Logwood Extract Natural Dye
Haematoxylum campechianum L. · Concentrated Logwood Extract
Logwood Extract is a powerful natural dye obtained from the heartwood of the logwood tree. It produces rich purples, violet-blues, blue-greys, charcoal and near-black shades, depending on the fibre preparation, mordant, pH and quantity used.
As a concentrated extract, only a small amount is required compared with raw logwood chips. It dissolves readily in warm water and is suitable for immersion dyeing, textile printing, inks and other colour applications.
At a glance
| Feature | Details |
|---|---|
| Botanical name | Haematoxylum campechianum L. |
| Common names | Logwood, Campeche wood |
| Plant part | Heartwood |
| Form | Concentrated powdered extract |
| Material | Natural plant dye extract |
| Main colourants | Haematoxylin and haematein |
| Colours | Purple, violet-blue, blue-grey, charcoal and near-black |
| Suitable fibres | Wool, silk, cotton, linen, hemp and other prepared fibres |
| Washfastness | Good when correctly mordanted and dyed |
| Lightfastness | Moderate; improved in darker, iron-modified shades |
Understanding Logwood Extract
The principal colourant in logwood is haematoxylin. Through exposure to air and during dyeing, haematoxylin oxidises to form haematein, which produces the characteristic purple, blue and dark tones associated with logwood.
Colour development is influenced by:
- Fibre type and preparation
- Mordant
- Water chemistry
- Dye concentration
- Bath pH
- Iron modification
Logwood is highly concentrated and can produce strong colour at relatively low percentages.
Possible colours
| Method | Possible result |
|---|---|
| Aluminium-mordanted fibre | Purple, violet and blue-purple |
| Unmordanted fibre | Paler, less durable lavender, mauve or grey-purple |
| Mildly acidic conditions | Warmer red-purple and violet shades |
| Mildly alkaline or mineral-rich water | Cooler blue-purple and blue-grey shades |
| Light iron modification | Grey-purple, blue-grey and charcoal |
| Gallotannin and iron | Charcoal to near-black |
| Indigo underlayer followed by logwood | Deep navy, blue-black and complex near-black |
These shades are indicative rather than guaranteed. Always sample first when working towards a particular colour.
How much to use
Because this is a concentrated extract, begin with:
| Depth of shade | Logwood Extract |
|---|---|
| Pale lavender or grey-purple | 0.5–1% WOF |
| Medium purple | 1–2% WOF |
| Deep purple or violet-blue | 3–5% WOF |
| Very dark shades | Begin at 5% WOF and build through additional applications if required |
WOF means weight of dry fibre. For example, 2% WOF equals 2g of extract for every 100g of dry fibre.
Using very large quantities does not produce a better or more colourfast result. Logwood generally responds well to gradual colour building.
Preparing the fibre
Wool and silk
For clear purple and violet shades, mordant protein fibres with alum before dyeing. We generally recommend 7.5–15% alum WOF, adjusted for the fibre and desired result.
Treat silk gently and avoid unnecessary heat or prolonged exposure to iron.
Cotton, linen and other cellulose fibres
For durable colour on cellulose, we recommend a two-stage mordanting process:
- Apply a tannin to the well-scoured fibre.
- Follow with an aluminium mordant such as alum with soda ash, aluminium acetate or aluminium lactate.
The aluminium stage turns the tannin treatment into insoluble tannates within the fibre. Tannin or aluminium used alone is not equivalent to the complete two-stage process.
Find our cellulose mordanting guide here.
Suggested dyeing method
- Prepare: Scour and mordant the fibre using a method appropriate for its fibre type.
- Measure: Begin with 1–2% Logwood Extract WOF for a medium shade.
- Dissolve: Mix the extract with a small amount of warm water to create a smooth liquid.
- Make the bath: Add the dissolved extract to enough water for the fibre to move freely.
- Add the fibre: Wet the prepared fibre thoroughly before adding it to the dye bath.
