Henna – the leaves are harvested from the shrub Lawsonia inermis. Henna produces a brown colour tending toward a red-orange on protien fibres. The dye comes from leaves that are dried and ground into a powder. Henna bonds well with protein, hence is used to dye skin (mendhi), hair, fingernails, leather, silk and wool. On cellulose fibres henna yields light yellow greens.
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: when using ground henna at 20-50% WOF on mordanted fibres, rich browns are achieved on protein fibres and “latte” like colours to soft greens on cellulose fibres. There is no need to make an extract, just add the powder directly to the dyebath. Simmer the fibres in the dyebath until the desired colour is obtained – approximately 1-2 hours.
Iron at 2-4% can slightly deepen and enrichen the brown colour. Altering the pH of the henna dyebath does not alter the colour.