Symplocos Bark Powder — Plant-Based Aluminium Mordant

Symplocos is a remarkable natural mordanting material and a true alternative to alum.

Like club moss, the symplocos tree is a bio-accumulator of aluminium. Its powdered bark can replace aluminium sulfate in traditional dye recipes, allowing you to create 100% plant-based, long-lasting colors.

Used before natural dyeing or eco-printing, symplocos improves light-fastness and wash-fastness, while offering a more organic and historically grounded approach to mordanting.

Please note: some dyes — especially madder and logwood — will produce different shades compared to results achieved with regular alum. This is part of the unique character of symplocos.

How to Use

Because many variables influence the strength of symplocos, there is no single fixed recipe. Fiber type, fabric thickness, water quality, and heating time all affect the outcome.

Recommended Amount (WOF)

20–100% WOF (Weight of Fiber)
This range may sound broad, but it reflects real working conditions.

As a practical starting point:
→ Begin with 50% WOF, then adjust as you gain experience.

General guidelines:

• Silk needs less than cotton

• Thick or dense fabrics need more than thin ones

• Longer heating produces a stronger mordant

Water Quality

Use soft water whenever possible.

If your water is very hard:

• Add Calgon, or

• Add 0.5 g cream of tartar per liter of water

Mordant Bath Preparation

1. Add symplocos powder to water

2. Heat and boil for at least 30 minutes

3. The powder will sink to the bottom of the pot

If dyeing yarns:
→ Filter the liquid before use to prevent gritty particles from lodging in the fibers.

Fiber Instructions

Silk

• Pre-wet fiber

• Heat in the filtered mordant liquid for 90 minutes at 70 °C

• Do not exceed this temperature,  prolonged high heat may damage silk

• Rinse in tepid water

The fabric may appear pale yellow, this disappears after dyeing.

Cotton

• Boil cotton together with the mordant liquid for 30 minutes

• Rinse in tepid water

A pale yellow tone may appear and will disappear after dyeing.

Reuse

A symplocos mordant bath can be reused once, producing lighter results.