- Dye: Warm gradually to approximately 80–85°C and hold for 45–60 minutes. Stir or turn the material carefully for even colour.
- Develop: Allow the fibre to cool in the bath. Longer contact or a second application can deepen the shade.
- Aerate: Remove the fibre and allow it to aerate so the colour can develop fully.
- Finish: Rinse thoroughly and wash gently.
Avoid vigorous boiling, particularly when dyeing wool or silk.
Modifying with iron
Iron shifts logwood towards blue-grey, charcoal and near-black. Start carefully, as too much iron can dull the colour and damage fibres.
We recommend beginning with 1% ferrous sulphate WOF:
- Add the dissolved iron to the warm dye bath near the end of dyeing.
- Return the fibre to the bath for up to 10 minutes. Use a shorter time for silk and delicate materials.
- Remove and hang the fibre to aerate for approximately 10 minutes.
- Repeat the brief immersion and aeration cycle if necessary.
- Up to three cycles are usually sufficient.
- If the result remains too light, add a further 1% iron and repeat.
A total of 1–3% iron WOF is normally sufficient. Higher quantities increase the risk of fibre damage.
Ferrous acetate may be used as a more controlled alternative to ferrous sulphate, particularly for delicate textiles.
Creating deep navy and black shades
Logwood can contribute to deep charcoal and near-black shades when combined with gallotannins and carefully controlled iron.
For a fuller blue-black, indigo and madder may also be used. Always apply the indigo first:
- Dye the prepared fibre in an indigo vat.
- Rinse and oxidise thoroughly.
- Apply the tannin and mordant treatment appropriate for the fibre if required.
- Overdye with Logwood Extract.
- Finish with a carefully controlled iron modification if a darker shade is needed.
Applying indigo first prevents logwood, tannin, dyes and mordant residues from contaminating the indigo vat.
Tips from the dye pot
| Tip | Details |
|---|---|
| Begin with a small quantity | Logwood Extract has exceptionally strong colouring power. |
| Dissolve thoroughly | Make a smooth liquid with warm water before adding it to the bath. |
| Build colour gradually | A second dyeing may give better control than one excessively strong bath. |
| Allow oxidation | Logwood colour continues to develop through contact with air. |
| Watch the water | Mineral content and pH can shift purple towards red-purple, blue or grey. |
| Use iron sparingly | Small additions can create dramatic colour changes. |
| Treat silk carefully | Reduce heat, exposure time and iron concentration for delicate fibres. |
| Keep notes | Record fibre preparation, mordant, pH, concentration and iron treatment. |
Colour samples
The colour photographs illustrate the range of purple, violet-blue and dark shades that Logwood Extract can produce. Differences in fibre, mordant, water chemistry, concentration and finishing will produce different results.
The photographed colours are representative only and should not be treated as guaranteed colour matches.
Colourfastness
Logwood generally has good washfastness when applied to properly prepared and mordanted fibres.
Its lightfastness is considered moderate. Darker shades and iron-modified colours may perform better, but prolonged exposure to strong sunlight can still cause fading.
For textiles that will receive extensive light exposure, sampling and lightfastness testing are recommended.
Natural variation
This is a natural plant extract. Its colour, particle size and dye strength may vary slightly between batches.
The powder may appear red-brown or purple-brown before use. This does not represent the final dyed colour.
Storage and safe handling
- Store tightly sealed in a cool, dry place away from direct sunlight.
- Avoid creating or breathing dust.
- Work in a well-ventilated area.
- Prevent contact with the eyes, mouth and open wounds.
- Wear suitable protective equipment when handling the powder.
- Follow the safety instructions supplied with all mordants and modifiers.
- Use dedicated dyeing utensils and containers.
- Keep away from food and out of reach of children and pets.
- For textile, ink and craft applications only.
- Not intended for food, cosmetic or medicinal use.
What you receive
Your chosen net weight of concentrated Logwood Extract powder, supplied in a resealable pouch.
Textiles, display vessels and photographic props are not included.
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