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Choosing Which Fibres To Use With Natural Dyes

It might seem obvious to assume that natural dyes derived from plants would work best on plant based fibres, but this isn’t always the case. There’s certainly some things which do work best on plant (cellulose based) fibres, but others work far better on animal (protein based) fibres. So how do you choose, and how is the process of dyeing different for cellulose and protein fibres?

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Which fibre to use

Choosing a fibre to use is a very subjective thing, there’s no right or wrong answer – as long as it’s a natural fibre or something derived from a natural fibre, like Tencel, as trying to use natural dyes on synthetic fibres just won’t work. The right fibre for you could be whatever you think is right for a project, a person you’re giving the fibres to after dyeing, or perhaps just wanting to experiment with something new.

Typically, the most common fibre to dye with is sheep’s wool. There’s a few reasons for this – it’s not overly expensive, pretty easy to get hold of, and there are lots of dyestuffs which work especially well on sheep’s wool. There could be several reasons why you don’t want to work with sheep’s wool though – perhaps you’re allergic to it or maybe you’re vegan – and so (unsurprisingly) the next most common fibre to dye with is cotton. These are by no means the only fibres you have to choose from though – especially plant based fibres, as there’s more innovation every year, with the ability to create yarns from roses, seaweed, mint and even lotus plants. There aren’t yet that many yarns made from these fibres though, so you may have to wait for spinners to start producing yarns from these fibres, unless you’re a spinner yourself.

Experimenting with using natural dyes on undyed natural fibres is extremely fun
Different natural dyes will produce different colours depending on the type of fibre you're trying to dye

Dyers will typically learn to love one fibre in particular, but there’s nothing stopping you from experimenting with new and different fibres. The best advice I can offer on choosing a yarn is to choose what’s right for you and what you’re wanting to achieve – if you’re planning on making a super snuggly winter jumper, alpaca might be best (it’s very warm while also being reasonably lightweight, soft and hypoallergenic) whereas if you want to make a summer top then something like bamboo or linen might be a good idea (they’re lightweight, breathable and more sustainable than cotton).

Not all plant fibres react to natural dyes the same way, neither do protein fibres – and often cellulose fibres will have an entirely different colour to protein ones (brown onion skins yield a rusty colour on wool and a sunny yellow on cotton, for example). If you want to dye a specific type of fibre, it’s therefore always best to dye a small sample piece first. This will give you a better idea of the colour and intensity to expect when dyeing a larger quantity of that fibre.

Mordanting your fibres

If you haven’t heard this term before, mordants are the fixing agent for a dye; depending on who you ask, the word derives from the French and/or Latin word meaning “to bite”. Mordanting is usually done before applying dye to your fibres, so that when exposed to colour your fibre can properly absorb the pigments and form a chemical bond with the fibre – though sometimes you can mordant at the same time as or even after dyeing.

The most common mordant used in natural dyeing is alum (potassium aluminium sulfate) which is non-toxic and generally considered the safest mineral mordant you can use. You can mordant both protein and cellulose fibres with alum, though it’s necessary to add cream of tartar when mordanting protein fibres, as this helps the fibres retain clear, bright colours when dyeing.

You can also mordant with iron, copper, tin and chrome, but as you go through that list they get progressively more dangerous – for you as well as the environment. I therefore wouldn’t recommend mordanting with any of them, though its up to you whether you choose to use iron or copper as a colour modifier.

Aside from the mineral mordants, there are also a few plant mordants.

If you’re using cellulose fibres, you could have a go at mordanting with tannins from myrobalan, oak galls or perhaps staghorn sumac. Tannins can be used on most cellulose fibres, though do be aware that some people can have a severe allergic reaction to staghorn sumac.

The high concentration of oxalic acid makes rhubarb a powerful natural mordant which has been used by Tibetans for centuries to mordant protein fibres – though be sure to use a well ventilated area if mordanting with rhubarb, as oxalic acid is poisonous and the fumes really aren’t good for you.

There’s also several fixatives you might wish to try, either in addition to or instead of mordants. Fixatives are different to mordants in that they tend to coat the fibre rather than chemically bonding with it. There’s a bit of a debate over whether mordants and fixatives are the same thing or not, but it seems to be a bit of “you say tom-ay-to, I say tom-ah-to“. They do very, very similar jobs.

