Warp and Weft Calculations: How to Make a Fabric Heavier Without Changing Its Character

Applying Cloth Weight Rules to Both Warp and Weft

The earlier calculations and rules were explained mainly with reference to warp yarns. However, the same rules are equally applicable to weft yarns.

The only change is in terminology. For warp, we speak of ends per inch. For weft, we speak of picks per inch. The principle of calculation remains exactly the same.

Therefore, when a whole cloth is to be made heavier or lighter while keeping the same character, both the warp and the weft must be adjusted proportionately.

Earlier, the rules were used to find the new warp count and the new ends per inch. But a real woven cloth usually contains both warp and weft.

Warp means the lengthwise yarns in the fabric.

Weft means the crosswise yarns inserted during weaving.

If the cloth weight is to be increased or decreased while preserving the same fabric character, then the following must be recalculated:

The warp count must be changed.

The weft count must be changed.

The ends per inch must be changed.

The picks per inch must be changed.

This keeps the cloth balanced. Otherwise, the fabric may become too dense, too loose, too stiff, or quite different in handle and appearance.

Given Example

The original cloth is made with:

Part of Cloth	Original Construction
Warp	56 ends per inch of \(2/30s\) yarn
Weft	60 picks per inch of single \(18s\) yarn

The requirement is:

Increase the weight by one-fifth.

So we need to find the new warp count, new weft count, new ends per inch, and new picks per inch.

Step 1: Convert the Folded Warp Yarn to Equivalent Single Count

The warp yarn is given as:

\(2/30s\)

This means that two yarns of \(30s\) count are folded or twisted together.

In an indirect count system, when two equal yarns are folded together, the equivalent count becomes half.

\(2/30s = 15s\)

Therefore, the warp behaves like a single yarn of approximately:

\(15s\)

So:

Given warp count \(= 15s\)

Given weft count \(= 18s\)

Step 2: Understand “Increase the Weight by One-Fifth”

If the cloth is to be made one-fifth heavier, the original cloth weight may be treated as 5 parts.

An increase of one-fifth adds 1 more part.

\[ \text{Original weight} = 5 \]

\[ \text{Increase} = 1 \]

\[ \text{Required weight} = 6 \]

Therefore, the required cloth weight and given cloth weight are in the ratio:

\[ \text{Required weight} : \text{Given weight} = 6 : 5 \]

Step 3: Find the New Warp Count

The rule for finding the required yarn count is:

\[ \text{Required count} = \text{Given count} \times \frac{(\text{Given weight})^2}{(\text{Required weight})^2} \]

For warp:

\[ \text{Given warp count} = 15s \]

\[ \text{Given weight} = 5 \]

\[ \text{Required weight} = 6 \]

Therefore:

\[ x = 15 \times \frac{5^2}{6^2} \]

\[ x = 15 \times \frac{25}{36} \]

\[ x = \frac{375}{36} \]

\[ x = 10.42 \]

So the required warp count is approximately:

\[ 10.4s \]

In the old notation, this may be written as about:

\[ 10 \frac{5}{12}s \]

So the warp changes from:

\[ 15s \rightarrow 10.4s \]

Since the fabric is becoming heavier, the yarn count becomes lower, meaning the yarn becomes coarser.

Step 4: Find the New Weft Count

The original weft count is:

\[ 18s \]

Using the same rule:

\[ x = 18 \times \frac{5^2}{6^2} \]

\[ x = 18 \times \frac{25}{36} \]

\[ x = \frac{450}{36} \]

\[ x = 12.5 \]

So the required weft count is:

\[ 12.5s \]

The weft changes from:

\[ 18s \rightarrow 12.5s \]

Again, because the cloth is becoming heavier, the weft yarn also becomes coarser.

Step 5: Find the New Ends Per Inch

Once the warp count is changed, the sett must also be adjusted. For this, we use the shortcut rule:

\[ \text{Required weight} : \text{Given weight} :: \text{Given ends} : \text{Required ends} \]

Here:

\[ \text{Required weight} = 6 \]

\[ \text{Given weight} = 5 \]

\[ \text{Given ends} = 56 \]

Therefore:

\[ 6 : 5 :: 56 : x \]

\[ x = \frac{56 \times 5}{6} \]

\[ x = \frac{280}{6} \]

\[ x = 46.67 \]

So the new ends per inch should be approximately:

\[ 46.7 \]

In practical terms, this may be taken as:

47 ends per inch

The number of warp threads per inch is reduced because the new warp yarn is coarser.

