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Monday, April 27, 2009

Textile printing

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

In printing, wooden blocks, stencilsengraved plates, rollers, or silkscreens are used to place colours on the fabric. Colourants used in printing contain dyes thickened to prevent the colour from spreading by capillary attraction beyond the limits of the pattern or design.

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

  • Direct printing, in which colourants containing dyes, thickeners, and the mordants or substances necessary for fixing the colour 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 uncoloured patterns against a coloured ground.
  • Discharge printing, in which a bleaching agent is printed onto previously dyed fabrics to remove some or all of the colour.

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 colours.[1] Most modern industrialised printing uses direct printing techniques.

Textile printing was introduced into England in 1676 by a French refugee who opened works, in that year, on the banks of the Thames near Richmond. Curiously enough this is the first print-works on record; but the nationality and political status of its founder are sufficient to prove that printing was previously carried on in France. In Germany, too, textile printing was in all probability well established before it spread to England, for, towards the end of the 17th century, the district of Augsburg was celebrated for its printed linens, a reputation not likely to have been built up had the industry been introduced later than 1676.

On the continent of Europe the commercial importance of calico printing seems to have been almost immediately recognized, and in consequence it spread and developed there much more rapidly than in England, where it was neglected and practically at a standstill for nearly ninety years after its introduction. During the last two decades of the 17th century and the earlier ones of the 18th new works were started in France, Germany, Switzerland and Austria; but it was only in 1738 that calico printing was first, practiced in Scotland, and not until twenty-six years later that Messrs Clayton of Bamber Bridge, near Preston, established in 1764 the first print-works in Lancashire, and thus laid the foundation of what has since become one of the most important industries of the county and indeed of the country. At the present time calico printing is carried on extensively in every quarter of the globe, and it is pretty safe to say that there is scarcely a civilized country in either hemisphere where a print-works does not exist.

From an artistic point of view most of the pioneer work in calico printing was done by the French; and so rapid was their advance in this branch of the business that they soon came to be acknowledged as its leading exponents. Their styles of design and schemes of colour were closely followed-even deliberately copied by all other European printers; arid, from the early days of the industry down to the latter half of the 10th century, the productions of the French printers in Jouy, Beauvais, Rouen, Alsace-Lorraine, &c., were looked upon as representing all that was best in artistic calico printing. This reputation was established by the superiority of their earlier work, which, whatever else it may have lacked, possessed in a high degree the two main qualities essential to all good decorative work, viz., appropriateness of pattern and excellency of workmanship. If, occasionally, the earlier designers permitted themselves to indulge in somewhat bizarre fancies, they at least carefully refrained from any attempt to produce those pseudo-realistic effects the undue straining after which in later times ultimately led to the degradation of not only French calico printing design, but of that of all other European nations who followed their lead. The practice of the older craftsmen, at their best, was to treat their ornament in a way at once broad, simple and direct, thoroughly artistic and perfectly adapted to the means by which it had to be reproduced. The result was that their designs were characterized, on the one hand, by those qualities of breadth, flatness of field, simplicity of treatment arid pureness of tint so rightly prized by the artist; and, on the other, by their entire freedom from those meretricious effects of naturalistic projection and recession so dear to the modern mind and so utterly opposed to the principles of applied art.

There are six distinct methods at present in use for producing coloured patterns on cloth:

  1. Hand block printing.
  2. Perrotine or block printing by machine.
  3. Engraved plate printing.
  4. Engraved roller printing.
  5. Stenciling, which although not really a printing process may be classed here as one.
  6. Screen printing

This process, though considered by some to be the most artistic, is the earliest, simplest and slowest of all methods of printing.

In this process, a design is drawn upon, or transferred to, a prepared wooden block. A separate block is required for each distinct colour in the design.

A blockcutter carves out the wood around the heavier masses first, leaving the finer and more delicate work until the last so as to avoid any risk of injuring it during the cutting of the coarser parts. When finished, the block presents the appearance of flat relief carving, with the design standing out.

Fine details are very difficult to cut in wood, and, even when successfully cut, wear down very rapidly or break off in printing. They are therefore almost invariably built up in strips of brass or copper, bent to shape and driven edgewise into the flat surface of the block. This method is known as coppering.

To print the design on the fabric, the printer applies color to the block and presses it firmly and steadily on the cloth, ensuring a good impression by striking it smartly on the back with a wooden mallet. The second impression is made in the same way, the printer taking care to see that it fits exactly to the first, a point which he can make sure of by means of the pins with which the blocks are provided at each corner and which are arranged in such a way that when those at the right side or at the top of the block fall upon those at the left side or the bottom of the previous impression the two printings join up exactly and continue the pattern without a break. Each succeeding impression is made in precisely the same manner until the length of cloth is fully printed. When this is done it is wound over the drying rollers, thus bringing forward a fresh length to be treated similarly.

If the pattern contains several colours the cloth is usually first printed throughout with one, then dried, and printed with the second, the same operations being repeated until all the colours are printed.

Block printing by hand is a slow process it is, however, capable of yielding highly artistic results, some of which are unobtainable by any other method.

