Part A: How to Identify the Class of Dye on Cotton — The First Diagnostic Journey

General disclaimer: This article is intended for educational understanding of textile dye-class identification. The tests discussed may involve hazardous chemicals, heating, solvents, acids, alkalis, reducing agents, oxidizing conditions, and toxic vapours. These procedures should be performed only by trained personnel in a properly equipped laboratory with suitable personal protective equipment, ventilation, supervision, and waste-disposal practices. The article should not be used as a substitute for official standards, laboratory protocols, or professional safety guidance.

When we see a coloured cotton fabric, the first question is usually simple: What colour is it? But in textile testing, that question is not enough. A red cotton fabric may be dyed with a reactive dye, direct dye, azoic dye, vat dye, or even a pigment system. A black cotton fabric may be sulphur black, vat black, aniline black, or another dye class altogether. So the more useful question is: how does this colour behave when we challenge it?

Does it come out in solvent, bleed in alkali, re-dye white cotton, prefer wool, respond to reduction and oxidation, or behave like a colour formed inside the fibre? This is the heart of dye-class identification. We are not identifying the commercial dye name. We are identifying the application class of the dye.

Dye identification begins by observing behaviour, not merely shade.

The Basic Idea: Do Not Guess the Dye, Observe Its Behaviour

A dye class is not identified by looking at the shade alone. Many dye classes can produce similar-looking colours. The real clue lies in how the colour is held by the fibre. Some dyes are chemically bonded with cotton, some are held by physical affinity, some are developed inside the fibre, some can be reduced and reoxidized, some can be stripped and transferred to another piece of cloth, and some refuse to move at all.

Therefore, the testing sequence begins with broad observations and then becomes progressively more specific. The logic is similar to diagnosis: first ask general questions, then narrow down the possibilities. The fabric is not judged by appearance alone; it is questioned through a series of chemical behaviours.

Practical idea: The question is not only “What is the colour?” The better question is “What does the colour do when challenged?”

Step 1: Can the Colour Be Stripped Out?

The first test asks whether the dye can be removed from cotton by strong solvent treatment. The specimen is treated successively with strong solvent systems to see whether the colour can be stripped from the fibre. If the colour does not come out, or comes out only partly, it suggests that the dye is not merely sitting loosely on the fibre. It may be chemically fixed, or it may have been formed inside the fibre.

This points towards dyes such as reactive dyes and ingrain dyes, except azoic dyes. The logic is easy to understand. Reactive dyes form a chemical bond with cellulose. Once properly fixed, they do not easily leave the fibre. Similarly, ingrain colours are produced within the fibre structure, so they may also resist solvent stripping.

The first conclusion, therefore, is that if the dye refuses to strip, one should suspect a dye that is strongly fixed or internally formed. But this is still only a preliminary clue. Some other dyes may also behave stubbornly, so the sequence does not end here unless the evidence is strong. We move forward.

Step 2: If It Is Not Strongly Fixed, Does It Bleed in Mild Alkali?

If the first test does not clearly indicate reactive or ingrain behaviour, a fresh specimen is boiled in a mild alkaline solution. Now the question becomes whether the dye bleeds out into the solution. If the colour comes out, we have learned that the dye is extractable under alkaline conditions.

But bleeding alone is not enough for identification. The next question becomes more important: where does this extracted dye prefer to go? This is where the sequence becomes very intelligent, because it does not merely observe removal of colour; it observes the dye’s affinity for another fibre.

Step 3: If It Bleeds, Will It Re-Dye White Cotton?

After the dye bleeds into the solution, white bleached cotton is added along with salt. If this fresh white cotton becomes dyed approximately to the original shade, the behaviour suggests a direct dye. Direct dyes have natural affinity for cotton, and salt helps them move from the solution onto the cotton fibre.

This is one of the most elegant parts of the sequence. The dye leaves the original fabric and then goes onto another cotton sample. In doing so, it repeats its own application behaviour. We are not depending on colour appearance; we are watching the dye demonstrate how it behaves with cotton.

Step 4: If It Bleeds but Does Not Dye Cotton, Will It Dye Wool?

Sometimes the dye bleeds into the solution, but the added white cotton does not get dyed properly. At this point, we do not immediately reject the dye. Instead, we change the receiving fibre. The solution is made acidic, and wool is introduced.

If wool becomes dyed, the behaviour suggests an acid dye. Acid dyes usually have greater affinity for protein fibres such as wool and silk. Cotton is a cellulosic fibre and does not normally attract acid dyes in the same way. So if the dye does not properly go onto cotton but does go onto wool in acidic conditions, the behaviour points towards acid dye.

The sequence is logical. First we ask whether the dye comes out. Then we ask whether it goes back to cotton. If it does not, we ask whether it goes to wool. One observation leads naturally to the next.

Transfer behaviour helps distinguish direct dyes from acid dyes.

Step 5: If It Does Not Bleed Much, Will Mordanted Cotton Pick It Up?

Now consider another possibility. The original specimen does not bleed much in the mild alkaline solution, or the bleeding is very slight. At this stage, the test moves towards another dye class. The specimen is treated with acetic acid and heat, and then mordanted cotton is introduced.

If mordanted cotton becomes dyed, the behaviour suggests a basic dye. Basic dyes do not behave like ordinary direct dyes on untreated cotton. However, mordanted cotton can attract them because the mordant acts like a bridge between the dye and the fibre.

This step is important because it shows that dye identification is not only about extracting the colour. It is also about understanding the relationship between dye, fibre, and auxiliary treatment. Ordinary cotton may not reveal the basic dye clearly, but mordanted cotton may catch it.

Step 6: What If a Direct Dye Has Been After-Treated?

Sometimes a direct dye may not behave like a normal direct dye because it has been treated after dyeing to improve fastness. Such treatment may reduce its tendency to bleed or transfer. This creates a practical problem: a direct dye may be present, but its normal behaviour may be hidden.

So the sequence introduces an acid pre-treatment. After this treatment, the sample is tested again for direct dye behaviour. If direct dye behaviour appears after this treatment, the indication is an after-treated direct dye.

This is especially relevant in commercial textiles. Many direct dyes are after-treated with fixing agents or resins to improve wash fastness. Because of that, the dye may not behave like an untreated direct dye in the first test. The acid treatment helps reveal what the after-treatment was hiding.

Step 7: If These Dyes Are Absent, Move to Reduction Behaviour

If reactive, ingrain, direct, acid, and basic dye behaviours are not established, the test sequence moves to another family of dyes. Now the question changes completely. Instead of asking whether the dye bleeds or transfers, we ask whether the dye responds to reduction and oxidation.

This shift is important because some dye classes are applied through a reduction–oxidation mechanism. They may not simply dissolve and transfer like direct dyes. Their identity is revealed when their chemical state is changed. In other words, these dyes must be challenged chemically before they reveal themselves.

Step 8: Does the Dye Reduce, Transfer, and Reoxidize?

A fresh specimen is treated under reducing alkaline conditions. Then white cotton and salt are added. If the colour transfers to the white cotton and returns after oxidation, the behaviour suggests a sulphur dye. Sulphur dyes are applied in a reduced soluble form and then oxidized back into an insoluble coloured form inside the fibre.

Their diagnostic sequence is therefore: reduce the dye, make it mobile, allow it to transfer, oxidize it again, and see whether the colour returns. This is very different from direct dye behaviour. A direct dye is identified by affinity and transfer, while a sulphur dye is identified by chemical transformation.

