Vegetable Dyes Part 10

(5) JADE GREEN (1 lb.)

Mordant with 1/3 oz. Cream of Tartar and 4 oz. Alum for 1/2 hour. Take out wool and air. Cool bath a little and add half the amount of the indigo extract to be used (according to shade of green required, 1/2 oz. indigo extract makes a good colour). Enter wool and stir rapidly for 5 minutes or so without boiling. Take out wool. Mix in the rest of the indigo extract. Enter wool and boil for 10 minutes. Take out wool. Throw away a quarter of the water and add some with 3/4 oz.

fustic extract. Enter wool and boil for 1/2 hour to an hour.

CHAPTER X

THE DYEING OF COTTON

The dyeing of cotton is difficult with the natural dye stuffs, there are only a few colours which can be said to be satisfactory. The fastest known in earlier days was Turkey red, a long and difficult process with madder and not very practical for the small dyer. It had its origin in India where it is still used; red Indian cotton is one of the fastest colours known. Catechu is another excellent cotton dye used for various shades of brown, grey and black. A cold indigo vat is used for blue, Indigo Extract is not used. Yellows can be got with weld, flavin, turmeric (for which cotton has a strong attraction), and fustic. Great care is to be taken in dyeing yellow as it is not very fast to light. Greens may be got by dyeing in the indigo vat and then with a yellow recipe, purples from logwood with tin mordant, but purples and greens are unsatisfactory, and not suitable to the vegetable dyer.

BOILING OUT

Before dyeing cotton in the raw state, or in yarn spun direct from the raw state, it must be boiled for several hours to extract its natural impurities. For dark colours water alone may be used, but for light and bright colours a weak solution of carbonate of soda, 5%; or of caustic soda, 2%, should be used.

MORDANTS

_Alum._ Alum (1/4 weight of cotton) is dissolved in hot water with carbonate of soda crystals, or other alkali (1/4 weight of alum); work cotton in the solution, steep for several hours or overnight. Then well wash. Aluminium acetate solution as for silk (page 56) may be used. After drying, the cotton may be pa.s.sed through a fixing solution of some alkali, for examples see page 50. Before mordanting with alum, the cotton is often prepared with tannic acid.

_Iron._ Iron is usually employed as a "saddening" agent, i.e. the cotton after dyeing is steeped in a cold solution of the mordant. A further use is in dyeing black, when the cotton, after being prepared with tannin, is steeped in a cold solution of Iron. This process by itself gives a dark colour before any dye is used.

_Tin._ Tin is rarely used alone as a mordant for cotton but brightens the colour in combination with other mordants.

_Chrome._ Chrome is used for browns and other colours with Catechu.

After boiling in a solution of the dye stuff, boil a short time in chrome solution, this oxidizes the colouring matter of the Catechu.

_Copper._ Copper is sometimes added in small quant.i.ties to the dye bath for brown or yellow to vary the shade.

_Tannin (Tannic acid)._ Cotton and linen strongly attract tannin and when prepared with it they are able to retain dyes permanently. Cotton saturated with tannin attracts the dye stuff more rapidly, and holds it. Tannic acid is the best tannin for mordanting as it is the purest and is free from any other colouring matter; it is, therefore, used for pale and bright shades. But for dark shades, substances containing tannic acid are used, such as _sumach_, _myrobalans_, _valonia_, _divi-divi_, _oak galls_, _chestnut_ (8 to 10 per cent tannin), _catechu_.

Cotton and linen are prepared with tannin after they have been through the required cleansing, and, if necessary, bleaching operations. A bath is prepared with 2 to 5 per cent of tannic acid of the weight of the cotton, and a sufficient quant.i.ty of water. For dark shades, 5 to 10 per cent should be used. The bath is used either hot or cold. It should not be above 60C. The cotton is worked in this for some time, and then left to soak for 3 to 12 hours, while the bath cools. It is then wrung out and slightly washed.

The following gives the relative proportions of the various substances containing tannin:--1 lb. tannic acid _equals_ 4 lbs. sumach, 18 lbs.

myrobalans, 14 lbs. divi-divi, 11 lbs. oak galls.

_Examples from various recipes_:

For 10 lbs. cotton use 12 ozs. tannic acid.

" 50 " " " 10 lbs. sumach.

" 40 " " " 10 lbs. "

" 20 " " " 2 lbs. yellow (or black) catechu.

" 20 " " " 3 lbs. catechu with 3 ozs. blue vitriol.

Some recipes soak the cotton 24 hours, others 48.

RECIPES FOR DYEING

(1) INDIGO VAT

Take 3 oz. well ground indigo, mix into a paste with hot water. Slake 3 oz. Quicklime and boil with 6 oz. Potash or Soda ash in sufficient water, let it settle, pour off the clear liquor in which dissolve the indigo paste, boil or keep hot 24 hours; it should then have the consistency of thick cream, with much froth. During the boiling, slake another 3 oz. quicklime, boil in a pint of water for 15 minutes, let settle, pour off the clear liquor in which dissolve 4 to 5 oz. green copperas. Add the indigo and copperas solutions to 5 gallons water, stir well, let vat rest, stir once or twice during 24 hours or until it appear ready for dyeing. Before use it should be stirred and let stand 2 hours. It should be a clear yellowish green with much sc.u.m.

The cotton to be dyed should be entered in dips of increasing lengths of time, as 1, 5, 10, 20 minutes, and aired in between, according to depth of shade required. It should then be well washed, pa.s.sing through water slightly acidulated with Sulphuric acid (a teaspoonful to 1 gallon). When this vat appears exhausted and turns a dark colour it may be revived by adding 2 or 3 oz. Green Copperas dissolved as before. When again exhausted, more of all the ingredients must be added.

