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Grammar of textile design (Volume c.2) online

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Fig. 399.— (B) Showing the manner in which Warp and Weft would inter-
weave in a 5-Pick Figured Terry Fabric, to develop the Pattern
indicated en bloc at A.



little, if any, appreciable difference between the two arrange-
ments. In practice, however, an advantage is afforded by the



TEREY PILE FABRICS.



175




176 GRAMMAE OF TEXTILE DESIGN.

two-and-two over the alternate disposition of warp ends. This
arises from the fact that, with such a disposition of the two series
of threads, either consecutive pile warp ends or consecutive
ground warp ends always interweave in an opposite manner to
each other (excepting in the example of five-pick terry fabric just
described). Therefore, by placing two threads of the same series
in the same dent of the reed, they are never either up or down
together for the same picks of weft, but always occupy opposite
positions ; whilst a reed wire separates a pile and ground warp
end that are contiguous, and that are sometimes up or down
together at the same time. Hence, these two circumstances
conduce to the formation of a clearer warp shed for the passage
of a shuttle during weaving.

In the production of terry pile fabrics of strong and heavy
textures, such as linen Turkish towels, it is a common practice to
employ what is termed a double reed. Such a reed virtually
consists of two reeds placed one behind the other, with a space
of about i in. between them, and constructed in such manner that
the wires of one reed are placed exactly midway between those
of the other, thereby constituting a compound reed whose prac-
tical counts or sett equals twice that of the single reeds. The
objects of such a reed are to obtain greater resistance when beat-
ing up weft, and also to gain a little more space for yarn and
thereby diminish the abrasive frictional action of the reed upon
the warp ends.

Another practical point in terry weaving has reference to the
manufacture of those fabrics in which coloured threads are em-
ployed for the production of striped counterchange effects, as
seen in roller towelling and bordered towels. It is well known
to all practical men that however near to the reed the temples
are placed, there is a greater or lesser degree of contraction in
width at the fell of cloth. It follows, therefore, that the inward
pull of cloth will cause warp ends to bear on the outer sides of
reed wires around which they bend. For this reason it is
found advantageous (when pile and ground warp ends are
alternated with each other) to place pile warp ends on the left,
and ground warp ends on the right, through each dent towards
the left-hand selvedge, and in the reverse order through the dents



TEEEY PILE FABEICS. 177

towards the right-hand selvedge. The object of this arrange-
ment (which is particularly desirable where figured counter-
change stripes occur) is to cause ground warp ends, which are
taut, to bear against the reed wires, and to allow pile warp ends,
which are slack, to lie on that side of ground warp ends nearest
the selvedges, and so avoid the risk of pile warp ends being
impeded in their passage between reed wires and ground warp
ends ; an evil which is liable to occur if that course is not
adopted.



12



CHAPTER IX.
GAUZE AND LENO FABRICS.

§89. *' Gauze" and " leno " are terms which designate
different varieties of one of the most interesting types of woven
fabrics comprised under the generic term of *' cross-weaving ".
The distinctive characteristic feature of this type of fabrics is
the pecuHar crossing of warp ends ivith each other, caused by
puUing them out of their normal straight and parallel course,
first to one side and then to the other side, of other warp ends,
which cross and recross in some definite order.

Cross-weaving is a useful principle extensively adopted in the
production of silk, cotton, worsted and linen textures, for
almost every variety of purpose — as ladies' and children's wear-
ing apparel, cm'tains, antimacassars, and many others. It is
also frequently applied in combination with tissue, lappet and
swivel figuring (described in Chapter X.) piques, and many
other types of fabrics. When it is applied to fabrics of an ex-
tremely light, open and flimsy texture, and especially if pro-
duced from silk, they are usually described as " gauze " fabrics ;
but if applied decoratively to heavier textures of cotton and
linen, they are usually termed **leno" fabrics, of which there
are two distinct classes, namely, (1) '* net leno," and (2) " leno
brocade " fabrics, each comprising several varieties.

"Net lenos" are chiefly produced by means of healds, and
are usually characterised by a decidedly striped formation
developed by the introduction of comparatively coarse threads,
termed " net" warp ends, which usually assume a more or less
zigzag course, and produce a series of ''net" leno stripes.
Sometimes the vertical stripes are crossed by a series of hori-
zontal ones to produce a "check" pattern. Net leno fabrics

(178)



GAUZE AND LENO FABRICS. 179

offer unlimited scope to a capable designer in the production of
decorative leno effects, which are frequently of a most interest-
ing and sometimes of a very beautiful and attractive character.
And it is, perhaps, not too much to say that no other principle
of weaving is capable of yielding such variety of exquisite de-
•corative effects for so small an expenditure of artistic or technical
effort.

