We have two herbal mordants for natural dyes. They are made primarily from Myrobalan which like other plant-based mordants, gallnuts, sumac or tara pods, is high in tannins. These are very eco-friendly mordants and help to give very rich colors.
The first, simply named Herbal Mordant is made from a combination of Myrobalan (Terminalia Chebula) and Pomegranate (Punica Granatum). The second, Natural Mordant is a Myrobalan extract and is more specifically for cellulose fibers like cotton, hemp and linen.
Myrobalan and pomegranate are also used as dyes but they are high in tannins which also makes them good mordants. Herbal Mordant can be used for all fibers. It is very easy to use, eco-friendly and requires a very small amount, only requiring 4% weight of fiber. So, for example, if dyeing 100 gm of fiber, you would use 4 gm of mordant (one kilogram of fiber, use 40 grams of mordant; one pound of fiber, use .6 an ounce of mordant). For cellulose fibers you follow with a second mordant of alum sulphate or alum acetate for even better results.
To use this mordant, mix the powder with hot water into a paste and then mix into a larger pot of hot water. This mordant will not fully dissolve. There will still be bits of plant material but because so little is required, it is quite easy to rinse out of the fiber. Allow the mordant bath to simmer for about 20-30 minutes. Cotton-type fibers can then be added immediately and simmered for another 30-60 minutes. For wool, allow to cool back to room temperature, add the fiber and either allow to sit for at least 24 hours or gently reheat for 30-60 minutes. The bath should again be cooled down before removing the wool. This is to prevent felting as much as possible. Silk does not shrink but be careful not to raise the water temperature above 80C (176F) or it can lose it's sheen.
Once mordanting is finished, remove the fiber from the bath and rinse it well (handle wool very gently to prevent felting - have a rinse bath ready to lower the fiber into). Once fiber is rinsed it can be dyed immediately or fully dried and stored for future dyeing.
Natural Mordant can also be used on all fibers but it is significantly more expensive and so is recommended for cellulose fibers in particular. Cellulose does not take to natural dyes as readily as protein fibers like wool and silk so Natural Mordant definitely improves the outcome. It can be used alone but can also be used, like tannic acid or Herbal Mordant, as a pre-step to the mineral mordants. Alum and other mineral mordants do not bind to cellulose fibers as well without tannic acid first (or myrobalan or other high tannin plants).
For the Natural Mordant, use about 5% weight of fiber. Mix the powder extract with hot water. At first it will be gummy and it takes a few minutes to dissolve. Unlike the other, this mordant will fully dissolve. Add this mix to a larger pot of hot water. There is no need to simmer this mordant bath before adding the cotton or other cellulose fiber. Once the fiber is in, it can be simmered for about 30 minutes or allowed to sit for at least 24 hours. After this, remove the fiber and rinse it well. It can then be dyed or fully dried for future dyeing.
Warning: It is very important not to allow the fiber to air dry before the Natural Mordant has been fully rinsed out. Even when it is still in the mordant bath, do not allow the fiber to come above the water line. If dried on the fiber, this mordant will stain the fiber a dark brown which cannot be removed.
Blue Castle Fiber Arts is a small on-line fiber arts business and importer of natural dyes from India. We are located on the beautiful shores of Lake Ontario in Hamilton, Ontario, Canada.
This website focuses on our easy-to-use natural dyes and you will find plenty of information about them and how to use them. You can also visit our supplier's website here: Sam Vegetable Colours.