Perrotine printing

The perrotine is a block-printing machine invented by Perrot of Rouen in 1834, and practically speaking is the only successful mechanical device ever introduced for this purpose. For some reason or other it has rarely been used in England, but its value was almost immediately recognized on the Continent, and although block printing of all sorts has been replaced to such an enormous extent by roller printing, the perrotine is still largely employed in French, German and Italian works.

The construction of this ingenious machine is too complex to describe here without the aid of several detailed drawings, but its mode of action is roughly as follows: Three large blocks (3 ft. long by 3 to 5 in. wide), with the pattern cut or cast on them in relief, are brought to bear successively on the three faces of a specially constructed printing table over which the cloth passes (together with its backing of printers blanket) after each impression. The faces of the table are arranged at right angles to each other, and the blocks work in slides similarly placed, so that their engraved faces are perfectly parallel to the tables. Each block is moreover provided with its own particular colour trough, distributing brush, and woolen colour pad or sieve, and is supplied automatically with colour by these appliances during the whole time that the machine is in motion. The first effect of starting the machine is to cause the colour sieves, which have a reciprocating motion, to pass over, and receive a charge of colour from, the rollers, fixed to revolve, in the colour troughs. They then return to their original position between the tables and the printing blocks, coming in contact on the way with the distributing brushes, which spread the colour evenly over their entire surfaces. At this point the blocks advance and are gently pressed twice against the colour pads (or sieves) which then retreat once more towards the colour troughs. During this last movement the cloth to be printed is drawn forward over the first table, and, immediately the colour pads are sufficiently out of the way, the block advances and, with some force, stamps the first impression on it. The second block is now put into gear and the foregoing operations are repeated for both blocks, the cloth advancing, after each impression, a distance exactly equal to the width of the blocks. After the second block has made its impression the third comes into play in precisely the same way, so that as the cloth leaves the machines it's fully printed in three separate colours, each fitting into its proper place and completing the pattern. If necessary the forward movement of the cloth can be arrested without in any way interfering with the motion of the block, san arrangement which allows any insufficiently printed impression to be repeated in exactly the same place with a precision practically impossible in hand printing.

For certain classes of work the perrotine possesses great advantages over the hand-block; for not only is the rate of production greatly increased, but the joining up of the various impressions to each other is much more exacting fact, as a rule, no sign of a break in continuity of line can be noticed in well-executed work. On the other hand, however, the perrotine can only be applied to the production of patterns containing not more than three colours nor exceeding five inches in vertical repeat, whereas hand block printing can cope with patterns of almost any scale and continuing any number of colours. All things considered, therefore, the two processes cannot be compared on the same basis: the perrotine is best for work of a utilitarian character and the hand-block for decorative work in which the design only repeats every 15 to 20 in. and contains colours varying in number from one to a dozen. -

Other Methods of Printing

Although most work is executed throughout by one or other of the six distinct processes mentioned above, combinations of them are not infrequently employed. Sometimes a pattern is printed partly by machine and partly by block; and sometimes a cylindrical block is used along with engraved copper-rollers in the ordinary printing machine. The block in this latter case is in all respects, except that of shape, identical with a flat wood or coppered block, but, instead of being dipped in colour, it receives its supply from an endless blanket, one part of which works in contact with colour-furnishing rollers and the other part with the cylindrical block. This block is known as a surface or peg roller. Many attempts have been made to print multicolour patterns with surface rollers alone, but hitherto with little success, owing to their irregularity in action and to the difficulty of preventing them from warping. These defects are not present in the printing of linoleum in which opaque oil colours are used, colours that neither sink into the body of the hard linoleum nor tend to warp the roller.

The printing of yarns and warping is extensively practiced. It is usually carried on by a simple sort of surface printing machine and calls for no special mention.

Lithographic printing, too, has been applied to textile fabrics with somewhat qualified success. Its irregularity and the difficulty of printing all over patterns to repeat properly, have restricted its use to the production of decorative panels, equal in size to that of the plate or stone, and complete in themselves.

Pad printing has been recently introduced to textile printing for the specific purpose of printing garment tags (care labels). Printed tags seem to be gradually replacing formerly standard sewn-in tags and thermally transferred labels.

Preparation of cloth for printing

Goods intended for calico printing ought to be exceptionally well-bleached, otherwise mysterious stains, and other serious defects, are certain to arise during subsequent operations.

The chemical preparations used for special styles will be mentioned in their proper places; but a general prepare, employed for most colours that are developed and fixed by steaming only, consists in passing the bleached calico through a weak solution of sulfated or turkey red oil containing from 21/2 per cent, to 5 per cent, of fatty acid. Some colours are printed on pure bleached cloth, but all patterns containing alizarine red, rose and salmon shades, are considerably brightened by the presence of oil, and indeed very few, if any, colours are detrimentally affected by it.

Apart from wet preparations the cloth has always to be brushed, to free it from loose nap, flocks and dust that it picks up whilst stored. Frequently, too, it has to be sheared by being passed over rapidly revolving knives arranged spirally round an axle, which rapidly and effectually cuts off all filaments and knots, leaving the cloth perfectly smooth and clean and in a condition fit to receive impressions of the most delicate engraving. Some figured fabrics, especially those woven in checks, stripes and crossovers, require very careful stretching and straightening on a special machine, known as a stenter, before they can be printed with certain formal styles of pattern which are intended in one way or another to correspond with the cloth pattern. Finally, all descriptions of cloth are wound round hollow wooden or iron centers into rolls of convenient size for mounting on the printing machines.

