6). Yellow for Wool.
Mordant with alum and tartar, and dye with 5 or 6 lbs. of weld for every lb. of wool. Common salt deepens the colour. If alum is added to the dye bath, the colour becomes paler and more lively. Sulphate of iron inclines it to brown.
7). Weld Yellow for Silk.
Work the silk (1 lb.) for an hour in a solution of alum, 1 lb. to the gallon, wring out and wash in warm water. Boil 2 lbs. weld for ½ hour; strain and work the silk in this for ½ hour. Add 1 pint alum solution to the weld bath and return the silk; work ten minutes, wring out and dry.
OLD FUSTIC.
Fustic is the wood of Morus tinctoria, a tree of Central America. It is used principally for wool. It does not produce a fast dye for cotton. With Bichromate of Potash as mordant, Old Fustic gives old gold colour. With alum it gives yellow, inclining to lemon yellow. The brightest yellows are got from it by mordanting with Tin. With copper sulphate it yields olive colours. (4 to 5% copper sulphate and 3 to 4% tartar). With ferrous sulphate, darker olives are obtained (8% ferrous sulphate). For silk it does not produce as bright yellows as weld, but can be used for various shades of green and olive. Prolonged dyeing should always be avoided, as the yellows are apt to become brownish and dull. The chips should be tied up in a bag and boiled for ½ hour before using. It is still better to soak the wood over-night, or boil up in a small vessel and strain into the dye bath. The proportion of Fustic to be used for a good yellow is 5 to 6 parts to 16 parts of wool.
Recipes for dyeing with Old Fustic.
1). Old Gold for Wool. Boil the wool with 3 to 4% Chrome for 1 to 1½ hours. Wash, and dye in a separate bath for 1 to 1½ hours at 100°C. with 20 to 80% of Old Fustic.
2). Light Yellow for Silk. Work the silk for ¼ to ½ hour at 50° to 60°C. in a bath containing 16% alum and a decoction of 8 to 16% of old Fustic. For dark yellow the silk is mordanted with alum, washed and dyed for about an hour at 50°C., with 50 to 100% of Fustic. The colour can be made faster and brighter by working the silk in a cold solution of nitro-muriate of Tin for an hour.
3). Bright Yellow for Wool. Mordant wool with 8% of stannous chloride for 1 to 1½ hours, and 8% of tartar. Wash, and dye with 20 to 40% of Fustic at 80° to 100°C. for 30 to 40 minutes.