Textile printing

Today's traditional textile and fashion market place is going through creative, technical and product development changes. Change is defined as verb meaning to make it different.

The five  printing methods are distinguished by the method of image transfer and by the ordinary types of image bearer employed. Depending upon the process, the printed design is transferred to the substrate either directly nor indirectly. In direct printing, the image carrier to the material, example of direct printing are, flexography, screen printing and letterpress printing processes. In indirect or offset printing the image is transferred so quickly.

Textile printing is the process of applying color to fabric. In printing block and stencils plates, rollers, are used to place colors on the fabric. To prevent the color from spreading by capillary attraction beyond the limits of the pattern or design.

 

Some techniques were separately fashionable in 19th century, since were combination techniques in which indigo resist was used to make blue background prefer to block printing of other colors. Most modern industrialized printing uses direct printing techniques.


The general theory of printing

The printing of textile materials is the application of color according to a predetermined design.
The printing paste which is applied to textile material consists of dye, water, thickener and hydrocarbon solvent or oil. After the printing paste is applied the textile material is usually steamed. This is to enable the dye molecules to migrate from the surface of the fibers and to enter the fiber polymer system. Steaming swells the fibers and ensures better penetration of the dye and improved color fastness properties of the textile material.

The general theory of printing explains the interaction, on steaming, between the dye, fiber, water, thickener and hydrocarbon solvent. More specifically, it explains how within the printing paste:
1) Forces are repulsion are developed between the dye molecules and the constituents of the printing paste; and
2) Forces of attraction are developed between the dye molecules and the fibers of the textile material to be printed.      

Textile orientation is an ancient art. It refers to the different processes by which fabrics are printed in colored design print fabric. Example of Greek fabrics from the 4th century B.C have been found. India exported block prints to the Mediterranean region in the 5th century B.C.

The invention of a dyed cotton fabric dating backward to the Indus Vally civilization demonstrates that the art of dyeing with the use of mordants was well known to the Indian dyers 5000 years ago. This form of dyeing was responsible for making India famous all over the world for its dyed and printed fabrics.

The dye molecule
The dye molecules are organic molecules which can be classified as:
1) Anionic - in which the color is caused by the anionic part of the dye molecule;
2) Cationic - in which the color is caused by the cationic part of the dye molecule;
3) Disperse - in which the color is caused by the whole molecule.
The first two molecule types are applied from an aqueous solution. This third is applied from an aqueous dispersion.

The role of the thickener

The purpose of the thickener is to produce a medium for the dye paste and resultant product is called the printing paste. The printing paste is an emulsion of thickener and hydrocarbon, such as white spirit or very light hydrocarbon oil, plus a surface active agent. This surface active agents enables the emulsification of the thickener with the hydrocarbon to form printing paste of uniform consistency. The uniform consistency of the printing paste is referred to as its viscosity. The viscosity of the printing paste is very important as it influences the clarity and appearance of the printed pattern. The success of printing textile materials depends very much on the type and quality of the thickener.

Thickeners can be any of the following:
1) Natural gums, such as gum arabic, acacia gums or gums prepared from starches and other polysaccharides;   
2) The man-made, natural polymer-based gums, for example, water soluble cellulose ethers, such as carboxymethyl cellulose, methyl and ethyl cellulose, and sodium alginate; or
3) Occasionally, made-made, synthetic compounds such as polyvinyl alcohol.

Methods of textile printing
         i) Hand printing
         ii) Block printing
         iii) Screen printing
         iv) Spray printing
         v) Kalamkari
         vi) Batik
         vii) Discharge printing
         viii) Tie and dye

The trying of cloth with thread and then dyeing it is the simplest and perhaps on the plain piece of cloth. It is also the earliest forms of decorated textiles.
The fabric is washed. Often it is dipped in the mordant so that it can absorb the dye.The cloth is folded, first lengthwise then width wise into four fold. The patterns on the body are then indicated all over the surface with the use of blocks dipped in grue, a red mud color. The cloth is then printed with the left hand, one knots follow another, using the same thread.