The art of making colours for textile printing demands both chemical knowledge and extensive technical experience, for their ingredients must not only be properly proportioned to each other, but they must be specially chosen and compounded for the particular style of work in hand. For a pattern containing only one colour any mixture whatever may he used so long as it fulfils all conditions as to shade, quality and fastness; but where two or more colours are associated in the same design each must be capable of undergoing without injury the various operations necessary for the development and fixation of the others.

All printing pastes whether containing colouring matter or not are known technically as colours, and are referred to as such in the sequence.

Colours vary considerably in composition. The greater number of them contain all the elements necessary for the direct production and fixation of the colour-lake. Some few contain the colouring matter alone and require various after-treatments for its fixation; and others again are simply mordants thickened. A mordant is the metallic salt or other substance that combines with the colouring principle to form an insoluble colour-lake, either directly by steaming, or indirectly by dyeing.

All printing colours require thickening, for the two-fold object of enabling them to be transferred from colour-box to cloth without loss and to prevent them from running or spreading beyond the limits of the pattern.

Silk printing calls for no special mention. The colours and methods employed are the same as for wool, except that in the case of silk no preparation of the material is required before printing and the ordinary dry steaming is preferable to damp steaming.

Both acid and basic dyes play an important role in silk printing, which for the most part is confined to the production of articles for wearing apparel dress goods, handkerchiefs, scarves, articles for which bright colours are in demand. Alizarine and other mordant colours are mainly used, or ought to be, for any goods that have to resist repeated washings and prolonged exposure to light. In this case the silk frequently requires to be prepared in alizarine oil, after which it is treated in all respects like cotton steamed, washed and soaped the colours used being the same.

Silk is especially adapted to discharge and reserve effects. Most of the acid dyes can be discharged in the same way as when they are dyed on wool; and reserved effects are produced by printing mechanical resists, such as waxes and fats, on the cloth and then dyeing it up in cold dye-liquor. The great affinity of the silk fiber for basic and acid dyestuffs enables it to extract colouring matter from cold solutions, and permanently combine with it to form an insoluble lake. After dyeing, the reserve prints are washed, first in cold water to get rid of any colour not fixed on the fiber, and then in hot water or benzene, to dissolve out the resisting bodies.

As a rule, after steaming, silk goods are only washed in hot water, but, of course, those printed entirely in mordant dyes will stand soaping, and indeed require it to brighten the colours and soften the material.

Sunday, April 26, 2009

Textile manufacturing

Textile manufacture is a major industry. It is based in the conversion of three types of fibre (fiber is an alternative spelling in the US but not in Britain and the Commonwealth) into yarn, then fabric, then textiles. These are then fabricated into clothes or other artifacts. Cotton remains the most important natural fibre, so is treated in depth. There are many sources of fibre, and variable processes available at the spinning and fabric-forming stages coupled with the complexities of the finishing and colouration processes to the production of a wide ranges of products. There remains a large industry that uses hand techniques to achieve the same results।
Cotton is the world's most important natural fibre. In the year 2007, the global yield was 25 million tons from 35 million hectares cultivated in more than 50 countries.
There are five stages
Cultivating and Harvesting
Preparatory Processes
Cotton is grown anywhere with long, hot dry summers with plenty of sunshine and low humidity. Indian cotton, gossypium arboreum is finer but the staple is only suitable for hand processing. American cotton, gossypium hirsutum produces the longer staple needed for machine production.Planting is from September to mid November and the crop is harvested between March and May. The cotton bolls are harvested by stripper harvesters and spindle pickers, that remove the entire boll from the plant. The cotton boll is the seed pod of the cotton plant, attached to each of the thousands of seeds are fibres about 2.5 cm long.
The seed cotton goes in to a Cotton Gin. The cotton gin separates the seeds and removes the "trash" (dirt, stems and leaves) from the fibre. In a saw gin, circular saw grab the fibre and pull it through a grating that is too narrow for he seeds to pass. A roller gin is used with longer staple cotton,. Here a leather roller captures the cotton. A knife blade, set close to the roller detaches the seed. by drawing them through teeth in circular saws and revolving brushes which clean them away.
The ginned cotton fibre, known as lint, is then compressed into bales which are about 1.5m tall and weigh almost 220 kg. Only 33% of the crop is usable lint. Commercial cotton is priced by quality, and that broadly relates to the average length of the staple, and the variety of the plant. Longer staple cotton ( 2 1/2 in to 1 1/4 in) is called Egyptian, medium staple ( 1 1/4 in to 3/4 in) is called American upland and short staple ( less than 3/4 in) is called Indian.
The cotton seed is pressed into a cooking oil। The husks and meal are processed into animal feed, and the stems into paper.

Preparatory Processes- Preparation of yarn
Ginning, bale-making and transportation is done in the country of origin.
Opening and क्लेअनिंग

Cotton mills get the cotton shipped to them in large, 500 pound bales। When the cotton comes out of a bale, it is all packed together and still contains vegetable matter. The bale is broken open using a machine with large spikes. It is called an Opener.In order to fluff up the cotton and remove the vegetable matter, the cotton is sent through a picker, or similar machines. A picker looks similar to the carding machine and the cotton gin, but is slightly different. The cotton is fed into the machine and gets beaten with a beater bar, to loosen it up. It is fed through various rollers, which serve to remove the vegetable matter. The cotton, aided by fans, then collects on a screen and gets fed through more rollers till it emerges as a continuous soft fleecy sheet, known as a lap.