Step 6: Find the New Picks Per Inch

The same rule is applied to weft, but instead of ends per inch, we use picks per inch.

\[ \text{Required weight} : \text{Given weight} :: \text{Given picks} : \text{Required picks} \]

Here:

\[ \text{Required weight} = 6 \]

\[ \text{Given weight} = 5 \]

\[ \text{Given picks} = 60 \]

Therefore:

\[ 6 : 5 :: 60 : x \]

\[ x = \frac{60 \times 5}{6} \]

\[ x = 50 \]

So the required picks per inch are:

\[ 50 \]

The weft sett changes from:

\[ 60 \text{ picks per inch} \rightarrow 50 \text{ picks per inch} \]

Final New Cloth Construction

The original cloth was:

Part	Original Construction
Warp	\(56\) ends per inch of \(2/30s\) yarn
Weft	\(60\) picks per inch of \(18s\) yarn

The new cloth, one-fifth heavier, should be approximately:

Part	New Construction
Warp	\(46.7\) ends per inch of \(10.4s\) equivalent warp
Weft	\(50\) picks per inch of \(12.5s\) weft

Since the original warp was a folded yarn, we should remember that the new warp count is the equivalent single count. If it is again to be made as a two-fold yarn, then the folded yarn must be chosen so that its resultant count is about \(10.4s\).

For example, a two-fold yarn close to that might be:

\[ 2/21s \]

because:

\[ 2/21s = 10.5s \]

So, in practical mill terms, the new warp could be approximately:

\(2/21s\) warp and \(12.5s\) weft

Why Ends and Picks Are Reduced

This is the most important point.

To make the cloth heavier, we are using coarser yarns.

\[ \text{Warp: } 15s \rightarrow 10.4s \]

\[ \text{Weft: } 18s \rightarrow 12.5s \]

Because the yarns are thicker, we cannot keep the same number of ends and picks per inch. If we did, the fabric would become too heavy and too crowded.

So the sett is reduced:

\[ \text{Ends per inch: } 56 \rightarrow 46.7 \]

\[ \text{Picks per inch: } 60 \rightarrow 50 \]

This keeps the fabric in the same general character while increasing the total weight by one-fifth.

Why the Rules Apply to Any Yarn Count System

There is a very important general point: these rules are not restricted to cotton counts.

They apply to any yarn-counting system because the calculation is based on proportion.

The author avoids referring to a particular yarn class or count system because the principle is general. It can apply to cotton, worsted, linen, silk, or any other yarn system, provided that the same system is used consistently.

However, one condition is important: the new cloth must be made from the same class of yarn as the original cloth.

That means if the given cloth is made from cotton yarn, the required cloth should also be calculated as cotton yarn. If it is worsted, it should remain worsted. If it is linen, it should remain linen.

Changing from one class of yarn to another is a different problem because different fibres and yarn systems behave differently. That is why separate rules are needed for changing from one class of yarn to another.

In Simple Terms

The earlier rules for changing yarn count and sett are not only for warp. They also apply to weft.

For a whole cloth, both warp and weft must be recalculated.

In the example, the original cloth was:

\[ 56 \text{ ends per inch of } 2/30s \text{ warp} \]

\[ 60 \text{ picks per inch of } 18s \text{ weft} \]

The required cloth is one-fifth heavier. The final result is:

\[ \text{Warp count: } 15s \rightarrow 10.4s \]

\[ \text{Weft count: } 18s \rightarrow 12.5s \]

\[ \text{Ends per inch: } 56 \rightarrow 46.7 \]

\[ \text{Picks per inch: } 60 \rightarrow 50 \]

So, the whole cloth becomes heavier, but because both yarn count and sett are adjusted proportionately, it remains of the same general character.

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Yarn Count and Cloth Weight: How to Make the Same Fabric Heavier or Lighter- Continued

Adjusting Ends Per Inch When Yarn Count Is Changed

This post continues from the earlier rule where we first found the new yarn count needed to make a cloth heavier or lighter while keeping the same character.

In the earlier example, the original cloth used 20s warp, and we wanted the new cloth to be one-sixth heavier. By that rule, we found that the new warp count should be approximately 15s. Since 15s is coarser than 20s, it will help increase the weight of the cloth.

But after finding the new yarn count, one more adjustment is necessary: we must also find the correct ends per inch, also called the sett.

