Lac
Laccifer lacca
Lac Extract – From the scale insect Kerria lacca found throughout India, south east Asia, Nepal, Burma, Bhutan and south China. Lac is found in the wild and is also cultivated. The female lac insects invade host trees and the insect secretes a resin that covers its colony. When harvested, the covering is broken off the branches and is known as stick lac. The resin is used to make shellac. The dye must be extracted from the stick lac before it can be used to colour cloth.
Lac extract yields crimsons to burgundy reds to deep purples. The colours are similar to those from cochineal but warmer, softer, and more muted. The lac dye has high light and washfastness on silk and wool. Only small quantities are needed for a medium depth of shade.
See the MAIWA GUIDE TO NATURAL DYES
Mordanting: Use alum mordant at 15% WOF for protein fibres. For cellulose, first mordant with tannin at 8% WOF, then either 1) use alum at 15% with soda ash at 2% or 2) use aluminum acetate at 8%. Note that lac extract has reduced light and washfastness on cellulose fibres.
Dyeing with the extract: Use at 5-10% WOF for a medium to dark depth of shade. Dissolve extract in water and simmer with fibre for 45 minutes, leave overnight for richest colours.
Options: Lac is very sensitive to pH. A beautiful red can be obtained by adding cream of tartar at 6% WOF. Alternatively, adding an alkali like soda ash will yield plum purples. The addition of iron at 1-2% WOF will give blackened purples.
Below: Lac 20% WOF
