Workshops / Workshop 6
Plant dyeing at the kitchen table
Colour cloth with marigold flowers, walnut hulls, tea and other common plants, and learn why colour stays in the cloth or washes out.
In brief
Natural dyes come from plants and other sources. For the colour to last, it must bond to the fibre. Wool and silk take dye readily; cotton and linen need extra preparation. A mordant, usually alum, is a mineral salt that helps colour bond with the fibre. Always test for fading and washing before trusting a colour.
What it is
A dye is a coloured substance that sinks into a fibre and stays there. A pigment, by contrast, sits on top of a surface. Many plants contain coloured compounds, but only some are good dyes, because many fade quickly in light or wash out.
Fibres fall into two broad groups. Protein fibres (wool, silk) take natural dyes fairly easily. Plant fibres made of cellulose (cotton, linen) are harder: they are usually scoured, treated with a tannin and then with alum before dyeing.
| Source | Part used | Typical colour | Notes |
|---|---|---|---|
| Marigold flowers | Dried flower heads | Yellow to gold | Easy and cheap; may fade faster than weld |
| Walnut hulls | Green or dark husks | Brown | Rich in tannin, so needs little or no mordant; wear gloves |
| Tea | Dried leaves | Tan to light brown | Tannin-rich; also used as a first bath for cotton |
| Weld | Plant tops | Clear yellow | A traditional yellow dye; usually used with alum |
| Madder | Roots | Red to orange-red | A traditional red; dull brown if the bath is overheated |
| Woad or indigo plants | Leaves, fermented or processed | Blue | Needs a special vat; the blue appears when cloth meets the air |
| Avocado skins and pits | Skins and stones | Soft pink to peach | A modern favourite; results vary |
Results vary with the water, the fibre, the mordant and the amount of plant material. Treat the table as a guide, not a promise.
Why mordants and tests matter
Mordant comes from a French word meaning “to bite”. A mordant is a metal salt that helps the dye grab the fibre. Alum (a salt of aluminium) is the most common and the safest for beginners; iron darkens or “saddens” colours; copper, tin and chromium salts are more hazardous, and a beginner should not use them. Tannin, from tea, oak galls or walnut, helps plant fibres hold the alum.
Two simple tests show whether colour is reliable. For lightfastness, cover half of a dyed sample with card and leave it in a bright window for several weeks; compare the covered and exposed halves. For washfastness, wash a small sample with a mild soap and see whether colour runs or fades.
How to dye a test strip
- Prepare. Use dedicated pots and tools that will never again touch food. Wear gloves and work in a well-ventilated space, with an adult to help with hot water.
- Scour. Wash the fibre with a mild soap to remove oils and finishes, and rinse it.
- Mordant. Dissolve the alum in hot water as the packet or a trusted recipe says, add the wet fibre, hold it below boiling for about an hour, then let it cool in the bath. Cellulose fibres need the tannin step first.
- Make the dye bath. Simmer the plant material in water for about half an hour, then strain it.
- Dye. Add the wet, mordanted fibre and simmer gently. Do not boil wool: heat and rough handling felts it. Leave the fibre in the bath until the colour looks right, then let it cool.
- Finish. Rinse until the water runs clear, wash with a mild soap and dry out of direct sunlight.
- Record. Pin a snippet into a notebook with the plant, mordant, fibre, amounts and date.
Safety. Hot liquids burn. Do not taste, eat or drink in the dye space. Do not breathe powders: wear a mask when weighing alum and powdered dyes, and keep them away from children and pets.
How synthetic dyes changed the craft
| Year | Event |
|---|---|
| Ancient | Dyed textiles survive from thousands of years ago; blue, red and yellow plant dyes were traded widely |
| 1856 | William Henry Perkin, aged 18, made the first synthetic dye, mauveine, by accident while trying to make a medicine |
| 1868 | Chemists Carl Graebe and Carl Liebermann made the red dye of madder, alizarin, in a laboratory |
| 1897 | Synthetic indigo went on sale on a large scale |
Cheap synthetic dyes quickly replaced madder and indigo in industry, and fields that had grown dye plants for centuries were turned to other crops. Today natural dyeing continues as a craft, for its colours, its history and its connection to plants.
Effects and legacy
Dyeing connects chemistry, farming, trade and fashion. The dye trades helped shape agriculture and commerce, and the move to synthetic dyes was one of the first big industrial chemical successes. It also created new kinds of waste water, which is why careful disposal matters.
Check yourself
Read the question, think of your answer, then open it with a tap or the Enter key.
Which fibres take natural dye most easily?
Protein fibres such as wool and silk.
What does a mordant do?
It helps the dye bond to the fibre so that the colour lasts.
Why should dye pots never be used for food?
Some dyes and mordants are not safe to eat, and traces can remain.
How do you test lightfastness?
Cover half of a dyed sample and leave it in a bright window for several weeks; compare the two halves.
Why must you not boil wool in a dye bath?
Heat and rough handling felt the wool.
What was mauveine?
The first synthetic dye, made by William Henry Perkin in 1856.
Basis of the facts
Where these facts come from. The chemistry of natural dyes and mordants follows Cardon (2007) and Hofenk de Graaff (2004); craft guidance on scouring, tannin and alum is standard. The dates are historical records: mauveine in 1856 (Garfield, 2000), synthetic alizarin in 1868 by Graebe and Liebermann, and synthetic indigo sold from 1897. Dye colours in the table are typical, and vary. The safety notes are general; follow the instructions on any product you use. See the sources list.