When I first looked into natural dyeing it seemed so complicated and I didn't think I'd ever be able to do it. Once I'd figured it all out, I realised it's actually quite simple, so I decided to write a tutorial for anyone else who thinks the whole thing looks very exciting but a bit too complicated. I've never written a tutorial before so please comment or send me a message on my tumblr if something doesn't make sense.
There are 4 main steps:
a) Scour wool
b) Mordant wool
c) Make dye
d) Dye wool
And there are a few more than 4 ingredients:
Yarn - must be 100% or a high percentage NATURAL fibres. This includes wool, bamboo, merino etc.
A few old saucepans - most tutorials suggest a big pot like an old pressure cooker, but it depends how much wool you want to dye at a time. If the wool fits comfortably then it's fine. I say old saucepans because it's best not to eat out of them once they've been used for dyeing (I assume because of unknown chemical reactions, or if using garden plants that might be poisonous...but I don't really know!)
Dye material - anything that you think might have colour in it. I will post a list of things I've used after this tutorial.
A mordant - alum (aluminium potassium sulphate if you want to find it on ebay!), vinegar or salt.
A sieve - should probably also be one you won't use for cooking.
Cream of tartar if using alum
Essentially this just means to wash wool. It's easy to do, simply soak the skeins of wool in warm soapy water for 2 hours or longer. I use washing-up liquid because it's quite tough so should get rid of the natural oils or any treatments on the wool. Rinse in cold water afterwards. It's best not to go from cold to hot temperatures too quickly because the wool will start to felt.
There are a few different options here, but alum is the safest (no fumes) and most consistently satisfying that I've used. Other options are salt (for berries or fruit-based dyes), vinegar (for vegetable and other plant dyes), or iron sulphate (I've never used it but apparently it 'saddens' colours).
To mordant with alum, use 8g of alum and 7g of cream of tartar per 100g of wool (weighed dry). My scales are awful so my amounts are probably horribly off and it still works, so don't stress about making the weights super exact. Dissolve these in boiling water, then add more water to fill the pot. The website I used suggested a 10 litre pot for 100g of yarn but I forgot about that so ended up dyeing at least 400-500g in my 10 litre pot. It doesn't seem to have made any difference as long as the wool is saturated with water. Add the wool then bring the water to boil and simmer for an hour. If you simmer for longer than this it will start to smell like wet dog, so not a good idea. Either leave to cool and rinse in cold water, or rinse in hot water straight away. Once again, you don't want sudden temperature changes or the wool will start to felt.
To mordant with vinegar use 1 part white vinegar to 4 parts water, put the wool in and simmer for an hour, then rinse. This really smells so make sure you ventilate the room!
To mordant with salt use 1 part salt to 16 parts water, put the wool in and simmer for an hour, then rinse.
The main difference between using salt/vinegar and using alum, is that alum will give deeper and more contrasting colours, whereas salt and vinegar both give pastel colours. I use alum for all of my dyes and if I want a pastel colour I just use a more diluted dye.
c) Making dye
The general rule is 100g of dyestuff to 100g of wool. When you're experimenting that's probably a good place to start, and then once you've got an idea of how it works you can just make it up. NOTE, do not use 100g of onion peel! The peel from just 1 or 2 onions can dye a whole 100g of wool, you don't need very much at all.
Chop up your dyestuff, or mush it up a bit if it's berries and cover with water (about twice the amount of water to dyestuff). Bring to the boil and simmer for up to an hour.
Once it's reached an hour it's unlikely more colour will come out. With stuff like onion peel you only need to simmer for about 10 minutes. Strain the bits out using a sieve.
For beans or other dried things that you need to soak (black beans, for example), soak for 12 hours, drain (and save!), then soak for another 12 hours and use both lots of drained water for your dye.
Put the wool into the dye. If you want to be sure that it will dye evenly, wet the wool before putting it into the dye, or wear rubber gloves and squeeze it until it is saturated with dye.
Simmer for an hour. Don't let the dye boil because the agitation will almost certainly felt the wool.
You can also cold dye the wool. I do this using jars, and leave the wool to soak for 24 hours before rinsing it out. Some colours seem to work better with cold dyeing, and others better with hot, it's all about experimentation.
Rinse out the wool and hang it to dry. Wool holds a LOT of water so give it a gentle squeeze before hanging it out to dry or it will take days.
I have a few specific posts on tumblr showing how I used each dye material, so click here for those.