Birch leaves are used in Russia to improve the colour of madder. They are added to the dye bath.
Recipes for use of Madder.
1). Red for Wool.
For 100 oz. (6¼ lbs.) wool.
Mordant 8 oz. Alum and 2 oz. Tartar. Boil the wool in the mordant for one hour and wash in cold water. Dye: 50 oz. Madder. Enter the mordanted wool, raise to boil and boil gently for one hour. Wash thoroughly in cold water and dry. If the water is very soft, a small quantity of lime or chalk added to the dye bath improves the shade. Alder bark or alder leaves added to the dye bath darkens the colour. The best results are obtained when the dye bath is maintained just under the boiling point.
2). Reddish brown for Wool.
Mordant with 3% bichromate of potash and dye with Madder. Good results can be got by the single bath method. ([See page 14], No. 3.)
3). Brownish red for Wool.
Mordant the wool with 6 to 8 per cent. of alum and 5 to 7 per cent. of tartar. Dye with 60 to 80% of Madder. Begin the dyeing at about 40°C., and raise the temperature of the bath gradually to 80° to 100°C., in the course of an hour, and continue the dyeing about an hour. Wash and dry. The colour can be brightened by adding a small proportion of stannous chloride to the mordant or it can be added to the dye bath towards the end of the dyeing.
Brighter shades are got by keeping the temperature at about 80°C., and prolonging the dyeing process. After dyeing, the colour can be brightened by working the wool at 70°C., in a weak soap bath, or a bath containing bran.