Before a single leaf touches the fabric, the cloth itself has to be prepared to hold colour permanently — and that preparation starts with foraged, plant-based materials of its own.
Where the Botanicals Come From
Every print starts with what nature (and sometimes what we've reclaimed) provides. We forage leaves like wood apple straight from the source for their vein structure and pigment, and we also work with flowers that would otherwise go to waste — garlands and offerings past their first life, given a second one on cloth instead of ending up in a bin.
Two Fibre Families, Two Different Chemistries
Hemp, linen, and cotton are cellulose (plant-based) fibres. Unlike protein fibres such as silk, cellulose naturally repels metallic mordants — apply alum directly to cotton or linen and most of it washes straight back out, leaving pale, fleeting colour. Getting permanent, production-quality colour onto plant cloth takes a two-step process: a tannin bath, followed by a metallic mordant bath.
The Materials, and Why We Use Them
| Stage | Material | Why |
|---|---|---|
| Pre-wash (scour) | Soda ash & neutral soap | Strips the natural waxes and sizing plant fibres arrive in, so water and tannin can penetrate evenly. |
| The binder (tannin) | Harad (Myrobalan) | Cellulose won't bond directly to alum — Harad is the bridge. It bonds to the fibre, and the alum then bonds to it. Leaves a warm, buttery base colour. |
| The binder (tannin) | Oak gallnut / tara powder | A "clear" tannin — same bridging job as Harad, without shifting the base colour. Used for bright pinks and stark whites. |
| The fixative (mordant) | Aluminium acetate | The gold standard for cotton, linen, and hemp — bonds more effectively to cellulose than plain alum, for brighter, faster colour. |
| The fixative (mordant) | Potassium alum + soda ash | The traditional route — needs the soda ash to shift its alkalinity so it will take on plant fibre. |
The Procedure
- Scour. Weigh the dry fabric to set the WOF (Weight of Fabric). Simmer at roughly 82°C (180°F) with 2% WOF soda ash and 1% WOF neutral detergent for 1–2 hours, then rinse until the water runs clear.
- Tannin bath. Dissolve Harad (roughly 10–15% WOF) in hot water, submerge the scoured fabric, hold at roughly 71°C (160°F) for an hour, then let it steep as it cools — ideally overnight. The longer it steeps, the stronger the bond.
- Mordant bath. Dissolve aluminium acetate (roughly 5–8% WOF) and submerge the tannin-treated cloth. Hold at roughly 49°C (120°F) for 45–60 minutes, stirring so the metal bonds evenly across the yardage.
- Cure. Extract the excess moisture, hang to dry in the shade, then rest the bone-dry fabric for 3–5 days. This curing window is what lets the alum-tannin bond harden permanently into the fibre — skip it, and the colour won't hold.
For a 5kg batch of linen, that works out to 100g soda ash, 50g neutral soap, 750g Harad, and 250g aluminium acetate, in a liquor ratio of at least 20:1 to 30:1 (100–150 litres of water) so the cloth can move freely without creasing.
Silk Follows a Different Path
As a protein fibre, silk bonds directly to metal — no tannin bridge needed. We scour it gently (neutral soap only, never soda ash, never above 60°C) and mordant with potassium alum at 15% WOF, holding at 82°C for 45–60 minutes before letting it cool in the bath overnight for the strongest bond.
It's slower than synthetic dyeing by days, not minutes. That's the trade-off for colour that doesn't fade in the wash.