Mixing & Scutching

Carding: the fibres are separated and then assembled into a loose strand (sliver or tow) at the conclusion of this stage.
The cotton comes off of the picking machine in laps, and is then taken to carding machines. The carders line up the fibres nicely to make them easier to spin. The carding machine consists mainly of one big roller with smaller ones surrounding it. All of the rollers are covered in small teeth, and as the cotton progresses further on the teeth get finer (i.e. closer together). The cotton leaves the carding machine in the form of a sliver; a large rope of fibres.
Note: In a wider sense Carding can refer to these four processes: Willowing- loosening the fibres; Lapping- removing the dust to create a flat sheet or lap of cotton; Carding- combing the tangled lap into a thick rope of 1/2 in in diameter, a sliver; and Drawing- where a drawing frame combines 4 slivers into one- repeated for increased quality.
Combing is optional,but is used to remove the shorter fibres, creating a stronger yarn.

Drawing the fibres are straightened
Several slivers are combined. Each sliver will have thin and thick spots, and by combining several slivers together a more consistent size can be reached. Since combining several slivers produces a very thick rope of cotton fibres, directly after being combined the slivers are separated into rovings. These rovings are then what are used in the spinning process. Generally speaking, for machine processing a roving is about the width of a pencil.Next, several slivers are combined. Each sliver will have thin and thick spots, and by combining several slivers together a more consistent size can be reached. Since combining several slivers produces a very thick rope of cotton fibres, directly after being combined the slivers are separated into rovings. These rovings (or slubbings) are then what are used in the spinning process.
Generally speaking, for machine processing, a roving is about the width of a pencil.
Drawing frame: Draws the strand out
Slubbing Frame: adds twist, and winds on to bobbins
Intermediate Frames: are used to repeat the slubbing process to produce a finer yarn.
Roving frames: reduces to a finer thread, gives more twist, makes more regular and even in thickness, and winds on to a smaller tube।
Spinning- Yarn मनुफक्तुरे

The spinning machines take the roving, thins it and twists it, creating yarn which it winds onto a bobbin.
In mule spinning he roving is pulled off a bobbin and fed through some rollers, which are feeding at several different speeds.This thins the roving at a consistent rate. If the roving was not a consistent size, then this step could cause a break in the yarn, or could jam the machine. The yarn is twisted through the spinning of the bobbin as the carriage moves out, and is rolled onto a cop as the carriage returns. Mule spinning produces a finer thread than the less skilled ring spinning.
The mule was an intermittent process, as the frame advanced and returned a distance of 5ft.It was the descendant of 1779 Crompton device. It produces a softer less twisted thread that was favoured for fines and for weft. It requires considerable skill, so was womens work.
The ring was a descendant of the Arkwright water Frame 1769. It was a continuous process, the yard was coarser, had a greater twist and was stronger so was suited to be warp. Requiring less skill it was mens work. Ring spinning is slow due to the distance the thread must pass around the ring, other methods have been introduced. These are collectively known as Break or Open-end spinning.
Sewing thread, was made of several threads twisted together, or doubled.
This is the process where each of the bobbins is rewound to give a tighter bobbin.
Folding and twisting
Plying is done by pulling yarn from two or more bobbins and twisting it together, in the opposite direction that that in which it was spun. Depending on the weight desired, the cotton may or may not be plied, and the number of strands twisted together varies.
Main articles: Singe#Textiles and Gassing
Gassing is the process of passing yarn, as distinct from fabric very rapidly through a series of Bunsen gas flames in a gassing frame, in order to burn off the projecting fibres and make the thread round and smooth and also brighter। Only the better qualities of yarn are gassed, such as that used for voiles, poplins, venetians, gabardines, many Egyptian qualities, etc. There is a loss of weight in gassing, which varies' about 5 to 8 per cent., so that if a 2/60's yarn is required 2/56's would be used. The gassed yarn is darker in shade afterwards, but should not be scorched.
Weaving-Fabric manufacture
The weaving process uses a
loom. The lengthway threads are known as the warp, and the cross way threads are known as the weft. The warp which must be strong needs to be presented to loom on a warp beam. The weft, passes across the loom in a shuttle, that carries the yarn on a pirn. These pirns are automatically changed by the loom. Thus, the yarn needs to be wrapped onto a beam, and onto pirns before weaving can commence.
After being spun and plied, the cotton thread is taken to a warping room where the winding machine takes the required length of yarn and winds it onto warpers bobbins
Warping or beaming

Racks of bobbins are set up to hold the thread while it is rolled onto the warp bar of a loom. Because the thread is fine, often three of these would be combined to get the desired thread count.[citation needed].
Slasher sizing machine needed for strengthening the warp by adding starch.
Drawing in, Looming
The process of drawing each end of the warp separately through the dents of the reed and the eyes of the healds, in the order indicated by the draft.
Pirning (Processing the weft)
Pirn winding frame was used to transfer the weft from cheeses of yarn onto the pirns that would fit into the shuttle
Main article: Power loom
At this point, the thread is woven. Depending on the era, one person could manage anywhere from 3 to 100 machines. In the mid nineteenth century, four was the standard number. A skilled weaver in 1925 would run 6 Lancashire Looms. As time progressed new mechanisms were added that stopped the loom any time something went wrong. The mechanisms checked for such things as a broken warp thread, broken weft thread, the shuttle going straight across, and if the shuttle was empty. Forty of these Northrop Looms or automatic looms could be operated by one skilled worker।

