The Bio-Based Pigments Behind Formwork IO’s Carbon Negative Paving Block
Our environmentally friendly construction goals necessitated pigments and dyes that were renewable, non-toxic, biodegradable and locally sourced. We experimented with a wide range of sustainable and carbon neutral pigments, before settling on our final palette. With the advent of interesting new bio-colourants, we narrowed our selection down to three exquisite pigments — green algae, coffee and indigo.
Choosing Sustainable and Natural Colours
The toxicity of synthetic dyes has become a cause of grave concern to environmentalists. Construction products, which are often a complex mixture and contain additives, pigments, and stabilisation agents are often in contact with rain or seepage water during their lifetime and may release potentially harmful compounds by leaching.
Studies demonstrate that compounds released by construction products are found in storm water and other bodies of water and that the release of biocides in urban areas can be comparable to the input of pesticides from agricultural uses. It’s undeniable — synthetic dyes have an adverse effect on all forms of life, and to ensure our carbon negative paving block didn’t have the same drawbacks as a product, we dove into research on the available bio-ethical and environmentally friendly alternatives.
A Sustainable Palette: The Parameters
Renewable: Spirulina is a renewable resource that can be cultivated in waste waters, making it a sustainable alternative to synthetic pigments. Additionally, spirulina cultivation can help purify the water by removing nutrients and pollutants.
Local sourcing: Spirulina can be sourced locally or abroad, depending on availability. This can help reduce transportation costs and promote local production.
High stability: Spirulina pigment has high stability and resistance to UV light and weathering, making it suitable for use in outdoor applications like bricks.
Coffee grounds are a natural and renewable resource that can be locally sourced, giving us the opportunity to work with local communities and support sustainable practices. Using coffee grounds as a pigment is an eco-friendly alternative to synthetic pigments, helping reduce waste and promote sustainability. In addition to being environmentally friendly, coffee grounds are also cost-effective. As a byproduct of the coffee industry, they are readily available and often discarded after use. This makes them an affordable pigment that can help reduce production costs.
Indigo: Indigo is a timeless colourant from classic blue jeans to Japanese Indigo Shibori. Natural indigo dye comes from the Indigofera plant (or Isatis tinctoria) and has long been used by ancient civilisations from India, East Asia, Mesopotamia to Mesoamerica. In addition, dark blue tones are also suitable for permanent/exterior spaces that are impacted by sunlight, rain and wear and tear.
The indigofera species is found all over the world. The dye is obtained by processing the plants’ leaves. The leaves are first soaked in water and fermented in order to convert the glycoside indicant which is naturally present in the plant into the blue dye idigotin. The Romans used indigo as a pigment in painting, for medicine and cosmetics. It was a luxury item that was imported from India into the Mediterranean by Arab merchants. Today, indigo is also produced synthetically and available in various shades.
The three natural colourants — green algae, coffee and indigo — met our sustainability criteria, but also created a contemporary palette that demonstrated the versatility and aesthetic potential of Formwork IO’s carbon negative paving block.