Testing of Natural dyed materials

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It is always useful and interesting to test the dye which is to be used on a sample of the yarn or fabric to be dyed. The outcome will depend on the fabric, the mordant that has been used and dye that has have been chosen. Testing is best carried out on a series of marked (for identification) samples, which have been mordanted with a number of different mordants. Tests can be carried out for light, water and washing fastness using simple standard test methods. 

Test method for fastness to washing

To test for fastness follow these steps:

Examination:

Source: Dyeing and printing: a handbook, ITDG Publishing

Processing of the plant can take one of many forms, but usually takes the form of soaking or boiling the plant to extract the dye. Some plants, such as indigo, need special preparation for use. Some plants will need boiling to extract their dye while others can merely be soaked for extended periods. Detailed instructions for processing of a wide variety of plants can be found in some of the texts given in the reference chapter at the end of this document.

The process of dyeing

Application of the Dye

Dyeing can be carried out at any of the following stages in the textile manufacturing stage:

It is essential for the correct identification of the fibre or other fabric to be made before dyeing commences.

Methods of dyeing

There are a number of methods of applying dye to a fabric. Although the most common method used for applying natural dyes is the vat method, there are techniques which have been developed to allow patterns to be incorporated during the dying process. It is worth bearing in mind that using natural dyes is a complex art and the skills required for using natural dyes are learned over many years. Don’t be put off if you don’t get the desired results at the first attempt!

Vat Dyeing

In the simplest form of dyeing a textile material is immersed in dye and gradually brought to the boil. Alternatively the fibre is allowed to sit and soak for several hours or days. During this period, agitation is necessary to allow full penetration of the textile by the dyestuff. Depending on the type of fabric and dyestuff used, certain salts or acids may be added to assist absorption of the dye.

The principal difficulty in dyeing mixed yarns and fabrics is to achieve the same color in both fibres. Cotton fibres may, for instance, absorb dyes rapidly, while the wool fibres will have to be boiled over an extended period to reach the same depth of shade. This could lead to significant damage to the material. In this case a chemical compound would need to be used to restrain the rate at which the cotton fibre takes up the dyestuff.

The amount of dyestuff which is used is usually given in the recipe. It is usually quoted as a percentage weight of the fabric to be dyed. Here below find a typical, simple recipe for dyeing using natural dyestuff, in this case onion skins.

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Recipe for dyeing wool with onion skins

Fabric: applicable to wool or other animal (protein) fibres.

• You will need:

• 100 grams of natural wool
•  30 grams of onion skins (use only the dry, brown, outer skins)
•  8 grams of alum (the mordant)
•  7 grams cream of tartar (the assistant)
•  Some liquid detergent (the scouring agent)
•  A water supply*

If a larger quantity of wool is to be dyed, increase the quantities proportionally.

Weigh the wool. All weights given are relative to the dry weight of the wool. Skeins of wool are tied loosely in several places to prevent tangling. In this case the recipe calls for 30% dyestuff i.e. the weight of the dyestuff is 30% that of the fabric to be dyed.

The wool should be scoured. This means getting the wool completely clean. For this the wool is soaked overnight in a liquid detergent solution. Rinse the wool well and gently squeeze out the excess water. Use lukewarm water and avoid sudden changes in the temperature of the water which cause the wool to felt or mat.

Next the skein will be mordanted. Dissolve the alum and cream of tartar in a little hot water and then add this solution to cool water in the mordant pan. Immerse the wetted yarn and then place the pan on the heat source. Slowly raise the temperature to 82oC (180oF) and simmer for 45 minutes. Leave to cool, then remove the wool and rinse well.

To prepare the dye bath, place the onion skins in the dye pan and cover them with water. Slowly heat the dye bath to boiling point. Simmer for about 45 minutes by which time all the color should have been extracted from the onion skins. Remove from the heat, allow to cool and then strain of the liquid form the skins.

The dyeing process is then carried out. The mordanted, thoroughly wetted fabric is placed into the now cool dye bath. Replace the heat under the dye bath, bring the temperature up to boiling point and then immediately reduce the heat to 82oC (180oF) and simmer for 45 minutes or until the wool is the required color. Remember that wool is darker when wet than when dry. Remove the wool from the dye bath if no further uptake of dye is required, or allow the fabric to cool with the liquid in the dye bath. Do not cool quickly with cold water.