Step 9: If It Does Not Behave Like Sulphur Dye, Is It Oxidation Black?

Black shades require special care because not every black behaves like sulphur black or vat black. Some blacks are produced by oxidation reactions on the fibre. If the previous reduction-transfer route does not confirm sulphur dye behaviour, a special reaction is used to check for oxidation black, also known as aniline black.

The practical meaning is that some black colours are not ordinary applied dyes. They are produced by oxidation chemistry on the fibre, and therefore they need a separate diagnostic path. This is a useful reminder that a shade name such as “black” tells us very little; the method of producing that black matters greatly.

Step 10: Does the Colour Change Under Reduction and Return on Oxidation?

If sulphur dye and oxidation black are not indicated, the next possibility is a dye class that also depends on reduction and oxidation: vat dye. Vat dyes are insoluble dyes that are temporarily converted into a soluble reduced form during dyeing. After entering the fibre, they are oxidized back into their insoluble coloured form.

The diagnostic clue is that the colour changes or is discharged under reducing conditions but returns when oxidized. This reversible behaviour is the key. Vat dyes do not behave like direct dyes because they are not simply dissolved and absorbed in the ordinary way. They depend on a change of chemical state.

Reduction and oxidation behaviour helps reveal sulphur and vat dye classes.

Step 11: What If the Direct Dye Was Modified with Metal Salts or Formaldehyde?

Some direct dyes are after-treated not merely with resin but with metallic salts or formaldehyde-type treatments. These treatments improve fastness and alter the dye’s behaviour. So the test sequence also checks for direct dyes after-treated with chromium salts, copper salts, or formaldehyde.

This part of the sequence is not asking only what dye is present. It is also asking whether the dye has been chemically after-treated. That question matters because after-treatment can hide or modify normal dye behaviour. In commercial terms, this is very practical: a fabric may have started with a direct dye, but after-treatment may make it behave differently during extraction, washing, or testing.

Step 12: If Earlier Groups Do Not Respond Clearly, Consider Azoic Dyes and Pigments

Finally, if the specimen does not respond clearly to the earlier tests, or responds only slowly and incompletely, the sequence moves towards dyes and pigments that are more difficult to classify through ordinary extraction behaviour. This includes azoic dyes and pigments.

Azoic dyes are often formed inside the fibre by a coupling reaction. Because the colour is developed within the fibre, it may not behave like a dye that was simply absorbed from a dyebath. One of the tests uses repeated treatment with pyridine. The logic is based on whether the colour continues to bleed or whether bleeding gradually decreases and stops.

If bleeding continues through repeated treatment, azoic dye behaviour may be indicated. If bleeding is slight and decreases or stops, diazotized and developed dye behaviour may be indicated. The important idea is that azoic colour is not merely applied; it is developed. Therefore, its identification requires a different kind of questioning.

The Whole Sequence in One Flow

The diagnostic journey begins by asking whether the dye can be stripped. If it cannot be stripped, reactive or ingrain behaviour is suspected. If it can bleed, the next question is whether it re-dyes cotton. If it re-dyes cotton, direct dye behaviour is suspected. If it does not dye cotton but dyes wool, acid dye behaviour is suspected. If mordanted cotton takes it up, basic dye behaviour is suspected.

If direct dye behaviour appears only after acid treatment, after-treated direct dye behaviour is suspected. If these possibilities are absent, the enquiry moves to reduction and oxidation. If the dye reduces, transfers, and reoxidizes, sulphur dye behaviour is suspected. If a black shade gives special oxidation-black behaviour, aniline black is considered. If the colour disappears and returns through reduction and oxidation, vat dye behaviour is suspected.

If after-treatment chemicals such as chromium, copper, or formaldehyde are detected, modified direct dyes are considered. If earlier tests fail or respond incompletely, azoic dyes and pigments are examined. This is not a random list of chemical tests. It is a carefully arranged diagnostic sequence in which each result answers one question and creates the next question.

Simple Practical Table

Question Asked During Testing	What the Behaviour Suggests
Does the dye resist solvent stripping?	Reactive or ingrain dye
Does the dye bleed and re-dye white cotton?	Direct dye
Does the dye bleed but dye wool instead of cotton?	Acid dye
Does mordanted cotton pick up the colour?	Basic dye
Does direct dye behaviour appear after acid treatment?	After-treated direct dye
Does the dye reduce, transfer, and reoxidize?	Sulphur dye
Does black show special oxidation-black reaction?	Aniline black
Does colour return after reduction and oxidation?	Vat dye
Are chromium, copper, or formaldehyde after-treatments indicated?	After-treated direct dye
Does repeated pyridine treatment show azoic behaviour?	Azoic or developed dye

Why This Matters to Textile Professionals

For a laboratory person, this sequence is a testing route. For a merchandiser, it is a way of understanding why fastness differs. For a textile student, it is a lesson in dye-fibre chemistry. For a quality professional, it is a reminder that shade appearance alone is never enough.

Two fabrics may look similar but behave very differently in washing, rubbing, light exposure, stripping, or processing. The difference often lies in the dye class and the method of application. A reactive-dyed cotton behaves differently from a direct-dyed cotton. A sulphur-dyed black behaves differently from an oxidation black. A vat dye behaves differently from an azoic dye. An after-treated direct dye behaves differently from an untreated direct dye.

Final Thought

The first part of dye identification is not about naming the dye. It is about listening to the behaviour of the colour. Some colours come out, some refuse to move, some move to cotton, some move to wool, some need mordanted cotton, some disappear and return, some are formed inside the fibre, and some are changed by after-treatment.

The tester’s job is to follow these clues step by step. In the simplest words: do not ask only, “What is the colour?” Ask, “What does the colour do when challenged?”

Acknowledgement: This article is based on the preliminary identification logic given in Annex A of IS 4472 Part 1:2021.

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Silk Fabric Terms Explained — Part 5: Indian Silk Terms — Bafta, Kora, Ghicha and Matka

In Part 1, we created a practical map for understanding silk fabric terms.

In Part 2, we discussed silk yarn terms such as raw silk, bivoltine silk, China silk, katan and organzine.

In Part 3, we understood twist-based sheer fabrics such as chiffon and georgette.

In Part 4, we studied the crepe family.

Now we come to a very important part of silk terminology:

Indian silk terms.

This part will explain terms such as bafta, kora cloth, ghicha, ghicha-ghicha fabric, matka and matka fabric.

These terms are important because they do not belong only to textbook textile vocabulary. They also belong to Indian craft, handloom, trade and market vocabulary.

A word like matka is not merely a yarn name.

It carries the story of pierced cocoons, waste silk, hand spinning, rough texture and Indian handloom character.

A word like kora is not merely a fabric name.

It tells us about undegummed silk, gum content and the condition of the yarn.

A word like bafta tells us that Indian fabrics have often used fibre combinations intelligently — silk in warp and cotton in weft.

Central idea: Indian silk terms should be understood as technical words, market words and craft words at the same time.

Indian silk terms map: bafta, kora, ghicha and matka explained through fibre, yarn, process and fabric character. Click image to view full size.

Why Indian Silk Terms Need Special Attention

Many textile terms used in India are not purely technical.

They are born from:

• local weaving practice,
• handloom traditions,
• raw material availability,
• market usage,
• regional vocabulary,
• and long experience of fabric making.

