Natural dye reference: fiber prep, color sources, mordants, and fast troubleshooting

Intent: give makers a compact, reliable reference for natural dyeing that actually produces repeatable color. Benefit: clear fiber prep steps, beginner-safe mordants, plant sources, pH tricks, safety rules, and a troubleshooting map.

Why this reference matters

Natural dyes can be luminous or muddy. The difference is usually prep and process: clean fibers, accurate ratios, heat control, and simple record-keeping. This guide keeps decisions short and repeatable so your swatches become a library you can trust.

Fiber first: match method to material

• Cellulose fibers (cotton, linen, hemp): need thorough scouring and a mordant system that includes tannin before alum for best depth.
• Protein fibers (wool, silk): scour gently; alum works well without a separate tannin step for many recipes.
• Synthetics & blends: natural dyes have poor uptake on synthetics; high natural-fiber blends do better.

Prep and mordants that work

Scour (clean) the fiber

• Cotton/linen: hot wash with a neutral detergent and a pinch of soda ash; rinse until water runs clear.
• Wool/silk: warm water with neutral soap; avoid agitation and big temperature swings to prevent felting.

Mordant basics

• Alum for protein fibers: common starting point for bright, lightfast color on wool and silk.
• Tannin + alum for cellulose: a light tannin bath (for example, gallnut, myrobalan) followed by alum helps dyes bond to cotton and linen.
• Iron as modifier: small amounts shift colors darker or moodier; use sparingly to avoid fiber damage.
• Avoid heavy-metal mordants for home use: skip methods that rely on chrome or tin in a home studio.

Color sources: quick picks that behave

• Madder roots: warm reds to corals on alum-mordanted fibers; richer with calcium present.
• Cutch: caramel to brown; easy, reliable, and layer-friendly.
• Weld or marigold: clear yellows; great mixers for green or orange blends.
• Indigo: the non-mordant exception; needs a reduced vat (fructose, henna, or other systems). Dip, air, repeat.
• Logwood: purple to gray; sensitive to pH and iron, so sample first.
• Avocado pits/skins: soft peach to dusty pink on cellulose with tannin plus alum; color varies widely.
• Black tea or pomegranate rind: gentle tannin sources that shift tone and help on cellulose.

pH and modifiers: small changes, big shifts

• Acid shift (a little citric acid or vinegar): often brightens yellow ranges, can warm some reds.
• Alkaline shift (a little soda ash or washing soda): can push yellows toward green, increase uptake for some dyes; go gentle on wool.
• Iron bath (very dilute): saddens hues toward olive, slate, or charcoal; quick dips are usually enough.

Process framework: scour → mordant → dye → modify → rinse → cure

1. Weigh goods: record weight of fiber; base all additions on this.
2. Scour: clean as above; rinse thoroughly.
3. Mordant: prepare an appropriate bath; keep temps steady and avoid boiling protein fibers.
4. Dye: strain plant solids if needed; add well-wetted fibers; bring to working temp and hold with gentle movement.
5. Modify: test a swatch in separate jars for pH or iron shifts before committing the whole batch.
6. Rinse and cure: cool slowly, rinse to near-clear, then hang or lay flat. Many colors settle and deepen after a short rest.

Troubleshooting: symptom → likely cause → quick fix

• Pale, uneven color: poor scouring or rushed mordant. Fix: re-scour; repeat mordant with good agitation.
• Muddy mixes: throwing many plant sources together. Fix: layer one dye at a time; sample before combining.
• Patchy indigo: vat not reduced or fabric not fully wetted. Fix: check reduction, de-bubble surface, wet out thoroughly, dip briefly, oxidize, repeat.
• Fiber feels harsh: strong alkali or long iron soak. Fix: reduce alkali strength; keep iron dips short and well diluted.
• Color washes out fast: weak bond or no mordant where needed. Fix: confirm fiber type, use tannin plus alum on cellulose, avoid over-soaping first wash.

Swatch discipline that pays off

• Label each swatch with fiber type, mordant, dye, weight of goods, ratio, temp window, and any modifiers.
• Dry-down can shift color; judge after full dry and a day of rest.
• Keep a ring or binder so future projects start from known results.

Methods, assumptions, limits

• Methods: home-scale, water-bath dyeing with food-safe stainless or dedicated enamel vessels; reduced indigo vat for blue.
• Assumptions: clean, soft to moderate water; stable heat source; access to basic PPE.
• Limits: plant materials vary by source; exact shade control requires sampling and notes rather than fixed recipes.

FAQ

Can I use kitchen pots?

Dedicate pots and tools to dye work only. Keep dye gear separate from food prep to reduce exposure and cross-contamination.

Do I need to pre-wash store-bought fabric?

Yes. Remove sizing and finishes so dyes can bond. Expect a visible improvement in depth and evenness after proper scouring.

How do I improve lightfastness?

Start with well-known, tested dyes, choose the right mordant system, and avoid harsh detergents in early washes. Store textiles away from direct sun.

Safety

• PPE: wear gloves and eye protection; avoid breathing powders; work with good ventilation.
• Separate gear: use dedicated dye pots, spoons, buckets, and strainers. Do not repurpose for cooking.
• Chemicals: measure carefully; label jars; never mix unknowns; keep acids and alkalis out of children’s reach.
• Water & disposal: strain solids, compost plant matter if appropriate, and dispose of spent baths per local guidance; keep heavy-metal mordants out of home studios.
• Skin & respiratory: some plants and modifiers can irritate skin or airways. Stop if you react and seek guidance if symptoms persist.

Sources

• Maiwa — Natural dyes overview (maiwa.com)
• Botanical Colors — Learn natural dyeing (botanicalcolors.com)
• Dharma Trading — Natural dye basics (dharmatrading.com)
• NC State Extension — Indigo fundamentals (ncsu.edu)
• OSHA — General chemical safety (osha.gov)

Further reading: The Rike: natural dye reference material