Silk goods are dyed much in the same way as woollens, but the process is conducted with less heat:—
1. A bath of nut-galls is given for 12 to 36 hours, occasionally working the goods therein; they are next taken out, rinsed, and well aired, after which they are passed for a few minutes through a bath containing sulphate of iron, and are then again drained, rinsed, and aired. The steep in the nut-gall bath may be repeated, if necessary, followed, as before, by the iron-bath previously replenished with a little fresh copperas. The whole quantity of galls to be taken for 1 lb. of silk varies with their quantity from 1⁄2 to 3⁄4 lb., that of the copperas (for the first bath), from 3 to 4 oz.
2. (For 1 cwt. of silk.) Boil 22 lbs. of bruised Aleppo galls, for 2 hours, in 90 to 100 galls. of water, observing to add boiling water from time to time, to compensate for that lost by evaporation; to the clear bath add 32 lbs. of copperas, 7 lbs. of iron-filings, and 21 lbs. of gum; digest with agitation for 1 hour, and when the ingredients are dissolved, pass the silk (previously prepared [‘galled’] with 1⁄3rd of its weight of gall-nuts) through the bath for about an hour; then rinse and air it well; next leave it in the dye-bath for 6 to 12 hours; and this immersion or steep may be repeated, if necessary, at will. This is said to be the process commonly adopted for velvet at Genoa and Tours.
3. (For 5 lbs. of silk.) Turn the goods for an hour through a mordant formed of 1 lb. of copperas and 2 oz. of nitrate of iron (dyer’s), with sufficient water; after rinsing in cold water and airing them, ‘work’ them for an hour in a decoction made of 5 lbs. of logwood and 1 lb. of fustic; then lift them from the bath, add 2 oz. of copperas, reimmerse, and ‘work’ them well for 10 or 15 minutes longer; lastly, rinse, air, and finish. A full deep black.
4. (For 5 lbs.) For the mordant use 1⁄2 lb. of copperas; rinse, and air; for the ‘dye-bath,’ a decoction of 4 lbs. of logwood to which 1⁄2 pint of stale urine has been added; after ‘lifting’ the goods add 2 oz. more of copperas to the bath, and work for 15 minutes, as before. A good black. By adding 2 oz. of dyer’s nitrate of iron to the mordant the same ingredients will give a deep black; and by substituting a little white soap for the urine, and omitting the addition of copperas to the logwood-bath, it will give a blue-black. The last may also be produced by first dyeing the goods deep blue as with ‘prussiate,’ and omitting the urine and soap, in which case one half only of the logwood will be required.
d. For Wool:—
To produce a good permanent black on wool or woollen goods, they must be first dyed of a deep blue in the indigo-vat, or, more cheaply, by the Prussian-blue process. When the goods are coarse or common, and price is an object, they are generally ‘rooted’ instead of being ‘blued.’ This consists in giving them a dun or brown colour with the husks of walnuts or the roots of the walnut-tree, or with other like cheap astringent substances.
1. (For 1 cwt. of wool.) Good logwood-chips, 20 lbs., and Aleppo-galls, 18 lbs.; are inclosed in a coarse bag, and boiled with water, q. s., for 5 or 6 hours; 1⁄3rd of this decoction is then transferred into another copper, with verdigris, 2 lbs., and a sufficient quantity of water having been added, the goods (previously dyed dark blue) are passed through the liquor for two hours, at a heat slightly below the boiling-point. The goods are next lifted and drained, another 1⁄3rd of the decoction of logwood and galls, with copperas, 9 lbs., added to the boiler, after which the fire is lowered, and as soon as the copperas is dissolved, the cloth is returned to the bath, and again well ‘worked’ for at least an hour. It is then taken out, thoroughly aired, and the remaining 1⁄3rd of the decoction added, with sumach, 20 lbs. The whole is then brought to a boil, and sulphate of iron, 2 lbs., together with a pailful of cold water, thrown in; after which the goods are put in a third time, and ‘worked’ for one hour; they are then taken out, rinsed, aired, and again passed through the bath for another hour. After being thoroughly rinsed, the goods are at once either ‘fulled,’ dried, and folded, or are further softened and beautified by passing them for 15 minutes through a hot weld-bath (not boiling), when they are rinsed, &c. (but not ‘fulled’), as before. A beautiful though expensive dye. With management the above quantities of the ingredients will dye 11⁄4 or even 11⁄2 cwt. of wool.
2. (For 1 cwt.) The cloth (previously dyed blue) is ‘galled’ with 5 lbs. of nut-galls, and then dyed in a bath made with 30 lbs. of logwood, to which about 5 lbs. of copperas has been added; after which it is rinsed, aired, and ‘fulled,’ as before. This is said, by Lewis, to be the usual proportions and plan adopted by the English dyers.
3. (For 1 cwt.) Make a bath, as before, with fustic, 2 lbs.; logwood, 5 lbs.; and sumach, 10 lbs.; work the (blued) cloth for 3 hours at the boiling heat, or near it; lift it out, add sulphate of iron, 101⁄2 lbs., and when dissolved, pass the cloth through it for 2 hours; rinse, air well, and again pass the goods through the bath for an hour; lastly, rinse until the water runs clear. Inferior to the last, but less expensive.