Sunday, 29 May 2011

Indigo Dyeing using Fermentation Vat



Some Notes on Indigo Dyeing using Fermentation Vat

1. Indigo itself doesn not exist as such in nature. It is easily formed by oxidation of a a part of plant called IndigoFera by exposure to air. 

2. Simply speaking, Indigo itself is a blue solid. It is insoluble in water, acid and alkalies. If Hydrogen is added to it, or chemically speaking it is "reduced" by many reducing agents- It changes to "Indigo White" which is colorless. This indigo white can dissolve in water, in presence of alkalies, to a bright yellow liquid. When Textile substance is dipped in it and exposed to air, white indigo takes up oxygen and get converted into blue coloring matter. 

3. In fermentation method water is made alkaline with the the addition of Lime or Alkali. Then substances are added which can ferment easily in the presence of alkali, for example wheat bran (madder is added to expedite the fermentation). It takes about two to three days to ferment and then indigo is added. This bath can be used for several days or even weeks. Fresh indigo and other ingredients are added from time to time. The color of bath is light greenish yellow in color with a blue or bluish green scum. Goods immersed in this bath turns yellow. When they are taken out and exposed to air, the yellow color quickly changes to blue.

3. The color of the bath is very important. If it is bright yellow, it means too much alkalanity and more indigo should be added. If the color is too dark, it needs more lime or other alkali. 

4. After the color has changed, the goods should be rinsed well in two or three waters. After that should be boiled for several minutes in a soap bath to washoff the loose dyestuff and prevent rubbing. Rubbing can also be prevented by building up deep shades by successively dippings in the moderately weak vats, rather than obtaining the shade once for all. 

Here are some tips (Source)

1. Keep the vat covered. The level of water in the pot should be to the brim.

2. Wet out your fibers well. Any air remianing in the fiber will oxidise the indigo in the vat. 

3. Enter the fiber into the vat very carefully, to avoid any air in the wet. 

4. Always work under the vat. 

5. For greens, dye with indigo first. Then rise well and overdye with alum mordant and any yellow dye ( traditionally Turmeric). For purples, dye the Indigo first, rise well, mordant and dye with any red dye. 

Remember, you can use various chemicals to  reduce the indigo vat. The alkalnity of these chemicals vary from Soda Ash ( Sodium Carbonate), Slaked Lime ( Calcium Hydroxide), Sodium Hydrosulphide to Caustic Soda ( Sodium Hydroxide) in that order(from low to high). 

Sources


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Saturday, 28 May 2011

Some Notes on Denim Washing



There are four main processes in the Denim washing


- Pretreatment
- Stone or Enzyme Wash- To adjust the surface effect
- Bleaching- To adjust the color
- Finishing- To adjust the handfeel of the garment

Pretreatment involves removal of impurities from the garments and desizing the garment. It also involves prevention of creases in the garment. Wetting Dispersing agent is used in desizing process. It should be able to rapidly wet the jeans so that it can prevent white lines of creases and prevents back staining. Back staining is the redeposition of indigo dyed short fibers, or loose indigo, removed during desizing, stone-washing or enzyme washing. Backstaining reduces the contrast of warp and undyed weft. It also stains pockets and labels and it is more prone ot ozone and yellowing. An anticrease agent is added to prevent crease formation during the washing process. 

Enzyme in garment Industry

Enzyme is a kind of protein. They help the chemical reaction but themselves do not take part in chemical reaction. The starting molecule in a reation is called substrate and the yield molecule is called substate. Enzymes and substrate work like lock-key model so only one enzyme is useful for one type of substrate. Enzymes are better than chemical catalyst because they act in mild conditions such as room temperature. They are also biodegradable. Many enzymes are used in garment washing. An enzyme called Amylase is used in removing starch in desizing. Celullase is used in breaking and removing cellulose fibers. Laccase is used in biobleaching and catalase is used as an anti peroxide. 

Stone and Enzyme Wash

Cellulase weaken the surface fibers which are then mechanically torn off during processing, taking with them indigo. However, they need mechanical action to work. Hence they are used with stones. Cellulase is also used in biopoloshing, which removes surface fibers and make the surface smooth. 

Bleach 

Laccase enzyme decolorises indigo without using bleach. It provides very good contrast and since it attacks only indigo dye and not the fiber so it gives excellent tensile strength. 