The three primary movements of a loom are shedding, picking, and beating-up.
Shedding: The operation of dividing the warp into two lines, so that the shuttle can pass between these lines. There are two general kinds of sheds-"open" and "closed." Open Shed-The warp threads are moved when the pattern requires it-from one line to the other. Closed Shed-The warp threads are all placed level in one line after each pick.
Picking:The operation of projecting the shuttle from side to side of the loom through the division in the warp threads. This is done by the overpick or underpick motions. The overpick is suitable for quick-running looms, whereas the underpick is best for heavy or slow looms.
Beating-up: The third primary movement of the loom when making cloth, and is the action of the reed as it drives each pick of weft to the fell of the cloth.
The Lancashire Loom was the first semi-automatic loom. Jacquard Looms and Dobby Looms are looms that have sophisticated methods of shedding. They may be separate looms, or mechanisms added to a plain loom. A Northrop Loom was fully automatic and was mass produced between 1909 and the mid 1960s। Modern looms run faster and and do not use a shuttle: there are air jet looms, water jet looms and rapier looms.
Ends and Picks: Picks refer to the weft, ends refer to the warp। The coarseness of the cloth can be expressed as the number of picks and ends per quarter inch square , or per inch square. Ends is always written first. For example: Heavy domestics are made from coarse yarns, such as 10's to 14's warp and weft, and about 48 ends and 52 picks.
Associated job titles
Draw boy
When a hand loom was located in the home, children helped with the weaving process from an early age. Piecing needs dexterity, and a child can be a productive as an adult. When weaving moves from the home to the mill, children were often allowed to help their older sisters, and laws have to be made to prevent Child Labour becoming established,
Knitting by machine is done in two different ways; warp and weft. Weft knitting (as seen in the pictures) is similar in method to hand knitting with stitches all connected to each other horizontally. Various weft machines can be configured to produce textiles from a single spool of yarn or multiple spools depending on the size of the machine cylinder (where the needles are bedded). In a warp knit there are many pieces of yarn and there are vertical chains, zigzagged together by crossing the yarn.
Warp knits do not stretch as much as a weft knit, and it is run-resistant. A weft knit is not run-resistant, but stretches more, this is especially true if spools of Lycra are processed from separate spool containers and interwoven through the cylinder with cotton yarn giving the finished product more flexibilty making it less prone to having a 'baggy' appearance. The average t-shirt is a weft क्नित
Finishing- Processing of Textiles
The grey cloth,woven cotton fabric in its loom-state, not only contains impurities, including warp size, but requires further treatment in order to develop its full textile potential. Furthermore, it may receive considerable added value by applying one or more finishing processes.
Depending on the size that has been used, the cloth may be steeped in a dilute acid and then rinsed, or enzymes may be used to break down the size.
Scouring, is a chemical washing process carried out on cotton fabric to remove natural wax and non-fibrous impurities (eg the remains of seed fragments) from the fibres and any added soiling or dirt. Scouring is usually carried in iron vessels called kiers. The fabric is boiled in an alkali, which forms a soap with free fatty acids. (saponification). A kier is usually enclosed, so the solution of sodium hydroxide can be boiled under pressure, excluding oxygen which would degrade the cellulose in the fibre. If the appropriate reagents are used, scouring will also remove size from the fabric although desizing often precedes scouring and is considered to be a separate process known as fabric preparation. Preparation and scouring are prerequisites to most of the other finishing processes. At this stage even the most naturally white cotton fibres are yellowish, and bleaching, the next process, is required.
Main article: Textile bleaching
Bleaching improves whiteness by removing natural coloration and remaining trace impurities from the cotton; the degree of bleaching necessary is determined by the required whiteness and absorbency. Cotton being a vegetable fibre will be bleached using an oxidizing agent, such as dilute sodium hydrochlorite or dilute hydrogen peroxide. If the fabric is to be dyed a deep shade, then lower levels of bleaching are acceptable, for example. However, for white bed sheetings and medical applications, the highest levels of whiteness and absorbency are essential.
Main article: Mercerized cotton
A further possibility is mercerizing during which the fabric is treated with caustic soda solution to cause swelling of the fibres. This results in improved lustre, strength and dye affinity. Cotton is mercerized under tension, and all alkali must be washed out before the tension is released or shrinkage will take place. Mercerizing can take place directly on grey cloth, or after bleaching.
Many other chemical treatments may be applied to cotton fabrics to produce low flammability, crease resist and other special effects but four important non-chemical finishing treatments are:
Main article: Singe#Textiles
