FORTALEZAS DEBILIDADES Local propio con infraestructura multifuncional

The process of creating designs for knitted, woven or printed fabric is called textile design. Designs for both woven and printed textiles often begin with a drawing or watercolor sketch of what the final design would look like.

Traditionally, drawings of woven textile patterns were translated onto special forms of graph paper called point papers which were used by the weavers in setting up their looms. Currently, most professional textile designers use some form of computer aided soft-wares created especially for this purpose.

3.2.1 Cloth Weaving

Weaving is also a technique employed by textile designers. Weaving is a textile craft in which two distinct sets of yarns or threads, called the warp and the filling or weft (meaning "that which is woven"), are interlaced to form a fabric or cloth.

The warp threads run lengthways on the piece of cloth, and the weft runs across from side to side, across the bolt of cloth.

The device used for weaving cloth is called a loom. The device secures the warp threads in place while filling threads are woven through them. There are different types of looms viz: the horizontal loom and the vertical loom (Fig.32a and 32b), while some are operated manually (as in the case of the looms used by traditional weavers in Nigeria). Others such as the loom used in the weaving of the majority

of commercial fabrics in the West are computer-controlled as exemplified in the type known as Jacquard looms.

The way the warp and filling threads interlace with each other is called the weave.

There are three types of basic weaves, namely: plain weave, satin weave, or twill.

There are different types of woven cloth. Some are plain and woven in one colour or a simple pattern, while others are woven in decorative or artistic designs.

Fig.32b: A Traditional Loom

Source: The Decorative Arts of Africa Fig. 32a: A Jacquard Loom

Source: Wikipedia, the Free Encyclopedia

As noted above, generally, weaving involves the interlacing of two sets of threads at right angles to each other: the warp and the weft. The warp is held tight and in parallel order by means of a loom (some types of weaving may use other methods). The loom is warped (or dressed) with the warp threads passing through heddles on two or more harnesses.

During weaving, the weaver moves the warp threads up or down by the harnesses creating a space called the shed. The weft thread is wound onto spools called bobbins. The bobbins are placed in a shuttle that carries the weft thread through

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the shed. The raising and lowering sequence of warp threads creates many possible weave structures.

Self Assessment Exercise 1

Briefly describe the weaving process.

3.2.2 Textile Printing

Another technique used by textile designer is printing. Textile printing is the process of applying colour to fabric in specific patterns or designs bonded with the fibre, of the fabric on which it is printed to make them resistant to washing and friction. Textile printing is said to have been introduced into England in 1676 by a French refugee who opened workshop in that year on the banks of the Thames near Richmond.

Textile printing is a bit like dyeing fabric. The difference is that in dyeing proper, the whole fabric is uniformly covered with one colour, but in printing one or more colours is applied to the fabric in only certain selected portions, and in sharply defined patterns.

In printing, wooden blocks, stencils, engraved plates, rollers, or silk-screens are used to place colours on the fabric. Special colourants are used in printing. These are colourants which have dyes that have been deliberately thickened to prevent the colour from spreading by capillary attraction beyond the limits of the pattern or design (Fig. 33).

Fig. 33: A Printed Design

There are three styles of traditional textile printing techniques. These are: direct printing, discharge printing and resist dyeing.

• Direct printing: In this process, colourants that contain dyes, thickeners and mordants (substances necessary for fixing the colour on the cloth) are printed in the desired pattern. Most Modern industrialized printing techniques utilize the direct printing techniques.

• Discharge printing: This is a process in which a bleaching agent is printed onto previously dyed fabrics to remove some or the entire colour.

A mordant is printed in the desired pattern prior to the dyeing of the cloth. The colour adheres only where the mordant was printed.

• Resist dyeing: This technique involves the printing of a wax or other substance onto fabric which is later dyed. The waxed areas resist the dye, leaving un-coloured patterns against a coloured ground.

Self Assessment Exercise 2

Briefly describe the dyeing processes.