MORDANTS for NATURAL DYEING & CONTACT PRINTING
From MIAWA WEBSITE
The Maiwa Guide to Natural Dyes
What they are and how to use them
We've divided the section on Mordants into three parts. We start with some explanations and then describe different mordants, tannin’s, and other additives. We will give detailed procedures in part three. What follows depends on knowing what fiber you are working with. You may wish to review fibers before reading on.
There are only a few dyes(1) (such as indigo) that can effectively be put on a fiber without first mordanting. these are called Substantive Dyes.
The substantive natural dyes do not need a mordant to color fibers. These include the tannic acid from gall nuts, walnut leaves, turmeric, as well as alizarin reds from annatto, cochineal and safflower, indigo and the purple of some molluscs. Using mordants on these dyes will modify the color.
Mordanting the fiber is perhaps the most important step in successful dyeing and eco-printing. It is often rushed or even omitted because no visible change occurs. When teaching natural dyeing or eco-printing, we have found that once students understand how important it is to mordant their fabrics correctly before they start working, then they are well on their way to successful and satisfying results.
Advanced dyers also use mordants to modify colors. Mordants can be added through block printing or silk screening techniques, or the application can be controlled through resist techniques. This gives a variety of methods to add pattern to a cloth. Some very subtle effects may be created through control of mordants and tannin’s.
Mordants facilitate the bonding of the dyes to the fabric. I like to think of it as a “primer” for dyes. There are so many mordants and each one creates different shade from a particular dyestuff. As mentioned earlier we do not recommend mordants such as chrome, copper and tin. Although these metallic salts work well to fix the dyes and provide an alternate palette, they are a health hazard and produce toxic waste which requires special disposal. Mordants such as alum, iron, and tannin are safer to use and can produce myriad colors when used in conjunction with the appropriate natural dye. The most frequently used method is pre-mordanting (before dyeing). Occasionally the mordant is added to the dye bath (one-pot dyeing) and sometimes it is added after the dye bath (post-mordanting or after-mordanting).
Alum – Potassium aluminum sulfate (PAS) is the mordant most frequently used by dyers for protein (animal) and cellulose (plant) fibers and fabrics. It improves light and wash fastness of all natural dyes and keeps colors clear. It is inexpensive and safe to use (see our safety notes). This form of alum is refined from bauxite, the raw state of aluminum ore, and is free from the impurities (such as iron) some other alums can contain.
Use at 12-20% WOF (weight-of-fiber). Sometimes we use a combination of two mordants of alum. For example, we will mordant once with alum at 15% WOF and then again with a fresh mordant bath of alum at 15% WOF. Or we will do a tannin/alum/alum mordant to achieve slightly richer colors.
Alum Acetate – Aluminum acetate is sometimes used as the preferred alum mordant for cellulose fibers and fabrics. It is refined from bauxite and acetic acid is used as a purifying agent. For this reason some natural dyes develop to a richer shade on cellulose. Alum acetate is the recommended mordant for printing with natural dyes. It is more expensive and sometimes hard to find, however you can make your own by using the recipe below.
Use at 5-8% WOF
Homemade Alum Acetate – The dyer may make aluminum acetate from sodium acetate and potassium aluminum sulfate and, depending on the availability of these materials in your area, this can be cost effective.
To make enough aluminum acetate to mordant 1 kilo of fabric, combine in 3 litres of hot tap water:
150 g sodium acetate
150 g potassium aluminum sulfate
This can be added to your mordant bath.
Aluminum triformate is a room temperature dye for all cellulose and protein fibers including wool, silk, cotton, hemp and linen. Unlike other mordants, it works on either a calculation of grams per Liter (gpL) or weight of fiber (WOF) and it is a cold process as no heating is required. Therefore, you can create a cold water mordant bucket, add a few items and mordant, or you can weigh a specific amount and mordant. We have used it successfully with both methods.
The gpL method allows you to create a mordant bath of a specific strength, based on how many liters of water your bucket can hold. This bucket can be reused and topped off as needed by using the same gpL calculation. The WOF method is used primarily when weighing mordants and dyes and allows you to quickly and easily calculate how much to measure.
Each of these methods have their advantages for the artisan dyer. If you want to dip a scarf or two in mordant and then move on to dyeing without a lot of calculating, then the gpL method is good for you as there is no additional weighing, heating or handling hot mordanted items. On the other hand, if you need to keep careful records and dye the same thing, then you can also use the mordant as a percentage of the WOF.
gpL: the recommended gpL for aluminum triformate is 20gpL, or 20 grams for every liter of water that your bucket can hold.
– OR –
WOF: the recommended amount of aluminum triformate is 5-10% WOF. A larger percentage of the WOF will result in deeper colors.
