the MAIWA JOURNAL: January 2013

The Maiwa Guide to Natural Dyes
What they are and how to use them

Cotton mordanted with alum.

How To Mordant
Here we give the procedure for mordanting. Once again, the procedure depends on the fibre type.

Always use clean non-reactive vessels: stainless steel, unchipped enamel, glass, or plastic. Iron or copper vessels can also be used but the metal will react with the dyebath. Iron will dull or “sadden” colours. Copper will tend to brighten them.

Mordanting wool, silk or protein fibres

Weigh the fibre dry, then scour.
Measure alum at 15% WOF
Measure cream of tartar at 6% WOF (optional, see cream of tartar, mordants part 1).
Dissolve both the alum and the cream of tartar in very hot water in a non-reactive container.
Add the dissolved chemicals to the dye kettle with enough warm water 45º C (110º F) to cover the fibre when it is added - usually a 30:1 ratio of water to fibre. Stir well.
Add the scoured, wet fibre. Over 30-45 minutes bring the temperature up to 90º C (195ºF) Just under simmer for wool, and 85ºC (185ºF) for silk. Hold for one hour, gently turning the fibre regularly.
Let cool in the bath for 20 minutes.
Remove the fibre from the mordant bath. Allow to hang evenly over a non-reactive rod (stainless steel, plastic) until it stops dripping. Rotate the yarn or fabric frequently so the alum is evenly distributed.
Store the yarn or cloth in a damp white cloth for 24-48 hours. Keep it damp during this entire period if proceeding to dyeing. If you are going to store the fibre longer, then it needs to dry completely and then be stored in a dark place.

Mordanting cotton or cellulose fibres

Weigh the fibre dry, then scour.
Choose your mordants (see individual dyes for recommendations). For multiple mordant baths tannin must always be done first. Each bath must be completed before starting the next one.

Cotton after treating with pomegranate.

tannin

Measure tannin to the recommended WOF for the tannin you are using. Dissolve in hot water. Add to mordanting kettle. Fill the kettle with enough water to fully cover the fibre when added.
Add scoured, wet fibre.
Heat to 87 - 93ºC (190 - 200ºF) hold for 45 minutes, gently turning the fibre regularly.
At this point the fibre may be rinsed and mordanted with alum, or left to steep for 8-24 hours before rinsing (steeping will give deeper colours).

Aluminum Potassium Sulfate

Measure alum at 15% WOF. Dissolve in hot water. Add to mordanting kettle. Fill the kettle with enough water to fully cover the fibre when added.
Add wet fibre (already mordanted with tannin).
Heat to 87 - 93ºC (190 - 200ºF) hold for 45 minutes, gently turning the fibre regularly. .
At this point the fibre may be a) rinsed and remordanted, b)rinsed and dyed, or c) left to steep for 8-24 hours before rinsing (steeping will give deeper colours). If you are going to store the fibre then it needs to dry completely and then be stored in a dark place.

Aluminum Acetate

For this mordant you do not “cook” the fibre. You begin with very hot tap water 38 - 50ºC (100 - 120 ºF) but do not maintain heat. Because it is not heated, a plastic container may be used for mordanting.

Measure aluminum acetate at 8% WOF, dissolve in hot water, add to mordanting kettle. Or use your homemade aluminum acetate. Top up the kettle with enough hot tap water 38 - 50ºC (100 - 120 ºF) to fully cover the fibre when added.
Add wet fibre (already mordanted with tannin).
Let fibre sit for 1 - 2 hours stirring from time to time. Keep the kettle covered so that it retains its heat.
Remove fibre and hang to dry. 5 Chalk(1) (fix) the fibre. Dissolve 50 g of chalk (calcium carbonate) in 5 litres of warm water. Dip fibre into this solution. Fully wet the fibre, wring out and proceed to dyeing. If using wheat bran, mix 100 g of wheat bran in 5 litres of warm water, fully wet the fibre, wring out and proceed to dyeing. These solutions may be maintained over time and occasionally refreshed (after every 10 kg of fibre).
Proceed to dyeing or if you are going to store the fibre then it needs to dry completely and then be stored in a dark place.

*Aluminum acetate must be fixed to the fibre prior to dyeing. In some cultures this is known as “dunging” as cow dung is used. Dung is high in phosphates, but you may also use wheat bran or calcium carbonate (our preferred choice).

Iron

Iron may be added to the dyepot or it may be done as a separate step after dyeing.

Measure iron at 2% WOF. Dissolve in hot water. Add to mordanting kettle. Fill the kettle with enough water to fully cover the fibre when added.
Add wet, mordanted fibre
Heat to 71 - 77ºC (160 - 170ºF) hold for 30 minutes.
Rinse well. Remember always thoroughly scrub a pot that has been used to iron mordant or it will sadden the next dye bath. Note cellulose fibres can be fully dried and stored before dyeing. Fibres do not need to be remordanted between dyes. Once a fibre has been mordanted it can be dyed and then overdyed without any further mordanting.