(2) LIME COPPERAS VAT

2 oz. Indigo, 4 oz. Copperas, 5 oz. Quicklime (fresh). Mix Indigo into a paste with hot water. Dissolve copperas in hot water. Slake lime.

Fill earthenware jar with about 5 gallons cold water and add the Indigo, copperas and slaked lime in that order. Stir well, cover and let stand till next day or until vat is in proper condition; it should be clear brownish yellow with possible blue sc.u.m. There will be some sediment. The dyeing process is as in (1).

(3) RED

(For 1 lb. cotton.) The Turkey Red process is long and difficult. (1) Boil yarn 6 to 8 hours in a solution of carbonate of soda, 1-1/2 oz., wash well and dry. (2) Prepare a solution of 2 fluid ozs. Turkey Red oil, 2 ozs. carbonate of soda at 100F., work cotton in this till thoroughly saturated, wring out, dry. (3) Repeat No. 2. (4) Repeat No.

2. (5) Steep 3 or 4 hours in solution of 1 oz. carbonate of soda at 100F., wring out, dry. (6) Repeat No. 5 with a slight increase of soda. (7) as No. 6. (8) Steep 10 hours in water at 100F., dry. The cotton should now be clear white. (9) Steep 4 hours in solution of 1-1/2 oz. tannic acid or 4 oz. Galls, at 100F., wring out, dry. (10) Steep 24 hours in solution made by dissolving 10 oz. alum in hot water, and slowly adding 2-1/2 oz. carbonate of soda crystals, wring out and dry. The cotton is now grey coloured. (11) Dye with 2 lbs.

madder. Bring slowly to the boil, boil for 1 hour, a white sc.u.m on the surface denotes the cotton has absorbed all its colour. A teaspoonful of chalk may be added to the dye-bath. The cotton is now dark claret colour. (12) To brighten, boil 3 or 4 hours in a solution of 1/2 oz.

carbonate of soda crystals and 1/2 oz. soap. The bath should be covered, except for a small outlet for the steam which otherwise should be retained as much as possible. (13) The cotton can be further brightened by boiling with 1/2 oz. soap and a teaspoonful of Tin. Wash and dry.

(4) RED

(For 1 lb.) After boiling out in soda, wash and dry. Steep overnight in a hot bath of 1-1/2 oz. Tannic acid or 4 oz. Galls, dry, steep in cold solution of 1/4 lb. alum and 1/2 oz. chalk, dry, add 2 oz. more alum to solution and steep as before, wash and dry. Dry with 12 oz.

Madder, bring to boil in 1 hour and boil a few minutes, rinse, re-dye as above, pa.s.s through warm soap bath, 2 oz., wash and dry.

(5) YELLOW

(For 1 lb.) Mordant twice in Aluminium acetate, as described for silk (page 73), or in 1/4 lb. alum and 1-1/2 oz. chalk, steeping in cold solution. Pa.s.s through weak bath of chloride of lime, wash, dry. Dye with 2-1/2 lbs. weld and 1/2 oz. copper sulphate, boil for 1 hour, then boil with soap. Or dye with 2 to 3 oz. Quercitron, which should be brought slowly to the boil and boiled for a few minutes only.

(6) YELLOW

(For 1 lb.) Steep overnight in hot bath of 1-1/2 oz. Tannic acid, or 4 oz. Galls, wring out, dry. Work 2 hours in bath of 1/4 lb. alum and 1/2 oz. chalk, dry, pa.s.s through weak bath of chloride of lime about 1 oz., dry. Return to alum bath and repeat process, wash well, dye slowly with 1-1/2 oz. Flavin.

(7) ORANGE

(For 1 lb.) Boil 2 oz. Annatto with 1 oz. carbonate of soda crystals for 1/2 hour, then add to a bath containing a teaspoonful of Turkey Red Oil, boil for 10 minutes. Take off boil, enter yarn, boil for 1-1/4 hours, let cool to hand heat, remove yarn, wash slightly and dry quickly.

(8) BROWN

(For 1 lb.) Enter in one bath 1 oz. Cutch, in another 1/2 oz. Chrome.

Enter cotton in cutch bath, boil 20 minutes, wring out, boil 10 minutes in chrome bath. Add 6 oz. fustic or 1 oz. flavin to cutch bath, re-enter cotton. Repeat above until the required depth of colour is reached, finish in cutch bath to obtain deepest shade, which may be darkened by adding 1 drachm or so copper sulphate. A greyish drab may be got by adding ferrous sulphate. All shades of brown may be obtained by decreasing or increasing the amount of cutch or by adding a little logwood or fustic, in which latter case the cotton should have been previously mordanted.

(9) BLACK

(For 1 lb.) Wash, steep overnight in hot solution of tannic acid, 1 oz., wring out without washing, work for 10 minutes in soda bath, at a temperature of 50 to 60C., 1-1/4 oz. Wring out, work in cold solution of copperas, 1-1/4 oz., for 1/2 hour, return to soda bath for 1/4 hour. Wash, dye in bath of logwood 12 oz., madder 2-1/2 oz., and fustic 8 oz. Enter into cold bath and raise gradually to boiling, boil for 1/2 hour, pa.s.s through warm solution of chrome, 1 oz., wash, work through warm soap bath.

Greys may be obtained with 1 to 5 per cent of logwood after mordanting in a weak solution of iron.

THE ZINC-LIME INDIGO VAT