1. What is Tartan?
Tartan can initially appear complex in design but is based on a simple concept - a pattern of
stripes which repeats in both a horizontal and verticle direction - in weaving terms the 'warp' and
the 'weft'. A sequence of stripes (the sett) starting at one edge is repeated but in reverse order
round a 'pivot' point. The sett reverses again and repeats round a second pivot point - see diagram
'A'. This process continues for the width of the material in question. The same sett and mirroring
sequence occurs in the weft - diagram 'B' - continuing for the entire length of the material. The
resulting combination of warp and weft is the tartan - diagram 'C'. (Note that the pivots
themselves are not doubled in the mirroring process).
Illustrations by Don Pottinger
{gallery}large_images{/gallery}Click on this image for an enlarged view
Some tartans - known as 'asymetrical' or 'non mirrored' do not reverse the sequence at the pivot
points but simply repeat the sett in the same sequence. A very small number of tartans have
different thread counts for the warp and the weft.
A description of a tartan can be written in a format known as the 'thread count' or the 'sett'. This
identifies the colour and width of the stripes between two pivot points and incorporates the same
information for the pivot points themselves. It takes the form of e.g. B16, LG8, K4, G24, K6 -
reading the sequence from the left. The outside threads (B16 and K6 in the example given) are
the pivot points. The colour is determined by a one to three letter shorthand - 'K' for example is
black, 'B' is blue, 'LG' is light green and so on. The number after the letter is the proportional
measurement - it does not matter what unit of measurement is used as the actual tartan pattern
will remain the same - reflecting the abstract nature of tartan design. Traditionally the number
refers to the number of threads used to set the loom but this can of course vary depending on the
type and weight of thread used - modern tartan fabric can be made from silk, wool, cotton, poly-
viscose, etc. In addition tartan designs are now used extensively on non-woven materials - paper,
plastics, packaging, wall coverings, etc. although some claim that a tartan needs to be woven
before it can be considered a 'true' tartan.

2. UNIT Ⅱ
Compound Structure
Introduction:
Fundamental and combined weaves are considered to be simple, though there is a great variety of
types and constructions. In these weaves, only one system of warp threads is interlaced with one
system of weft threads at right angles. Due to this, the methods of construction of these weaves
and production of fabrics of such weaves at textile mills are rather simple.
Compound weave fabrics are of a specific structure, therefore special methods and
mechanisms should be used in their production.
Chapter Six
Backed weaves
The principle of backing a cloth with a second series of either weft or warp threads is to add
extra weight and warmth without interfering with the smooth surface of the fabric. The end uses
of backed cloths range from apparel to furnishing.
6.1 Backed warp weaves
1. Concept:

3. These are weaves which have two systems of warp and one system of weft. The face weave is
formed by interlacing face warp and weft. The back weave is formed by interlacing back warp
and weft.
2. Construction of warp backed weaves:
(1) Selection of face weave and back weave:
The face weave can be same as the back weave, and can be differ from the back weave, but
the face weave should be warp-faced weave such as 3/1 twill, back weave should be weft-faced
weave such as 1/3 twill.
(2) Selection of the starting point in construction of a back weave:
In order to get a better appearance of the fabric, the backing stitches (back warp floats) should
be hidden between floats on the face. So the warp floats of the back weave should be in the
middle of the adjacent warp floats of the face weave. The setting of the face warp should be
dense enough to prevent the binding marks of the back warp showing through.
(3) Determine the arrangement of the face and back warp:
The threads of the back warp can be arranged either alternately or in the proportion of two
face threads to one back thread, i.e, m:n = 1:1 or m:n = 2:1.
(4) Calculate the “new repeat”
Ro= )
Ry=
Here: LCM—Least common multiple.
Ro—The warp repeat of the backed weave.
Ry—The weft repeat of the backed weave.
Rm—Face weave warp repeat.
Rn—Back weave warp repeat.
m, n—The warp arrangement of face weave and back weave.
(5) transferring the weave:

4. E.g. A backed weave:
Face weave : ↗
Back weave : ↗
Warp ration: 1:1
Ro =
= 4×2 = 8
Ry = = 4
Construction of an backed warp weave diagram.
(1) Select : the face weave 3/1 Z twill,
the back weave 1/3 Z twill. See Fig. 6.1.
(A), (B). Arrangement 1:1.
(2) Determine the starting point which must meet the previous point (2), i.e. stitching float
should be covered by the face warp float. See Fig. 6.1 (C)
The Arabic numbers indicate the face warp ends.
The Roman numbers indicate the back warp ends.
The dots indicate the back warp threads over the weft threads.
(3) Calculate the repeat and outline the repeat.
Here: Ro = 8 Ry = 4. See Fig. 6.1 (D)
(4) Transferring the weaves
See Fig. 6.1 (E).

