Printing

or Calico Printing, the process of impressing designs of one or more colors upon fabrics. Not only cotton, but woolen, silk, and linen textures, may be printed, as well as unwoven yarns. The methods employed for printing different textures are essentially the same.

Printing is a complex process, enlisting the arts of designing, engraving, and dyeing, as well as the science of chemistry. While classed among the processes of manufacture, calico printing, as it is called, stands very close to the fine arts; since the printer must understand how to arrange colors harmoniously, how to make various shades relieve each other, just which colors in a design should be clear and brilliant and which tints or shades are more effective. He must know how to make the pattern, or certain parts of the pattern, stand out more or less distinctly according to the tone of the ground color. In fact, he must know color as an artist knows it.

It is supposed that the art of printing cottons and linens originated in the far East. Mention is made by historians, as early as 327 B. C., of the fine flowered chintzes of India, and it is probable that the art had been practiced to some extent for centuries. The printing of textiles was introduced into Europe toward the close of the seventeenth century. The pattern was laid upon the cloth with a mordant, that is, a substance which penetrates and sometimes has an affinity for the fibers, and at the same time possesses the property of forming an insoluble compound about the fibers with the coloring matter subsequently employed. If, therefore, a number of different mordants were used on different parts of the white cloth, the dye bath would produce different colors or shades in the result. The finished print was often both durable and beautiful, but the method was tedious. About the middle of the eighteenth century, Robert Peel, grandfather of Sir Robert Peel, the statesman, invented block printing. Wooden blocks were so engraved that the pattern stood out in relief. A block was prepared for each color. The blocks were furnished with handles, and with brass pins at the corners which served as guides in the regular distribution of the pattern and in bringing different parts of the pattern into exact juxtaposition, when several blocks were required for the several colors of the same design. The cylinder printing machine was invented in 1785, since which time improvements have followed each other in rapid succession until the process seems well nigh perfected. At Fall River, Massachusetts, twenty-five yards of cloth can be printed with patterns involving sixteen colors in the space of one minute.

At the present time methods and processes of printing vary according to material, style, and quality desired. Some firms purchase the raw cotton and put it through all the various processes,--spinning, weaving, bleaching, singeing, shearing, mercerizing, printing, together with the numerous washings, steamings, and dyeings which fabrics must undergo before they are ready for the market. In most cases, however, the cloth is woven elsewhere and received at the "print-works" in its unbleached state--"in the gray" as it is called by manufacturers. The cloth is first singed, then bleached. It must be bleached until chemically pure, or the action of the dye might be interfered with. After bleaching, the cloth is sheared or cropped. The next process is starching, which is done to fill up the spaces between the threads, so that the pattern will be imprinted more plainly. The patterns are engraved on copper cylinders about three and a half feet long by six inches in diameter. A different cylinder is required for each color of the pattern. If the pattern is to be printed in one color, the entire design is engraved on one cylinder. If two or more colors are desired, a part of the design only is engraved on each cylinder, the work being done so carefully that when the cloth is carried over one cylinder after another, the various parts of the pattern will come into exact juxtaposition, producing a complete and perfect design. These cylinders are placed in a printing machine which will carry any number up to twenty. Each cylinder is fed with its own color by a roller which revolves in a dye trough or "color box." In simple patterns, as stripes, three colors may be produced from two printings, or the use of two cylinders. This is done by allowing the two colors to overlap, thus forming a third color.

In printing, the white cloth is wound on a huge drum and fed to the press like a roll of paper. As the web passes through, it receives the imprint in color from each cylinder and emerges as "print." The colors are not always apparent at first. Certain processes may be necessary to bring them out. This is due to the fact that a mordant has been used with the color, or must be used after the colors are imprinted, to cause the dye to unite permanently with the fiber. In other instances the mordant is printed upon the goods, and may be in part or wholly invisible until subsequent dyeing and washing gives color to the design imprinted with the mordant and leaves the remainder of the fabric white.

According to the most common method of printing, called technically the "steam style," each color or dye is mixed with its own particular mordant before printing. After leaving the printing machine the cloth is subjected to the action of live steam, which causes the chemical combination of color and mordant, and induces the absorption of this compound by the fiber. The steaming process requires experience, care, and judgment, as no fixed rules can be laid down as to the length of time the goods should be steamed, the amount of moisture used, etc.

Various other methods of combining mordant and dye to produce different effects are in use. They are named from the dye with which they were first used, as "Madder style," "Indigo style," etc., or from some distinctive feature of the process, as "Discharge style," "Resist style," or "Bandana style."

The old block method of printing is used in place of the cylinder machines for printing very sheer textures, such as netting and chiffon; also for some mixed goods and for cloth over forty inches wide. It is also used in warp printing to produce effects impossible to obtain by printing directly on cloth. In warp printing, the warp is mounted on the loom as for ordinary weaving. A few wefts are woven into it at distances of a few inches apart. It is then removed from the loom, stretched on tables, and the open warp printed in designs by the block process. The warp is returned to the loom and is woven as usual. The design is, of course, less distinct than when printed on a woven web, but the process produces a peculiar and pleasing effect.

See Singeing; Weaving; Bleaching; Calico; Dyeing; Mordant; Bandana