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.
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.
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.
Myrobalan - This dyestuff consists of ground nuts of the Terminalia chebula tree. This tree grows in Nepal, India, Sri Lanka, Burma, Thailand, Indochina and south China. It may be classed as both a mordant and a dye, giving a light buttery yellow when applied. It is an important tannin based mordant for cotton in India and southeast Asia due to the light warm colour it imparts to the cloth. Myrobalan is a good foundation for overdyeing. It is also the perfect colour to lay down under a single indigo dip for teal. When used as a tannin mordant myrobalan requires 15-20% WOF. If using to create a soft butter yellow use 20-30% WOF.
Mordanting: use alum mordant at 15% WOF for protein fibres and cellulose fibres (there is enough tannin in the myrobalan so that mordanting with tannin is not required).
Dyeing: Add myrobalan powder to the dye or mordant bath, bring bath up to 55ºC (130ºF) and then add fibre. Continue heating bath to a high simmer (approximately 83ºC (180ºF)) hold for one hour. Adding iron (2-4% WOF) to the bath will produce soft lichen greens to deep grey-greens.