5. (A) (B) (C) (D)
(E)
(E)
Fig. 6.1 Construction of backed warp weave
6.2 Backed weft weaves
1. Concept:
These are weaves which have two systems of weft and one system of warp. The face weave is
formed by interlacing warp and back weft. The back weave is formed by interlacing warp and
back weft.
2. Construction of backed weft weaves:
The principles of the construction of backed weft weaves are similar to backed warp weaves.
(1) Selection of face weave and back weave

6. The face weave can be same as back weave, and can differ from the back weave, but the face
weave should be weft-faced weave such as 1/3 twill, back weave should be warp-faced weave
such as 3/1 twill.
(2) Determine the stitching distribution
The correct stitching plays a very important part in the construction. On no account must it be
visible on the face of the fabric.
The density of the fabric also plays an important part in achieving perfect stitching.
(3) Determine the arrangement of the face and back weft. The threads of the back weft can be
arranged either alternately or in the proportion of two face threads to one back thread, i.e., m:n
=1:1 or m:n = 2:1.
(4) Calculate the new repeat
The calculation of the new repeat is similar to backed warp weaves. The difference is
replacing the warp by weft.
Construction of an backed weft weave diagram is similar to backed warp weaves. We learnt
previously. Same example are shown bellow:

7. Example 1: See Fig. 6.2.
Cross-section:
Face weave = pick 1
Back weave = pick 2
Arrows = stitches.
Development of structure.
Face weave: 1/3 Z twill
Back weave: 3/1 Z twill
Stitching is marked with circles (lowering of ends).
Horizontal lines between face picks represent back picks 2,
4, 6, 8. The back picks are stitched between weft floats of
the face picks.
The stitching should be distributed in rotation over every
end to avoid different tension on individual ends.
The correct stitching plays a very important part in the
construction. On no account must it be visible on the face of
the fabric.
Transferring the weaves.
Warp: solid Weft: 1 face-1 back.
Repeat: 4 ends/8 picks.
Face weave on odd picks,
Back weave with stitching on even picks.
Lifters/: ends over back picks,
Circles are cancelled lifters (lowering of ends).

8. Reversible weave: identical interlacing on both sides of the fabric.
Completed structure with draft and lifting plan.
These symbols represent warp up.
Fig. 6.2
Construction of weft backed weave.

10. Example 2:
Weft Backed
In very dense warp setts the stitching points of the backing weft may be extended over two or more repeats of
the face weave.
Cross-section:
Face weave = pick 1
Back weave = pick 2
Arrows = stitches
Face weave: 2/2 Z twill, repeated twice
Back weave: 7/1 satin
Repeat: 8 ends/16 picks
Warp: solid
Weft: 1 face-1 back pick

11. Cross-section:
Face weave = Pick 1
Back weave = pick 2
Arrows = stitches
Face weave: 2/2/1/3 Z twill
Back weave: 7/1 Z twill
Repeat: 8 ends/16 picks
warp: solid
Weft: 1 face-1 back pick

12. Fig. 6.3 Construction of weft backed weave
Example 3: see Fig. 6.4
Weft Backed
Examples of reversible weaves. The heavier yarn count in weft covers the finer warp on both sides of the
fabric entirely. These fabrics generally receive a milling and raising finish.
Cross-section:
Face weave = pick 1
Back weave = pick 2
Arrows =stitches.
Face weave: 1/4 sateen
Back weave: 4/1 satin
Repeat: 5 ends/10 picks
Warp: solid
Weft: 1 face-1 back pick

13. Cross-section:
Face weave = pick 1
Back weave = pick 2
Arrows = stitches
Face weave: 1/7 sateen
Back weave: 7/1 satin
Repeat: 8 ends/16 picks
Warp: solid
Weft: 1 face-1 back pick
Identical interlacing on both sides of the fabrics.
Fig. 6.4
Construction of backed weft weaves

14. Example 4: see Fig. 6.5
Weft Backed
Development of patterns with two effects. The cross-section shows the
interchanging of face and back picks.
Effect I
Face weave: 1/3 broken twill (pick 1,3, 5, 7)
Back weave: 3/1 broken twill (pick 2, 4, 6, 8)
Effect II
Face weave: 1/3 broken twill (pick 2, 4, 6, 8)
Back weave: 3/1 broken twill (pick 1,3, 5, 7)
Check-pattern.
Motif
To enlarge the design each section of the structure can be repeated to
achieve the required size.
Repeat of one section: 4 ends/8 picks
Warp: solid
Weft: 1 face-1 back pick
This example can be woven with 8 shafts.

15. When developing patterns, it is important to plan the weaves to cut with each other at the point of interchange
between face and back. This assures clarity of design.
Motifs.
Each square represents 4 ends/8 picks.
Each symbol of the condensed draft above the motif represents one group of four shafts.
These examples can be woven with 16 shafts.
These motifs can be developed with the same weaves as above.
Fig. 6.5
Construction of patterns of backed weaves

16. 3. Fabrics setting:
The proper set and yarn linear density are also important in achieving perfect appearance.
The warp density should be considerable lower, and the weft density should be higher due to
the fabric effect depending the weft.
The count for the backing pick can be softer in twist, but should not be heavier than the face
yarn, especially on a 1 face-1 back ratio.
The warp yarn should be stronger considerably due to its bearing the beating force during
weaving process.
Homework:
1. Construct backed warp weaves:
(1) Face weave 3/1↗, back weave 1/3↗, arrangement of face warp and back warp m:n=1:1
(2) face weave 8/5 satin, back weave 1/3↗, m:n=1:1.
2. Construct backed weft weaves and their cross-section diagram.
(1) face weave 1/3 broken twill, back weave 3/1 broken twill, m:n=1:1.
(2) face weave 2/2↗, back weave 3/1↗, m:n=1:1.