Lac extract is a red dye extract from the scale insect Laccifer lacca.
The female lac insects invade host trees and secretes a resin that contains red dye.
The resin is harvested from the branches and is known as sticklac.
There are two primary components – the resin and the dye. To be useful for dyeing the colourant is separated from the resin – it is then referred to as lac extract. The resin is used to make shallac. It is used for lacquer and as a protective covering for wood.
Lac extract yields crimsons to burgundy reds to deep purples. It is similar to cochineal but the colours are softer and more muted.
It has good light and washfastness on silk and wool – but not so good on cellulose fibres.
MORDANT – Alum mordant with 15% WOF on protein fibres – 8% tannin and 15% alum on cellulose fibre.
DYEING WITH LAC – Lac is a strong natural dye.
10g of extract will dye 100g of fibre.
With warm water make a paste with the lac extract.
3/4 fill a dye bucket with water and add the lac paste.
Simmer gently for 1 hour. Turn off heat. Leave to cool.
The addition of an alkali like soda ash will yield plum/purples and the addition of iron will yield blackened purples.
Add mordanted – pre-wetted fibre to the dye bucket.
Raise temperature to a gentle simmer and hold at that temperature for 1 hour – stirring gently from time to time.
Turn off heat.
Leave to cool and soak overnight.
Wash. Rinse. Wash