This section contains information on natural dyes, eco-dyeing and dyeing techniques. It is a work in progress and new information will be added in a structured way on a regular basis. We hope you will find it useful and that it will inspire you to try new, adventurous and beautiful dyeing projects!
Alum The specific compound is hydrated potassium aluminium sulfate (potassium alum). Alum has been used as a mordant since ancient times and is already mentioned in Egyptian papyri (see Early Uses of Natural Dyes).
Alum can be obtained from alunite, bauxite or clays. The process for each is slightly different but involves calcinating and mixing it with sulphuric acid, and removing traces of iron. The end result, potassium aluminium sulfate, is a purified product. Contamination with iron sulfate was greatly disliked even in ancient times as it darkened and dulled dye colours (see About Alum).
Alum is one of the mordants which produces brighter colours. Curiously in Birmingham, UK, there is an area called "Alum Rock".
Iron Iron is a mordant, a colour modifier and a dye. As a colour modifier, it "saddens", or darkens, fibre colours, resulting in less bright and saturated colours compared to alum.
Iron water As its name indicates, iron water is water which contains some form of iron, and which can be added to a dye-bath. There are two main sources of iron water, both used by dyers.
1. Ferrous sulphate is a light blue-green powder, ready to use. Dissolving a very small amount in water is sufficient. After a while, the solid deposit takes the familiar orange colour of rust.
2. Homemade iron water, preferred by eco-dyers: put small iron objects, such as nails, in a container with water and leave to rust. The addition of a small amount of salt or hydrogen peroxide greatly speeds up the rusting process.
The use of iron water as a dye is described by Jenny Dean in her book Colours from Nature. It produces a yellow/orange colour in fibre.
Note: Like most things in natural dyeing, you need to experiment to find the iron concentration and dyeing time that produces the required result. Commercial ferrous sulphate can be weighed in order to control iron concentration and achieve some level of reproducibility, which is virtually impossible with home-made iron water.
Copper Copper is poisonous and we not recommend its use.
Mordant Mordants are substances which fix the dye to the fibre. In fact, most natural dyes would not set on natural fibres without the use of mordants, before or during the dyeing process. Mordants also have an effect on the resulting colour and hue. Some dyes like indigo do not require the use of mordants. See Mordants for a more in-depth explanation.
Myrobalan The common name myrobalan can refer to several unrelated fruit-bearing plant species, so the botanical name of the species is necessary in order to identify the exact kind. The results are different depending on species. The most common types are terminalia chebula, terminalia bellirica or phyllanthus emblica linn. In natural dyeing, myrobalan is the powder obtained by grinding the myrobalan nuts, which is rich in tannins and behaves both as a mordant and a dye, dyeing fabric a golden colour.
The advantage of using myrobalans is that they provide an all vegetable solution without the use of commercial or home-made chemical products.