pre-mordant the scarves received). 

Collecting the Lichen

Lichen is very slow-growing, so collect it responsibly. It is typically considered ethical to gather lichen that has been dislodged from its habitat, unless other restrictions apply. Only collect lichen that has fallen naturally from trees or rocks to protect the ecosystem, and only collect what you need.

A collection of lichen from our yard, gathered in 2020

Dyeing the Fabric

 Dyeing fabric with lichen is very similar to dyeing with plants or mushrooms. Bring the dye bath to a simmer, pre-soak the silk or wool fabric or fiber in warm water, add the fabric to the dye pot, and simmer. As with mushrooms, one caveat when working with protein fiber is to make sure the temperature difference is very similar when going from one pot to another.

As with mushrooms, delayed rinsing improves color and light fastness. Casselman recommends that with lichen-dyed fibers, it is essential to cool the yarn before rinsing. Lichen-dyed fibers are more color and light fast if they are not rinsed for at least 24 hours; this stabilizes the dye and prevents after-dye runoff. She describes her technique for delaying rinsing in Lichen Dyes: The New Source Book (see "Dye Bath", page 27):

... first leave the fiber in the ammonia or boiled water dye bath to cool for 24 hours. Then, remove the fiber, place it in a colander over a pail and leave it another 24 hours. (What you collect can be reused.) After two days, rinse the fiber (which may be completely dry) in cold water. Even with dark colors, there will be very little dye run off, and your reward is improved fastness.

To prepare the dye bath, rinse the lichen to clean it and place it in a clean non-reactive pot. Cover the lichen with water and soak it overnight (24-36 hours). After 24 hours, I tested the lichen water and the pH registered 5 (moderately acid).

Cover the lichen with water and soak overnight

Add a splash of vinegar to the lichen and water in the non-reactive pot. I decided to add 1/4 cup of vinegar after watching the Wolf lichen video posted by Myra Made Color. In the video, Dorothy Beebee made the comment that when the dye bath registers pH 4, the acid releases pigment. I'm not sure if this is a universal principal or just true for Wolf lichen, but it seemed to be the case with the lichen fermentation project (see Dye Project: Lace Lichen (Fermentation). After adding the vinegar, I tested the lichen water and the pH registered between 3 and 4 (moderately acid).

Bring the temperature of the dye bath to 150 to 180 °F. This typically takes about 30-60 minutes. I followed Casselman's recommendation to bring the temperature to a maximum of 180 °F (82 °C), and maintain the temperature for 10 minutes. Then, reduce the temperature to 160 °F (70 °C) and continue to heat gently for one hour, without boiling. While the dye bath is coming to temperature, pre-soak your wool or silk in warm water. This improves how the fabric takes up the dye.

Pre-soak the fabric in warm water

Add the fabric to the simmering dye pot and stir to distribute evenly. I decided not to strain out the lichen for this project. Casselman describes cooking the fabric right in with the lichen for more color, as does Dorothy Beebee, so I'm  going to give that a try. Add more water to cover the fabric if necessary. This will not dilute the dye; it just ensures better distribution of the dye to the fabric. Let simmer for about an hour, keeping the temperature between 150 to 180 °F. I tried to keep it at 160 degrees °F.

The lichen has dropped to the bottom of the pot leaving an interesting shade of brown dye

Scarves simmering in the dye pot

Remove the dye pot from the heat, and use the delayed rinsing technique recommended by Casselman in Lichen Dyes: The New Source Book. Leave the fiber in the dye bath to cool for 24 hours. Then, remove the fiber, place it in a colander over a pail and leave it another 24 hours. Any dye you collect can be reused.

Letting the dye set (heat extracted lichen dye bath)

After two days, rinse the fiber (which may be completely dry) in cold water. I ran the fabric through the washing machine to rinse, using cold water and no detergent. Note that the many bits of lichen washed away nicely. Hang to dry.

Two weeks later, wash with a mild pH-neutral soap, such as Synthropol or Professional Textile Detergent, to wash out any unbound dye. Air dry out of direct sunlight. The resulting color is a lovely honey gold.

The Results

The final result of dyeing with our unknown lichen was a lovely honey gold (or butterscotch). The color appears darker when the fabric is wet, but is still pleasing as the silk and silk/wool blend fabric dries.

Left: unknown lichen mix (heat extract, acidic dye bath, silk/wool blend)
Right: unknown lichen mix (heat extract, acidic dye bath, silk)

Even though the dye liquor looks a bit like dirty dish water, I decided to store the unused dye for a future dye project. I filtered out the lichen pieces and discarded them, and labeled the jars for future use.

Filter out the lichen pieces from the dye liquor

Store the dye liquor for future projects

Learn More

• Byrd, Margaret. "How to Make Natural Dyes with Lichen". Color Quest, December 9, 2022. Good overview, which includes information about the fermentation and boiling water methods, as well as a photo-oxidized method (ammonia bath, color emerges when fiber is removed from the bath). https://www.youtube.com/watch?v=VaYI7U7ZHEU

• Casselman, Karen Diadick. Lichen Dyes: The New Source Book (Dover Publications, 2001). Second edition of the original, published by Studio Vista Publications, 1996. This slim book is packed with information (see Lichen Dyes: The New Source Book).

• "How to Make a Natural Dye Using Lichens". Myra Made Color (June 4, 2022). Myra uses Wolf lichen (Letharia vulpina) to dye 100% wool, no mordant, using the water boil dye process. BeeBee made an interesting comment that when the dye bath registers pH 4, the acid releases pigment. I'm not sure if this is a universal principal or just true for Wolf lichen, but worth exploring. https://youtu.be/RUUeAX4D1uE

• McDonnel, Zoe. "Introduction to Dyeing with Lichens", Wildcraft Dyeing (June 28, 2021). Lichens and what you need to know to get started on natural dyeing with lichens. McDonnel discusses the two types of dyeing (boiled water method and ammonia/fermentation method). https://www.youtube.com/watch?v=B8KfXIIUB_M