The wood of Caesalpinia sappon was used on a large international scale throughout world history and remained a major source of red dye up to the end of the 19th century – once popular in late medieval times. It is still used on a smaller scale by craftsmen and artists today.
It can be used to dye silk, wool, cotton, matting and basket fibres.
The wood is ground into a course powder or wood chips – moistened with water and fermented for a few weeks to increase the colour power of the dye.
For crimson reds:-
Mordant protein fibres at 15% WOF. Mordant cellulose fabrics with tannin 8% and then alum at 15%
The dye takes time to be extracted – simmer 50% WOF of the wood chips for 1 – 3 hours and leave to cool overnight.
(50g of brazilwood will yield deep reds for every 100g of mordanted fibre.)
The next day – strain through cheesecloth or a plastic sieve.
The strained woodchips can be dried and used again for paler colours.
Pour the strained liquor into the dye bucket and with sufficient water to cover the intended material to be dyed so that it can be fully submerged and move freely around the dye bath. At this point add a little chalk (calcium carbonate) as this will make a difference to the colour achieved. Without the addition of calcium carbonate the fibres are likely to lean towards orange (you may want that) however by adding just a pinch of chalk (dissolved in hot water and stirred) the colour turns red. Adding another pinch of chalk changes the colour again – leaning towards crimson and lavender.
Add pre-wetted mordanted fibre to the dye bath and simmer for an hour.. Leave to cool.
Rinse. Wash. Rinse.
Dry out of direct sunlight.
The first dyebath will produce a crimson red, The second dyebath can be used to achieve beautiful shades of pink and coral.
By changing the pH to acidic (vinegar) you can get an orange-red colour or alkaline (soda ash) you can get blue-red to purple.
A small amount of iron will turn the fibre towards lavender.