Natural dyeing

Natural Dyes – Preparing to Dye

Introduction to Natural Dyes

I enjoy learning about and using natural dyes to dye yarn, and latterly, wool and silk fabrics. There are many natural dye books available which give you techniques and methods to create beautiful colours. The following are the methods I use at home in my dye studio to prepare yarn, fibre and fabrics to dye.

Health and Safety when using natural dyes

Although natural dyes are natural, they are still chemicals, and so you must pay careful attention to how you prepare and use them, and then dispose of them.

  • Always work in a well ventilated space away from any food preparation, ideally outdoors. Avoid breathing any dust or fumes, and wear a face mask if necessary.
  • Always use pans and utensils which are dedicated for the task and won’t be used for food afterwards.
  • Only create as much dye as you need to avoid unnecessary waste.
  • Dispose of natural dyes carefully, very well diluted on the flower garden or down a drain. Don’t put diluted dyes on vegetable or fruit plants.
  • Store dyes in clearly marked containers away from the reach of children and pets.
  • Don’t eat, drink or smoke in the dye area.
  • Wear gloves and protective clothing to avoid splashes and possible acid or alkali burns.
  • Prepare the work area beforehand to ensure that hot pans etc are moved as little as possible.
  • Keep water and dyes away from electrical cables and sockets.
  • Don’t eat or drink any dyes, mordants or modifiers.


Yarns, fibres and fabrics benefit from scouring, even if they are ‘brand new’ and look clean. The purpose of this is to wash off any residual oils and chemicals which may have been present when the fibre was manufactured. It helps to ensure the fibres are clean and able to absorb mordant and or dye colours evenly and prepares them for natural dyeing.

To scour yarn, fibre and fabrics, place them in a large pan of water, with a drop of pH neutral detergent. Heat the pan to 80 – 100 degrees c for about an hour. Allow the pan to cool completely then pour off the water which will probably look murky. Repeat the process until you are confident the fibres are clean and the water is no longer murky. Any remaining oil or dirt on the fibres can resist dyes and cause patchy dyeing results.

Cellulose yarns, fibres and fabrics need to be mordanted in a different way after scouring.

Mordanting protein fibres before natural dyeing

Although some natural dyes are ‘substantive’ and have their own inbuilt mordant (often tannins) I tend to scour and mordant batches of yarns ready for use with any natural dyes (unless I am doing a specific experiment or test.) Generally speaking, I use alum with cream of tartar. The dye pouches I sell have enough mordant with them for 100g yarn/fibre/fabric. This is 10g alum (Aluminium Sulphate) and 8g cream of tartar (Potassium Bitartrate). The cream of tartar helps brighten the dye colours.

The exception to this is Logwood which needs 22g alum and no cream of tartar to get good purple colours. (The cream of tartar shifts the pH acidic which modifies the purple colour more red/brown.)

I have recently used Titanium to mordant yarns but don’t have enough experience to comment confidently.

How to mordant protein yarn, fibres or fabric

To mordant your yarn/fibre/protein fabric you need to know the weight of your item to be dyed. This is the Weight of Fibre (WOF) and mordants and dye amounts are calculated on this.

Alum is between 7-10% WOF and cream of tartar (to brighten colours) is between 6-8% WOF. Less is often better than more. Add cream of tartar to a jug of warm water, stir well then add alum. Pour these into a pan of water. Add your wetted, scoured fibre and heat at 60 degrees c for 45 minutes then leave to cool.

For fibres which are going to be dyed with logwood, the method is the same, omitting the cream of tartar.

Rinse the remaining mordant of the yarn, fibre or fabric and they are ready to dye. You can use them straight away or dry, label and store for later. Be sure to label with the amount of alum and cream of tartar used so you don’t use the wrong one for logwood dyeing.

What’s next?

Once your yarn, fibre or fabric has been scoured and mordanted, it is prepared and ready to dye.

Read the next blog to see which dye you are using and my suggestions of how to create a dye and use if safely.

(Ceramic bowls made by Crowan Pottery, from Magpie and Butterfly shop in Marazion.)

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