Why Ends Per Inch Must Be Changed

If we simply replace 20s yarn with 15s yarn but keep the same number of ends per inch, the cloth will not remain of the same character.

There are two reasons for this.

First, the diameter of the yarn changes. A 15s yarn is thicker than a 20s yarn. Therefore, the spacing between yarns must also change. If we put the same number of thicker yarns into one inch, the fabric may become too crowded, stiff, dense, and different in feel.

Second, the weight change will not remain in the required proportion. The target was to make the cloth one-sixth heavier, meaning the weight ratio should be:

6 : 7

But if the same number of ends is used after changing from 20s to about 15s, the weight increase will be too much. The passage says the increase would be roughly in the ratio:

15 : 20

or approximately:

3 : 4

This means the cloth would become about one-third heavier instead of one-sixth heavier. So, to keep the fabric character balanced, the number of ends per inch must be reduced.

Rule: Finding the New Ends Per Inch

As the square root of the count of yarn in the given cloth is to the square root of the count of yarn required for the new cloth, so is the ends per inch of the given cloth to the ends per inch of the required cloth.

In formula form:

√Given count : √Required count :: Given ends : Required ends

This rule is based on the idea that yarn diameter changes according to the square root relationship of yarn count.

In indirect count systems, such as cotton count:

Lower count = coarser yarn

Higher count = finer yarn

So, when we move from 20s to about 15s, the yarn becomes thicker. Therefore, fewer ends per inch are needed.

Example

Suppose the original cloth has:

60 ends per inch

The original count is:

20s

The required count is approximately:

14.69s

or nearly:

15s

Using Rule 48:

√20 : √14.69 :: 60 : x

Now:

√20 ≈ 4.47

√14.69 ≈ 3.83

So:

4.47 : 3.83 :: 60 : x

Therefore:

x = (60 × 3.83) / 4.47

x ≈ 51.4

So the required sett is approximately:

51 to 52 ends per inch

or roughly

51.4 ends per inch

Therefore, the new cloth should use about 51 to 52 ends per inch, instead of 60 ends per inch.

Rule: Same Rule Using Squares

As the count of yarn in the given cloth is to the count of yarn in the required cloth, so is the square of the ends per inch of the given cloth to the square of the ends per inch of the required cloth.

In formula form:

Given count : Required count :: Given ends² : Required ends²

Using the same example:

20 : 14.69 :: 60² : x²

This becomes:

20 : 14.69 :: 3600 : x²

Therefore:

x² = (14.69 × 3600) / 20

x² = 2644.2

x = √2644.2

x ≈ 51.4

So again, the required sett is about:

51.4 ends per inch

This rule avoids using square roots at the beginning, but eventually the square root has to be taken at the end.

Meaning of “Ends Per Inch” or “Sett”

The words ends per inch and sett are used together.

Ends per inch means the number of warp threads in one inch of fabric.

Sett means the closeness of the threads in the fabric. In some systems, sett may be expressed differently, but the principle remains the same. The rule is based on proportion, so it can be applied to any sett system, not only ends per inch.

This is similar to the earlier rule about yarn count. The exact count system does not matter, as long as the same system is used consistently.

Rule: The Shortcut Rule

After explaining the two rules, there is a much simpler practical rule.

As the required weight is to the given weight, so is the ends per inch of the given cloth to the ends per inch of the required cloth.

In formula form:

Required weight : Given weight :: Given ends : Required ends

In our example, the cloth is one-sixth heavier.

So:

Given weight = 6

Required weight = 7

Therefore:

7 : 6 :: 60 : x

So:

x = (60 × 6) / 7

x = 360 / 7

x = 51.43

So the required ends per inch are:

51.43

Again, this gives the same answer. So the new sett should be about:

51 to 52 ends per inch

Why the Shortcut Works

The shortcut works because the yarn count was already adjusted using the square of the weight ratio.

In the earlier example:

20s → 14.69s

This count change already follows the relationship needed for the new cloth weight. Therefore, when finding the new sett, the relationship between the old and new yarn diameters corresponds directly with the weight ratio.

That is why:

√20 : √14.69

becomes equivalent to:

7 : 6

So instead of doing a longer square-root calculation, we can directly use:

7 : 6 :: 60 : x

This gives the same answer much faster.