** Leno " brocades are ordinary brocade fabrics in which the
gauze principle of weaving is introduced as an additional means
of embellishment. They are produced by means of a Jacquard
machine, and usually consist of a gauze or leno figure sur-
rounded by a ground of the plain or calico weave, or vice versa ;
and sometimes either warp, weft, or both are allowed to float
where required for the purpose of developing ordinary brocade
flguring. An interesting variety of leno brocade fabrics are
those in which both leno brocade and also net leno figuring
are employed for the development of stripes of each kind
arranged either alternately or otherwise. In the production of
this variety of fabrics it is usual to employ a compound harness
consisting of a Jacquard mounting for the leno brocade stripes,
and a heald harness for the net leno stripes.

Plain Gauze.

§ 90. The simplest example of gauze or cross- weaving is that
in which one or two warp ends in regular succession cross each
other on successive picks, or pairs of picks, so as to produce an
open net-like structure of uniform texture, as represented at C,
Fig. 401. This diagram indicates the method of drafting warp
ends through the healds and reed at A, and the order of
shedding at B, to produce the gauze structure represented at C.
By studying that diagram in conjunction with those given in
Figs. 402, 403 and 404, the principles of cross-weaving, which
are generally so puzzling to students, will be easily understood.

Shedding harnesses for cross-weaving, whether they consist of
healds or Jacquard mountings, may be constructed on either of
two systems known as a " bottom-doup " or a " top-doup "
arrangement, according to whether the " doups " are situated



180



GEAMMAE OF TEXTILE DESIGN.



beloiv or above warp ends respectively, as will be presently ex-
plained. A heald harness with a " bottom-doup " arrangement,



Draft
SDSDSDSD



Sheddin^i Plan



Slackener q
Back Rest C



liick Standard E
Regular HeaJd F

Front Standard G
Doup Heald H



Reed I

Cross Shed
Open Shed
Cross Siied
Open Shed
Cross Shed
Open Shed



4



4



i ^c



B



1 2
Picks






SDSDSDSD



Fig. 401.— Graphic Diagram representing a Plan of Simple Gauze Cloth, at C;
also the method of drawing-in Warp Ends through the Healds and Reed, at
A ; and the Shedding Plan, at B.

and also the formation of the sheds for the production of plain
gauze, are graphically represented by diagrams Figs. 402, 403



GAUZE AND LENO FABRICS.



181



Easer or Slackener



Back Rest




Back Standard Heald



Regular Heald



Front Standard Heald
Doup Heald



Standard or Regular Warp End
Doup Warp End



EIG 402 -Graphic illustration of a Bottom-doup Heald Harness, with all Healds
down, and the Warp Shed closed.



182 GEAMMAE OF TEXTILE DESIGN.

and 404. In those diagrams, the healds are shown perspec-
tively, and with the object of making their functions clear and
distinct only one heald eye is shown on each heald. Fig. 402
shows all parts in their normal or inoperative position. Warp
ends, all of which come from the same warp beam, are separated
into two divisions of alternate threads respectively termed
" standard " or " regular" warp ends S, and doup warp ends D.

The essential features of this harness are — a heald (G),
termed the "front standard," situated immediately in front of
all other healds, and a half -heald termed the "doup heald"
(H) placed in front of the front standard, and consisting of a
number of loops or slips (J), termed " doups," whose upper
parts pass over the eyes of the "front standard," and return
through them, to prevent their withdrawal. The doups are
attached to a single heald-stave (H), situated beloio w^arp ends ;
hence the term " bottom-doup" as distinguished from a " top-
doup " harness, in which the doups are attached to a stave
situated above warp ends.

Standard warp ends pass from the warp beam to cloth in a
perfectly straight course, first over the back rest (C), thence
through the respective eyes of a regular heald (F), and through a
dent of the reed (I). Doup warp ends pass over a bar variously
termed the "easer," "vibrator" or "slackener " (B), situated a
little to the rear of, and in a little higher plane than, the back
rest (C) ; thence through eyes of a heald (E) termed the " back
standard ". From here they pass in front of heald eyes govern-
ing standard warp ends, and then cross underneath the latter
from right to left, after which they pass through a loop (J)
attached to a single heald-stave (H) (situated below warp ends),
and finally they pass through the same dents of the reed (I) as
their fellowjstandard warp ends.

