Silk is covered with a natural gum which has to be removed before the dyeing process can begin. This is done by boiling for one hour or more in a bath containing soap, 2 to 8 ozs. to the pound of silk according to the amount of gum on the silk. It is then well washed, and is ready for mordanting.

The mordants mostly used are Alum, for most of the bright colours. Tin, for brightening some colours, and as a separate mordant for others. Iron, for black dyeing. Chrome, for certain browns such as catechu.

The principal Alum mordant is Acetate of Alumine, prepared as follows: Let 3 lbs. Alum and 3 ozs. chalk be dissolved in 1 gallon of warm water in an earthenware pan, add the chalk slowly to the Alum. Add 2 lbs. white acetate of lead, stir occasionally during 24 to 36 hours. Let it remain 12 hours at rest. Decant and preserve the clear liquor, being careful not to stir up the sediment. Pour 2 gallons of water on the sediment, and stir occasionally for 12 hours. Let it rest 12 hours. Decant the clear and add to the first lot. Bottle for use. It keeps about three weeks. Of the mordant 2 parts are diluted with 1 of water, and the silk is well worked in this for 10 minutes, after being wetted down. Steep for 12 hours, wring out and dry. Wet down again and return to the Alum liquor, work for 10 minutes, steep 12 hours, dry. When thoroughly dry, wash well in several changes of water before dyeing. For less bright colours one mordanting may be sufficient.

The mordant is used for successive batches of silk until exhausted; the fresher the mordant, the better for brighter colours. Silk should be dyed as soon after it is dried as is convenient.

Another Alum mordant. Dissolve 25 per cent of Alum in hot water and add 6 per cent carbonate of soda crystals. Fill up a jar with water and steep silk in it over-night. It must be washed before dyeing.

RECIPES FOR DYEING

(1) INDIGO VAT FOR BLUE

Silk is dyed in a similar manner as described for wool, but requires stronger vats and longer dips to obtain the same depth of colour. See page 33.

(2) INDIGO EXTRACT FOR BLUE

Dye at a temperature of 40 to 50 deg.C. with as much Indigo Extract dissolved in the bath as is required for the desired depth of shade. If the silk has been first mordanted with alum, compound colours can be obtained by the addition of a red or yellow dye to the bath.

(3) CRIMSON

Mordant with Alum or Aluminium Acetate and dye with 40 to 50 per cent Cochineal. A teaspoonful of Tin, dissolved in cold water, may be added to brighten. Boil well. It is advisable to wash in soap after using tin as it prevents the latter making the yarn brittle.

(4) MADDER RED

Mordant with Alum or Aluminium Acetate. Dye with 80 to 100 per cent Madder and a handful of bran per pound of silk. Bring slowly to the boil in 1 hour, boil a few minutes. It should be brightened by boiling a short time in soap, with a little tin.

(5) YELLOW

Mordant with Alum or Aluminium Acetate. Various Dyes may be used. Weld: Dye with 150 per cent. Flavin: Dye with 1 oz. to the pound, with a teaspoonful Tin. Fustic: Dye with 50 per cent, or more. Quercitron: Dye with 10 to 20 per cent. A little chalk may be added towards the end.

The shades may be varied by the addition of small quantities of madder or cochineal. Orange may be obtained by the use of Madder, 2 to 4 ozs. per pound, with Flavin or Fustic.

(6) GREEN

Greens may be obtained by dyeing with any of the yellow dyes and blueing in the Indigo Vat or with Indigo Extract. If the colour is thin, it should be dyed a deeper blue in the vat and then re-dyed with yellow. A strong clear yellow is needed for a good green.

(7) PURPLE

Dye silk blue in Indigo Vat. Then dye without mordanting in Cudbear.

(8) ORANGE (1 lb.)

Mordant with Alum Acetate. Dye with 1/2 lb. Madder, 2 ozs. Flavin and 1 oz. tin.

Enter the tin first in a cold bath. Mix Flavin and Madder into a paste and add to the bath. Bring to the boil slowly, boil for 10 minutes. Wash in soap.

(9) BLACK (1 lb.)

Mordant with Alum Acetate. Dye with 6 ozs. logwood, 3/4 oz. flavin, 1 oz. Iron. Mix all together and boil for 1/2 hour. Wash thoroughly.

(10) BLACK

(1) Mordant with basic ferric sulphate and after allowing the
silk to lie for some time, wash well and soap at 90 deg.C.

(2) Dye with 50 per cent Fustic, 10 per cent Ferrous Sulphate
and 2 per cent Copper Acetate.

(3) Dye with logwood 50 per cent and soap.

(11) GREY WITH BRACKEN (1 lb.)

Mordant with 1 oz. Iron and 2 ozs. Cream of Tartar. Boil a quantity of young bracken tips for 1/2 hour. Strain. Boil silk in the decoction for about an hour.

(12) BROWN WITH LICHEN (1 lb.)

Mordant with Alum Acetate. Put into the dye bath the quantity of lichen according to required colour with about a teaspoonful of Acetic Acid. Boil from 1 to 3 hours.

(13) ORANGE (1 lb.)

1 oz. tin, 1/2 oz. Oxalic Acid, 2 oz. Flavin. Enter silk and boil for 1 hour. Remove silk and add to the bath 1 oz. tin, 1 oz. Oxalic, 2 oz. Cochineal. Boil for 1 hour or more.

(14) BLACK (1 lb.)

Mordant with 2 oz. logwood extract, 1-1/4 oz. fustic extract, 1-1/4 oz. iron, 1/2 oz. copper sulphate. Boil for 1 hour. Take out and rinse. To the same bath add 1-3/4 oz. logwood extract, 1 oz. fustic extract, 7 oz. madder. Enter silk and boil for 1 hour. Wash in soap.

(15) YELLOW (1 lb.)

Mordant with 1 oz. Bichromate of Potash. Boil 1 hour. In a separate bath put 1 lb. weld and boil for 1 hour.

(16) RED (1 lb.)

Mordant with 1-3/4 oz. tin and 1-3/4 oz. oxalic acid. Boil for 1 hour. Then add 3/4 lb. cochineal and 6 oz. madder. Boil well and wash in soap.

(17) BROWN (1 lb.)

Mordant with 1 oz. Copper sulphate. Boil for 1 hour. Take out silk and add 2-1/2 oz. madder, 1 oz. fustic chips, and boil for 1 hour.

(18) RED (1 lb.)

Dissolve 1 oz. Tannic Acid in hot water. Enter silk and leave for 24 hours, stirring occasionally. Rinse well in two waters. In a fresh bath, put 4 oz. cochineal. Enter silk. Bring to boil and let blue colour develop. Lift, and add 1 oz. cochineal & 1 oz. tin. Re-enter silk & boil well. Wash in soap.