Plant-based pigments as a sustainable alternative to textile dyes, don’t work as much as we would have hoped for. A conversation with designer Laura Luchtman
Innovating textile dyeing: plant-based pigments aren’t sustainable enough
The dyeing process takes several different steps. First, the pre-treatment, a process for prior fabric dyeing involving scouring and bleaching to produce white fabrics by destroying the colorings matter with minimum degradation of the fiber. After that, the fabric enters the dyeing process. The dyes from aqueous solution absorb into the surface of the fabric or else the particles are diffused into the fibers.
After the fibers are dyed, they get post-treated to ensure the color stays on the fabric. Usual dying processes require boiling temperatures, huge amounts of energy and water. A segment of the industry that alone generates up to ten percent of global CO2 emissions.
More ‘sustainable’ practices have proven to be just faint countermeasures to traditional methods. Pigments extracted from plants have their own limitations, such as instability against light and heat.
Pigments extracted from plants have their own limitations
The main disadvantage is that due to their low water solubility, plant pigments still require large amounts of water, chemical fixing agents, and huge amounts of raw material to extract very little amount of pigment. Designers Laura Luchtman and Ilfa Siebenhaar, in a six years span where they conducted a series of experiments, discovered the potentialities of micro-organisms such as bacteria, for the production of pigment.
Their project falls into the category of bio design, a cross-pollination of nature, science and design, where living organisms are an integral part of the designing process. ‘Living Colour’ started in 2016 in collaboration with Hogeschool Rotterdam University of Applied Sciences. Each week they learned new tools, software and skills to investigate how the textile and fashion industry can benefit from new technologies, processes, and business models. Throughout their investigation they studied the bacteria’s optimal growth conditions for pigment production, their ways to speed up the growth process and the possibilities of growing bacteria in patterns by subjecting them to sound frequencies.
Pigment producing bacteria for textile dyeing
Why bacteria? Certain species have the ability to produce colorful molecules like carotenoids and violacein. As opposed to regular dyes, these colors are biodegradable. They also have many clinical properties: they are anti-oxidant, anti-cancer, anti-biotic, antiviral and antibacterial.
Lampoon interviewed designer Laura Luchtman to understand more about the project ‘Living Color’ and the experiments they have conducted. «Me and Ilfa had a connection and the same idea about the industry. Ilfa was already thinking about working with mycelia, mushroom roots, and bacteria when we met. I didn’t know anything about these microorganisms, and I didn’t even know that you could see them with your naked eye and not just under a microscope. Without a scientific background, we needed help from scientists to help with the extraction methods. Starting a collaboration with the Rotterdam University of Applied Scientists, we worked in their labs together with students and teachers».
The experimental phase: microorganisms are fed nutrients to secrete colors
Only aerobic bacteria are pigmented. In general, pigment production depends on factors like light, pH, temperature, and nutritional growth medium. The designers created their own process by skipping a lot of steps of traditional dyeing. They used untreated fabric, placed it in a liquid or solid nutrient medium with the bacteria and then they let it grow for three or four days under room temperatures. The amount of water they required was very little, the one needed for the bacteria in order to multiply, absorb the nutrient and secrete the pigment. In that sense, much less energy and resources are involved. After dyeing, the fabric doesn’t need post-treatment.
«We only use naturally occurring bacteria», explained Luchtman; «they are not genetically modified. They live in the soil, in the roots of plants, in water. The bacteria that we use to extract purple pigments from can be found on the back of animals, like the salamander. It protects it from fungi infection. The yellow one lives on the human skin. Each of these bacteria produce their own color. There are different strains and different types and they all have their own conditions in which they like to grow: temperature, aliments, incubation period, some take 3 to 4 days, others take several weeks».
Laura Luchtman: How and why the bacteria produce the pigment
Not every bacteria produces pigment, most don’t. How and why the bacteria produce the pigment is not completely known yet. It is part of their metabolism of nutrients, engaging on this activity to protect themselves against UV infrareds, other bacteria, other fungi or just to prolong their life cycle and to survive their living conditions. It doesn’t happen like flowers or plants, that they use colors to attract other living organisms, it’s the other way around.
According to the ‘Living Color’ report
Purple pigment comes from Janthinobacterium lividum, a soil-dwelling bacteria which produces various shades of purple pigments called violacein. The optimum growth temperature is a comfortable 25°C. Red is from Arthrobacter agilis which produces a pigment going from pink to red called carotenoid. It can fight hexavalent chromium, ironically used in the textile dyes and can cause severe irritation to humans.
It can also reverse the effect of agricultural pesticides in the ground. This species prefers temperatures between 25 to 30°C. Lastly, yellow pigment comes from Micrococcus luteus, found in places such as the human skin, water, dust and soil. This pigment has the ability to absorb UV radiation that no current sunscreen can block. It requires 37°C.
The cymatics research: sound to stimulate pigment production
«We found out that sound frequencies create geometrical patterns in solid and liquid matter. We wanted to grow the bacteria into patterns» told Luchtman.
They are cultivated on the textile, where they keep growing. They leave natural growth patterns, expanding towards where there’s more nutrients and more oxygen. The cymatics research gave back unexpected results: «We put the bacteria into small petri dishes with food and a piece of textile measuring 9 cm diameter, placed them on top of speakers, each one with a different frequency, going from very low to high. A plastic membrane is placed over the speaker to protect it, filled with a small layer of water, cornstarch, ink and turmeric. After three days, we expected to see patterns; instead, we found solid color and no patterns at all».
Sound can move through air, liquids and solids. These sound waves create visible and invisible patterns. Vibration of sound frequencies causes Faraway waves that form patterns in liquids. On solid resonating surfaces, these sound waves can be visible by the use of particles and powders called Chladni figures.
All bacteria behaved the same
A further evaluation with scientists about color, evenly spread onto the piece of cloth, clarified that all bacteria behaved the same. The result was given by the movement of the sound frequencies, which spread oxygen and food evenly so the textile was dyed plainly.
The performance of bacteria is tested on different types of textiles. They can equally dye materials from natural or synthetic fibers to fiber blends. The structure of the fabric affects the attachment of the color for the way it was knitted or woven. «We can mostly dye any fabric. Sometimes the color is lighter and other times it is really intense. On some synthetic fibers it is almost neon».
Organic silk and deadstock fabric
Luchtman explained their favorite material to work with is organic silk and deadstock fabric. They want to avoid using new fabrics. It doesn’t really matter what material you use: the bacteria perform equally, while the color payoff may differ. It’s about nuances and shades. After working with these microorganisms, the pieces are put in the autoclave at 121°C for 5-10 minutes to kill the bacteria. This procedure leaves the color intact.
«We challenge the industry to make these bacterial pigments into dry dyes, offering a countermeasure to the excessive use of water and toxic chemicals involved in the current textile dyeing processing».
Laura Luchtman
Textile and Surface Designer and studio owner at Kukka. She teamed up with fashion designer Ilfa Siebenhaar in the ‘Living Colour’ project, exploring the possibilities of natural textile dyeing with bacteria that produce pigment.
