Since the dawn of mass production and with it the use of synthetic dyes, natural dyeing was increasingly in danger of becoming a long-lost ancient technique. In recent years, as consumers have become much more conscious of the need for environmental protection and a sustainable lifestyle, natural dyeing has seen a resurgence. This has seen it slowly regain its relevance among fashion designers, fabric producers and technologists, dyestuff suppliers and of course, consumers.

Naturally safe and harmless

Natural dyes and colourants are derived from vegetables, animals or minerals, with vegetable dyes being the most numerous group. Humans discovered natural dyeing technology as early as in the New Stone Age.

Without a doubt, dyes are used commonly in textile and leather production but they exist also in several key consumer product categories such as cosmetics, food, candles and paper.

Although natural dyes are generally safe and harmless, their limitation in colour-offering and high fastness properties saw them swiftly lose the ground battle with synthetic dyes. Now as consumers are more acutely aware of the impact and trace their purchased goods leave on the environment, and the harmful effects of synthetic dyes on human health, natural dyes are returning to mainstream production.

Indigo blue or Kamala red

As mentioned above, natural dyes are derived mainly from vegetables, but it is also possible to find dyes and colourants derived from animals or minerals.

Some of the most common colours and colourants for each source are:

• Vegetal:
• Indigo (Blue; Indigofera leaves)
• Kamala (Red; Kamala tree seeds)
• Myrobalan (Yellow, Green, Black; Indian gooseberry fruit)
• Animal:
• Cochineal insect (Red)
• Lac insect (Red, Violet)
• Octopus/cuttlefish (Brown)
• Mineral:
• Iron oxide (Red, Black, Yellow, Brown)

Sustaining the colouring while remaining safe

Natural dyes can be used alone for textile and leather processing but the fastness and shading assessment of the coloured materials often do not yield satisfactory results. To improve the fastness, brilliancy and shading properties, metallic mordants can be applied.

Metallic mordants are metal atoms that attach to the dye to improve the bonding between the dye and its substrate, thereby improving the colourfastness performance. Aluminum potassium sulfate, stannous chloride, ferrous sulfate and copper sulfate are some of the most used mordants.

Fabric or dyestuff suppliers should be cautious in the selection and use of these mordants, as certain metals or its salts are known for being hazardous to the environment and health. They may cause several skin and other diseases including dermatitis, irritation, allergy, skin micro-flora reduction, liver damage, pulmonary congestion and cancer.

An important additional point to consider is that natural dyes could come from animal sources so when promoting or marketing the natural dyes products, it is invalid to claim that the products are vegan unless this has been duly verified.

If you are planning to employ natural dyes in your production, or purchase natural dyes fabrics or final goods for sale, you need to pay attention to the amount of hazardous chemicals and metals so you are providing goods that are genuinely safe to the environment and people. Equally important is that you have the colourfastness and durability performance assessed to avoid customers being upset with the quality and damage to your reputation.

Textiles and leather experts at Eurofins are happy to assist you in achieving any queries in relation to natural dyes. You can count on our expertise to set up testing programmes, identify colourants or state your vegan claims.

Learn more about our testing services

www.eurofins.com/textile-leather/services/testing-services/

More about support to your vegan claim

www.eurofins.com/textile-leather/services/sustainability/vegan-verification/