This is why Indian silk terms often carry more meaning than their short definitions suggest.

For example, if we say matka, the definition may say that it is yarn spun from pierced or waste cocoons.

But practically, the word also suggests:

• irregularity,
• slub-like texture,
• rustic look,
• handloom character,
• heavier feel,
• and earthy appearance.

Similarly, ghicha suggests a yarn drawn by hand from tasar cocoons, but in fabric language it also suggests natural unevenness and a craft-based surface.

So while reading Indian silk terms, we should not ask only:

What is the definition?

We should also ask:

What kind of yarn, handle, texture, craft process and market identity does this word suggest?

1. Bafta

Bafta is an Indian term for a fabric made with silk warp and cotton weft, used as dress material.

This is a very interesting fabric idea.

In bafta, silk is used in the warp direction and cotton is used in the weft direction.

This means the fabric is not fully silk and not fully cotton. It is a silk-cotton combination.

Practical Understanding

Bafta shows how Indian textile traditions often combine beauty with practicality.

Silk in the warp can give:

• lustre,
• strength,
• richness,
• and a silk-like appearance.

Cotton in the weft can give:

• comfort,
• absorbency,
• economy,
• and a more wearable handle.

So bafta is not simply a cheaper substitute for silk. It is a practical construction where two fibres are used intelligently.

Why Silk Warp and Cotton Weft?

In weaving, warp yarns have to withstand more tension and abrasion. Silk, when properly prepared, can give strength and lustre in the length direction.

Cotton in the weft can give comfort and body across the width of the fabric.

This combination may make the fabric suitable for dress material where appearance, comfort and cost all matter.

Bafta in simple words: Bafta is a silk-cotton fabric, traditionally made with silk in the warp and cotton in the weft.

2. Kora Cloth

Kora cloth is a silk fabric mainly made of mulberry silk used in both warp and weft in an undegummed and untwisted condition.

It is used for printed sarees, scarves and printed dress materials.

Kora cloth is classified into two varieties:

1. Single kora — where the warp is single ply and the weft is two ply.
2. Double kora — where the warp is two ply and the weft is three ply.

Practical Understanding

The key word in kora is undegummed.

Silk naturally contains gum called sericin. When this gum is not removed, the silk remains firmer, stiffer and more wiry compared to fully degummed silk.

So kora cloth has body because the silk is still in a raw or gum-containing condition.

Why Kora Is Useful for Printing

Kora cloth is often used for printed sarees, scarves and dress materials.

There are two practical reasons:

First, the fabric has body because of the gum.

Second, the relatively firm surface can be useful for handling, printing and finishing.

After processing, the fabric may be softened or finished depending on the product requirement.

Single Kora and Double Kora

The classification of kora cloth into single and double varieties is related to the ply structure of warp and weft.

Variety	Warp	Weft	Practical Meaning
Single kora	Single ply	Two ply	Lighter construction
Double kora	Two ply	Three ply	Heavier and stronger construction

This shows that even within one fabric name, construction may vary.

So when someone says “kora”, a merchandiser should still ask:

Is it single kora or double kora?

Kora in simple words: Kora cloth is an undegummed silk fabric, often used for printed sarees, scarves and dress materials.

Bafta and kora construction: silk warp-cotton weft, undegummed silk, single kora and double kora. Click image to view full size.

3. Ghicha

Ghicha is the yarn drawn by hand out of tasar cocoons without twisting, traditionally with the help of an earthen pot.

This definition is very short, but it is full of meaning.

Ghicha is connected with:

• tasar silk,
• hand drawing,
• waste or irregular cocoons,
• absence of twist,
• and traditional yarn-making practice.

Practical Understanding

Ghicha yarn is not like smooth reeled mulberry silk.

It is more irregular.

It has a natural, handmade character.

The yarn may show unevenness, thickness variation and texture.

This irregularity is not necessarily a defect. In ghicha-based fabrics, it is often the main appeal.

Why Ghicha Has a Rustic Character

Since ghicha is drawn by hand and without twist, it does not have the smoothness and uniformity of filature silk.

The result is a yarn that looks more natural and less polished.

When woven into fabric, it creates a textured surface.

This makes ghicha suitable for products where natural, handmade and earthy character is desired.

Ghicha in simple words: Ghicha is a hand-drawn tasar silk yarn with natural irregularity and rustic character.

4. Ghicha-Ghicha Fabric

Ghicha-ghicha fabric is a medium-weight fabric made from tasar waste silk yarn. It is hand woven and used for dress making and furnishing.

This fabric carries forward the character of ghicha yarn.

Because the yarn is irregular and handmade, the fabric also has a textured and natural look.

Practical Understanding

Ghicha-ghicha fabric is usually not smooth, flat or highly lustrous like fine mulberry silk.

It is more:

• textured,
• medium weight,
• rustic,
• earthy,
• handmade-looking,
• and suitable for natural design aesthetics.

It may be used in dress materials, furnishings and products where surface character is important.

Why It Is Suitable for Furnishing

A medium-weight textured silk fabric can work well in furnishing because it gives visual richness and tactile interest.

Unlike very delicate sheer silk fabrics, ghicha-ghicha has more body and presence.

Ghicha-ghicha fabric in simple words: Ghicha-ghicha fabric is a handwoven medium-weight fabric made from tasar waste silk yarn, known for its natural texture.

5. Matka

Matka is the yarn spun by hand appliances out of mulberry pierced and other waste cocoons, traditionally with the help of an earthen pot.

Matka is one of the most important Indian silk terms because it represents a completely different side of silk.

When people think of silk, they often think of smoothness and shine.

Matka reminds us that silk can also be rough, irregular and textured.

Practical Understanding

Matka yarn is made from pierced cocoons and waste cocoons.

A pierced cocoon cannot usually give continuous reeled silk because the filament has been broken.

So instead of reeling a continuous filament, the silk is spun.

This gives the yarn an uneven, slub-like and textured appearance.

Why Matka Is Different from Raw Silk

Raw silk is reeled silk with gum.

Matka is spun silk made from pierced or waste cocoons.

This is a very important difference.

Feature	Raw Silk	Matka
Source	Reeled from cocoon filaments	Spun from pierced or waste cocoons
Structure	More continuous	More irregular
Surface	Firmer, but may still be smoother	Rough, slub-like, textured
Character	Raw, gum-containing silk	Rustic spun silk
Common use	Various silk fabrics	Handloom, dress material, furnishing

So matka should not be confused with raw silk.

Both may feel less soft than degummed silk, but their technical origin is different.

Matka in simple words: Matka is a hand-spun silk yarn made from pierced or waste cocoons, giving a rough and textured character.

6. Matka Fabric

Matka fabric is an Indian term for a rough handloom fabric made from yarn spun out of pierced cocoon in the weft and organzine in the warp.

It is used as dress material, furnishing, cushion covers and similar products.

This definition is very useful because it tells us both yarn and fabric construction.

Direction	Yarn Used	Purpose
Warp	Organzine	Strength and stability
Weft	Matka yarn	Texture and rustic appearance

Why Organzine Is Used in Warp

As discussed in Part 2, organzine is a strong silk yarn used mainly in the warp direction.

Warp yarns face tension and abrasion during weaving.

Therefore, organzine gives stability and strength.

Why Matka Is Used in Weft

Matka yarn gives the fabric its rustic and textured appearance.