When the skein of wool is cool, rinse it thoroughly in several changes of water until the water is clear, then wash the skein of wool in soapy water, rinse and allow to dry.

*Ordinary tap water is normally suitable for dyeing. If ‘soft’ water is called for then rain water can be used. A plentiful supply of fresh water is always required when dyeing.

Source: The Craft of Natural Dyeing, Jenny Dean

Batik

Batik is a starch resist-dyeing process, developed on the Island of Java in modern-day Indonesia. Color is prevented from reaching certain areas of a fabric by covering these areas with molten wax. The fabric is starched prior to the design being drawn upon it. The wax is applied with a type of cup with a fine pouring spout, usually made of copper. The technique has been developed to a high art form in Indonesia from where it is exported to many parts of the world. Batik paintings, as well as sarongs and lengths of fabric, are produced. When the fabric is dyed, all waxed areas resist the dyestuff. The wax is then removed by placing the fabric in boiling water. For patterns with many colors the same procedure is repeated until the full design is completed.

Tie-dyeing

Tie-dyeing is another popular artisanal dyeing technique. In this resist-dyeing process, waxed thread is tightly tied around the areas chosen to resist the colored dyestuff, and the fabric is dipped into the dye. The waxed thread is then removed and the fabric dried. This process can be repeated for each colour to be added.

Obtaining unusual colours

Colours other than those obtained by simply using a single dye, can be obtained by mixing dyes or dyeing a fabric more than once in different dyebaths. The colour triangle on the next page is a useful tool in determining the colours needed to produce a required shade.

Wild

Mangosteen

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References and further reading

Foulds, John, Dyeing and printing: a handbook, ITDG Publishing, 1989. The text and line drawings describe chemical dyeing and printing techniques as they apply to small-scale operations. 128pp. Sayadda R. Ghuznavi, Rangeen – Natural dyes of Bangladesh, Vegetable Dye Research and Development Society, Bangladesh, 1987. This interesting book gives listings of indigenous Bangladeshi plants as well as recipes for their use. Dalby, Gill and Dean, Jenny, Natural Dyes in Luapula Province (Zambia): Evaluation of Potential for Production, Use and Export. Working Paper 22, Development Technology Unit, University of Warwick, Coventry CV4 7AL, UK. 1988. Dean, Jenny: The Craft Of Natural Dyeing, Search Press, 1994 This guide tells how to grow and find, harvest, and use all NON-TOXIC dyes in nature. It is excellent for children. She lists dyestuffs that provide a full spectrum of colours and explains how to test plant dyestuffs for colour potential. 64 pgs, 30 colour photos, 16 illustrated charts, paperback. Cowan, Wavell: Operating A Business In The Small Business Space. A must for anyone who contemplates starting a small business. Xeroxed, spiral bound, non-profit 67 pp.

McRae, Bobbie: Colors From Nature: Growing, Collecting, and Using Natural Dyes How to grow dye plants, recognise and collect wild plants, and even find dyes in the produce department of the grocery store. Step-by-step instructions for over a dozen naturally dyed crafts projects. 168 pp.

Useful addresses

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Useful internet addresses

http://www.earthguild.com/products/Dyes/dye.htm Homepage of Earth Guild (see addresses section above).

http://www.slonet.org/~crowland/textile-processing-articles.htm Carol Todd’s Natural Dyeing Homepage. Sells books and electronic database of plants and natural dyes.

http://www.hillcreekfiberstudio.com/Workshops.htm Hillcreek Fibre Studio. Runs workshops on weaving and natural dyeing. Based in the USA.

There are many recipes for natural dyeing given on the Internet. Enter a search on ‘Natural dyeing’ and this will yield a wealth of recipes, suggestions and ideas for the novice (and experienced) dyer.

By the courtesy of:

Practical Action
The Schumacher Centre for Technology & Development
Bourton on Dunsmore
RUGBY
CV23 9QZ
United Kingdom

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