Lac is a natural dye that is extracted from scale insects (Kerria lacca) found in Asia. Lac has been used as a natural dye for hundreds of years.
You will get reds from lac, ranging from crimson to burgundy. Lac reds are softer and warmer than cochineal reds. A pinch of iron modifies the colours towards purple.
Lac is very sensitive to pH, an increase in alkalinity turns the colours plum purple, while acidity gives bright oranges. However, colours that have been modified by a change in pH can change back to red after rinsing.
Wash and mordant the wool (follow Scouring the wool and Mordanting with alum for details).
Make a paste with 1 teaspoon (6 grams) Lac extract and a small amount of warm water. Fill a saucepan with water and add the Lac extract paste.
Add the pre-wetted mordanted fibre. Bring the dye bath to a gentle simmer (about 80 degrees C) and then keep at that temperature for about 45 minutes, stirring gently from time to time. Leave overnight to cool.
Lac is a very strong natural dye and 6 grams of Lac extract will dye two 100 gram hanks of Blue-faced Leicester superwash wool to a crimson and raspberry, respectively, depending on water quality and other factors. For even darker colours, re-mordant the fibre and dye with another 6 grams of lac extract.
We advise you to experiment as dye colours will vary with the type of fibre, the mordant and the quality of water.
Our Lac extract is shipped as a dry, bright red crystalline powder that is very stable and has a high colour fastness on wool and silk. Lac is not as fast on cellulose (plant) fibres.
from:Natural standard substance
No comments:
Post a Comment