Yellowing

The discolouration of textiles, i.e. a change of shade or loss of whiteness, giving a yellow tint, is commonly known as YELLOWING.Yellowing is due to many reasons. Cotton, yellows with age. However aging cannot make severe yellowing happen. Certain lubricants used in weaving and knitting can cause yellowing. The Anti oxidants present in these oils can cause a type of yellowing called as phenolic yellowing. The anti oxidants are also present in packaging materials and silicon softeners. Also temperature of drying and curing during processing can scorch the fibers and cause yellowing. 

Indigo dyed fabrics are more prone to yellowing. Indigo when exposed to NOx or Ozone can produce yellow colored compounds. Indigo itself through simple oxidation can transform into yellow colored compounds. 

There are specialised anti-yellowing softeners available. This work by either forming a protective filem, or by reacting the pollutants to form colorless compounds.

The source of these notes this presentation. This also contains images and chemical reactions. You can also view images of various denim washes here. One more resource is here.


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Saturday, 21 May 2011

Resources for Textile Technology Students



If you are a student of textile technology, you will find this site very useful. The owners of the sites are themselves textile students who have put together all the resources at one place.

While surfing I came across one more site, again very useful for textile students.

Please do not miss their blog.


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Some Selected Notes on Textiles: Part -5



Flammability Test

This is important for nightwear as they are finer and thinner than regular wear and are more prone to flammability than other fabrics.

In the testing, among other things time required for the flame to travel a certain distance is determined. It is now mandatory to have a flammability test if the fabric GSM is less than 88 grams.


Samples are tested both as submitted and after one cycle of washing and dry cleaning to obviate any instance of flammbility finish that might get washed of after one washing. Also iginition behaviour of the fabric is observed. Normally 5 specimens are tested. If they do not get ignited than 10 specimen are tested.

Butane gas of specified parameter is used. Based on the ignition behaviour, fabric is classified into Class I, class II and Class III. You can learn about the classification here.

You can read some facts about fabric flammability here.


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Tuesday, 17 May 2011

Some Selected Notes on Textiles- Part 4




- Colorfastness to Light: In this the samples is exposed to a light source along with blue wool sample. The fading is observed and the rating is given.  The main difference between American and European Standards is that American standard is time bound. In European standards it is not a time bound test but fading bound test- means you have to keep on exposing the sample till the sample fades to that of blue scale. Factors affecting lightfastness are the type of dyes used, depth of shade, surface structure and finishing chemicals. 

- A cotton pigment printed fabric cannot be dry cleaned . In dry cleaning solvent called Perc- Perchloro Ethylene or Tetrachloroethylene. Pigments are very susceptible to dry cleaning- they will come out. Perc is the only solvent that do not blast. In exports they use MTO . The problem with perc is that it damages Ozone layer. Perc will take out the pigments from the print. However, if you dry clean with MTO, nothing will happen.  Perc does not smell as much as MTO does.  To test for dry cleaing, a bag is prepared where instead of steel balls, stainless steel discs are added. 

- To remove smell from pigment printed fabric, it has to be cured well. To do it, maintain a temperature of 150 deg and allow the fabric for 10 minutes. It will cause phosphoric acid to get liberated and pigment get fixed- for that Diammonium phosphate needs to be added – so fixation takes place under acidic condition.  

- When testing for shrinkage, the fabric is conditioned for 24 hours. Then it is subjected to washing process for 45 minutes to 1 hours. Then it is dried and reconditiond before remeasuring.

- When testing for shrinkage, soft water is used. Alum can be used for softening. Just move the alum on the upper surface for a few times. Now decant the upper portion and use the rest of the water for testing. One can also use wetting agent. 

- Drying can be line drying, wet drying, tumble drying or drip drying. 



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Sunday, 15 May 2011

Some Selected Notes on Textiles- Part 3



- Color Fastness to Rubbing – There are two types of it, dry and wet. Dry rubbing is important for the materials like sofa covers where a person sits on it. Normally it is done using Croakometer with 10cm track length and 9.8 N force.

- For all colorfastness evaluation it is done either visually or using spectrophotometer. Normally worst rating is given.

- Colorfastness to water – It is done to measure colorfastness to water under intimate contact when getting wet, for example contact of inner wear to outer garments in rain. The sample is wet in distilled water , put between two acrylic sheets and then it is clamped under a force of 4.5 kg and put in incubator at 37 degrees Celsius for  4 hours.

- Colorfastness to Water is not the same as colorfastness to washing.  In measuring colorfastness to water we use distill water, whereas in colorfastness to washing, the detergent is used which makes the pH alkaline. A case is cited where a fabric had excellent colorfastness to washing but poor colorfastness to water. It can be due to the fact that the fabric was dyed with reactive dyes. There was some hydrolyzed dye present, but it had no reactivity and hence it was unable to react with water so there was no bleeding. On the other hand that hydrolyzed dye migrated in case of pressure and water hence had poor colorfastness to water.  Thus rigorous soaping could have solved the problem. Taking the other aspect, a fabric had poor colorfastness to washing but excellent colorfastness to water. It can be due to the fact the dye is probably sensitive to the pH.