(In order to prevent confusion of terms, the attention of
students is specially directed to the apparent inconsistency in the
use o£ the^term "back standard" to describe those healds (E)
which govern doup warp ends when the latter are raised on the
normal side of their respective standard warp ends (to form
" open " sheds), instead of that term being used to describe the
regular healds (F) which govern standard or regular warp ends.



GAUZE AND LENO FABEICS.



183



Easer or Slackener




Back Standard Heald



— Regular Heald

Doup Heald
Front Standard Heald



Standard or Regular Warp End
Doup Warp End
^^ — Open Shed
— Cross Shed

Open Shed
Cross Shed

Fig. 403.— Graphic Diagram of a Bottom-doup Heald Harness, showing the
Formation of an Open Shed.



184 GRAMMAR OF TEXTILE DESIGN.

The term ''hack standard," however, is that established by
custom to distinguish the healds that are complementary to,
and which govern doup threads in conjunction with, ''front
standard " healds).

§ 91. In the production of a simple gauze texture entirely de-
void of figuring, two distinct forms of shedding are required,
namely, a straight or "open " shed, and a "cross " shed. A
straight or open shed is one in which warp ends are separated
without being deviated from their normal parallel course. Its
formation with a bottom-doup harness (as illustrated in Fig.
403 and indicated in the shedding plan of Fig. 401) is effected by
raising both the back standard healdE (which controls "doup "
warp ends) and the "doup " heald stave, H. By raising the
half-heald stave, " doups " J become slackened, and thereby re-
lease their control of " doup " warp ends, which are quite free
to return from their crossed position on the left, to their open
or parallel position on the right of standard warp ends. Thus by
raising the "back standard" E, "doup" warp ends are raised
on that side of " standard " warp ends which they occupy before
being crossed underneath those threads, without being impeded
by the " doup " slips, which, being slack, are taken up by their
respective " doup " warp ends.

A " cross " shed is one in which " doup " warp ends are raised
on the opposite side of "standard" warp ends to that which
they occupy in the healds before being crossed — that is, on their
crossed side. Its formation, as illustrated in Fig. 404, is accom-
plished by raising both the " front standard " heald G and the
" doup " heald H together. Unless means were adopted for its
prevention, the formation of a " cross " shed would impart ab-
normal tension to "doup" warp ends, in consequence of the
short interval or " stretch " of warp between the " fell " of cloth
and the eyes of heald F, around which " doup " warp ends bend
on being raised. Such undue strain is prevented by passing
"doup" warp ends over an easing bar or "slackener" B,
situated in the rear of the back rest C. By that means " doup "
warp ends are allowed a little longer course or "stretch" be-
tween the warp beam and " fell " of cloth. Thus, when a
" cross " shed is formed the " easer " or " slackener " is brought



GAUZE AND LENO FABKICS.



185



Baser or Slackeuer - — ./
Back Rest -




Back Standard Heald



Regular Heald
Front Standard Heald
Doup Heald



Standard or Regular Warp End
Doup Warp End
Cross Shed

/- Open Shed

Cross Shed
Open Shed

Fig 404 -Graphic Diagram of a Bottoni-doup Heald Harness, showing the
Formation of a Cross Shed.



186 GRAMMAR OF TEXTILE DESIGN.

forward from its normal position (indicated by dotted lines) to
slacken the "doup" warp ends, and thereby prevent undue
tension being imparted to those threads. This function is
variously described as "easing," "slackening" and "vibrating".
An examination of the gauze structure represented in Fig. 401,
and also of Figs. 403 and 404 will show that "standard" warp
ends are never raised, and that "doup " warp ends are raised for
every pick of weft inserted — first on the right and then on the
left of "standard" warp ends alternately. That peculiarity,
however, is characteristic of plain gauze weaving only, and not
of cross weaving generally ; otherwise the development of figur-
ing (as exemplified in "net leno " and "leno brocade" fabrics)
could not be accomplished. In those fabrics all warp ends,
whether "standard" or "doup" threads, may be raised as
desired to produce any ordinary woven effect in combination
with cross weaving, and their construction is governed by the
same general principles as those underlying the construction of
simple gauze.

Net Leno Fabrics.

