4. BioChromes¶
Research & Exploration of Natural Dyes¶
Context & Inspiration¶
Natural dyeing in Iceland presents unique challenges due to the country’s geographical isolation and limited native plant diversity. As Guðrún Bjarnadóttir explains in her text Plant Dyeing in Iceland, Iceland is home to around 500 species of vascular plants, compared to over 1,300 in Norway and between 4,000–6,000 in Britain and Ireland. This disparity significantly impacts the availability of naturally occurring dye colors.
For example, durable blue dyes are nearly impossible to source locally, and deep reds are rare. Historically, Icelandic dyeing traditions have relied on imported plant species, especially over the past 300 years. This context is important because it shapes what is possible—and what must be innovated—in the Icelandic practice of natural dyeing.
With this in mind, my goal for this assignment was to explore biochromes (biological color sources) using locally available or natural materials, while also adapting to material limitations. This project combines traditional methods with experimental techniques to create natural, sustainable dyes and apply them to various fabrics and fibers.
- Text reference - PLANT DYEING IN ICELAND by Guðrún Bjarnadóttir
Weekly Assignment: Natural Dyeing with Mordants¶
What is a Mordant?¶
A mordant is a substance that helps dye bind to fabric, improving colorfastness and preventing fading. The word “mordant” comes from the Latin mordere, meaning “to bite,” which reflects how the mordant helps the dye “bite” into the fabric fibers.
Common natural mordants include alum (aluminum sulfate), tannins, and iron salts. However, due to limited local availability in Iceland, I used vinegar as a more accessible substitute. Although not a true mordant, vinegar can help open the fabric fibers, making them more receptive to natural dyes.
Ingredients & Materials¶
ingredients
- 500 ml Vinegar
- 500 ml Water
Fabric
- Hemp
- Cotton
- Lycra
yarn
- Cotton 2x
- Hemp
- Jute
- Nylon
- Recycled Cotton
Ribbon
- Silk 2x
- Satin 2x
Fabric Preparation & Mordanting¶
Step 1: Preparing the Fabric¶
Before any dyeing could begin, I carefully sewed the edges of all fabric samples to prevent fraying during the boiling process. This step helps preserve the structure and shape of the fabric while ensuring better dye absorption.
Step 2: Mordanting with Vinegar¶
For the mordanting process, I prepared a solution of vinegar and water and boiled the fabrics in it. After heating, I allowed the fabric to soak overnight, giving it time to fully absorb the solution and become more receptive to the dye. Although not as effective as aluminum salts, vinegar still helped the fabric take on color more evenly and with better vibrancy.
Dye Extraction & Application¶
Red Cabbage Dye¶
Step 1: Preparing the Cabbage¶
I chopped and submerged red cabbage in 1700 ml of water, boiling it for 2 hours to release the pigment. Once softened, I blended it into a smooth paste.
amount
1523.9615g
Step 2: Concentrating the Dye¶
The blended mixture was simmered for an additional 2 hours to intensify the color. After cooling, the dye was ready for filtration.
Step 3: Straining the Dye¶
I filtered the dye twice—first through a coffee filter, then through cheesecloth—to remove solids and create a smooth, clean liquid.
Step 4: Unexpected Reaction¶
ingredients
Part 1: Salt only
100% solution: 425 ml dye + 4 tablespoons salt
50% solution: 212.5 ml dye + 212.5 ml water + 4 tablespoons salt
25% solution: 106.25 ml dye + 318.75 ml water + 4 tablespoons salt
12.5% solution: 53.125 ml dye + 371.875 ml water + 4 tablespoons salt
Part 2: Salt and baking soda
100% solution: 425 ml dye + 4 tablespoons salt + 4 tablespoons baking soda
50% solution: 212.5 ml dye + 212.5 ml water + 4 tablespoons salt + 4 tablespoons baking soda
25% solution: 106.25 ml dye + 318.75 ml water + 4 tablespoons salt + 4 tablespoons baking soda
12.5% solution: 53.125 ml dye + 371.875 ml water + 4 tablespoons salt + 4 tablespoons baking soda
During testing, some fabric samples dyed with red cabbage turned green in the 50% and 12.5% dilution levels. Upon investigation, I discovered this was likely caused by a chemical reaction with the worn Teflon coating of the cooking pot, where the exposed metal affected the dye's pH, altering the final color.
Red Cabbage + Modifiers¶
To test pH responsiveness, I used various modifiers: - Baking Soda – shifts the color to blue-green - Cream of Tartar – slightly lightens and warms the tone - Vinegar – produces a deep magenta or purple hue
This demonstrated red cabbage's versatility as a pH-sensitive natural dye, capable of producing a range of colors from a single source.
Violet Flower Dye¶
Step 1: Flower Collection¶
I picked fresh violet flowers from my garden, making sure they were clean and free from insects. I stored them between damp cheesecloths to preserve freshness until dye extraction.
Step 2: Preparing the Dye Bath¶
I weighed 27 g of flowers and added 300 ml of water to create the dye bath. This ratio was chosen to ensure a rich color.
Step 3: Boiling and Concentration¶
The mixture was boiled for 1.5 hours, reducing the liquid to 129 ml of concentrated dye.
Step 4: Filtering¶
The mixture was filtered using a coffee filter, resulting in a smooth and pigmented solution ready for application.
Dried Lupine Flower Dye¶
Step 1: Powder Preparation¶
I ground dried lupine flowers into a fine powder, ending with 8.7 g of pigment material.
Step 2: Dye Bath Creation¶
I added 200 ml of water and boiled the mixture for 30 minutes to extract the dye.
Step 3: Measuring Yield¶
The result was 48 g of extracted dye, rich in pigment and suitable for fabric testing.
Step 4: Filtering¶
To finish, I filtered the liquid through a coffee filter to remove solids and impurities, leaving behind a smooth dye.
Reflection¶
This project was an in-depth exploration of natural dyeing methods using local and biodegradable materials, adapted to Iceland's unique ecological constraints. From sewing fabric edges to prevent damage during boiling, to using vinegar as a stand-in mordant, every step was carefully planned and executed with sustainability in mind.
Each dye—red cabbage, violet flowers, and dried lupine—offered its own unique set of challenges and surprises, especially when interacting with pH, material types, or cooking surfaces. The unexpected color changes, particularly with red cabbage, highlighted how sensitive natural dyes can be and how equipment choice matters just as much as ingredients.
This assignment demonstrated the potential of using plant-based pigments in a sustainable and creative way, reinforcing the value of traditional knowledge, experimentation, and adaptability. While Iceland may have fewer plant dye resources than neighboring countries, the ability to work with what's available—and find beauty in the limitations—is what makes this kind of work truly rewarding.