- Colorfastness to Perspiration- Test is done similar to Colorfastness to water; the only difference is that a solution is prepared which simulate perspiration and the fabric is dipped in it, rest of the procedure is the same. Two types of solutions are prepared , one simulating alkaline perspiration with a pH of 8.0 and the other simulating acidic perspiration with a pH of 5.5. To prepare this solution Sodium Chloride and Lactic Acid are the main ingredients. The test conditions of 37+- 2 deg Celcius for four hours under a pressure of 5 kg. – Picture Source and Procedure



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Some Selected Notes on Textiles- Part 2



- Acid dyes are used for silks. There are three categories of acid dyes- Leveling or strong acid dyes, Milling or weak acid dyes and super milling or fast acid or neutral dyes. The colorfastness of fabric is decided by which of these dyes are used.

- Colorfastness to wet scrubbing is only for pigment printing. Pigment has no affinity to fiber yet it can be applied to all the fibers.  Here a brush is used to see the shade change. 

- Colorfastness to ozone is used only for Denim, which tends to turn yellow either due to atmospheric fumes or ozone. 

- REACH- Registration Evaluation Authorisation of Chemicals is a European document which enlists 800 chemicals which are carcinogenic. Out of which 56 chemicals are SVHC- substances of very high concern. Out of these 56, only 25 are related to textiles. 

- Presence of Alkyl Phenol Ethoxylate is a compound present in cheap detergents. 

- Colorfastness is the property of a color to retain its color under different conditions of use. 

- Colorfastness to washing is checked for many different fibers using a multifiber fabric. It is important to know the colorfastness against different fibers as we don’t know which all fibers will go together in a washing load. Please see Picture Source and Procedure here.

Washing Fastness Tester




- ISO grey scales are used. There are two types of shade cards- color staining and color change ( shade change).  Grey scales are used as opposed to colored scale because only intensity of color change is seen vis-a –vis intensity of grey scale. 

- Internationally a ½ point deviation is acceptable. Normally the evaluation should be done by minimum two people. This is done with D-65 light source for evaluation. 

- This scale is used  for all tests except light fastness ( For light fastness we use 8 scale- Blue wool scales are used)

- Cross staining is transfer of color from a darker to lighter component within the fabric. 

- A case is sited where there was a red dress with white piping. The red dress had a colorfastness of 4-5. But still it was enough to make the white piping pink which was not acceptable. For this case the minimum acceptable fastness was 5. 

- When measuring colorfastness to washing, the test replicates 5 typical home launderings. 

- The Load contains multi fiber test fabric, standard reference detergent, steel balls, washing devices and grade 3 water ( grade 1 is the purest). Addition of steel balls accelates the process. In testing silks steel balls are not used. 


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Saturday, 14 May 2011

Some Selected Notes on Textiles - Part 1




- Strength of Cotton is in between silk and wool. Silk is the strongest fiber.

-  Cotton is less elastic than Silk.

- Cotton wrinkles as the cellulose from which it is made has hydrogen bonds that break when washed due to agitation or mechanical action. They are formed again when ironed but in different places. Read more...

- Perspiration is of two types- Alkaline and acidic. Majority of the perspiration is alkaline. Cotton is not affected by alkaline perspiration whereas silk does.

- Coloration principle involves physical absorption of water soluble dyes, transferring of dye on to fiber, dye becoming water soluble and is retained inside the fiber.

- Reactive dyes physically react with fibers and form covalent bonds. The process involves two steps: 1. Dyeing with the dye in presence of salt to effect as exhaustion as possible ( transferring of dye from solution to fabric) and 2. Chemically reacting the dye with water in presence of alkali like soda ash.

- Reactive dyes also react with the water in which they are dissolved.  This is called hydrolysis of dyes. These hydrolysed dye has to be removed from the fiber by proper soaping else color fastness will be a major issue.

- Disadvantage of reactive dyes are that the hydrolysis accompanies fixation, as told earlier. Also there there is approximately 30% wastage of dye due to hydrolysis. Only 70% of the dye react with fiber.  To remove hydrolysed dyes there is an excessive consumption of water. Also colored effluent discharge is a major problem. It also involves large amount of electrolyte ( Common salt) as a exhaustive agent. It is also costlier. 