Singeing is designed to burn off the surface fibres from the fabric to produce smoothness. The fabric passes over brushes to raise the fibres, then passes over a plate heated by gas flames.
Another finishing process is raising. During raising, the fabric surface is treated with sharp teeth to lift the surface fibres, thereby imparting hairiness, softness and warmth, as in flannelette.
Main article: Calender
Calendering is the third important mechanical process, in which the fabric is passed between heated rollers to generate smooth, polished or embossed effects depending on roller surface properties and relative speeds.
Shrinking (Sanforizing)
Main article: Sanforization
Finally, mechanical shrinking (sometimes referred to as sanforizing), whereby the fabric is forced to shrink width and/or lengthwise, creates a fabric in which any residual tendency to shrink after subsequent laundering is minimal.
Main article: Dyeing
Finally, cotton is an absorbent fibre which responds readily to colouration processes. Dyeing, for instance, is commonly carried out with an anionic direct dye by completely immersing the fabric (or yarn) in an aqueous dyebath according to a prescribed procedure. For improved fastness to washing, rubbing and light, other dyes such as vats and reactives are commonly used. These require more complex chemistry during processing and are thus more expensive to apply.
Main article: Textile printing
Printing, on the other hand, is the application of colour in the form of a paste or ink to the surface of a fabric, in a predetermined pattern। It may be considered as localised dyeing. Printing designs on to already dyed fabric is also possible.
Economic, environmental and political consequences of cotton manufacture
The growth of cotton is divided into two segments i.e. organic and genetically modified. Cotton crop provides livelihood to millions of people but its production is becoming expensive because of high water consumption, use of expensive pesticides, insecticides and fertiliser. GM products aim to increase disease resistance and reduce the water required. The organic sector was worth $583 million. GM cotton, in 2007, occupied 43% of cotton growing areas..
The consumption of energy in form of water and electricity is relatively high, especially in processes like washing, de-sizing, bleaching, rinsing, dyeing, printing, coating and finishing। Processing is time consuming. The major portion of water in textile industry is used for wet processing of textile (70 per cent). Approximately 25 per cent of energy in the total textile production like fibre production, spinning, twisting, weaving, knitting, clothing manufacturing etc. is used in dyeing. About 34 per cent of energy is consumed in spinning, 23 per cent in weaving, 38 per cent in chemical wet processing and five per cent in miscellaneous processes. Power dominates consumption pattern in spinning and weaving, while thermal energy is the major factor for chemical wet processing.
Wool comes from domesticated sheep. It forms two products Woolens and Worsteds. The sheep has two sorts of wool and it in the inner coat that is used. This can be mixed with wool that has been recovered from rags. Shoddy is the term for recovered wool that is not matted, while mungo comes from felted wool. Extract is recovered chemically from mixed cotton/wool fabrics.
The fleece is cut in one piece from the sheep.This is then skirted to remove the soiled wool, and baled. It is graded into long wool where the fibres can be up to 15 in, but anything over 2.5 inches is suitable for combing into worsteds. Fibres less than that form short wool and are described as clothing or carding wool.
At the mill the wool is scoured in a detergent to remove grease (the yolk) and impurities. This is done mechanically in the opening machine. Vegetable matter can be removed chemically using sulkphuric acid (carbonising). Washing uses a solution of soap and sodium carbonate. The wool is oiled before carding or combing.
Woollens: Use noils from the worsted combs, mungo and shoddy and new short wool
Combing: Oiled slivers are wound into laps, and placed in the circular comber. The worsted yarn gathers together to form a top. The shorter fibres or noils remain behind and are removed with a knife.
Synthetic fibres are the result of extensive development by scientists to improve upon the naturally occurring animal and plant fibres. In general, synthetic fibres are created by forcing, or extruding, fibre forming materials through holes (called spinnerets) into the air, thus forming a thread. Before synthetic fibres were developed, artificially manufactured fibers were made from cellulose, which comes from plants.
The first artificial fibre, known as artificial silk from 1799 onwards, became known as viscose around 1894, and finally rayon in 1924. A similar product known as cellulose acetate was discovered in 1865. Rayon and acetate are both artificial fibres, but not truly synthetic, being made from wood. Although these artificial fibres were discovered in the mid-nineteenth century, successful modern manufacture began much later in the 1930's. Nylon, the first synthetic fibre, made its debut in the United States as a replacement for silk, and was used for parachutes and other military uses.[citation needed]
The techniques used to process these fibres in yarn are essentially the same as with natural fibres, modifications have to be made as these fibers are of great length, and have no texture such as the scales in cotton and wool that aid meshing।