Since weft yarns are inserted across the fabric and do not face the same level of loom tension as warp yarns, the irregular matka yarn can be used more effectively in weft.

This combination gives matka fabric its character:

• stable warp,
• textured weft,
• handloom look,
• rough surface,
• and natural feel.

Practical Understanding

Matka fabric is valued because it is not perfectly smooth.

Its unevenness gives it personality.

It is often used where designers want a natural, craft-based and less glossy silk look.

It may be suitable for:

• kurtas,
• jackets,
• blouses,
• sarees,
• cushion covers,
• furnishing,
• and lifestyle products.

Matka fabric in simple words: Matka fabric is a rough handloom silk fabric made with strong organzine warp and textured matka weft.

Ghicha and matka process: tasar hand-drawn yarn, pierced cocoons, spun silk, organzine warp and textured fabric. Click image to view full size. AI generated image. Can have mistakes in the depiction. 

How Bafta, Kora, Ghicha and Matka Differ

These terms are often grouped together because they are Indian silk-related terms. But technically they are quite different.

Term	Main Category	Key Idea	Practical Character
Bafta	Silk-cotton fabric	Silk warp and cotton weft	Dress material, practical blend
Kora cloth	Undegummed silk fabric	Mulberry silk in raw/undegummed state	Firm, useful for printed sarees/scarves
Ghicha	Yarn	Hand-drawn tasar yarn without twist	Rustic, irregular, natural
Ghicha-ghicha fabric	Fabric	Tasar waste silk handwoven fabric	Medium weight, textured, furnishing/dress use
Matka	Yarn	Hand-spun yarn from pierced/waste cocoons	Rough, slub-like, textured
Matka fabric	Fabric	Organzine warp and matka weft	Rough handloom fabric, dress/furnishing use

This table shows that we should not treat all these terms as fabric names.

Some are yarn terms.

Some are fabric terms.

Some indicate fibre combination.

Some indicate gum condition.

Some indicate waste-silk utilization.

That is why classification is important.

Technical Note: Reeled Silk, Drawn Silk and Spun Silk

To understand these Indian terms better, we should understand three ideas:

1. Reeled Silk

Reeled silk is obtained by unwinding continuous filaments from good cocoons.

It is generally smoother and more uniform.

Examples connected with reeled silk include raw silk, filature silk, katan and organzine.

2. Drawn Silk

Drawn silk, as in ghicha, may be pulled or drawn by hand from cocoons or silk material.

It is less regular than reeled silk and has a more handmade character.

3. Spun Silk

Spun silk is made from broken filaments, pierced cocoons or waste silk.

Matka belongs to this world.

It is not continuous like reeled silk. It is more irregular and textured.

Simple technical flow:

Good cocoon + continuous filament = reeled silk

Hand drawing from tasar material = ghicha-type yarn

Pierced/waste cocoon + spinning = matka-type yarn

This difference explains why ghicha and matka look and feel different from smooth silk.

Practical Note for Buyers and Merchandisers

When buying Indian silk fabrics such as bafta, kora, ghicha or matka, do not rely only on the name.

Ask these questions:

Question	Why It Matters
Is the fabric pure silk, silk-cotton or silk-waste based?	Helps identify composition and value
Is the silk reeled, drawn or spun?	Explains smoothness or irregularity
Is the fabric raw, undegummed or degummed?	Affects stiffness, lustre and handle
Is the yarn twisted or untwisted?	Affects strength and texture
Is organzine used in warp?	Indicates warp stability
Is matka or ghicha used in weft?	Explains rustic texture
Is it single kora or double kora?	Affects weight and strength
What is the intended use?	Dress material, saree, furnishing or accessory

The same word may mean slightly different things in different markets.

Therefore, the buyer must convert the market word into a technical specification.

Common Confusions

Confusion 1: Matka and Raw Silk Are the Same

They are not the same.

Raw silk is reeled silk with natural gum.

Matka is spun silk made from pierced or waste cocoons.

Both may have body, but their origin and yarn structure are different.

Confusion 2: Kora Means Any White Silk Fabric

Not exactly.

Technically, kora refers to silk fabric in an undegummed and untwisted condition, mainly mulberry silk.

The gum content is important.

Confusion 3: Ghicha and Matka Are the Same

They are related to irregular silk yarns, but they are not identical.

Ghicha is hand-drawn, often from tasar cocoons.

Matka is hand-spun from pierced or waste cocoons, often mulberry.

Confusion 4: Bafta Is Pure Silk

Bafta is not pure silk. It is traditionally made with silk warp and cotton weft.

Confusion 5: Roughness Means Poor Quality

Not always.

In matka and ghicha fabrics, roughness and irregularity may be part of the desired fabric character.

The question is whether the irregularity is intentional, controlled and suitable for the end use.

Knowledge Nugget

Indian silk terms teach us that silk is not always smooth, shiny and delicate.

Silk can also be:

• firm,
• raw,
• rustic,
• textured,
• hand-drawn,
• hand-spun,
• blended,
• and craft-based.

In fact, many Indian silk fabrics are beautiful because they preserve the character of the yarn.

The unevenness is not removed completely.

The gum is not always removed immediately.

The waste cocoon is not wasted.

The hand process is not hidden.

This is the beauty of Indian textile vocabulary.

It does not only describe fabric.

It preserves process.

Quick Recap

Term	One-line Meaning
Bafta	Fabric made with silk warp and cotton weft
Kora cloth	Undegummed, untwisted mulberry silk fabric
Ghicha	Hand-drawn tasar silk yarn without twisting
Ghicha-ghicha fabric	Medium-weight handwoven fabric from tasar waste silk yarn
Matka	Hand-spun silk yarn from pierced or waste cocoons
Matka fabric	Rough handloom fabric with organzine warp and matka weft

Main lesson: Indian silk terms connect yarn, process, handloom practice and market identity.

Reflection Questions

1. Why is bafta considered a practical silk-cotton construction?
2. What does the word undegummed tell us about kora cloth?
3. How is ghicha different from smooth reeled silk?
4. Why does matka fabric have a rough and textured appearance?
5. Why should roughness not always be treated as a defect in Indian silk fabrics?

Final Words

Bafta, kora, ghicha and matka are not just names.

They are windows into Indian textile thinking.

Bafta shows how silk and cotton can be combined for practical use.

Kora shows the importance of gum and raw silk condition.

Ghicha shows the beauty of hand-drawn tasar silk.

Matka shows how pierced and waste cocoons can become valuable textured fabric.

These terms remind us that fabric knowledge is not only found in laboratories and standards.

It is also found in weaving centres, handloom clusters, yarn practices, market language and craft memory.

So when we hear an Indian silk term, we should listen carefully.

The word may be small.

But behind it, there is fibre, yarn, process, touch, tradition and experience.

General Disclaimer

This article is intended for general textile education and practical understanding. Textile terms, fabric names and trade usages may vary across regions, weaving clusters, suppliers and markets. The descriptions given here should be used as a learning guide and not as a substitute for laboratory testing, formal product specifications, buyer-approved standards or supplier technical data sheets. For commercial buying, quality control, fibre declaration or legal compliance, fabric composition, construction, yarn type, finish and performance should be verified through appropriate testing and documentation.

