Colourfast natural dyes – How long do the colours last?

Have you ever wondered about how long natural dyes last? Maybe you’d like to learn a little more about natural dye fixatives? In today’s post I’m going to do just that! We will explore how colourfast natural dyes are on yarns and fabrics and look at just a few natural dyes and mordants you can try at home.

A bit of history.

Natural dyes have been used for millennia but it was really in the 16th – 18th centuries that the skills of natural dyeing became an artisan profession with standards and a professional guild. Dyed fabrics ranged from basic home spun and woven to the finest linens, velvets and wool. The most skilled dyers could command high prices for the quality and consistency of their work, including how colourfast it was. Fashions in colours came and went, just like today. Dyers maintained notebooks with colour samples and “recipes” of dyers were often closely guarded secrets. Several years ago a book was published which is a translation of one of these notebooks and it gives a fascinating insight into the life of a master dyer in 18th century Langedoc, France. (The Dyer’s Handbook, Memoirs of an 18th century Colourist.)

Categories of dyes:

Natural dyes can be categorised into 3 groups according to their colourfast properties:

Substantive: Substantive natural dyes are colourfast, light fast and wash fast. They are plant dyes which have their own fixative and don’t require any additional mordant. These dyes include bark dyes such as Buckthorn Bark (Yellow), which contains natural tannins, and those dyes which contain Alizarin red such as annatto, cochineal and safflower. Lichens are also substantive dyes, but should only be used sparingly due to their very slow growth and environmental significance. Not all lichen give good colours either! Madder (brick red to peach and pale pink) Chamomile (golden yellows) Woad (blue) and Rhubarb root are all substantive. Essentially, these dyes don’t need a fixative to give a good colour which is colourfast.

Buckthorn colourfast natural dye
Buckthorn colourfast natural dye

Adjective: These dyes are relatively light and colourfast when they are used with a mordant which helps to fix the colour at a molecular level to the fibre. The most commonly used (and very safe) mordant is alum (potassium aluminium sulphate) with cream of tartar (like you use in baking.) There are lots of natural dyes that fix well with mordants to give a beautiful range of colours which resist fading. Colours such as Logwood for purples, brown and blues.


Fugitive: This group of dyes literally “run away” as the name suggests! You may have seen posts on the internet about using beetroot or red cabbage as a natural dye, and seen amazing red and pink colours….. However, both these natural colours are fugitive; they will wash away and fade to pale grey quite quickly, even if you use a mordant. However, if you are dyeing a yarn or piece of fabric for the exact colour you may want to choose one of these dyes. Just remember the colour will wash out and fade. As a general rule, dyes that come from flowers or vegetables are fugitive.

Other fugitive dyes are rose petals, turmeric, and spinach. Some professional natural dyers are a bit dismissive of these fugitive dyes because they may not be of a commercial quality. For first time natural dyers they are ideal because they are easy to find in your store cupboard or larder.

About Mordants.

The most usual mordant for adjective and fugitive dyes is a combination or alum and cream of tarter. Alum is a naturally occurring chemical salt, commonly used in a wide variety of products including foods, deodorants and aftershave. It is easily available from online supermarkets. Cream of tartar is used as a raising agent in home baking and can be bought from the supermarket.

These 2 minerals are used in combination, in varying proportions, according to the dye colour to be fixed. Mordant literally means ” to bite” or “to grip” in French and this is what it does. It helps the colour grip to the fibre.

In years gone by, mordants were made from metals like tin. These are hardly ever used now due to the toxicity. Alum and cream of tarter are both harmless. Mordant solution can be safely disposed of down the sink or drain, or poured onto the garden.

Want to know more?

There are a wealth of natural dye books available, as well as courses ranging from beginners to advanced and covering all aspects of natural dyeing.

Please email me if you need help finding resources in your area.

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