Monday, April 6, 2009


Burn Test - CAUTION. WARNING. BE CAREFUL! This should only be done by skilled burners! Make sure there is a bucket of water nearby and that you burn in a metal bucket or non-plastic sink.

To identify fabric that is unknown, a simple burn test can be done to determine if the fabric is a natural fiber, man made fiber, or a blend of natural and man made fibers. The burn test is used by many fabric stores and designers and takes practice to determine the exact fiber content. However, an inexperienced person can still determine the difference between many fibers to "narrow" the choices down to natural or man made fibers. This elimination process will give information necessary to decide the care of the fabric.

WARNING: All fibers will burn! Asbestos treated fibers are, for the most part fire proof. The burning test should be done with caution. Use a small piece of fabric only. Hold the fabric with tweezers, not your fingers. Burn over a metal dish with soda in the bottom or even water in the bottom of the dish. Some fabrics will ignite and melt. The result is burning drips which can adhere to fabric or skin and cause a serious burn.

Cotton is a plant fiber. When ignited it burns with a steady flame and smells like burning leaves. The ash left is easily crumbled. Small samples of burning cotton can be blown out as you would a candle.

Linen is also a plant fiber but different from cotton in that the individual plant fibers which make up the yarn are long where cotton fibers are short. Linen takes longer to ignite. The fabric closest to the ash is very brittle. Linen is easily extinguished by blowing on it as you would a candle.

Silk is a protein fiber and usually burns readily, not necessarily with a steady flame, and smells like burning hair. The ash is easily crumbled. Silk samples are not as easily extinguished as cotton or linen.

Wool is also a protein fiber but is harder to ignite than silk as the individual "hair" fibers are shorter than silk and the weave of the fabrics is generally looser than with silk. The flame is steady but more difficult to keep burning. The smell of burning wool is like burning hair.

Man Made Fibers

Acetate is made from cellulose (wood fibers), technically cellulose acetate. Acetate burns readily with a flickering flame that cannot be easily extinguished. The burning cellulose drips and leaves a hard ash. The smell is similar to burning wood chips.

Acrylic technically acrylonitrile is made from natural gas and petroleum. Acrylics burn readily due to the fiber content and the lofty, air filled pockets. A match or cigarette dropped on an acrylic blanket can ignite the fabric which will burn rapidly unless extinguished. The ash is hard. The smell is acrid or harsh.

Nylon is a polyamide made from petroleum. Nylon melts and then burns rapidly if the flame remains on the melted fiber. If you can keep the flame on the melting nylon, it smells like burning plastic.

Polyester is a polymer produced from coal, air, water, and petroleum products. Polyester melts and burns at the same time, the melting, burning ash can bond quickly to any surface it drips on including skin. The smoke from polyester is black with a sweetish smell. The extinguished ash is hard.

Rayon is a regenerated cellulose fiber which is almost pure cellulose. Rayon burns rapidly and leaves only a slight ash. The burning smell is close to burning leaves.

Blends consist of two or more fibers and, ideally, are supposed to take on the characteristics of each fiber in the blend. The burning test can be used but the fabric content will be an assumption.

washing care symbol download

Garment Care Symbols


Dry Clean

This is the dry cleaning symbol, but the symbol itself doesn't tell the full story. There should be an additional letter inside the circle, indicating what type of dry cleaning a garment can be put through. In addition, the bar underneath the symbol gives additional information.




Material Types

  Dry Clean

Dry CleanArticles cleanable in all normally available dry cleaning solvents, using any solvent, cycle, moisture & heat. 
  Wool, cotton, rayon, linen, polyester and nylon.

Dry Clean (Not Trichloroethylene)

Dry Clean (Not Trichloroethylene)Fabrics which are stable inperchloroethylene, and hydrocarbons, without restriction.Wool, cotton, rayon, linen, polyester and nylon, where restrictions on agitation are not indicated.

Dry Clean (Not Trichloroethylene)

Dry Clean (Not Trichloroethylene)Garments cleanable in the above range but with restrictions on heat, water addition and agitation.Acrylics, polyesters and silks where weaves, surfaces or fibre mixes make garments or fabrics sensitive to treatment.

Dry Clean (Petroleum Solvent) 

Dry Clean (Petroleum Solvent)Articles cleanable in hydrocarbons (white spirit) and solvent 113 using normal dry cleaning techniques.Garments where surfaces, additions or materials are sensitive to cleaning solvents or heat. 

Dry Clean (Petroleum Solvent)

Dry Clean (Petroleum Solvent)          Fabrics sensitive in normal cleaning solvents but with further restrictions on water addition, agitation and heat.Any fabric with this symbol is very sensitive to heat and movement. It should be cleaned in a bag and not pre or post treated.

 Dry Clean (Short Cycle)

Dry Clean (Short Cycle)Dry clean using the short cycle. 
Dry Clean (Reduced Moisture)
Dry Clean (Reduced Moisture)Dry clean using reduced moisture 

 Dry Clean (Low Heat)

Dry Clean (Low Heat)   Dry clean on a low heat setting 

Dry Clean (No Steam)

Dry Clean (No Steam)Dry clean using no steam 

Do Not Dry Clean

Do Not Dry CleanDO NOT DRY CLEANPolyolefins: Items with special finishes or additions





Iron (Normal)

The ironing symbol lets you know that you can iron a garment or fabric. However the dots let you know what temperature you can iron at.




Material Types

 Iron (Normal)

Iron (Normal)

Garments may be ironed at any temperature, using steam or dry.


Iron (Low Heat)

Iron (Low Heat)

Garments may be ironed using steam or dry, at Low setting, 110°C (230°F), only.

Acrylic, nylon, acetates and polyester.

Iron (Medium Heat)

Iron (Medium Heat)

Garments may be ironed using steam or dry, at Medium setting, 150°C (300°F).  

Wool, Polyester mixtures

Iron (High Heat)

Iron (High Heat)

Garments may be ironed using steam or dry, at High setting, 200°C (390°F).

Cotton, linen viscose and derivatives of viscose.

Do Not Steam

Do Not Steam

Garment may be ironed, but only dry. Using steam may damage the garment.


Do Not Iron

Do Not Iron

Garment may not be ironed.