How to Determine Fibre Composition in Blended Fabrics

Blended fabrics are very common in textiles. A fabric may contain polyester with cotton, cotton with viscose, acrylic with wool, elastane with cotton, or many other combinations. But when a fabric is made from more than one fibre, one important question arises:

How do we know the percentage of each fibre in the fabric?

This is important for quality control, costing, labelling, performance evaluation, buyer communication, export documentation and compliance.

Why Are Fibres Blended?

No single fibre gives all the desirable properties needed in a fabric. One fibre may give strength, another may give comfort, another may improve appearance, and another may reduce cost.

For example, polyester has very good strength, but it does not absorb much moisture. Because of this, 100% polyester fabric may not feel as comfortable as cotton. When polyester is blended with cotton, the fabric can get the strength of polyester and the comfort of cotton.

Fibre blending is generally done for three major reasons:

• To obtain different properties
• To suit changing fashion requirements
• To control the cost of the fabric

Once fibres are blended, it becomes necessary to determine the actual percentage of each fibre in the fabric. This is usually done by dissolving one fibre selectively and weighing the remaining fibre.

Visual 1: Why fibres are blended — strength, comfort, fashion and cost.

Basic Principle of Fibre Composition Testing

Most chemical methods for fibre composition work on a simple principle:

One fibre is dissolved in a specific chemical, while the other fibre remains undissolved.

The undissolved fibre is then:

• filtered,
• washed,
• neutralised if required,
• dried,
• cooled,
• weighed.

From the weight of the remaining fibre, the percentage of each fibre in the blend can be calculated.

1. Polyester and Cellulosic Fibre Blends

This method is used for blends such as:

• Polyester + cotton
• Polyester + viscose

A small sample of the blended fabric, usually 0.5 to 1.0 gram, is weighed accurately and placed in a flask. Then 75% w/w sulphuric acid is added. The material-to-liquid ratio is kept at about 1:200.

The flask is kept in a water bath at 50 ± 5°C for about one hour.

In this process, the cellulosic fibre dissolves, while the polyester remains undissolved.

The remaining polyester fibre is then:

• filtered,
• washed properly with water,
• neutralised with dilute ammonia solution,
• dried at 110°C,
• cooled,
• weighed.

The weight of the remaining fibre gives the percentage of polyester. The percentage of cotton or viscose can be calculated by subtracting the polyester percentage from 100.

Example:

If polyester remaining after the test is 65%, then:

Cellulosic fibre percentage = 100 − 65 = 35%

So the fabric composition is:

65% polyester and 35% cotton or viscose.

Visual 2: Selective dissolution principle — dissolve one fibre, weigh the remaining fibre.

2. Cotton and Viscose Blends

Cotton and viscose are both cellulosic fibres, so their separation is more delicate. The Bureau of Indian Standards has described four methods for determining cotton and viscose percentages:

1. 60% w/w sulphuric acid method
2. Sodium zincate method
3. Formic acid and zinc chloride method
4. Cadoxen solution method

Among these, the 60% w/w sulphuric acid method is commonly used.

60% w/w Sulphuric Acid Method

In this method, 0.5 to 1.0 gram of sample is weighed accurately and placed in 60% w/w sulphuric acid. The material-to-liquid ratio is kept at 1:100.

The solution is stirred properly by mechanical action for about 30 minutes.

In this process:

• Viscose dissolves
• Cotton remains undissolved

The cotton fibres are then filtered out and washed. After that, they are washed with water and treated with dilute ammonium hydroxide solution for neutralisation. Finally, they are dried and weighed.

However, in this method, the weight of cotton may also reduce by about 5%. Therefore, a correction factor is applied to calculate the actual cotton percentage accurately.

3. Polyester, Cotton and Viscose Blends

In a three-fibre blend containing polyester, cotton and viscose, separation is done step by step.

First, the sample is placed in 60% w/w sulphuric acid.

In this stage:

• Viscose dissolves first.
• Cotton and polyester remain.

The remaining fibres are washed, dried and weighed.

Then the remaining fibres are placed in 75% sulphuric acid.

In this stage:

• Cotton dissolves.
• Polyester remains.

The final remaining fibre is polyester. It is washed, dried and weighed.

In this way, the percentage of viscose, cotton and polyester can be determined separately.

4. Acrylic Blends with Wool, Silk, Cotton, Viscose, Polyester or Nylon

Acrylic fibre may be blended with many other fibres such as wool, silk, cotton, viscose, polyester or nylon.

In such blends, acrylic is first dissolved in dry dimethyl formamide, commonly known as DMF.

In this method:

• Acrylic dissolves in DMF.
• Other fibres remain undissolved.

The undissolved fibres are filtered, washed, dried and weighed. From this, the percentage of acrylic fibre in the blend can be calculated.

5. Protein Fibres with Cotton, Polyester, Nylon or Acrylic

Protein fibres include fibres such as wool and silk.

When protein fibres are blended with cotton, polyester, nylon or acrylic, they can be separated using alkali.

The accurately weighed sample is placed in a conical flask. Then 5% w/w sodium hydroxide or potassium hydroxide solution is added. The mixture is boiled for about 10 minutes.

In this process:

• Protein fibres dissolve.
• Other fibres remain undissolved.

The remaining fibres are filtered and washed thoroughly with water. Then they are washed with dilute acetic acid to neutralise the alkali.

Finally, the sample is dried, cooled and weighed. From this, the percentage of protein fibre and the other fibre can be calculated.

6. Polyester with Cotton or Viscose

Polyester can also be determined by using meta-cresol.

In this method, the blended fibres are weighed accurately and heated with meta-cresol.

In this process:

• Polyester dissolves.
• Cotton or viscose remains undissolved.

The remaining insoluble fibres are washed, dried and weighed. From this, the percentage of polyester is calculated.

7. Elastane, Spandex or Lycra with Cotton or Viscose

Elastane is also known by names such as spandex and Lycra.

When elastane is blended with cotton or viscose, it can be separated using DMF.

In this method, the mixed fibres are treated with DMF.

In this process:

• Elastane dissolves in DMF.
• Cotton or viscose remains undissolved.

The remaining fibres are filtered, washed, dried and weighed. From this, the percentage of elastane is calculated.

Visual 3: Fibre blend testing summary — fibre blend, chemical used and fibre dissolved.

Summary Table: Fibre Blend Testing Methods

Fibre Blend	Chemical Used	Fibre Dissolved	Fibre Remaining
Polyester + cotton/viscose	75% sulphuric acid	Cotton/viscose	Polyester
Cotton + viscose	60% sulphuric acid	Viscose	Cotton
Polyester + cotton + viscose	60% and 75% sulphuric acid	Viscose first, then cotton	Polyester
Acrylic + other fibres	DMF	Acrylic	Other fibres
Wool/silk + cotton/polyester/nylon/acrylic	Sodium hydroxide or potassium hydroxide	Wool/silk	Other fibres
Polyester + cotton/viscose	Meta-cresol	Polyester	Cotton/viscose
Elastane/spandex/Lycra + cotton/viscose	DMF	Elastane	Cotton/viscose

Why Fibre Composition Testing Matters

Fibre composition testing is very important in the textile industry because it helps in:

• correct fabric labelling,
• buyer compliance,
• export documentation,
• quality control,
• cost verification,
• performance evaluation,
• identifying wrong claims in fabric composition.

For example, if a fabric is sold as 80% cotton and 20% polyester, a laboratory can verify whether the actual fibre content matches the claim.

