There are so many mordant variations and we urge you to experiment and find the one that works best for you. If you’re not familiar with the term, mordanting is the most important process of preparing fibers to accept color. Mordanting prepares fibers to bond with natural dyes and is typically a separate immersion bath for the fibers. Many natural dyes require the use of a mordant to achieve the most durable and long lasting colors.
Though you might start with the tried and true aluminum mordants, consider trying tannin-rich extracts that not only offer a base color, they prep your fiber for more color to lay on top. Tannins can also be used as adjuncts with aluminum sulfate or aluminum acetate to further strengthen the mordant bond and that is how they are most often used because they create the best performance and results. The use of tannins is typically used with cellulose fibers as they can sometimes change the hand of protein fibers like silk and wool, so aluminum sulfate is still the best option for animal fibers.
Tannin is present in a number of different dyestuffs, and depending on how dark it is, does create a brown shade. If you want to use a “clear” tannin like gallo-tannin, the color will be a pale tan and is normally not noticeable in the final dyed textile.
We offer a How-To on mordanting on our site using aluminum acetate for plant fibers and aluminum sulfate for animal fibers but consider these 10 tannins you can use as a mordant adjunct or on their own.
Pomegranate: Pomegranate extract (Punica granatum), is known as anaar in India and granada in Spain. It grows wild in India, Italy, North Africa and China. Some use Pomegranate extract as both a tannin-rich mordant in India, and as a dye. Pomegranate is an aromatic dye that yields a matte green-yellow color. It yields rich blue greens when overdyed with indigo or dark olive greens when combined with Logwood or iron.
Chestnut: Chestnut (Castanea sativa) is a native to Southern Europe. People used it historically for tanning leather in Europe and North America. On fibers, chestnut extract yields a soft yellow which is excellent for combining with other colors. It’s also great for overdyeing with indigo for a rich teal. The chestnut color yields a warm gray shade with the addition of iron. It is one of those subtle, aromatic dyes that combines with other colors to add an intriguing “pop” to your color palette.
Cutch: Cutch (Acacia catechu) is the rich reddish brown color seen in Indian textiles. It is both a dyestuff and tanning agent. It has been used in India since ancient times. To make cutch extract, cutch wood is soaked in hot water until the liquid becomes syrupy. The dye liquid is cooled, pressed and cut into cubes and dried. Then the cubes are ground into powder for dyeing. Cutch extract is sweet smelling in the dye bath and yields rich red browns with long cooking times.
Oak Galls: Whole and ground oak galls (sometimes called oak apples or gall nuts) are small to medium-sized round hard growths that are high in tannin, and are an ancient mordant. They are an essential ingredient in making oak gall ink and can also be combined with iron to produce gray to black shades on textile fibers.
Quebracho Moreno: Quebracho Moreno is high in tannin and can be used as a tannin mordant or a dye on cellulose fibers.The name is due to its hardness, and comes from two Spanish words, quebrar and hacha, meaning the axe breaker. In fact, quebracho has been used locally for posts, telegraph poles, bridge timbers, railway ties, paving blocks and for any construction where great durability is desired. The extract will produce a golden brown color and will darken slightly on exposure to direct sunlight.
Gallo Tannin: Gallo Tannin extract (Tannin) comes from gall nuts, which contain approximately 50-60% tannin and has a lovely tea-like aroma. The gall nuts are formed on oak trees when a twig or branch is invaded by a wasp. The oak creates a The dye is very light, imparting a subtle beige color. Its power comes when it is combined with iron to create silver, gray and black in combination with other dyes.
Tara: (Needs botanical name) Tara powder is widely used as a light-colored tannin in leather industry. It has a high gallic acid tannin content between 30 and 50% tannins, making it ideal for mordanting. Like many high tannin dyes, it has a pleasant, tea-like aroma. Tara powder is the Quecha word for the shrubby tree Caesalpinia tinctoria, native to South America. The pods are the source of the dye.
Wattle: (Needs botanical name) Wattle is a member of the Acacia family and is used extensively in leather tanning as it is prized for its even coverage and penetration of skins and pelts for tanning. Natural dyers use wattle extract as one of the rich tannins to create iron-based grays and blacks or to overdye with indigo to create interesting muted greens. The color is a beige with a pink cast and it has a characteristic toasted wood smell.
Myrobalan: (Terminalia chebula) is a common dye throughout India. It grows primarily in the foothills of the Himalayas. It is an upright tree with small oval leaves and lovely bright yellow flowers. Myrobalan is a primary component for cotton dyeing in India. Similarly, we often employ it as a mordant prior to creating brown and black on cotton fabrics. Myrobalan extract overdyed with indigo makes a beautiful teal color. Use a higher percentage of myrobalan to yield a brownish yellow.
Walnut: Black walnut (Juglans nigra) is a common source of brown dye throughout North America. The fleshy hulls are full of tannin, juglone and other pigments and are the primary source of the dye. Walnut hulls were used to dye hair, make inks and clothing and are also used in herbal medicine. The rich brown color develops with oxygen, so it is necessary to simmer the walnut powder for about two hours with an overnight cool down before adding the fiber. Botanical Colors walnut hulls are a fine powder, not an extract, and potent.