Cutch Extract – This powder is an extract prepared from steeping the wood of the Acacia catechu tree in hot water until a syrupy liquid immerges. This is dried and then ground into powder. It is common to most parts of India, Burma, Indonesia and Peru. Indian cutch is by far the most beautiful. It is a good source of colourfast shades of brown - cinnamon, nutmeg, and clove. Cutch extract contains tannin as well as the dye compound catechu. It is easily soluble in water. Cutch has excellent light and washfast properties. It requires 20-50% WOF to dye a medium depth of shade.
Mordanting: use alum mordant at 15% WOF for both protein and cellulose fibres (there is enough tannin in cutch so mordanting with tannin is not required).
Dyeing: completely dissolve the powdered cutch (sometimes cutch will come a little chunky) in boiling water and add it to dyebath.
Deeper colours can be achieved by first soaking the cutch extract in a weak mixture of caustic soda. Add 1 tsp lye or sodium hydroxide to 4 litres (1 gallon) of water. Soak for 1 hour. Then add more water and neutralize with acetic acid or vinegar to pH7. Add this neutral solution to the dyebath.
Fibres are then added and the dyebath is kept at a low simmer for at least two hours. Cutch does not easily exhaust and dyebaths can be used multiple times for lighter shades.
The alum mordant yields toffee browns. The addition of iron at 2-4% WOF yields chocolate browns, while a soda ash rinse will redden the cutch colour. The addition of 2% WOF hydrogen peroxide during the final 15 minutes of dyeing will darken cutch considerably. Allowing the fibre to cool down and sit in the dyebath overnight will give the darkest shades.