Similarly, in stretch fabrics, the elastane percentage may be small but very important. Even 2% to 5% elastane can change the stretch, recovery and comfort of the fabric.

Important Precautions

While carrying out fibre composition testing, the following precautions are important:

1. The sample should be weighed accurately.
2. The correct chemical concentration should be used.
3. The material-to-liquid ratio should be maintained.
4. Temperature and time should be controlled.
5. The residue should be washed completely.
6. Neutralisation should be done properly.
7. The sample should be dried and cooled before final weighing.
8. Correction factors should be applied wherever required.

Small errors in weighing, washing or drying can affect the final fibre percentage.

Conclusion

Fibre blending is done to improve fabric properties, reduce cost and meet fashion requirements. But once fibres are blended, it becomes necessary to know their exact proportion.

The basic method of fibre composition analysis is selective dissolution. One fibre is dissolved in a suitable chemical, while the other fibre remains. The remaining fibre is then washed, dried and weighed.

Different fibres require different chemicals. Polyester, cotton, viscose, acrylic, wool, silk and elastane all behave differently in different solvents. Therefore, correct identification of the fibre blend is necessary before selecting the test method.

For merchandisers, textile students, quality professionals and buyers, understanding these methods is very useful. It helps them read laboratory reports better and understand how fibre composition claims are verified scientifically.

Understanding 75% (w/w) Sulphuric Acid and M:L Ratio

In textile testing instructions, we often come across statements such as:

Add 75% (w/w) sulphuric acid (M:L :: 1:200).

At first glance, this looks like a short laboratory instruction, but it contains two important pieces of information. The first is the concentration of sulphuric acid, and the second is the amount of acid solution to be used in relation to the weight of the textile material.

What is meant by 75% (w/w)?

The term w/w means weight by weight. Therefore, 75% (w/w) sulphuric acid means that 75 parts by weight of pure sulphuric acid are present in 100 parts by weight of the final solution.

In simple terms:

\[ 75\% \; (w/w) = \frac{75 \text{ g pure } H_2SO_4}{100 \text{ g final solution}} \]

So, if we prepare 100 g of 75% (w/w) sulphuric acid solution, it should contain 75 g of pure sulphuric acid and 25 g of water.

What is meant by M:L :: 1:200?

The term M:L means Material to Liquor ratio. In textile processing and testing, “material” usually refers to the fabric, fibre, yarn, or textile sample. “Liquor” refers to the solution in which the textile material is treated.

Therefore:

\[ M:L = 1:200 \]

means that for every 1 g of textile material, 200 mL of acid solution should be used.

Fabric Weight	M:L Ratio	Required Acid Liquor
1 g	1:200	200 mL
2 g	1:200	400 mL
5 g	1:200	1000 mL
10 g	1:200	2000 mL

The general formula is:

\[ \text{Liquor required in mL} = \text{Weight of material in g} \times 200 \]

Example: If the fabric sample is 5 g

If the fabric sample weighs 5 g and the required M:L ratio is 1:200, then:

\[ 5 \times 200 = 1000 \text{ mL} \]

So, 5 g of textile material will require 1000 mL of 75% (w/w) sulphuric acid solution.

How to Prepare 75% (w/w) Sulphuric Acid Solution

Since the concentration is given as w/w, the correct method is to prepare the solution by weight, not simply by volume. Laboratory concentrated sulphuric acid is commonly about 98% (w/w), not 100% pure. Therefore, we must account for this while calculating the amount of concentrated acid required.

Suppose we want to prepare 100 g of 75% (w/w) sulphuric acid solution.

Required pure sulphuric acid:

\[ 75 \text{ g} \]

If concentrated sulphuric acid is 98% (w/w), then the amount of concentrated acid required is:

\[ \frac{75}{0.98} = 76.53 \text{ g} \]

Therefore, water required will be:

\[ 100 - 76.53 = 23.47 \text{ g} \]

For 100 g of 75% (w/w) sulphuric acid solution:
Take approximately 23.5 g water and slowly add 76.5 g concentrated sulphuric acid.

Preparation for 1000 g of Final Solution

If a larger amount is required, the same calculation can be scaled up. For example, to prepare 1000 g of 75% (w/w) sulphuric acid solution:

Required pure sulphuric acid:

\[ 75\% \text{ of } 1000 = 750 \text{ g} \]

Amount of 98% concentrated sulphuric acid required:

\[ \frac{750}{0.98} = 765.3 \text{ g} \]

Amount of water required:

\[ 1000 - 765.3 = 234.7 \text{ g} \]

For 1000 g of 75% (w/w) sulphuric acid solution:
Take 234.7 g water first, then slowly add 765.3 g concentrated sulphuric acid with stirring and cooling.

Important Safety Precaution

Always add acid to water, never water to acid.

Dilution of sulphuric acid releases a large amount of heat. If water is added directly to concentrated acid, the mixture can heat suddenly, splash, or even boil violently. Therefore, the safe method is to take the required quantity of water first and then add concentrated sulphuric acid slowly, with continuous stirring.

The preparation should be done using proper laboratory safety equipment such as chemical-resistant gloves, safety goggles, apron or lab coat, and acid-resistant glassware. Cooling should be provided if necessary, especially when preparing larger quantities.

Summary

Term	Meaning
75% (w/w)	75 g pure sulphuric acid in 100 g final solution
M:L	Material to Liquor ratio
M:L :: 1:200	1 g textile material requires 200 mL liquor
For 5 g sample	Required liquor = \(5 \times 200 = 1000\) mL
For 100 g of 75% solution	Use 23.5 g water + 76.5 g of 98% sulphuric acid

General Formula

If concentrated sulphuric acid strength is known, the required weight of concentrated acid can be calculated as:

\[ \text{Weight of concentrated acid} = \frac{\text{Required pure acid}}{\text{Strength of concentrated acid as decimal}} \]

For 98% sulphuric acid:

\[ \text{Weight of concentrated acid} = \frac{\text{Required pure acid}}{0.98} \]

Water required:

\[ \text{Water required} = \text{Final solution weight} - \text{Weight of concentrated acid} \]

Practical Note for Textile Testing

When a test method says 75% (w/w) sulphuric acid at M:L :: 1:200, it is not merely asking for “some strong acid.” It is specifying both the exact concentration of the acid solution and the amount of solution to be used per gram of textile material. Both are important because fibre dissolution, reaction rate, and test reproducibility depend strongly on acid concentration and liquor ratio.

Disclaimer: Sulphuric acid is highly corrosive and dangerous. The above explanation is for educational understanding of laboratory notation and calculation. Actual preparation and handling should be done only in a properly equipped laboratory by trained personnel, following the relevant test standard, institutional safety protocol, and the chemical safety data sheet.

General Disclaimer

This article is intended for educational and general textile knowledge purposes only. Actual fibre composition testing should be carried out only by trained laboratory personnel using recognised test standards, calibrated equipment, proper safety procedures and appropriate chemical handling protocols. Chemicals such as sulphuric acid, sodium hydroxide, potassium hydroxide, DMF and meta-cresol can be hazardous and should not be handled casually. Always refer to the relevant national or international testing standard before conducting any laboratory procedure.

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Silk Fabric Terms Explained — Part 4: Understanding the Crepe Family

In Part 1, we created a practical map for understanding silk fabric terms.

In Part 2, we discussed silk yarn terms such as raw silk, bivoltine silk, China silk, katan and organzine.

