Textile Printing Process, Type of Printing, and Printing Machinery

Textile printing is the process of applying color to fabric in definite patterns or designs. In properly printed fabrics the color is bonded with the fiber, so as to resist washing and friction. Textile printing is related to dyeing, whereas in dyeing proper the whole fabric is uniformly covered with one color, in printing one or more colors are applied to it in certain parts only, and in sharply defined patterns.

In printing, wooden blocks, stencils, engraved plates, rollers, or silkscreens are used to place colors on the fabric. Colorants used in printing contain dyes thickened to prevent the color from spreading by capillary attraction beyond the limits of the pattern or design.

Traditional textile printing techniques may be broadly categorized into three styles:

• Direct printing, in which colorants containing dyes, thickeners, and the mordant or substances necessary for fixing the color on the cloth are printed in the desired pattern.
• Resist dyeing, in which a wax or other substance is printed onto fabric which is subsequently dyed. The waxed areas do not accept the dye, leaving uncolored patterns against the colored ground.
• Discharge printing, in which a bleaching agent is printed onto previously dyed fabrics to remove some or all of the color.

Comparison Between Dyeing and Printing

Though dying and printing are the coloration processes using the same classes of dyes and other chemicals, they differ in the following aspects.

In printing, wooden blocks, stencils, engraved plates, rollers, or silkscreens are used to place colors on the fabric. Colorants used in printing contain dyes thickened to prevent the color from spreading by capillary attraction beyond the limits of the pattern or design.

Traditional textile printing techniques may be broadly categorized into four styles:

• Direct printing, in which colorants containing dyes, thickeners, and the mordants or substances necessary for fixing the color on the cloth are printed in the desired pattern.
• The printing of a mordant in the desired pattern prior to dyeing cloth; the color adheres only where the mordant was printed.
• Resist dyeing, in which a wax or other substance is printed onto fabric which is subsequently dyed. The waxed areas do not accept the dye, leaving uncolored patterns against the colored ground.
• Discharge printing, in which a bleaching agent is printed onto previously dyed fabrics to remove some or all of the color.

Resist and discharge techniques were particularly fashionable in the 19th century, as were combination techniques in which indigo resist was used to create blue backgrounds prior to block-printing of other colors. Most modern industrialized printing uses direct printing techniques.

Origin of Textile Printing

Woodblock printing is a technique for printing text, images or patterns used widely throughout East Asia and probably originated in China in antiquity as a method of printing on textiles and later paper. As a method of printing on cloth, the earliest surviving examples from China date to before 220, and from Egypt to the 4th century.

Textile printing was known in Europe, via the Islamic world, from about the 12th century, and was widely used. However, the European dyes tended to run, which restricted the use of printed patterns. Fairly large and ambitious designs were printed for decorative purposes such as wall-hangings and lectern-cloths, where this was less of a problem as they did not need washing. When paper became common, the technology was rapidly used on that for woodcut prints. The superior cloth was also imported from Islamic countries, but this was much more expensive.

The Incas of Peru, Chile, and Mexico also practiced textile printing previous to the Spanish Invasion in 1519; but, owing to the imperfect character of their records before that date, it is impossible to say whether they discovered the art for themselves, or, in some way, learned its principles from the Asiatics.

During the latter half of the 17th century the French brought directly by the sea, from their colonies on the east coast of India, samples of Indian blue and white resist prints, and along with them, particulars of the processes by which they had been produced, which produced washable fabrics.

Early Textile Printing Methods

The other forms of textile printing are stencil work, highly developed by Japanese artists, and block printing. In the latter method, a block of wood, copper, or other material bearing a design in intaglio with the dye paste applied to the surface is pressed on the fabric and struck with a mallet. A separate block is used for each color, and pitch pins at the corners guide the placing of the blocks to assure accurate repeating of the pattern.

• In-cylinder or roller printing, developed in 1785, the fabric is carried on a rotating central cylinder and pressed by a series of rollers each bearing one color. The design is engraved on the copper rollers by hand or machine pressure or etched by pantograph or photoengraving methods; the color paste is applied to the rollers through feed rollers rotating in a color box, the color being scraped off the smooth portion of the rollers with knives.

• More recent printing processes include screen printing. This is a hand method especially suitable for large patterns with soft outlines, in which screens, one for each color, are placed on the fabric. Then, the color paste is pressed through a wooden squeegee.

• Spray printing, in which a spray gun forces the color through a screen; and electrocoating, used to apply a patterned pile is the other latest printing process.

• In certain cases, the cloth is painted by using a pen with dyes and mordants. This method is known as kalamkari, a pen work. Printing the outline of the design and filling in the details with a kalam, a pen, combines the techniques of printing and kalamkari.

• Direct printing is practiced all over India where bleached cotton or silk fabric is printed with the help of carved wooden blocks.
  Another technique employed was printing with the use of mordants. Mordants are chemicals that absorb the dye. The cloth is first printed with mordants and then immersed in a dye bath. Only the sections that have absorbed the mordant absorb the dye. The cloth is then washed in flowing water and spread out to dry on the riverbank allowing the sun to develop the color. Then the untreated sections were bleached with local ingredients like goat droppings, etc. Recently, discharge printing with the use of chemicals has been developed. Here dyes when printed react on one another, either bleaching the background material or producing a different shade.