Cultures around the world have used salt or salt combined with lemon juice as a fixative for natural dyes for many years. The traditional dyeing centres I visited while in Peru used this combination on the alpaca yarn they spun. Salt is also commonly used to fix chemical dyes to plant fibres like cotton and linen, preventing colour bleeding while washing. Alternatively, you can try vinegar, baking soda or even soya milk as a fixative. (Note: if you’re allergic to soya but want to try milk, it seems that most protein based milks can act as a fixative too, such as almond or even cow’s milk).

Choosing which natural dyes to use on your fibres

Natural dyeing in Peru uses a lot of different plants
Here you can see a selection of plants used for natural dyeing in Peru and the colours they produce on alpaca yarn

This is where things can get a little tricky. A dyestuff that works beautifully on a protein fibre might not work at all on a cellulose fibre – in which case it may be worth giving milk a go as your fixative and seeing what the results are, as it’s protein based.

Start by working out what colour you want to try dyeing and go from there. There’s so many plants which give subtly different shades of the same colour that you’re bound to find something which works for you. If you haven’t already got a copy, I’d recommend Wild Colour by Jenny Dean – this book is widely seen as the bible for natural dyeing and contains lots of information on dyestuffs, including the colours they produce and whether they work best on protein or cellulose fibres. Likewise, The Modern Natural Dyer by Kristine Vejar looks to be a fantastic resource, containing such useful things as a colour chart for dyes which readily take to cellulose fibres, so you’ll have a good idea of what dyestuffs to start experimenting with when dyeing cellulose fibres.

Lots of dyestuffs can also produce different colours using colour modifiers or if you overdye them with something else – dyer’s greenweed and woad is a typical source of a bright, clear green for example, which is a surprisingly difficult colour to get naturally from dyestuffs. Colour modifiers are exactly as they sound – you use them generally after dyeing and they can produce a different colour to what you might normally get from a dyestuff. Iron can be used as a colour modifier, though it typically “saddens” colours by making them darker, more muted shades. Alternatively, some dyestuffs are sensitive to PH levels and it’s possible to get different colours by exposing the dyed yarn to either acidic or alkaline solutions. Red cabbage is the perfect example of this, producing a lovely turquoise in PH neutral water, bright blue in alkaline solutions and bright pink in acidic solutions.

I’ve experimented with a few “exotic” dyes (ones that need to be imported for use as a dyestuff) but I think once I’ve used these dyestuffs up I’d prefer to use dyes which are either locally available (in my kitchen, garden or local area) or readily grow in the UK. It just appeals more to me to create colour from what’s already around me here in the UK. If you choose to use imported dyestuffs, that’s okay too though – it’s a personal choice.

If you want to buy dyestuffs here in the UK, check out my post Another Way To Dye which has details on suppliers, as well as going into more detail about how to get started in natural dyeing.

Let the experiments commence!

While some natural dyes will produce easily repeatable results, you might find it takes a bit of experimenting to get things exactly as you might want. It’s a lot of fun experimenting with different dyestuffs, colour modifiers and fibre types though. Even experimenting with different water hardnesses and methods of dyeing (solar pots, cold water dyeing) gives interesting results and you may find you like the power efficiency of these options more than the speed that heating your dyes on a hob provides.

Learning to use natural dyes doesn't need to be expensive - you can use equipment you probably already have

Dyeing can also easily be done with equipment you have already in your kitchen or can be purchased at a low cost, though as you get further into your experiments you may need to look at catering equipment for producing larger batches of yarn. I currently have a 10L pot for bigger batches of yarn, though I can only really fit 500g of yarn in there, so if I start producing yarn as a product line I’d likely get an even bigger pot from a catering supplier to allow me to do bigger batches. This is important when you’re making things like jumpers, as these often require a lot of yarn – the sweater I made for my dad for Christmas ended up using 800g of wool and you could see the colour difference in the different batches of yarn I dyed (not that my dad cares and not that it detracts from the sweater in any real way).

Make sure to have fun and if you find a fibre you really love to work with, fantastic – but don’t let that stop you from continuing to experiment. I can almost guarantee you’ll become addicted to the feeling of being equal parts witch/wizard to mad scientist!