By adding to the madder some weld or bark, every shade from a brown to an orange may be pro duced, and with weld or bark, also, we obtain all colours from a dark olive to a bright lemon. In or der to produce the finest yellow or delicate lemon colour, the calico should be dried in the open air, as stove drying converts a yellow to an orange, and the dunging should not be performed at a higher temperature than 96° or 100°.
The calicoes are next to be brawled, an operation which is effected by removing them from the weld or madder copper to a boiler containing wheat bran and water, in which all stains arc cleared from the white portion, though at the risk of the colours be ing somewhat impaired. Mr. Parker has found that a peculiar redness may be imparted to all madder colours, by raising them with a mixture of bran and madder, that is, by adding a little bran to the mad der, in the maddering process.
As the whites cannot always be cleared by the branning, lest the colours should be impaired, the rest of the operation of bleaching the whites is per formed by exposure on the grass for some days; but in Scotland, this process has been effected in a few minutes, by immersion of the colours in a weak so lution of one of the bleaching salts, such as oxymu Hate of potash, soda, and magnesia.
The mordaunts used by the calico printers are commonly acetate of iron for browns, blacks, Mars, Sce. and acetate of alumine for all shades of yellows and reds, &e. Nitrate of iron, obtained by dissolv ing metallic iron in a peculiar kind of aquafortis, yields blacks, which, like those obtained from galls, are applied at once to the cloth, and are not after wards raised by dying, like the black of the com mon iron liquor. Hence the black of the nitrate of iron can be mixed with other colours.
Another kind of calico printing, called resist work, is now in common use. A resist paste is composed of sulphate, nitrate, muriate, or acetate of copper, of which the sulphate is the best, mixed with flour paste, or any of the other gums, or with pipe-clay and gum. With this paste the pattern is printed on the calico, which when sufficiently dry is repeat edly dipped in the blue vat, till they have received the requisite depth of tint. The goods are then washed and passed through diluted sulphuric acid, and all the parts printed by the preparation of copper are found to be of a good white, in conse quence of having resisted the action of the indigo, though all the rest of the calico has been perma nently dyed. The deep blue calicoes, with white figures or white spots, are generally executed by the resist process with indigo; and by a peculiar method, with subsequent dying or madder, weld or bark, red or yellow spots or figures may be pro duced upon a blue ground.
A method of resisting, or stopping out particu lar colours with wax, though an expensive one, was formerly in general use, and wax is still em ployed in India for preserving the white portions. In the manufacture of silk Bandana handkerchiefs, a preparation of tallow and rosin, made fluid by heat, is used for printing the patterns, which are thus left white, and preserved from the operation of the indigo, which gives the rest a blue colour.
IVhen the ground is to be white, and only a sin gle sprig or small object is to form the pattern, it is executed by means of a pencil, with what is called pencil blue, which is formed of 10 oz. of finely ground indigo, 20 oz. of quick lime in lumps, 20 oz. of patash of commerce, and 10 oz. of orpiment, mixed up in a gallon of water, and thickened with gum senegal.
In another operation of calico printing, called chemical discharge work, the goods are dyed of one uniform colour, with a mixture of iron liquor, and any of the dyeing substances. When they are washed, dried, turned, and calendered, a discharg ing liquor is prepared by dissolving in one of the mineral acids a portion of one or more of the me tals, according to the nature of the colour to be discharged, or of that to be produced. For exam ple, if a piece of calico, treated with a decoction of Brazil wood, and dyed black by being maddered with iron liquor, be printed when dry, with a pecu liar solution of tin, the iron in the dye will be dis solved, and the printed part will instantly be con verted from a deep black into a brilliant crimson.
The introduction of cylinder printing into the calico manufacture, is a most important step in its progress. Cylinders from 18 to 42 inches long, and from 31 to 5 inches wide, are now formed by ham mering plates of copper into a circular form, though sometimes they are bored out of a solid mass of copper. The pattern is enchased on the surface. The cylinders furnish themselves with colouring matter, placed in a trough, and are kept clear by a steel knife, called the doctor, which passes over the surface, when they are charged with the thickened colour. The cylinder, thus coloured, rolls over the piece of calico, from one end to the other, and com municates the pattern with the greatest certainty and accuracy. Sometimes two cylinders are used to give two dilterent colours at the same time. Mr. A. Parkinson of Manchester, has invented a ma chine, on which one cylinder and two surface roll ers give three distinct colours.
Other machines have been employed, called sur face machines. They consist of cylinders of wood, with the pattern formed upon them, exactly like the pattern blocks already described. By means of those cylinder machines, a piece of calico, which employs a man and a boy three hours, may be done in three or three and a half minutes.
Hence the British calico printer has been able to finish calico goods, in which the printing consists of precipitating the colouring matter of logwood and other vegetable dyes, without using any mor daunt or previous preparation whatever, at the rate of one penny per yard, including every expense of colour, paste, and printing. In such goods, the pat tern will be washed out by the first shower of rain. For a full account of topical dyeing in calico print ing, the reader is referred to Parke's Chernieal Es says, from the information contained in which we have drawn up the above brief article. See also OUP article BANDANA HANDKERCHIEFS, Vol. III. p. 213.