Practical Interpretation

The full process is this:

First, to make the cloth one-sixth heavier, change the yarn count from:

20s → 15s approximately

Second, because the new yarn is thicker, reduce the ends per inch from:

60 → 51.4 approximately

So the new cloth construction becomes approximately:

15s warp with 51 to 52 ends per inch

This should produce a cloth that is heavier, but still of the same general character as the original cloth.

In Simple Terms

When yarn count is changed to alter cloth weight, the sett must also be changed.

If we make the cloth heavier, we use coarser yarn. But because coarser yarn is thicker, we must reduce the number of ends per inch.

In this example:

20s, 60 ends per inch

becomes approximately:

15s, 51.4 ends per inch

This gives a cloth that is one-sixth heavier but still similar in character to the original fabric.

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Yarn Count and Cloth Weight: How to Make the Same Fabric Heavier or Lighter

Changing Yarn Count to Make Cloth Heavier or Lighter

This rule is used when we want to make a new cloth of the same character, but with a different weight, by changing the yarn count.

In simple words, it answers this question:

If I want the same type of fabric, but heavier or lighter, what yarn count should I use?

Here, “same character” means the cloth should remain similar in general construction, appearance, handle, and fabric type. The main change is only in the weight of the cloth.

Meaning of the Rule

The rule says:

The yarn count changes in inverse proportion to the square of the cloth weight.

In the old wording:

As the square of the weight of the required cloth is to the square of the weight of the given cloth, so is the yarn count of the given cloth to the yarn count of the required cloth.

In formula form:

Required yarn count / Given yarn count = (Given cloth weight)² / (Required cloth weight)²

Or:

Required yarn count = Given yarn count × (Given cloth weight)² / (Required cloth weight)²

The important point is this:

If the cloth becomes heavier, the yarn count becomes lower/coarser.

If the cloth becomes lighter, the yarn count becomes higher/finer.

This is because, in cotton count and many indirect count systems, a lower count means a thicker yarn, and a higher count means a finer yarn.

Example Given

A cloth is made with:

20s warp

Now we want to make a cloth of the same character, but:

One-sixth heavier

This means the original cloth had 6 parts of weight. If it becomes one-sixth heavier, its new weight becomes:

6 + 1 = 7 parts

So the weight relationship is:

Given cloth weight : Required cloth weight = 6 : 7

Or in the form used in the rule:

Required weight : Given weight = 7 : 6

Applying the Rule

The rule says:

7² : 6² :: 20 : x

That means:

49 : 36 :: 20 : x

So:

x = (36 × 20) / 49

x = 720 / 49

x = 14.69

So the required yarn count is approximately:

14.7s

In practical terms, this would be taken as nearly:

15s

Therefore, to make the cloth one-sixth heavier, the warp should be changed from 20s to about 15s.

Why Does the Count Become 15s?

At first, it may seem surprising that increasing the cloth weight by only one-sixth changes the yarn count from 20s to about 15s.

But the rule uses the square of the weight ratio, not the simple weight ratio.

The required cloth is heavier in the ratio:

7 : 6

So the yarn count changes in the ratio:

6² : 7²

That is:

36 : 49

Therefore:

20 × 36 / 49 = 14.69

Since the required cloth is heavier, the yarn must be coarser. In cotton count, coarser yarn has a lower count, so 20s becomes approximately 15s.

Understanding “One-Sixth Heavier”

This part is very important.

If a cloth is made one-sixth heavier, it does not mean the ratio is 6:5. It means the original cloth had 6 parts, and one more part is added.

Original weight = 6

Increase = 1

New weight = 7

Therefore, the proportion is:

7 : 6

That is why the calculation uses:

7² : 6²

If the cloth were made one-seventh lighter, then the reverse would apply. The required cloth would be lighter than the original, so the yarn count would need to become finer, meaning a higher count.

Why the Count System Does Not Matter

This means the rule is not limited to cotton count, worsted count, linen count, or any other specific yarn count system. The rule is based on proportion.

So whether the yarn is expressed as 20s cotton, 20s worsted, or any other count system, the proportional calculation remains the same, provided the same count system is used consistently throughout the calculation.

The rule is concerned with the relationship between:

Cloth weight and yarn fineness/coarseness

It is not primarily concerned with the material itself.

Simple Interpretation

If we want to make the same type of cloth heavier, we need a thicker yarn.

If we want to make the same type of cloth lighter, we need a finer yarn.

But the change is not calculated directly by simple proportion. It is calculated using the square of the weight ratio.

