Understanding your fabric before you print or dye it

Before you start any dyeing, eco printing, or even felting, it’s important to know what your fabric is made of. All fibres fall into two main categories: protein fibres and cellulose fibres. And how they behave in dyeing and eco printing depends entirely on which group they belong to.

Here’s a simple guide to understanding the difference.

Protein Fibres – From Animals

Protein fibres come from animals—they’re made of natural keratin or fibroin proteins. These fibres are warm, soft, and often slightly elastic.

Examples include:

• Wool – from sheep
• Alpaca, Mohair, Cashmere – from various goats and camelids
• Silk – from silkworm cocoons

In the dye pot:

• Protein fibres love natural dyes—they bind easily, often with rich, deep results.
• They often don’t need as much mordanting as cellulose fibres. A simple alum soak is usually enough.
• They’re more sensitive to heat and pH, so gentle handling is essential.
• Eco prints on protein fibres can show incredible definition and colour clarity.

Cellulose Fibres – From Plants

Cellulose fibres come from plants—they're made of plant-based cellulose (like paper). These fibres are breathable, crisp, and strong when wet.

Examples include Cotton, Linen, Hemp, Ramie, Jute.

In the dye pot:

• Cellulose fibres are harder to dye naturally—they’re more stubborn!
• They require more mordanting, usually with tannin followed by alum (or other combinations).
• Natural colours can appear softer or paler unless properly pre-treated.
• Eco prints can still work beautifully, but require longer contact and heat, or extra additives like iron water.

What’s a Mordant?

A mordant is a substance that helps natural dyes or tannins stick to the fibre. Think of it like a bridge between the dye and the fabric.

• See our story on mordants for more information.

Warmly,
Jacqueline Damon
Tweed Valley Textile Company