Weld is of greater antiquity than most, if not all, other natural yellow dyes. It is cultivated for dyeing in France, Germany and Italy.
It is important as it dyes silk with a fast colour.
(1) OLD GOLD
Mordant with 2 per cent chrome and dye with 60 per cent of weld in a separate bath. 3 per cent chalk adds to intensity of colour.
(2) YELLOW
Mordant with alum, and dye with 1 lb. of weld for every pound 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.
(3) ORANGE
Mordant with alum with a little weld in the bath. Dye with weld. Add teaspoonful of tin to the dye bath. Boil in separate bath with 1/4 oz.
madder or cochineal to the pound.
_OLD FUSTIC_
Fustic is the wood of _Morus tinctoria_, a tree of Central America. It is used princ.i.p.ally for wool. 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 per cent copper sulphate and 3 to 4 per cent tartar). With ferrous sulphate darker olives are obtained (8 per cent 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.
RECIPES FOR DYEING WITH OLD FUSTIC
(1) OLD GOLD
Boil the wool with 3 to 4 per cent chrome for 1 to 1-1/2 hours. Wash, and dye in a separate bath for 1 to 1-1/2 hours at 100C. with 20 to 80 per cent of old fustic.
(2) OLD GOLD
Mordant with 3 per cent chrome, for 3/4 hour and wash. Dye with 24 per cent fustic and 4 per cent madder for 45 minutes.
(3) BRIGHT YELLOW
Mordant wool with 8 per cent of stannous chloride for 1 to 1-1/2 hours, and 8 per cent of tartar. Wash, and dye with 20 to 40 per cent of fustic.
(4) GREENISH YELLOW
Mordant wool with 3 per cent chrome, for 3/4 hour and wash. Dye with 6 per cent fustic, 33 per cent logwood. Boil 3/4 hour.
(5) YELLOW
Mordant with 25 per cent alum, wash after laying by for 2 days, dye with 5 to 6 oz. fustic to lb.
_TURMERIC_
Turmeric is a powder obtained from the ground-up tubers of _Curc.u.ma tinctoria_, a plant found in India and other Eastern countries. It gives a brilliant orange yellow, but has little permanence. It is one of the substantive colours and does not need any mordant. Cotton has a strong attraction for it, and is simply dyed by working in a solution of Turmeric at 60C. for about 1/2 hour. With silk and wool it gives a brighter colour if mordanted with alum or tin. Boiling should be avoided. It is used sometimes for deepening the colour of Fustic or Weld, but its use is not recommended, as although it gives very beautiful colours, it is a fugitive dye.
_QUERCITRON_
Quercitron is the inner bark of the _Quercus Nigra_ or Q. tinctoria, a species of oak growing in the United States and Central America. It was first introduced into England by Bancroft in 1775 as a cheap subst.i.tute for weld. He says,
"The wool should be boiled for the s.p.a.ce of 1 or 1-1/4 hours with one sixth or one eighth of its weight of alum; then, without being rinsed, it should be put into a dyeing vessel with clean water and also as many pounds of powdered bark (tied up in bag) as there were used of alum to prepare the wool, which is then to be turned in the boiling liquor until the colour appears to have taken sufficiently: and then about 1 lb. clean powdered chalk for every 100 lbs. of wool may be mixed with the dyeing liquor and the operation continued 8 or 10 minutes longer, when the yellow will have become both lighter and brighter by this addition of chalk."
Flavin is extract of Quercitron bark, and is much used for bright yellow with tin.
YELLOW (1 lb.)
Mordant with alum. Dye with 1 oz. Flavin.
ORANGE WITH FLAVIN OR QUERCITRON (1 lb.)
Put into bath first 1/2 oz. Cream of Tartar. Then 3/4 oz. tin mixed with water (important to enter the Tartar first). Enter yarn and boil for 45 minutes. In the meantime have mixed up 1/2 oz. Flavin and 1/2 oz. to 3/4 oz. Cochineal (according to depth of orange required) with 1/4 oz. tin with a little warm water. Remove yarn, enter flavin, madder and tin, take off the boil, enter yarn and stir well. Boil 30 minutes.
_BARBERRY_
The roots and bark of _Berberis Vulgaris_ is used princ.i.p.ally for silk dyeing, without a mordant. The silk is worked at 50 to 60C. in a solution of the dye wood slightly acidified with sulphuric, acetic or tartaric acid. For dark shades mordant with stannous chloride.
_DYER"S BROOM_
_Genista Tinctoria._ The plant grows on waste ground. It should be picked in June or July and dried. It can be used with an alum and tartar mordant and gives a good bright yellow. It is called greening weed and used to be much used for greening blue wool.
_PRIVET_
_Ligustrum Vulgare._ The leaves dye a good fast yellow with alum and tartar.
_HEATHER_
Most of the heathers make a yellow dye, but the one chiefly used is the Ling, _Calluna vulgaris_. The tips are gathered just before flowering. They are boiled in water for about half-an-hour. The wool, previously mordanted with alum or chrome according to the shade of yellow wanted, is put into the dye bath with the boiling liquor, which has been strained. It is then covered up closely and left till the morning. Or the wool can be boiled in the heather liquor till the desired colour is obtained.
_ONION SKINS_
Prepare by mordanting with alum. Take a sufficient quant.i.ty of onion skins and boil for 30 minutes. This gives a good yellow. The addition of tin will make the colour more orange.
CHAPTER VIII
BROWN AND BLACK
CATECHU ALDER BARK SUMACH WALNUT PEAT SOOT LOGWOOD AND OTHER DYES