Heavier cloth ⇒ lower yarn count

Lighter cloth ⇒ higher yarn count

In Simple Terms

A cloth made with 20s yarn is to be made one-sixth heavier while keeping the same character. Since one-sixth heavier means the weight changes from 6 parts to 7 parts, we use the squared ratio:

7² : 6² :: 20 : x

This gives:

x = 14.69

So, the required yarn count is nearly 15s.

Therefore, to make the fabric one-sixth heavier, the yarn must be changed from 20s to about 15s, because 15s is coarser and will produce a heavier cloth.

Having found the counts required, it will be necessary now to find the ends per inch of that count which will produce a cloth of the same character as the given cloth. Please continue here to read more. 

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What Is Cambric Fabric? Uses, Finish, and Construction

Cambric is a fine, closely woven fabric that originally referred to a high-quality linen cloth made at Cambrai, a town historically associated with fine linen weaving. Over time, the term was also used for a fine cotton fabric, especially a bleached cotton cloth with a smooth, clean appearance.

In its modern cotton form, cambric is usually made from fine cotton yarns and has a neat, compact texture. It is generally lightweight, smooth, and fairly firm. Because it is often given a slightly stiff and bright finish, it looks crisp and fresh. This makes it suitable for summer dresses, where a fabric needs to be light, clean-looking, and somewhat structured.

The stiffness and brightness of cambric are due not only to the weave but also to the finishing process. Finishing can change the handle and appearance of the cloth after weaving. A cambric may be made crisp, stiff, and glossy for dress purposes, or it may be made softer for lining purposes.

A special type called kid-finished cambric is used for dress linings. Here, the fabric is finished soft rather than stiff. The term “kid-finished” suggests a smooth, soft, supple handle, somewhat resembling the feel of fine kid leather. This makes the cloth comfortable when used inside garments.

Cambric is usually made with fine yarns. A common construction may use 60s to 80s cotton yarn in the warp and 80s to 120s cotton yarn in the weft. The warp is the lengthwise yarn in the fabric, while the weft is the crosswise yarn. The fabric may have around 96 ends per inch and about 80 to 144 picks per inch. Ends per inch refers to the number of warp yarns in one inch of fabric, while picks per inch refers to the number of weft yarns in one inch.

This high thread density gives cambric its fine, close, smooth texture. The use of finer weft yarns also helps produce a delicate and even fabric surface.

Embroidery cambrics are another variety. These are made especially for embroidery work, so the fabric needs to be fine, smooth, and regular enough to support stitches neatly. Embroidery cambrics may be made with 56s to 66s cotton warp and 60s to 80s cotton weft, with about 80 to 100 ends per inch and 84 to 140 picks per inch. This construction gives enough closeness and firmness for embroidery, while still keeping the cloth reasonably fine.

Cambric belongs to a family of fine cotton fabrics that includes jaconet, lawn, mull, nainsook, and fine muslin. These fabrics are often very similar in the grey state. The grey state means the fabric as it comes from the loom, before bleaching, dyeing, printing, or special finishing. At this stage, many of these fabrics may look quite alike because they are all made from fine, high-quality cotton yarns.

The main difference between them often comes after finishing. One fabric may be finished stiff and bright, another soft and dull, another very smooth and sheer, and another more open and delicate. Therefore, the same basic grey cloth can sometimes become quite different in final appearance and handle depending on how it is finished.

For example, cambric is often associated with a firm, bright finish. Lawn is usually finer, lighter, and crisper. Nainsook is generally softer and often used for undergarments or babywear. Mull is soft, light, and somewhat sheer. Fine muslin is delicate and loosely associated with very light cotton cloth. But these distinctions can overlap because manufacturers may vary the finish according to market requirements and end use.

A wide range of qualities is made in cambric and related fabrics. Some may be very fine and expensive, made with high-count yarns and close construction. Others may be cheaper, made with comparatively lower counts or less dense construction. Similarly, the finish may be adjusted depending on whether the fabric is meant for dresses, linings, embroidery, handkerchiefs, children’s wear, or decorative purposes.

In simple terms, cambric is a fine, smooth, closely woven cotton or linen fabric, usually bleached and often given a stiff, bright finish. Its identity depends not only on the yarn and weave, but also strongly on the finishing treatment. This is why cambric, lawn, mull, nainsook, jaconet, and fine muslin can be similar in the loom state but become different fabrics after finishing.

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