§ 92. In the production of typical net leno fabrics (as exem-
plified in the accompanying photographic reproductions), the
number of doup healds, front standard healds, back standard
healds, easers or slackeners, and extra warp beams containing
the net doup threads, must severally correspond with the number
of different schemes of douping in a single fabric. Thus, if all
doup warp ends in a piece of cloth cross their standard threads
either in the same direction or in opposite directions simul-
taneously, only one doup heald and one each of the other several
parts just enumerated would be required for its production.
The direction in which doup threads cross is quite arbitrary.
They may cross uniformly either in the same direction, or in
reverse directions (at the same time) as predetermined by the
manner in which they are crossed in the shedding harness before
being passed through their respective doups. If they are crossed
over (in the harness) in the same direction uniformly, they will
all cross in the same direction and at the same time in cloth, as



GAUZE AND LENO FABEICS. 187

exemplified in the second net leno stripe B, Fig. 409 ; but if some
doup threads are crossed over to the right, and others to the left,
of their respective standard warp ends, they will always cross in
opposite directions in cloth. Thus, by drafting alternate doup
threads in one direction, and intermediate threads in the oppo-
site direction, a neat diamond formation may be produced, as
exemplified in the net leno stripe A, Fig. 405, which illustrates
an example of net leno weaving produced by means of only one






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Fig. 405. — One-doup Net Leno Fabric, for which the Design, Draft and Shedding-
Plan are given in Fig. 406.

set of doups operating in conjunction with one back standard
heald.

For reasons subsequently stated in § 107 (in which the relative
merits of a tojj and a botto7n-d.ou^ harness are compared), it is
usual to weave net leno fabrics with a ^oj!?-doup harness. For this
reason, the "drafts " and shedding plans, for the samples of leno
fabrics represented in the accompanying illustrations, are adapted
for top-doup harnesses. With such a harness, the conditions of
shedding which obtain in respect of a bottom doup harness, as



188



GRAMMAR OF TEXTILE DESIGN.



explained in ^ 91, are simply reversed, just as if a bottom-doup
harness were inverted. By inverting the diagrams representing
a bottom-doup harness, given in Figs. 402, 403 and 404, and also
by reversing the shedding plan given in Fig. 401 (except that for
the easer), the conditions of a top-doup harness will be faithfully
represented (excepting that, being ink lines drawn on paper, and
not material threads, the relative positions of standard and doup
warp ends remain the same, whereas doup warp ends should
cross over the top of standard warp ends). Thus, an open shed

Design (A^



Picks



Easer

l^egular Healds
Back Standard

Plain Healds

Front Standard
Doup

Reed







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Fig. 406. — Design, Draft and Shedding Plan for Net Leno Fabric represented

by Fig. 405.



is formed with a top-doup harness by raising the heald govern-
ing standard warp ends, and also the front standard ; and a
cross shed is formed by raising the back standard controlling
doup warp ends, and also the heald governing standard warp
ends, and, at the same time, slackening doup warp ends to pre-
vent excessive strain upon them.

§ 93. Fig. 405 represents an example of net leno weaving
by means of only one set of doups. In that example, a net leno
stripe is developed at regular intervals, from four pairs of white
doup warp ends drafted alternately to the right and left of their



GAUZE AND LENO FABRICS.



189



respective standard warp ends, which latter consist of fine
threads taped in pairs. The intervening stripes consist of the
plain or calico weave, on which a spotted effect is developed by
means of extra picks of coarse white weft. These float loosely
underneath the leno stripes, whence they are subsequently cut
away, as seen in the corner turned down. The design, with the
draft and shedding plan for that cloth, are respectively indicated
at A, B and C, in Fig. 406. (Horizontal lines in the drafts and












Fig. 407. — Two-doup Net Leno Fabric, for which the Design, Draft and Shedding
Plan are given in Fig. 408.

shedding plans represent healds ; vertical lines in the drafts
represent warp ends ; and a circle placed on an intersection of
a warp end and heald indicates that such warp end is drawn
through such heald. Vertical lines in the shedding plan represent
picks of weft ; and a black spot placed on an intersection of a
heald and pick signifies that such heald is raised for such pick.)
For simplification of the shedding plan, the spotting with extra
weft, in the present example, is left out of consideration. By
carefully studying the design, draft and shedding plan of each of



190



GRAMMAE OF TEXTILE DESIGN.



the accompanying examples of leno fabrics their construction
will not be very difficult to understand. The action of the













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dividually from the design to the shedding plan.



GAUZE AND LENO FABRICS. 191

For the general guidance of students it may be stated that
with a top-doup heald harness, a cross shed is formed (in respect
of any one series of doup threads) by raising standard and doup
warp ends together, by means of their respective regular
healds and back standards, whilst the same doup threads are
held down in front by means of their front standard and doup
healds ; at the same time, doup warp ends are slackened by

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Online LibraryHarry NisbetGrammar of textile design (Volume c.2) → online text (page 11 of 19)