In Part 3, we understood twist-based sheer fabrics such as chiffon and georgette.

Now we come to one of the most important and most confusing families of fabrics:

The crepe family.

Crepe is not one fabric.

Crepe is a surface idea.

It refers to fabrics having a crinkled, puckered, grainy or pebbly surface. This effect may come from highly twisted yarns, special weave, chemical treatment, embossing or finishing.

This is why terms such as crepe, crepe fabric, crepe yarn, crepe-de-Chine, flat crepe and crepe-backed satin need to be understood together.

Central idea: Crepe is not only a fabric name. It is a fabric effect.

Crepe family map: yarn twist, weave, finishing and surface texture. Click image to view full size.

Why Crepe Is Confusing

Crepe becomes confusing because the word is used in many ways.

Sometimes crepe means the fabric surface.

Sometimes it means the yarn.

Sometimes it means a family of fabrics.

Sometimes it means a specific fabric, such as crepe-de-Chine.

For example:

Term	What It Refers To
Crepe	General crinkled or pebbly fabric effect
Crepe yarn	Highly twisted yarn used to create crepe effect
Crepe fabric	Fabric with crinkled, puckered or pebbly surface
Crepe-de-Chine	A specific lightweight silk crepe fabric
Flat crepe	A silk crepe with soft, almost imperceptible crinkle
Crepe-backed satin	A two-faced fabric: satin on one side, crepe on the other

So we should not ask only:

What is crepe?

We should ask:

Is the word crepe referring to yarn, surface, weave, finish or fabric type?

Once we ask this question, the family becomes much clearer.

1. Crepe

Crepe is a lightweight fabric made of silk, rayon, cotton, wool, man-made fibres or blends, characterized by a crinkled surface.

This crinkled surface can be produced in several ways:

• using crepe yarns,
• using high twist yarns,
• using special crepe weave,
• chemical treatment,
• embossing,
• or finishing.

Traditionally, crepe was mostly understood as a woven fabric. But crepe yarns are now also used to make knitted crepes.

Practical Understanding

Crepe is best understood by touching the fabric.

It does not feel completely smooth.

It may feel:

• crinkled,
• slightly rough,
• pebbly,
• springy,
• grainy,
• or softly puckered.

This surface gives the fabric a special appearance and handle.

Crepe fabrics often have better body than very smooth lightweight fabrics. They also hide minor wrinkles better because the surface is already textured.

Crepe in simple words: Crepe is a fabric with a deliberately crinkled, puckered or pebbly surface.

The word “deliberately” is important.

Crepe effect is not a defect. It is a planned fabric character.

2. Crepe Fabric

Crepe fabric is a fabric characterized by a crinkled, puckered or pebbly surface, usually made with highly twisted yarns in the weft and sometimes in the warp, or both.

A similar effect may also be obtained by using normal twisted yarn and crepe weave.

This definition tells us something very important:

Crepe effect may come from yarn or from weave.

That is why all crepe fabrics are not made in exactly the same way.

Crepe Effect from Yarn

When highly twisted yarns are used, the yarns try to contract or kink. During finishing, this creates unevenness and texture on the fabric surface.

This is the classic way of producing crepe effect.

Crepe Effect from Weave

Sometimes a crepe-like surface is produced by using a special crepe weave. In this case, the texture is not only due to highly twisted yarn but also due to interlacement pattern.

The weave scatters light and creates a broken, irregular appearance.

Practical Understanding

When you see a crepe fabric, ask:

Is the crepe effect coming from yarn twist, weave structure, finishing, or a combination?

This question is very useful for students, buyers and merchandisers.

Two fabrics may both be called crepe, but their construction may be very different.

3. Crepe Yarn

Crepe yarn is a highly twisted yarn, generally having about 1,200 TPM to 4,000 TPM, used for producing crepe effect in woven or knitted fabrics.

This is the foundation of many crepe fabrics.

A normal yarn lies relatively stable.

A highly twisted yarn stores energy.

When it is woven and later relaxed, the stored twist tries to express itself. This creates crinkle, grain and surface texture.

Practical Understanding

Crepe yarn is not a fabric. It is the yarn that helps create the crepe effect.

This distinction is important.

Term	Meaning
Crepe yarn	Highly twisted yarn
Crepe fabric	Fabric made with crepe effect
Crepe surface	Crinkled or pebbly appearance

Why High Twist Creates Crepe

When twist is inserted into yarn, the fibres or filaments are turned around the yarn axis.

At very high twist levels, the yarn becomes lively. It tries to twist back, curl or contract.

When such yarn is used in fabric, the yarn movement creates small irregularities on the fabric surface.

That is the beginning of the crepe effect.

Crepe yarn carries hidden energy. The fabric surface reveals that energy.

How crepe effect is produced: high twist yarn, crepe weave, chemical treatment and finishing. Click image to view full size.

4. Crepe/Georgette Yarn

Crepe/georgette yarn is a twisted yarn, usually with about 2,000 TPM to 3,600 TPM, generally made of two threads of raw silk.

This yarn is used for georgette and crepe-like fabrics.

We discussed this briefly in Part 3, but it is also relevant here because georgette belongs close to the crepe family.

Practical Understanding

Crepe/georgette yarn gives the fabric:

• grain,
• liveliness,
• drape,
• subtle crinkle,
• and a textured surface.

In georgette, this yarn is often arranged in S and Z twist directions to balance torque and create a uniform grainy surface.

So georgette can be understood as a sheer member of the crepe family.

5. Crepe-de-Chine Yarn

Crepe-de-Chine yarn, also called French yarn, is a hard twisted yarn, usually having about 1,600 TPM to 2,500 TPM. It is generally made from 3 to 5 raw silk threads.

It is used as weft in crepe-de-Chine.

This is a very specific yarn term.

The important points are:

• it is hard twisted,
• it is made from multiple raw silk threads,
• it is used mainly as weft,
• and it helps create the crepe-de-Chine fabric effect.

Practical Understanding

Crepe-de-Chine yarn is not the same as ordinary silk yarn.

Its twist level and multi-thread construction help create the soft crepe character of crepe-de-Chine fabric.

It does not usually produce a very harsh or rough crepe. Instead, it gives a refined and subtle crepe effect.

6. Crepe-de-Chine Fabric

Crepe-de-Chine fabric is a lightweight fabric made with highly twisted S and Z filament yarns alternating in the weft, and normally twisted filament yarn in the warp.

This definition is very important.

It tells us that crepe-de-Chine gets its character mainly from the weft yarn arrangement.

Breaking the Definition

Feature	Meaning
Lightweight fabric	It is not heavy or coarse
S and Z yarns	Yarns twisted in opposite directions
Alternating in weft	S and Z yarns are arranged alternately across the fabric
Normally twisted warp	Warp remains comparatively stable
Crepe effect	Comes mainly from high twist weft yarns

Why S and Z Twists Are Alternated

If only one direction of high twist is used, the fabric may become distorted.

By alternating S and Z twisted yarns, the twist forces are partly balanced.

This gives crepe-de-Chine a controlled crepe effect.

Practical Understanding

Crepe-de-Chine is usually smoother and softer than many rough crepes. It has a gentle crepe surface rather than a very strong crinkle.

It is suitable for:

• dresses,
• blouses,
• scarves,
• sarees,
• and flowing garments.

Crepe-de-Chine is a good example of controlled texture.