Osage on wool. Top at 20% WOF. Bottom with Iron at 2% WOF.

The Maiwa Guide to Natural Dyes

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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 fibre types. Now we move on to tannins which are necessary to get fast colours on cellulose fibres such as cotton. Detailed procedures will be described in the next post.

Tannin – Tannic acid is used to mordant cellulose fibres and fabrics before the alum mordant. Alum does not combine as readily with cellulose fibres as it does with protein fibres. Fortunately tannin has a great affinity for cellulose. Once mordanted with tannin, alum will combine well with the tannin-fibre 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 fibre. This belief explained some very unusual dye processes.

Many dyestuffs contain tannin (black oak, pomegranate, cutch, fustic, etc) and do not need an additional tannin mordant.

Tannins can be clear or they can add a colour to the fibre. This is a consideration when selecting a tannin. The two most popular tannins in the Maiwa 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

Sometimes the insect may escape this prison - in which case we see an escape hole in the gallnut. Sometimes the plant wins and the parasite remains in the nut.

The one that didn't make it out. Wasp found inside 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 nuts - the preferred tannin throughout Asia.

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.

India. Myrobalan being used on cotton.

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 colour changer. It has the added benefit of making naturally dyed colours more lightfast and washfast. It is more often used with cellulose fibres like cotton, linen, rayon and hemp and should be used with care on protein fibres as it can make them slightly hard or brittle. Iron shifts a colour to a deeper, darker shade. Dyers say it "saddens" the colour. If used in the mordant process that shift is more distinct than when used directly in the dyebath. Iron should be used at 2-4% WOF. More than that could damage the fibre.

Cambodia. Terracotta pots containing "ironwater"
for natural dyeing. The solution is prepared by
combining oxidized metal, water, mealy wheat
and jaggery (sugars).

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.

Comparison of a dye used alone and with iron.

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.

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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, tannins, and other additives. We will give detailed procedures in part three. What follows depends on knowing what fibre you are working with. You may wish to review fibres before reading on.

There are only a few dyes(1) (such as indigo) that can effectively be put on a fibre without first mordanting.

Mordanting the fibre is perhaps the most important step in successful dyeing. It is often rushed or even omitted because no visible change occurs. When we teach natural dyes, we notice that if students can grasp the necessity of good mordanting before they embrace the excitement of colours, then they are well on their way to successful and satisfying results.

Advanced dyers will use the mordanting step itself as a means to influence colour. Mordants can be added through blockprinting or silkscreening 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 tannins.

Mordanted yarns - almost indistinguishable from unmordanted yarns.

Mordants facilitate the bonding of the dyestuff to the fibre.There are many mordants and each one will encourage a 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 colours when used in conjunction with the appropriate natural dye. The most frequently used method is premordanting (before dyeing). Occasionally the mordant is added to the dyebath (one-pot dyeing) and sometimes it is added after the dyebath (postmordanting or after-mordanting). Mordant procedures for protein and cellulose fibres are not interchangeable.

mordants

Alum – Potassium aluminum sulfate is the mordant most frequently used by dyers for protein (animal) and cellulose (plant) fibres and fabrics. It improves light and washfastness of all natural dyes and keeps colours 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. 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 colours.

Alum Acetate – Aluminum acetate is sometimes used as the preferred alum mordant for cellulose fibres 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.

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.

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 dyebaths. It is used to soften wool, brighten shades, and point the colour of some dyes (it will move the fuschia of cochineal to a true red). Cream of tartar works best with animal or protein fibres and is seldom used with plant or cellulose fibres. Use at 5-6% WOF.

Up next - Tannins.

1 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 tannins. For the natural dyer who wishes the greatest flexibility we recommend that fibres always be properly mordanted.

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The Maiwa Guide to Natural Dyes
What they are and how to use them

Our Approach to Dyeing
Some thoughts on fugative colour and colour with conviction.

Dyed yarns and source materials in Peru.

If you go into your backyard and sample every plant growing there, chop them up and prepare a dye-bath, you will find that almost every single plant will produce some kind of colour on cloth. Is every plant, therefore, a dyeplant?

No. First wash the dye samples with water. Many will return to the undyed state immediately. Next leave the dye samples for a period of time. Many others will soon loose their colour even without exposure to sunlight. Wash again with a mild soap or expose your samples to the sunlight for a day and almost all will have left the cloth or faded to pale ghosts.

And so your journey to find beautiful shades and to encourage them to stay on the fibre has begun. A large amount of the knowledge will concern processes for preparing the fibre. You will make the acquaintance of mordants and tannins. You may be surprised to find that the master dyer’s skill is much more than knowing which plant gives which colour. Rather a dyer’s skill is an understanding of what process will change fugitive colour to colour with conviction, for different fibres and under different circumstances. In this light, the work of accomplished dyers is all the more impressive.

