Tannins for natural dyes
“Tea! that’s all I need, a good cup of tea”
Definition of tannin: a yellowish or brownish bitter-tasting organic substance present in some galls, barks, and other plant tissues, consisting of derivatives of gallic acid.
Tannins are used to assist some mordants for cellulose fibres and fabrics. Aluminium Potassium Sulfate does not bond very well with cellulose fibres and using a tannin can help it bond with the cellulose fibre. Many dyestuffs already contain tannin (pomegranate rinds, cutch, oak gall and eucalyptus etc.) these dyes do not need an additional tannin to help the Aluminium Potassium Sulfate bond.
Tannins can range in colour some are clear others add colour to the fibre. This is something to be aware of when you select your tannin for the mordant process. It’s a great idea to experiment with different tannin swatches and find the one that works best for you.
The guide below will help to give you an idea of which tannins will produce which colour.
Yellow Tannins: – Myrobalan, Pomegranate, Black Oak, Fustic
Red-Brown Tannins: – Cutch, Mimosa, Quebracho, Tea leaves, and some Sumacs.
Although some dyes contain tannins there is a technical difference between a dye and a tannin:
Tannins are a class of poly biomolecules that bind to the proteins of various organic compounds including amino acids. The term refers to the use of oak and other bark.
Tannins are described in species of the plant kingdom and are found in gymnosperm and angiosperms.
A dye is a coloured substance that is chemically bonded to another substance to which it's applied.
Dyes are coloured as they absorb the sunlight wavelength and are soluble in water. They are derived from the roots, barks and leaves.
