I like to show you how I use them, which is one of the many different ways to dye with onion skins.
I keep all the skins when we use onions and put them in a little fruitnet or in a paper bag, so that the air can get to them and they dry in the bag. When I have collected enough onion skins, minimum 100g of onion skins for 100g of dry weigth of fibres, I get some wool or silk together and prepare it for dyeing. See my previous post:
A mordant is needed for the dye to fix well to the fibres. Mordants will help the fibres to absorb the dye and make them colour fast.
I use alum (aluminium potassium sulphate). You can find this salt in many pharmacies. If you are lucky like me, you might be able to find the natural rock alum. I am very happy with that and I use it in the same way.
After washing the fibres well, I fill my dye pot with enough water, so that the fibres can move loosely. ( you can use a pot in any material, it will though affect the end result; stainless steel is neutral and will not react with the fibres).
I weigh the alum; 10% of the dry weight of the fibres, if you are going to dye wool and 20% for silk; and dissolve into the water.
Time to put the fibres in the pot and heat them to just under boiling temperature. I leave it at that temperature for about an hour and than let it cool down slowly.
You can let it go to boiling temperature and simmer it for an hour.
I avoid that for the following reasons:
-silk looses some of its lustre when boiled.
-I often dye wool slivers for feltmaking and if I would simmer them, they are more prone to start felting already in the dyepot, which makes felting harder later on.
I turn off the heat source and let the fibres cool down in the pot. I usually leave them in the alum solution overnight, so that the alum can more penetrate into the fibres.
Meanwhile, I soak the onion skins in water overnight and bring to just under boiling temperature the next day. When the solution is cooled down, I pass it through a sieve, even through a cloth, so that no little pieces stay in the water and dirty the wool. I dry the onion skins and use them for a later dye bath, they will give off less colour though.
Now, I can add the fibres to the onion water and bring the temperature to just under boiling point, leaving it there for about 60 to 90 minutes. If you try this, make sure all the fibres are completely immersed in the water. I do not stir too much when I am dyeing wool slivers, when dyeing with silk, I stir now and than.
I usually leave the fibres in the dye bath overnight.
Rinse and dry.
The result of the silk dyed in the first dye bath.
Onion skins give a beautiful gold colour. It is possible to dye more fibre in the leftover dye bath, it just will produce a lighter colour.
This silk is dyed in the second dye bath and shows a much lighter colour.
Here are a few possibilities to alter the colour and get different colours out of one dye bath:
1. alum mordant
2. alum mordant and put into a solution of washing soda after the dyeing.
3. alum mordant and put into iron water made with rusted nails, the colour gets more green if it is left in there for longer
4. is number 3 put into a solution of washing soda afterwards.
This shows how we can modify the colour by altering the pH. Adding lemon juice or vinegar will turn the wool more yellow. It is fun to play with these possibilities.