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Saturday, 7 May 2011

Toda Embroidery- A Tango of Needles



Toda Embroidery

Toda_embroidery

 

Toda people have a unique way of dressing. Both men and women cover themselves with a unique shawl  called Puthukuli which is designed and embroidered by themselves. It is intricately embroidered with red and blue or black threads at the borders. It is worn like a Roman Toga.  On one end of the cloth three stripes- two of red and one of black are woven into it. It is in these stripes that the embroidery is worked.  The darning stitch is used for embroidering motifs and patterns.  The base fabric is  bleached white cotton with a balanced weave structure. It enables the artisan to count and embroider the pattern.  No embroidery  frame is used  but instead they use their fingers to see, count and pick up threads by stretching the fabric. At each turn little tufts of threads are left protruding body. This technique ensures that each pattern created has a rich texture.  Patterns used for embroidery are similar to the ones used for tattoo marks.

Sources of Images and Text

1. http://www.cohands.in/handmadepages/pdf/331.pdf

2. http://www.parikramaholidays.com/pdf/Poothukuly-A-Toda-Ceremonial-Shawl.pdf

3.  A very nice story for children depicting Toda Culture http://www.arvindguptatoys.com/arvindgupta/22nbt-%20The%20Toda%20&%20The%20Tahr%20by%20E.R.C.%20Davidar.pdf

Toda_caricature

 

 

Wednesday, 4 May 2011

Chuna Patri Printing Process of Bagru



It is amazing to know the variety of printing processes used in traditional printing in India. One of them is Chuna Patri process used in Bagru.


In this process a solution is prepared using Patri( Aniline Hydrochloride), Potassium Chlorate and Copper sulphate. 

Potassium Chlorate
Aniline Hydrochloride( Patri)
Copper Sulphate

Fabric is dipped into it and while it is wet, it is printed with lime + Gum. Lime acts as a discharge and doesn't allow the black color to develop on those areas. 

Fabric Printed with Lime
It is then dried in the sun. Every part of the fabric which is not printed first turns green and then jet black upon exposure to sun.  

Fabric Turning Green on Exposure to Sun
Fabric Turning Black Gradually
The problem is that the Patri and Potash makes the fabric weaken so post washing is very important.  To get a grey, black color is added with lime. It gives some of the best Blacks and white you can ever find. 



The Dye class is aniline black, used by Century Textiles long ago for dyeing their umbrellas. Patri is Aniline Hydrochloride, also known as aniline salt. It is a product that is made by aniline oil and HCl. This is in the form of white flake crystals and used for making black color in textile printing. 

It works on the principle that when a salt of aniline in solution is exposed to the action of oxidizers, it yields a black dye of such depth that other dyes look grey or green in comparison. In this case the aniline salt dissolves in water to give a acidic solution with a pH of around 5. 

Cotton  is dipped in the solution containing aniline salt, potassium chlorate, which acts as an oxidizer and copper salt, which acts as an oxygen carrier. The dyed material them becomes greener due to formation of Emeraldine and then turns jet black. 

When a wet solution is then printed with lime, the Ca(OH)2 will neutralize the selected areas as well as bleach them by forming calcium chloride, which gives such a brilliant white color. 

Faults during Patri Printing

1. Unevenness: This is mainly due to uneven impregnation. It also occurs when the fabric is allowed to come in contact with water before it is turned black. Even wet hands will lead to unevenness. 

2. Greening: This is due to insufficient oxidation. Often this is observed after some storage. 

3. Rubbing: This is due to the improper dyeing conditions and chemicals. 

4. Bronziness: This is due to over oxidation.

5. Tendering: During the formation of black a considerable amount of free Hydrochloric Acid may be formed, which upon acting on the cellulose at the elevated temperature is likely to attack cotton and produce tendering by formation of hydrocellulose. It can also happen if the fabric is aged ( exposed to air) for a prolonged period before washing. It is suggested that Ammonium Chloride should be added in the liquor to prevent this tendering. 

Further Studies

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Sunday, 24 April 2011

Linen and Ramie




These nuggets of wisdom about Linen Fabric I have gathered from the website of Jayashree Textiles of Aditya Birla Group:

1.Linen was extensively used in the mummification process by the ancient Egyptians, as it helped preserve the dead body and to this day remains of some important mummies have their linen coverings intact.

2. In ancient Celtic times, linen was spun in an anti-clockwise direction as it was believed that this endowed mystical powers bringing the weaver good fortune

3. Scientists have recently discovered, cutting linen that was preserved in the British Museum woven 6000 years ago, is structurally perfect just as any new linen today. This reveals that linen has the ability to resist the effects of time and that linen is not affected by germs.

