The various classes or styles of calico-prints are usually arranged either according to the chief dyestuffs employed or their mode of ap plication. Each of these primary styles may be further separated into subdivisions, of which the most important are the discharge and resist styles, which refer to the manner in which the pattern is produced. The following include the chief styles of calico-prints at present in vogue: Madder Style.—This is so named because the chief dyestuff formerly employed in it was madder. This dyestuff belongs to the class of so-called mordant-colors. Such dyestuffs are worthless if employed alone by the calico printer and only furnish useful colors if applied m conjunction with certain metallic salts or mordants, of which the chief ones here em ployed are the acetates of aluminum and iron. At first the pattern is printed on the white calico with these or similar mordants alone, and only after they have been suitably fixed is the madder or other similar coloring matter ap plied in the dye-bath, where for the first time the desired colored pattern appears. The aluminum mordant yields red and pink, iron yields purple or black, a mixture of iron and aluminum yields chocolate, etc. The fixing of the mordant after printing and drying is effected by passing the printed calico through the so-called ageing-machine, a large chamber suitably heated and charged with moisture, where the acetic acid of the printed mordants is driven off, leaving the aluminum salt in an in soluble form on the calico. A more complete fixing of the mordant is subsequently effected by passing the fabric through solutions con taining silicate or arseniate of soda, and a final washing completes its preparation for dyeing. The dyeing operation consists in boiling the fabric in a solution or decoction of the requisite dyestuff. After dyeing, the stained unprinted portions are cleaned and purified, while the printed colors are rendered more brilliant by washing, soaping, coloring, etc. Variety of effect is produced by printing the same fabric two or three times (print, cover, pad) with various designs before proceeding to the age ing, etc. If in the first instance a portion of the pattern is printed with lime-juice (citric acid), it resists or prevents the fixing of the mordants applied over it in the second and third printings, and the part remains undyed and ap pears as a so-called resist white. In a simi lar manner stannous chloride, mixed with aluminum acetate before printing, resists the fixing of iron mordants printed over the alumi num mordant, and a resist red pattern under a purple cover is obtained, presuming madder to be the dyestuff employed. Alizarin now re places the madder formerly used, and similar variegated effects are obtained if other mordant dyestuffs are employed, for example, cochineal, quercitron bark, etc. Formerly a preparation of madder, termed gatancine, was largely em ployed, and gave rise to the garancine style, in which the colors were fuller and darker, the prevailing hues being browns, chocolates, drabs, etc. Since the range of colors yielded in the madder style is limited, additional colors, as green, blue or yellow, may be printed in by block after dyeing, etc., and are fixed by steam ing. If the whole fabric is evenly impregnated with mordant by means of a and dried, and then a pattern is printed over the mordant with lime-juice, the mordant is re moved or discharged in the printed parts, and remains white in the subsequent dyeing. Such a print would be termed a padded style with dis charge white.
Steam Many coloring matters, dif fering from each other widely in character, are fixed by the operation of steaming instead of by dyeing, so that this style is somewhat varied in character. Ordinary steam-colors consist of a thickened mixture of dyewood extract and mordant, with the addition of assistant metallic salts and acids. The mixture is printed upon the white calico, which, after drying, is exposed from a half to one hour in closed chambers to the action of steam. This steaming operation effects the combination of the coloring matter and mordant, and the color is thus developed and at the same time fixed upon the calico. Black is produced with logwood extract and chromium acetate, scarlet is produced with coch meal extract and stannous chloride. The prints
are washed and dried after steaming, the colors being usually bright, but not very fast. Steam colors, fast to light and soap, are obtained in a similar manner by printing mixtures of alizarin and allied coloring matters with mordants, and then steaming. These are used in the so-called madder extract or steam alizarin style, in which red, pink, purple, etc., appear. In the pigment style use is made of pigments, or insoluble colored mineral powders as ultramarine-blue, chrome yellow, Guignet's green, etc. These are mixed with a solution of egg or blood albumen, printed and steamed. The albumen coagulates on steaming, and thas adheres firmly to the cloth, at the same time enclosing the pigments within the coagulum. Such colors are fast to light and soap, and may therefore be printed simultaneously with the steam alizarin colors for the production of variegated fast prints. Another class of colors are the so-called basic colors, as magenta, aniline blue, etc. Their so lutions may also be thickened with albumen, printed and steamed, to give fast steam-colors. It is more usual, however, to print a mixture of the thickened color solution and tannic acid, and to pass the steamed print through a boiling solution of tartar emetic. By this means an in soluble color-lake (tannate of antimony and color-base) is fixed on the calico, which is fast to soaping but not to light Basic colors ap plied in this manner are now usually printed with the steam alizarin colors, instead of . pigments, thickened with albumen, and variegated fast prints are thus obtained. Loose pigment colors are basic colors thickened with starch or gum tragacanth only, and then steamed. Such prints do not even stand wash ing with cold water.
In this style use is made of the fact that turkey red is at once bleached by the action of chlorine. Plain dyed turkey-red calico is printed with tartaric acid, dried and passed through a solution of bleach ing-powder. In the printed parts chlorine gas is evolved, the red is destroyed and a white dis charge pattern is produced. A blue pattern re sults if Prussian blue is added to the printing mixture; yellow is obtained if a lead salt is added, and the fabric is afterward passed through bichromate of potash solution, where by yellow chromate of lead is produced; green results from a mixture of the blue and yellow ; black is printed direct. These and other dis charge colors may also be obtained by other methods.
Indigo Of the numerous indigo styles in use it is only possible to refer to one or two of the most important. Indigo blue pat terns on a white ground are obtained by print ing a thickened mixture of finely-ground indigo and caustic soda on white calico, previously im pregnated with glucose. A subsequent steaming reduces the indigo to indigo white, and causes it to penetrate the fibre, while a final washing oxidizes, regenerates and fixes the color. A resist white pattern on a blue ground is ob tained by first printing upon white calico a re sist paste composed of gum or flour, China clay, sulphate of copper, ttc. When the printed calico is dyed in the indigo vat the paste resists the entrance of the color, partly in a mechanical and partly in a chemical manner, hence the blue is only fixed in those parts which are unpro tected by the paste, after the removal of which by washing, the white pattern appears. Vari ous resist colors, as yellow, green, etc, are ob tained by the addition of different chemicals to the paste and altering the after-processes. A discharge white pattern on a blue ground is ob tained by printing on plain indigo-blue dyed calico a solution of bichromate of potash thick ened with gum, and then passing the fabric through a solution containing sulphuric and oxalic acids. During this passage there is liberated, in the printed parts only, chromic acid, which at once oxidizes and destroys the blue, producing the desired white pattern. Colored discharge patterns are produced simi larly by employing albumen thickening instead of gum thickening, and adding to the printing mixture such pigments as are not affected by acids, for example, vermilion, chrome yellow, Guignet's green, etc.