The fabric is not flat like plain silk, but it is not extremely rough either.

7. Flat Crepe

Flat crepe is a firm, mediumweight silk crepe with a soft, almost imperceptible crinkle.

It has crepe fillings alternating with two S and two Z twists. The surface is fairly flat.

Flat crepe may also be made of man-made fibres. It is used for dresses, negligees and blouses.

Practical Understanding

The name itself gives a clue:

Flat crepe is crepe, but with a flatter surface.

It does not have a very strong crinkled surface. The crepe effect is mild, controlled and subtle.

It gives a soft texture without making the surface too rough.

Why It Is Called Flat Crepe

In stronger crepes, the crinkling or grain may be clearly visible.

In flat crepe, the crinkle is almost imperceptible. The fabric surface remains fairly flat, but not completely plain.

So flat crepe can be understood as a refined crepe fabric with mild surface character.

8. Crepe-backed Satin

Crepe-backed satin is a two-faced fabric that can be used on either side.

One side is satin.

The reverse side, made of twisted yarns, is crepe.

This is a very interesting fabric because it combines two different surface characters in one cloth.

Practical Understanding

Satin side:

• smooth,
• lustrous,
• dressy,
• reflective.

Crepe side:

• textured,
• duller,
• grainy,
• less reflective.

This makes the fabric versatile.

A designer may use the satin side outside for shine, or the crepe side outside for a more matte and textured appearance.

Why Crepe-backed Satin Is Important

This fabric teaches us that fabric identity can be two-sided.

The same fabric can have two different faces because of yarn, weave and surface arrangement.

So when studying fabrics, we should examine both sides, not only the face side.

Crepe family comparison: crepe yarn, crepe-de-Chine, flat crepe and crepe-backed satin. Click image to view full size.

Crepe Family Comparison Table

Term	Type of Term	Main Character	Technical Basis
Crepe	General fabric family	Crinkled or pebbly surface	Yarn, weave or finish
Crepe fabric	Fabric type	Puckered or crinkled surface	High twist yarn and/or crepe weave
Crepe yarn	Yarn term	Highly twisted yarn	1,200–4,000 TPM
Crepe/georgette yarn	Yarn term	High twist silk yarn	2,000–3,600 TPM, often two raw silk threads
Crepe-de-Chine yarn	Yarn term	Hard twisted French yarn	1,600–2,500 TPM, 3–5 raw silk threads
Crepe-de-Chine fabric	Fabric type	Lightweight, soft crepe surface	S/Z high twist weft, normal warp
Flat crepe	Fabric type	Fairly flat, mild crinkle	Two S and two Z crepe fillings
Crepe-backed satin	Two-faced fabric	Satin face, crepe back	Satin weave plus twisted yarn reverse

Technical Note: Crepe Effect Can Be Produced in Four Ways

Crepe effect is not produced by only one method.

It can be created through:

1. High Twist Yarn

This is the most common method in silk crepes. Highly twisted yarn creates torque and surface crinkle.

2. Crepe Weave

A crepe weave uses an irregular interlacement arrangement to produce a broken, pebbly surface.

3. Chemical Treatment

Some crepe effects may be produced by chemical treatment, such as shrinkage effects.

4. Embossing or Finishing

A crepe-like surface can also be created mechanically through finishing.

This is why the buyer should ask how the crepe effect has been produced.

A true yarn-based crepe may behave differently from an embossed or finished crepe.

Practical Note for Buyers and Merchandisers

When buying crepe fabrics, do not rely only on the word “crepe”.

Ask the supplier:

Question	Why It Matters
Is the crepe effect yarn-based, weave-based or finish-based?	Explains durability of effect
What fibre is used?	Silk, rayon, polyester and blends behave differently
What is the twist level?	Helps identify true crepe yarn character
Is S/Z twist used?	Helps understand balance and surface texture
Is the crepe yarn in warp, weft or both?	Explains strength, texture and drape
Is it crepe-de-Chine, flat crepe or general crepe?	Helps identify exact product type
What is the fabric weight?	Affects fall, end use and transparency
Which side is intended as face?	Important in crepe-backed satin

The word “crepe” is only the beginning of the specification.

It is not the full specification.

Common Confusions

Confusion 1: Crepe Is One Fabric

No. Crepe is a family of fabrics and effects.

There are many types of crepe, including crepe-de-Chine, flat crepe, crepe georgette and crepe-backed satin.

Confusion 2: Crepe Yarn and Crepe Fabric Are the Same

They are not the same.

Crepe yarn is the highly twisted yarn.

Crepe fabric is the fabric showing crepe effect.

Confusion 3: All Crepe Effects Come Only from Yarn Twist

Not always.

Crepe effect can come from yarn twist, weave, chemical treatment, embossing or finishing.

Confusion 4: Crepe-de-Chine Is a Heavy Crepe

No. Crepe-de-Chine is generally lightweight and has a soft, refined crepe effect.

Confusion 5: Crepe-backed Satin Has Only One Usable Side

No. Crepe-backed satin is a two-faced fabric and may be used from either side.

Knowledge Nugget

Crepe is a wonderful example of how textile beauty can come from controlled irregularity.

A perfectly smooth yarn gives smoothness.

A highly twisted lively yarn gives movement.

A carefully balanced S and Z arrangement gives controlled texture.

A special weave gives broken reflection.

A finish can create surface character.

So crepe is not a defect.

It is planned disturbance.

It is controlled unevenness.

It is texture created by design.

Quick Recap

Term	One-line Meaning
Crepe	Fabric family with crinkled or pebbly surface
Crepe fabric	Fabric with crinkled, puckered or pebbly appearance
Crepe yarn	Highly twisted yarn used to create crepe effect
Crepe/georgette yarn	High twist yarn used for georgette and crepe-like fabrics
Crepe-de-Chine yarn	Hard twisted yarn used as weft in crepe-de-Chine
Crepe-de-Chine fabric	Lightweight fabric with alternating S and Z high twist weft
Flat crepe	Mediumweight crepe with mild, almost imperceptible crinkle
Crepe-backed satin	Two-faced fabric with satin face and crepe reverse

Reflection Questions

1. Why should crepe be understood as a family rather than one fabric?
2. What is the difference between crepe yarn and crepe fabric?
3. Why do S and Z twist yarns help in crepe-de-Chine?
4. How is flat crepe different from stronger crepe fabrics?
5. Why is crepe-backed satin considered a two-faced fabric?

Final Words

Crepe fabrics are beautiful because they are not flat.

They have life on the surface.

Their character comes from twist, weave, finishing and controlled irregularity.

Crepe yarn brings hidden energy into the fabric.

Crepe-de-Chine refines this energy into softness.

Flat crepe reduces the crinkle into a subtle surface.

Crepe-backed satin combines shine and texture in one fabric.

So the next time we touch a crepe fabric, we should not only say:

This fabric is crinkled.

We should ask:

What has created this crinkle?

That question takes us from market name to textile understanding.

And that is the real purpose of this silk terminology series.

General Disclaimer

This article is intended for general textile education and practical understanding. Textile terms, fabric names and trade usages may vary across regions, mills, suppliers and markets. The technical descriptions given here should be used as a learning guide and not as a substitute for laboratory testing, formal specifications, buyer-approved standards or supplier technical data sheets. For commercial buying, quality control or legal compliance, fabric composition, construction, twist, finish and performance should be verified through appropriate testing and documentation.

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