4. The word ‘spinster’, meaning single woman comes from the time when flax was still spun on spinning wheels by women. This skilled work was considered as an advantage when looking for a suitable husband. Single women were encouraged to sit outside and spin, so that they could be admired by potential suitors as they passed. As a result, the word gradually became associated with single woman.

5. ‘Flaxen hair beauty’ comes from the beauty of the flax fiber, which resembles golden hair.

Then there is a “caution” of confusing Linen against Ramie and other synthetic fibers and cotton slubs;  this reads as follows: 
1.   Ramie is being sold as Linen in India whereas Ramie is not Linen. 
2.   Ramie the Produce of China gets harsher after every wash and itches to the skin, whereas linen fabrics gets softer after every wash and becomes very much soothing to skin.
3.   Further cotton slubs, polyester slubs fabrics are also not linen, however they are being sold as linen misleading to the consumer.

A search about the Ramie Fiber and its comparison to Linen revealed to me an amazing treatise on the other natural fibers, which by itself very helpful but unfortunately deals very less with ramie and their potential for India. On probing further, I came to know this article on Ramie fiber.

A site selling Ramie fabric talks about “100% Ramie Linen Fabric-Ramie is a fiber similar to linen. In fact, it is almost impossible to tell the difference between this fabric and the most expensive linen”.

I just wonder what would be the price difference between these two fabrics. Ramie is reported to be twice strong than Linen.

A very useful article comparing Linen with Ramie says the following among other opinions: "Textiles made from ramie behave similarly to linen textiles. They are prone to wrinkling and will breakdown if sharply creased, so it is best to fold them loosely and store flat. One advantage ramie has over linen is that it is naturally bacteria- and mold-resistant. It holds dye well, although saturated colors can be prone to crocking, which is discoloration of skin or other fabrics that contact the dyed ramie at stress points or wet areas. Ramie 
can handle the same heat and agitation as linen."

A further research article says that “ Ramie is the strongest bast fiber and one of the strongest natural fibers comparable to cotton and silk. In terms of length to breadth ratio, whose higher value indicates better fiber quality, is even greater than cotton and linen. However Ramie is stiff and brittle with low elasticity".

I feel that Ramie has potential to be another fiber of the future


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Friday, 22 April 2011

All About Zari



Adapted from an Article here.

The following is the process used for making Zari:

Fiber

True zari, pasa, has the unique property of being limited only to pure gold and silver metal, a silver bar is covered with thin sheet of pure gold and then it is drawn into finer wire of different gauges to form “badla” (in local language) which is wounded over base yarn mainly on pure silk and the process of making this zari were done by manual operations.

Yarn

The silk yarns are basically used for the production of pure & imitation zari. In the process, the artisans procure pure silk of 13/15 and 20/22 denier. Once procured two silk yarns of 20/22 or 13/15 are twisted followed by degumming and dyeing as per the requirement

Technique

Manufacture of Real Zari

Process involved in the manufacture of Real Zari:

Stage – I
Dyeing of Cotton yarn or silk, or Art silk yarn.
Melting of Silver (Raw).
Preparation of Silver wire bars.
Hammering of Silver bars to form an elongated rod.

Stage – II
Drawing of silver wire of different gauges, coarse, medium, fine and superfine in Pawtha and Tania wire drawing units(From an ounce of silver into 3000 yards) of silver wire.

Stage – III
Flattening the wire in flattening machine (CHAPAD)- The flattened silver is called badla.
Stage – IV
Wrapping of flat silver wire on Pure silk, Art silk or Cotton on wrapping machine (Bitai Machine) to make real zari thread.- The thread is called Ruperi Zari Thread

Stage - V
Electroplating of Pure gold (24 carat) on real zari thread (Sona Gilit Bakda).
Stage - VI
Gold plated real zari thread is wound on reel (Flattened or Round Zari).

Process involved in the manufacture of Imitation Zari- also called Half fine zari

Stage - I
Copper wire drawing unit (Pawtha) - Copper wire rod drawn to 31s.w.g copper wire.
Drawing of Copper wire form 31s.w.g to 36s.w.g (Aara Machine)- SWG is the standard Wire Gauge.

Stage - II
Electroplating of silver on 36s.w.g copper wire (Chandi Gilit Bakda).

Stage - III
Further drawing of 36s.w.g silver electroplated copper wire into fine gauges (Tania Unit).

Stage - IV
Flattening of silver gilded copper wire wound on pechak (Chapad or Flattening Unit).