Cream of Tartar (cream of tartar)– is the sediment produced in the process of making wine. It is an optional addition to the alum mordant bath and to some dye baths. It is used to soften wool, brighten shades, and point the color of some dyes (it will move the fuchsia of cochineal to a true red). Cream of tartar works best with animal or protein fibers and is seldom used with plant or cellulose fibers. Use at 5-6% WOF.
TANNIN’S
Dyes which do not require mordants are sometimes referred to as substantive dyes. Indigo is the best example of a substantive dye. Occasionally the term substantive will be used for dyes like walnut and myrobalan which are are also tannin’s. For the natural dyer who wishes the greatest flexibility we recommend that fibers always be properly mordanted.
Natural Dyes - Mordants Part 2
The Maiwa Guide to Natural Dyes
What they are and how to use them
In our previous post we explained why mordanting was necessary and looked at the primary mineral mordant - Alum. We encouraged readers to review fiber types. Now we move on to tannins which are necessary to get fast colors on cellulose fibers such as cotton. Detailed procedures will be described in the next post.
Tannin – Tannic acid is used to mordant cellulose fibers and fabrics before the alum mordant. Alum does not combine as readily with cellulose fibres as it does with protein fibers. Fortunately tannin has a great affinity for cellulose. Once mordanted with tannin, alum will combine well with the tannin-fiber complex. For this reason, the order of a tannin-alum mordant combination is very important. Jim Liles, in his book The Art and Craft of Natural Dyeing presents an interesting historic perspective on the use of tannins on plant fibers - including the belief that it was necessary to "animalize" the fiber. This belief explained some very unusual dye processes.
Many dyestuff’s contain tannin (black oak, pomegranate, cutch, fustic, etc) and do not need an additional tannin mordant. I use these tannin enriched dyes as blankets when ecoprinting to achieve colored backgrounds
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 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 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: 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: 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: 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 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.
Tannins can be clear or they can add a color to the fiber. This is a consideration when selecting a tannin. The two most popular tannins in the studio are gallnut (oak gall) and myrobalan.
There are three types of tannins.
• Clear Tannins: “Gallic” - Gallnut, Tara, Sumac
• Yellow Tannins: “Ellegic” – Myrobalan, Pomegranate, Black Oak, Fustic
• Red-Brown Tannins: “Catechic” – Cutch, Quebracho, Tea leaves
Oak Gall - This is the earliest and richest source for natural tannin and is the clearest of the tannins. It is found in the gallnuts of oak trees. A gallnut is produced by the tree as a defense against insects who deposit their eggs in small punctures they make on young branches. The tree excretes a tannin-rich substance that hardens and forms a gallnut.
Gallnuts are collected and ground into a powder that may be used to mordant cloth, in leather tanning, or medicinally.
Use gallnut at 6-8% WOF.
Myrobalan - This dyestuff consists of ground nuts of the Terminalia chebula tree. This tree grows in Nepal, India, Sri Lanka, Burma, Thailand, Indochina and south China. It may be classed as both a mordant and a dye, giving a light buttery yellow when applied.
Myrobalan is an important tannin-based mordant for cotton in India and Southeast Asia due to the light warm colour it imparts to the cloth. The colour works well for overdyeing. Myrobalan is also the perfect colour to lay down under a single indigo dip for teal.
When used as a tannin mordant, myrobalan requires 15-20% WOF. If used to create a soft butter yellow colour 20-30% WOF is needed.
Iron (Ferrous Sulfate) – This is an optional step. Iron is used as a color changer. It has the added benefit of making naturally dyed colors more light fast and wash fast. It is more often used with cellulose fibers like cotton, linen, rayon and hemp and should be used with care on protein fibers as it can make them slightly hard or brittle. Iron shifts a color to a deeper, darker shade. Dyers say it "saddens" the color. If used in the mordant process that shift is more distinct than when used directly in the dye bath. Iron should be used at 2-4% WOF. More than that could damage the fiber.
When printing with natural dyes we recommend changing ferrous sulfate to ferrous acetate to avoid bleeding and ferrous transfer (the migration of iron).
Homemade Ferrous Acetate
5 g ferrous sulfate
100 ml vinegar
3 g lime (calcium hydroxide)
Combine the above ingredients in a plastic container and stir well. If thickening is required, weigh the amount of ferrous acetate you wish to thicken and add 1% of guar gum.
Ferrous acetate needs to be fixed. We use chalk (calcium carbonate) 50g in 5 litres of warm water. Once your ferrous acetate is fully dry dip it into this solution. This solution may be kept and reused again and again. Generally you may refresh with 50 g of chalk after each 10 kg of fabric. Full instructions are given in the next post.