Alkanet – Alkanna tinctoria or dyer’s alkanet is a very attractive purple colourant that is found in the roots of plants belonging to the borage family. It grows uncultivated throughout central Europe and extends to central Asia and North Africa. The extracted pigment is often used in cosmetics, soaps and pigments. The violet colourant from alkanet is not soluble in water. Before a dyebath is made the alkanet root must be soaked in a solution of alcohol and hot water – colourless rubbing alcohol or methylated spirits can be used (some dyers who do not like the smell of either of these solvents use vodka!). The colours produced on mordanted fabric and yarns are shades of grey, lavender and purple when used at 75-100% WOF. The colours achieved are beautiful but have moderate light fastness.
Mordanting: use alum mordant at 15% WOF for protein fibres. For cellulose mordant with tannin at 8% WOF and then alum at 15%, or alum acetate at 8%.
Dyeing: Use dried alkanet at approximately 75-100% WOF for rich colours. First, soak the alkanet in alcohol (or methylated spirits) for several days to extract the colour. When the liquid has developed a strong colour, add enough water for the fibres to move freely in the solution. Add the mordanted fibres and heat this dyebath up gently - but no higher than 60ºC (140ºF) - until all the colour has been taken up.
Adding iron to the dyebath at 2% WOF creates a range of greys and grey-violets.