Stage - V
Wrapping of silver gilded flat copper wire on yarn to make Imitation zari thread (Bitai Machine).- Called Half fine Zari Thread

Stage - VI
Lacquered or fast gilding on imitation zari thread (Gilit Bakda) -Called Half fine gold thread

The term gilding covers a number of decorative techniques for applying fine gold leaf or powder to solid surfaces such as wood, stone, or metal to give a thin coating of gold. A gilded object is described as "gilt".

Lacquer is a clear or coloured wood finish that dries by solvent evaporation or a curing process that produces a hard, durable finish. This finish can be of any sheen level from ultra matte to high gloss, and it can be further polished as required. It is also used for "lacquer paint", which typically is a paint that dries to a more than usually hard and smooth surface.

Stage - VII
Gilded imitation zari thread is wound on reel or on hand charkha for making small skeins of 5gms to 10gms.

For the manufacturing of embroidery materials, the process up to flattening is similar. The flattened wire (Badla or lametta) is then used in different equipment to make Zick, Chalak, Salma, Kangri, etc. For stars and similar items, the flattened strip is punched with dies of different design

For real zari, the basic metal used is silver while for imitation zari the basic metal used is copper.

Zari- Kalabattu, Tarkashi, Kasab

Embroidery done with metallic threads is called kalabattu and forms the zari.
Here the metal ingots are melted into metal bars called pasa from which lengths are got by beating it after treatment. This is then pulled through perforated steel plates to make it into wires, followed by the tarkashi process to make it thin with rubber and diamond dies.The last stage is called badla where the wire is flattened and twisted with silk or cotton thread to become kasab or kalabattu.This has uniform evenness, flexibility, softness, and ductility.Kasab can stand for real silver/gold, as well as for plated silver/gold or for an imitation in which a copper base is given a coat of silver or golden color to make the product less expensive.

Zari Terminology- Gijai, Sitara, Salma-Sitara, Tikora, Kora, Chikna, Karchob, Thapa 

Zari thread is used widely in weaving but more selectively in embroidery.For intricate patterns gijai or a thin, stiff wire is used.  Sitara, a small star-shaped metal piece is used for floral designs.This type of embroidery is called salma-sitara.The thicker kalabattu is a braided gold thread used for borders while the thinner variety is used at the end of the drawstring of purses or batwas, and in tassels, necklaces, and strings.Tikora is a gold thread spirally twisted for complicated designs.The dull zari thread is called kora and the more shiny one is called chikna.The equipment that is used for embroidery is a rectangular wooden-frame called karchob and a wooden leg called thapa used for sewing laces.

Different kinds of zari work

Zardozi: This is a heavy and more elaborate embroidery work which uses varieties of gold threads, spangles, beads, seed pearls, wire, and gota.It is used to embellish wedding outfits,heavy coats and other products. The material on which this kind of embroidery is done is usually heavy silk, velvet and satin.The kind of stitches found are salma-sitara, gijai, badla, katori, and seed pearls, among others.
Kamdani : This is a lighter needlework which is done on lighter material like scarves, veils, and caps using flattened wire.Ordinary thread is used and the wire is pressed down with the stitching producing a satin-stitch effect.The effect produced is glittering and is called hazara butti(thousand lights). 


Mina Work : This is thus called owing to its resemblance with enamel work.The embroidery is done in gold.

Kataoki Bel : This is a border pattern made of stiff canvas and the whole surface is filled with sequin edging.A variation of this border technique is lace made on net and filled with zari stitches and spangles.

Mukaish : This is one of the oldest styles and is done with silver wire or badla.The wire itself serves as a needle, piercing the material to complete the stitches.A variety of designs are produced in this manner. It is also known as the Fardi ka kaam in Lucknow. In Gujarat and Maharastra it is called Badla.

In both Kamdani and Fardi ka kaam, flattened wire is used. In Kamdani the wire is worked into motifs whereas in Mukaish tiny dot patterns are made. In kamdani the wire is attached to a small length of thread which is pulled by a needle. In Mukaish the wire itself is used as a needle. Below is an example of the Mukaish work. 

Tilla or Marori Work : This is the kind of embroidery where gold thread is stitched on to the surface with a needle.

Gota Work (Also adapted with the picture below from this source): The woven gold border is cut into various shapes to create a variety of textures in the patterns.In Jaipur the border of the material or sari is cut into shapes of birds, animals, and human figures, attached to the cloth, and covered with wires of silver and gold; it is surrounded by coloured silks.The work resembles enameling. 
  
