Lac Extract – a red dye extract from the scale insect Laccifer lacca which is found throughout India, south east Asia, Nepal, Burma, Bhutan and south China. It is found both in the wild and cultivated. The female lac insects invade host trees (mainly fig and acacia) and the insect secretes a resin that contains the red dye. When harvested, the resin is taken off the branches and is known as stick lac. The resin is also used to make shellac. The dye must be extracted from the resin before it can be used to colour cloth.
Lac extract yields crimsons to burgundy reds to deep purples. The colourant is similar to cochineal but colours achieved are warmer, softer, and more muted. The lac dye has high light and washfastness on silk and wool. 5-8% dye to WOF is all that is needed for a medium depth of shade.
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% – but note that lac extract has reduced light and washfastness on cellulose fibres.
Dyeing: Use at 10-15% WOF. Dissolve extract in water and simmer with fibre for 45 minutes, leaving overnight for richest colours. This dye is very sensitive to change in pH and develops to its fullest colour potential with the addition of cream of tartar at 6% WOF. The addition of an alkali like soda ash will yield plum purples and the addition of iron will give blackened purples.
See also Maiwa's Guide to Natural Dyes.
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.
Cochineal – is the most important of the insect dyes. The females of Dactylopius coccus colonize the prickly pear (nopal) cactus native to Mexico, Central and South America and the Canary Islands. Peru is currently the primary export country, shipping out over 4000 metric tons annually. This dye is found mostly in food, drugs and cosmetics. Cochineal has excellent light and washfastness and produces a powerful range of fuchsias, reds and purples. The colour changes with the mordants used and pH of the dyebath.
Although expensive, it is very concentrated. The bugs have a high dye content (carminic acid) and go a long way. You will need only 3-8% WOF for a medium depth of shade.
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%. If cream of tartar at 6% WOF is added to the alum mordanting bath or the dyebath, the colour achieved will be more towards Christmas red. With the addition of iron at 2-4% WOF to either the mordanting bath or the dye bath the colour will shift towards purple.
Dyeing: The colourant is first extracted from the dried insects. Gently grind the insects in a blender or use a mortar and pestle to crush them to a fine powder. Put this powder into a saucepan and cover with three inches of water. Boil for 30 minutes. Strain the liquid and set aside. Place the cochineal pulp back in the saucepan and again cover with water and boil for 30 minutes. Add this decanting to the first decanting. Repeat 2 more times. Some dyers will then keep the remaining pulp in a jar of water for several weeks and use in subsequent dyebaths.
The combined decantings are used to make a dyebath.
Cochineal is sensitive to acids and bases. The cochineal rich red can be shifted to orange with the addition of an acid (vinegar) and to a deep fuschia with the addition of an alkaline (soda ash). This sensitivity means the soaps used to pre or post wash your fibres must have a neutral pH.
Indigo (natural) – natural indigo powder is an extract prepared from Indigofera tinctoria which is cultivated for this purpose. Indigo is the legendary source of colourfast blues and its ability to produce a wide range of shades has made it the most successful dye plant ever known. Indigo grows all over the world but flourishes best in hot, sunny, humid areas. Indigo can give clear blues that range from the tint of a pale sky to a deep navy that is almost black. Our indigo comes from a farm in south India and is very strong (approx 50% indigotin). It reduces beautifully in an indigo vat. See Maiwa's Indigo Data Sheet for complete instructions.