(1) Methyl, 30 lb. yarn. - Dissolve 4 lb. Glauber salts, 2 lb. alum, in a sufficient quantity of water. Dissolve 1 1/2 oz. methyl blue (of Meister, Lucius, and Briining), and add it to the dye-beck. Enter yarn at 110° F. (43° C), turning rapidly, and dye to shade, raising the temperature to 120° F. (49° C).
(2) Light, 50 lb. bleached yarn. - Dissolve 3 lb. alum, 3 oz. tartaric acid, and 1/4 oz. "water-blue 6 B" (Berlin Aktein Gesellschaft fur Anilin-Farben). Enter yarns at 110° F. (43° C), turn rapidly, and raise the temperature to 130° F. (54° C), turning to shade. After the colour has become level, another 1/4oz. of the colour, previously dissolved, should be added to the beck.
(3) Corn Flower (Pittacal)
Prepare the cotton in a cold solution of tannin; wring and enter into a solution of tartar-emetic. Wring, and enter into a solution of acetate of pittacal, dissolved in acetic acid, diluted with a sufficient quantity of water, and then almost neutralized with ammonia.
(4) Navy, 11 Lb
Boil 2 lb. 3 oz. logwood, and dissolve in the clear hot liquid 26 oz. curd soap. Steep clear yarn in this liquor for 2 hours at 167° F. (75° C). Lift; add to the beck 26 oz. copperas; re-enter the yarns, and work till the colour is even. Wash in cold water, and work in a fresh beck with 17 1/4 oz. curd soap at 144° F. (62° C), for 1 hour. Then make up a boiling beck with 2 1/2 oz. of an aniline blue, soluble in spirit, and 2 lb. 3 oz. red liquor at 13o Tw. Work the yarn in this at a boil till the desired shade is obtained, and finally rinse.
(5) Aniline, 11 Lb
Boil 2 lb. 3 oz. sumach, or 6 1/6 oz. tannin in water; filter; dissolve 17 1/4 oz. curd soap in the clear solution, and enter the cotton over night into the hot liquor. Wring out, and make up a beck with acetate of alumina at 3° Tw., to which a clear solution of aniline blue is added according to the shade. Enter the cotton, and dye, raising the temperature to a boil for some time.
This colour dyes cotton without a mordant, producing rich blues with a greenish reflection, fast against soap and light. It dissolves readily in water.
Indigo being insoluble, cannot be applied to textile fibres by the ordinary dyeing process. It requires to be reduced to so-called " white indigo," when it becomes soluble, and is in that state deposited on the tissues of yarns, where it rapidly resumes its ordinary blue insoluble condition, and remains permanently fixed in the fibre.
In the case of cotton, the indigo vat is generally "set" in the following method. To about 2000 gal. water are added 60 lb. indigo, ground to an impalpable powder, 180 lb. slaked lime, and 120 lb. copperas. The lime and the copperas are added from time to time. The lime is put in first, and the vat is well stirred up before adding the copperas. There must be always sufficient lime present to dissolve the white indigo as it is formed. But if too much lime be present, an insoluble compound is formed, which renders the indigo useless for dyeing.
The yarns or pieces are simply steeped in, or rinsed through, the clear liquid of the vat, and then exposed to the air, when the greenish colour which they take at first is soon converted into a blue. The dipping and airing are repeated till the shade is obtained. The goods are then taken through very weak sulphuric acid, thoroughly well washed, and dried.
The vat for dyeing cotton, or any other vegetable fibre, is always worked in the cold.
An improvement in vat dyeing was invented and patented some years ago, by Schutzenberger and de Lalande. A solution of the bisulphite of soda, at 52° to 63° Tw., is placed in a covered vessel, containing zinc clippings, borings, etc, piled up so as to fill the tank, without occupying more that 1/4 of its total contents. After 1 hour's contact, the liquid is drawn off into a cistern, containing milk of lime, which decomposes the zinc salts. The clear liquid is then strained off. Soda or lime sufficient to dissolve the indigo is then added, and it is mixed with the indigo, which must be in perfectly fine powder. At once is produced a yellow solution, containing no soluble impurities, except the earthy matters which were present in the indigo itself. Access of air is avoided as much as possible during this process. In this manner, 2 lb. 3 oz. indigo can be dissolved in 7 1/2 to 26 pints of liquid. The vat is then filled with.cold water, if for cotton, and a suitable amount of indigo solution is added. An excess of the " hydrosulphite" is always present, whence the reduced indigo solution is almost wholly avoided, the blue indigo being reduced as quickly as formed.
The dye-liquor thus resists atmospheric action far better than the ordinary copperas vat, and is free from the inconvenience of always holding in suspension more or less peroxide of iron, carbonate of lime, etc, which must be allowed to settle before the vat can be used with advantage. By adding to the vat from time to time a little concentrated indigo solution, the strength can be maintained at any required point, and thus any given shade may be communicated by the smallest number of dips; the colours thus obtained are also brighter than those of the old process.
(8) Prussian, 10 Lb
Dissolve 11/2 lb. yellow prussiate of potash (potassium ferrocyanide) in 30 gal. water, and add to it 1/2 pint oil of vitriol (full strength sulphuric acid). Run the piece, or turn the yarns, 4 times, and then raise the colour in a beck of 60 gal. water, 1/2 pint nitrate of iron, and 1/4 pint oil of vitriol. Wash off, and dry.
Prussian blues are now almost entirely superseded by the coal-tar blues.