Natural dyes produce an extraordinary diversity of rich and complex colours as well as unexpected results, making them exciting to use. It is easy to design using natural colours as they complement each other well and rarely clash. Synthetic dyes, on the other hand, often look bright and garish and they require more skill in colour matching.
Naturally dyed yarns are full of pleasant surprises as well as being great motivators. You will find that you cannot wait to get back to work on your knitted jumper, cotton quilt or woven cushion and you will probably end up with very few unfinished or abandoned projects. Another advantage is that leftover yarn from one project can easily be incorporated into the next, avoiding a stash of unwanted yarns.
Where do they come from?
Most natural dyes come from dye plants, the best-known ones being woad, weld and madder from Europe, and brazilwood, logwood and indigo from the tropics. Some, such as cochineal, come from insects and a small number, including iron and copper salts, come from mineral sources.
Plant dyes may contain several compounds and their proportions vary with the type of soil and the climate where the plants were grown. A yarn dyed with madder roots has a wealth of colour variation, whilst the same yarn dyed with its synthetic equivalent, alizarin, lacks this subtle variation in colour and can look very uniform.
How permanent are they?
Some people think that plants produce only pale colours and that these colours fade quickly. Several plants do indeed yield fugitive or pale colours but traditional dye plants produce vibrant blues, greens, reds and yellows that can last for centuries.
If you look at well preserved textiles in museums, you will see that natural dyes age well. The same red in a newly finished Persian carpet mellows into different hues from the various dye lots that have been used, giving much pleasure to the eye. Synthetic dyes, on the other hand, fade rather than mature.
The secret of bright and long-lasting colours is good preparation and, like home baked bread, natural dyes require time. The yarns need to be properly scoured and mordanted before they are dyed. They may sit in the dye vat from an hour up to a month and the colours benefit from curing before the yarn is washed. Some people are put off by this lengthy process but most of the time the yarn is left unattended and you can get on with something else.
What about the mordants? Isn’t chrome toxic? Although chrome has often been used as a mordant, there is no need to use it if you don’t want to. The most popular wool mordants in current use are alum and cream of tartar and they are quite safe. Alum, for example, is used to treat drinking water and cream of tartar is used in baking cakes.
How long does it take?
Short of time? Synthetic dyes are like fast food, fine if you want quick results. They are also the pragmatic solution if you want to repeat the same colour precisely, although they require more calculation and measurement to achieve this. Natural dye extracts, however, are just as quick to use as synthetics but produce the genuine natural colours of real natural dyes.
Natural dyes usually require larger quantities than synthetic dyes. To dye 100 grams of wool for example, you might need up to 50 grams of dried madder root. Natural dye extracts do not require such large quantities and 10 grams of madder extract should easily dye 100 grams of wool. Some natural dyes are very strong and small amounts of cochineal, brazilwood and logwood dye a large amount of fibre. Synthetic dyes may be less costly to buy than natural dyes but the main cost is your time if you grow your own plant dyes and if you use the sun as a source of energy.