Traditionally Gota ribbons were woven with a wrap of flatened gold and silver wire and a weft of silk/cotton thread and used as functional and decorative trims for a variety of garments and textiles. Now there is a substitution of pure gold and silver with gilt or lurex and the mass production of gota on electrically powered swivel looms.

In the Technique of gota tukdi,gota is cut into shapes such as the gamla (flower pot),kairi(mango) and champak flower, and appliqued onto a base fabric embellished with embroidery techniques such as zardozid and ari.Gota patti involves the folding of tapes into basic rhomboid units,referred to as patti or leaves and combining them to create elaborate motifs and patterns that are sewn onto garments.

Kinari Work: A small variation is kinari work where the embellishments are done only at the edges in the form of tassels.

In the context of Traditional Sarees, Zari is of four types:

The popular zari numbers used are 1200, 1400, 1600 and 3700. The four types of zari commonly used in Banaras silk sarees are:

a) Pure zari
b) Tested zari
c) Powder zari
d) Plastic zari

The composition of different varieties of zari is presented here under:

a) Pure zari: This is also known as real zari. The centre core of pure zari is made up of degummed twisted red or yellow mulberry silk yarn; over which silver lametta and badla (flatten wire) is wound. The silver zari threads are electroplated with pure gold solution, to produce gold zari.

Updated on 21.12.2014


BIS ( Bureau of Indian Standards) have even specified the color and denier of the silk to be used in the core. As per them, the silk core is two ply 16/18 soft twisted yarn dyed in a red or yellow color.


As per them the zari is called pure zari only when the percentage of pure silver is not less than 50 percent of the mass of the zari material. In case the silver is coated with gold, the gold content shall not be less than 0.5 per cent of the zari material. 

b) Tested zari or Half Fine Zari: It is also called imitation zari because it has the external features of real zari and thus, resembles the real zari in terms of shine. This variety is similar to real zari except copper lametta used in place of silver and silver gilding is done on copper wire. For gold zari, the tested zari is electroplated with gold solution.

c) Powder zari or Imitation Gold Zari: The manufacturing process of powder zari is similar to tested zari, where in powder gilding is done on imitation zari in place of gold gilding. Thus artificial gold colour powder is superimposed to get the lustre and brilliance. This does not last long and it gets black in short time with use. It is quite cheap and mostly used on rayon fabrics. It almost resembles zari. 

d) Plastic zari: The manufacturing process is more or less same as other varieties. In this variety plastic thread is used as lametta instead of copper or silver. In this small thin plastic strips are superimposed in gold colour or in different assorted colours and made into zari. These are marketed under different trade names such as Rexor, Lurex etc.

e) Neem Zari: These yarns are used extensively in many branches of textile industry from wide weaving to narrow ribbons, embroidery, braids, knitting, twisting, laces, and inner gimp decoration.

hey further quoted that pure gold zari is the costliest of all and half fine gold is less costly in comparison. Imitation and plastic zari is cheapest among all. It is very difficult to distinguish between a pure gold zari and half fine zari. When a pure zari is burnt, the residue will give pure silver and gold, whereas half fine gives copper and very low percentage of gold. The last gives nothing but only ashes. Also the imitation zari will easily break when stretched between fingers. 

Sachha Kaam, Jhootha Kaam, Nakli Kaam and Rangeen Kaam

Nowadays the embroiders have given the prevalent threads a number of names such as sachcha kam refers to work with real gold zari, jhootha kam refers to copper plated wire,  while nakli kam refers to lurex wire or plastic is called rangin kam. 

All Banaras sarees are either woven with pure zari or other varieties (imitation, powder and plastic zari). Most of the time zari thread is purchased from Surat and sometimes from Banaras. The cost of pure zari ranged from Rs.10,000-13,000/kg, imitation zari  Rs.600-800/kg, powder zari Rs.2000/kg and plastic zari is Rs. 350-500/kg.

Master Weaver in India



Master weaver is generally termed as a super artisan in a particular textile craft. In handloom terminology of India, however, a master weaver is an entrepreneur who produces cloth by employing wage labour. He either directly sells to the the traders or sell it in the market.

There are basically two types systems employed by the master weaver. In one system, the weaver works at his home with his family. The raw material is supplied by the master weaver. Generally the waver works on a piece rate system. The good point of this method is the fact that whole family helps in the weaving process.

In the Karkhana system, the weaver works on the looms provided by the master weaver under one roof. Generally the weaver works on a time rate system.

This system has emerged as a dominant system in handlooms in India.

Please read the full report here.