Plasticised materials & some Acrylics





Machine Wash (Permanent Press)

This symbol solely refers to machine washing.  The correct temperature for washing has been indicated by a number inside the tub or a series of dots.




Material Types

Machine Wash (Permanent Press)

Machine Wash(Permanent Press)

Garments which have been permanently shaped (are wrinkle resistant) should be laundered in the "permanent press" cycle. This cycle normally involves a cold rinse before a reduced spin cycle.


Machine Wash (Gentle, Delicate)

Machine Wash(Gentle, Delicate)

Wash only on the gentle cycle, involving a reduced spinning cycle and gentle agitation.


Hand Wash Only

Hand Wash Only

Wash these garments using water, detergent or soap gently using your hands.


Do Not Wash

Do Not Wash

These garments cannot be safely washed. Usually, these will need to be dry cleaned.



 Machine Wash (NORMAL)

Machine Wash (NORMAL)When there is no temperature or dots in the symbol, and no line underneath, it is recommended the garment be washed with hottest available water temperature, as hot water washes better than cold. 

 Machine Wash (COLD)

Machine Wash (COLD)

Machine Wash (COLD)When 30C or one dot is shown, wash with gentle machine action for 1/2 load with a short spin.  The recommended maximum temperature for washing the garment is 30°C (85°F).

Silk and printed acetate fabrics with colours not fast at 40o.

 Machine Wash (WARM)

Machine Wash (WARM)

Machine Wash(WARM)When 40C or two dots are shown, wash with reduced action for 1/2 load capacity and short spin.  Warm 40o wash with normal agitation, rinse and spin.  The recommended maximum temperature for washing the garment is 40°C (105°F).Wool including blankets and wool mixes with cotton and rayon. Cotton linen and rayon where colours are fast at 40obut not at 60o. 

 Machine Wash (HOT)

Machine Wash (HOT)

Machine Wash (HOT)When 50C or three dots are shown, Hot wash with cold rinse and short spin or drip dry.  The recommended maximum temperature for washing the garment is 50°C (120°F).

White nylon or white polyester/cotton mixes.


 Machine Wash (HOT)

Machine Wash (HOT)

Machine Wash (HOT)When 60C or four dots are shown, wash on maximum agitation normal rinse and spin. The recommended maximum temperature for washing the garment is 60°C (140°F).Cotton, linen and rayon item which are both colour fast and have no special surface finishes 

 Machine Wash (HOT)

Machine Wash (HOT)

Machine Wash (HOT)When 70C or five dots are shown, wash with 1/2 load capacity and short spin.  The recommended maximum temperature for washing the garment is 70°C (160°F). 

White cottons and linens with delicate weaves prone to distortion.

 Machine Wash (HOT)

Machine Wash (HOT)

Machine Wash (HOT)When 95C or six dots are shown, wash 95oto boil wash with maximum agitation, normal rinse and spin The recommended maximum temperature for washing the garment is 95°C (200°F).

White cotton and linen with no special finishes










Material Types

 Tumble Dry (Permanent Press)

Tumble Dry (Permanent Press)Garments may be dried in a tumble dryer, but only on the "permanent press" setting. 

 Tumble Dry (Gentle)

Tumble Dry (Gentle)Garments may be dried in a tumble dryer, but only on the "gentle" setting. 

 Do Not Tumble Dry

Do Not Tumble Dry

Do Not Tumble DryGarment may not be tumble dried. Usually one of the alternative symbols below will be supplied. Wool, acrylic and most flocked polyesters

 Line Dry

Line DryHang the garment to dry.Any kind of fabric.

 Drip Dry

Drip DryHang the garment to dry, without shaping or smoothingSoft polyesters & acrylics

 Dry Flat

Dry FlatLay the garment out flat to dry.Acrylics, Cashmere Loose knitted knitwear

 Dry In Shade

Dry In ShadeThis symbol may appear in conjunction with Line or Drip Dry. Dry the garment in the shade, away from direct sunlight.Cotton, Linen and any vivid colour garment

 Do Not Wring

Do Not WringDo not wring the garment to dryWool, acrylic, Silk and most flocked polyesters


 Tumble Dry (Normal)

Tumble Dry (Normal)Garment may be tumble dried at the hottest available setting. 

 Tumble Dry (Cold)

Tumble Dry (Cold)Garment may be tumble dried only at the cold "No Heat" or "Air Only" setting. 

 Tumble Dry (Low Heat)

Tumble Dry (Low Heat)Garment may be tumble dried only at a low heat.Polyester, nylon, acetates, loose weave garments and those with surface finishes.

 Tumble Dry (Medium Heat)

Tumble Dry (Medium Heat)Garment may be tumble dried up to a medium heat only.Cotton and linen.

Tumble Dry (High Heat)

Tumble Dry (High Heat)Garment may be tumble dried at a high heat.Cotton and linen.










Material Types

 Bleach As Needed

Bleach As NeededAny bleach (including chlorine) may be used when needed on the garment.Cotton, acrylic, polyester

 Bleach As Needed

Bleach As Needed(Non-Chlorine Only) Only non-chlorine, colour-safe bleach may be used on these garments when needed.Some wools & silks, anything OK with chlorine bleach

 Do Not Bleach

Do Not Bleach Garments with this symbol are not able to withstand any bleach.Wool, silk