And yet, natural dyes suffer from considerable negative press. A person who purchases a naturally dyed garment is quite likely to blame the entire practice of natural dyeing if that garment wears unevenly, fades prematurely or does not live up to expectations.

The historical evidence of museum-quality textile collections from around the world clearly shows that natural dyes can produce vivid, rich colours that last for hundreds if not thousands of years. Dyers often take offence at the popular notion that natural dyes only produce short-lived unhappy shades of dull brown.

Naturally dyed tapestry in the Alcazar, Seville, Spain.
An idea of colour after centuries exposed to sunlight and weather.

Our goal in these instructions will be what we think of as legacy quality dyeing: the professional application of colour that will satisfy the demands of the purchasing public. For this reason we have omitted popular items such as onion skins from our notes. They do indeed give a colour on cloth. However, in our opinion the results are fugitive and so we cannot recommend them as a source of permanent colour. This guide does not attempt to detail every plant that will provide colour – only those that, in our experience, provide lasting, permanent results.

Dyeing to Discover

People work with colour for a variety of reasons. Artists, children, gardeners, craftspeople, natural explorers, all may have different goals from the production dyer.

Any person who has cooked beets has wondered if that blood-red colour in the pot could somehow be transferred onto a shirt. Stains - from mustard to wine - will also lead the curious to contemplate colour on cloth. This is a common starting point for many who are driven by a desire to learn and experiment. It is true that an interest in local or unusual sources can be more important than the permanence of the results.

All levels of chromatic exploration are to be encouraged. The botanical world is vast. For those interested in sampling it we offer ...

A Few Points About Plant Conservation

There are probably plants growing near you that will make interesting dyes. Different parts of the plant - bark, heartwood, sapwood, flowers, pods and seeds - all have potential.

Exercise caution when harvesting. Be aware of your local ecology. Never strip bark from live trees or prune in public areas. Sensitivity is especially important with lichens. Ecologically, windfall is often preferable to harvest, but don’t forget that windfall has its own ecosystem – a variety of insects, birds, animals and other plants depend on it. Often a local botanist or conservation officer can guide you to areas where harvesting is beneficial. Generally these specialists are keen to share knowledge and learn about the potential colorants in plants. Botanical gardens prune on a regular basis and are not usually opposed to distributing the waste. Such gardens can yield some exotic source material.

Keep in mind that, being unable to move, many plants use toxins as a defense mechanism. A common example is the rhubarb leaf. These contain one of the strongest natural acids (oxalic acid - often used by dyers). The deadly nature of the leaves is in sharp contrast to the edible pleasures of the stem. Respect the genius of the plant world and treat any unknown item as if it were potentially dangerous.

Maiwa sells dyes that are cultivated. Our policy is to work directly with farmers where we can visit the farm and observe the conditions of cultivation.

The Attraction of Natural Colour

Before starting to dye keep in mind that dyes are not like paints. They do not coat the fibre with a monochromatic opaque colour. Rather they add a hue to the fibre itself and augment it’s existing qualities. This is one of the facets that makes natural dyeing so exciting. There are the qualities of the fibre and there are the qualities of the dye and they work together to create an effect with character and personality, depth and texture.

Like any art, working with natural dyes rewards skill and experience. The novice may get immediate satisfaction from the application of natural colour – it is immensely pleasurable and the experience will change your world-view. But there is also enough scope and depth in the study of natural dyes to last many lifetimes.

As with fine wines, made from grapes that change each year to reflect the weather, the seasons, the conditions of the soil, and the tastes of the vintner; dyes will give slightly different shade each time they are harvested.

Preparation of morinda roots on the island of Sumba, Indonesia

What is Natural Colour?

Natural colours may include dyestuffs from animal, mineral and vegetable sources. We understand natural colours in opposition to artificial or synthetic colours. Synthetic colour was first discovered by William H. Perkin in 1856 when he synthesized mauve from coal-tar. Today synthetics are produced from petrochemicals.

Dye? Pigment? Or Stain?

A dye is a substance that will join in a molecular bond with a fibre in such a way as to give a colour.

A stain is the presence of a topical colourant on a fiber or cloth. A stain may be annoyingly permanent, yet still not be a dye.

A pigment is a colourant which has been made into an insoluble mineral salt. Typically for fine art, a pigment is suspended in a medium such as oil, acrylic, wax (encaustic) or water (watercolours).

Mineral Pigments

Mineral colours such as ochers, are considered natural. This doesn’t mean that they occur as ready-made products in nature, but, rather the pigment is obtained from the natural rock without any chemical transformation. Metallic copper minerals such as azurite and malachite are simply crushed to a fine powder and used as pigments. Natural materials can still be quite hazardous. This was true for the sumptuous but very poisonous pigments from quicksilver (mercury), arsenic, and lead that have been used in the past.

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