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Thursday, 21 April 2011

What is Super Combed Cotton



Combing operation necessarily eliminates a certain predetermined percentage of short fibers, which when spun produces a softer and smoother yarn. It also permits to spin to a fine count of yarn.

We sometimes segregate cotton yarns depending upon the percentage of short fibers removed during combing.

In Semi Combed Cotton the short fiber removal percentage is kept at 5-10%.

In Normally Combed cotton the short fiber removal percentage is kept between 10-20%.

In Super Combed cottons the short fiber removal percentage is over 20%.

A very nice introduction to combing for Textile Technologists can be found in this article.

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Monday, 11 April 2011

Ahimsa Silk : Is it really Non-Violent




Ahimsa Silk, also known as Peace Silk, is processed from cocoons without killing the pupae inside.

The main Arguments Against Ahimsa Silk are the two:

1. If the pupa is allowed to hatch, they will become caterpillars, it is impossible to feed so many. Thus instead of killing individual caterpillars, the offsprings are being killed.

2. In Eri Silk also, majority of the worms are starved to death after hatching. They are not flying off into woods.

As the Author says "I think it's mathematical sleight-of-hand to justify a high sale price for second-tier yarns"

Please read the full article here.

Similar Argument is given that Recycled polyester is more enviroonmentally sustainable than cotton. Read here


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Sunday, 10 April 2011

More about Tussar or Tussah or Tassar



Looking for Tussar, I came across several other interesting features. Some of these are as follows:

1. China exports two types of Tussar Silks: 33/37 D Water reeled and 70 D Dry Reeled Silk. I am just wondering if the "China" that is 50/70 quality that we use in India is dry reeled always.

2. There are 7 grades of quality of Tussar Exported by China, 4A, 3A, 2A, A, B, C and Off grade.


3. The standard moisture regain of Tussar Silk is 10% and density is 1.58 to 1.63 gms/cm3.


4. Elongation at break of water reeled tussar is 23% and dry reeled tussar is 16%.


5. China tussar is different from Indian ( Tropical ) tussar due to the fact the China Tussar the species of the worm is different and fed on "Oak Leaves" ( Also done in Himalyan Regions of the country). Whereas in India it is fed on "Arjun" and "Aasan" leaves. 


6. 8 is the usual number of cocoon filaments to form a single thread. The normal size of the thread produced is 30-35 deniers.


7.Tussar silk is the primary kind in the silk which lustrous,bright,soft handfeel,it has highest wear resistance in the natural faric. The Acid & Alkali Resistance of tussah silk is better than mulberry silk.


However I could not find out how they do dry reeling of tussar. Would require your inputs. 


And yes, I found the Tussar process practiced in Bihar, Bhagalpur. You can click here to find out more.

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Thursday, 10 March 2011

Process Control in Textile Chemical Processing



ABS Laboratories is mainly into manufacturing of Sulphur Dyes, Direct Dyes and  Reactive Dyes (HE class) for coloration of textile products. 


What is more important that on their website is a wealth of useful information for textile professional.


You can get characteristic shades of Sulphur, Direct and Reactive Dyes. If you also want to know how to apply sulphur dyes, click here to find out. 


And best of all they have an amazing document on the process control of Textile Chemical Processing. 

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Wednesday, 2 March 2011

A review of Cotton Spinning- Process Control Perspective



Update Note: This article was originally written in 2011. One of the external reference links used at that time is no longer active. I have retained the article because the broad ideas related to cotton spinning and process control may still be useful to students and textile professionals. I may update this article with fresh references in the future.

Monday, 28 February 2011

Dyeing of Ikat Orissa Yarn with Vat and Napthol Colors




Dyeing of Ikat Orissa Yarn with Vat and Napthol Colors

Vat Colouring of Handloom yarn:

For vat colouring of one muda ( equivalent to 10 hank/ phand locally or 8400 yards) of handloom yarn 2 gms of colour, 8 gms of caustic soda and 8 gms of hydrogen sulphide is added in 1.5 litres of hot water. The yarn is then dipped in the hot water and stirred. The yarn is then drained out of the container and allowed to cool down. It is then washed in cold water and then sun dried.

Napthal Colouring of Handloom yarn:

For napthal colouring of one muda  of handloom yarn 4 gms of caustic soda and 4 gms of napthal is added in 1.5 litres of water and boiled. The yarn is then dipped in the hot water and stirred. Subsequently the yarn is drained out of the container and allowed to cool down. 4 gms of colour is then added in another container having 1.5 litres of water and stirred. Now the napthal drained yarn is dipped in this container. Water is then drained out of the coloured yarn and sun dried.


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