Page:The American Cyclopædia (1879) Volume III.djvu/602

 596 CALICO PRINTING made in the art, the importance of which can scarcely be overrated. In some of its forms, not the most complete, it is stated that a mile of calico can be printed off with four different colors in one hour, and more accurately and with better effect than by hand blocks. One cylinder machine, attended by one man, can perform as much work in the same time as can 100 men with as many assistants. The inven- tion of the machine is commonly attributed to a calico printer named Oberkampf, at Jouy in France, and again to a Scotchman named Bell, who constructed one about the year 1785. But Dr. Muspratt maintains that the latter only is entitled to the credit of it, and that " cylinder printing is purely a British invention." The copper cylinders are from 30 to 40 in. in length, and from 4 to 12 in. in diameter. They are turned from a solid piece of metal bored through the axis, and the pattern is imprinted upon the surface from a steel cylinder called a mill, upon which the pattern is impressed, be- fore the steel is hardened, from another steel cylinder called the die, on which the design has been engraved in intaglio, as the copper finally receives it. The pattern is complete around the circumference of the roller, and each revolution of this exactly repeats it. In large calico print works the engraved copper rollers constitute a very important item in the investment of the capital, the value of the stock of these held by some of the larger print houses being rated even as high as $200,000. The value of a single one is often from $25 to $30. These cylinders, one for each color to be applied to the cloth, are set in a strong frame against the face of a large central drum, made of iron and covered with woollen cloth in sev- eral folds, between which and the engraving cylinders the calico is printed as it passes. The color is spread upon the rollers by their re- volving each one in contact with an attendant roller, which dips into a trough containing the coloring matter or the mordant properly thick- ened; thus the engraving rollers receive the color, and impart it as they revolve to the calico pressed between their face and that of the fixed drum. The superfluous color is taken cleanly off by a sharp blade of steel or other metal, against the edge of which the copper roller scrapes in its revolution. To this con- trivance the name of doctor is given. By its use only the color required to fill the depres- sions is left on the rollers, and the excess falls back into the trough. The employment of many engraved rollers in a single machine is attended with great difficulties, arising from the multiplication of all the other attendant parts in the same proportion. The cylinders have different diameters as the pattern re- quires, and must consequently revolve at differ- ent rates of speed. By passing under many rollers, the calico is in danger of being dis- placed and the regularity of the print dis- turbed. But when everything is exactly ad- justed, the work goes on with beautiful pre- cision, accomplishing an extraordinary amount of work. In the use of the cylinder machine, particular care is required that the colors and mordants should be brought to the proper con- sistency by a sufficient quantity of the thicken- ers or gums employed, so that they may not spread or run into each other; and that the selection of these thickeners should be with reference to the chemical effect that may re- sult from their mixture with the colors. The arrangement of the colors, too, in their order of succession, must be with reference to the effect that one may have by coming in contact with the other on the cloth. The rooms in which the operations are conducted require to be kept at a proper degree of humidity and warmth, the success of the delicate processes depending in great measure upon due attention to these particulars. As the cloth leaves the printing machine, it is drawn over rollers through a hot-air chamber, raised to the tem- perature of about 200, in which it is thor- oughly dried and the colors become set. The various methods of preparing and applying the colors and mordants are classed under six or more different styles, viz. : 1, the madder style; 2, the padding style; 3, the topical style, or printing by steam; 4, the resist or reserve style ; 5, the discharge style ; and 6, the China-blue or pottery style; to which some add the mandarining, in which the color is produced only on silk and woollen fabrics by the action of nitric acid upon the animal tissue. Two or more of these are commonly applied upon the same piece, to produce the various colors of the pattern. Each of them is a complicated process, involving numerous chemical operations, which would require vol- umes for their full description. The madder style is like that described by Pliny, quoted above. The coloring matter, which may be madder, or almost any organic dyestuff capable of imparting its color to water, and forming an insoluble compound with mordants, is not ap- plied to the cloth, but this is printed with the mordant instead, and the color is afterward brought out in the places to which the mordant has been applied by the ordinary methods of dyeing. By the different engraved rollers, each supplying a different mordant, various shades and colors are afterward brought out by one dye. Before the mordanted cloth is dyed it is hung for some time in airy chambers, in order that the mordants may intimately combine with the fibre. This operation is called ageing, and has recently been abbreviated by a process in which the goods are passed over rollers in a room in which a small quantity of steam is allowed to escape. But before the goods are in a state to receive the dye, it is necessary to remove that portion of the mordant which has not under- gone in the drying or ageing that chemical change which renders it insoluble and fixed in the spots to which it is applied ; if left, it would spread in the dye beck or vat, and cause the dye to adhere where it should not be seen.