The basics of low-warp tapestry
Diagrama de temas
-
-
-
There are two constant features : the lame and the portée.
The lame :
The warp is divided into 40 cm portions called lames.
Each lame is autonomous during the movement that alternatively pull down the even and odd threads.
This division allows weavers to weave together. Even if a weaver weaves alone, it would be difficult to work all the threads at the same time given the high tension on the warp threads.
This unit of measurement is used to indicate the weaving width of a tapestry or the width of the low-warp loom.
Example :
- A loom with 3 lames can accommodate a 120 cm warp, i.e. 3 x 40 cm.
- A loom with 5 lames can accommodate a 200 cm warp, i.e. 5 x 40 cm etc…
This measurement is useful :
- For the division, necessary for the preparation of the warp (warping or ourdissage).
- In order to know the width of a heddle bar.
- In order to calculate the number of threads per cm.
The portée :
A portée is always equivalent to a series of 12 warp threads.
The lame (40 cm) is made up of a number of portées (12 threads each) matching the size of the warp used.
- The more portées per lame, the thinner the warp thread and the weft.
- Conversely, the fewer portées there are per lame, the thicker the warp thread and the weft.
Example - a warp :
- in 13 portées will have 13 x 12 threads, i.e. 156 threads per cm by 40 cm.
- in 16 portées will have 16 x 12 threads, i.e. 192 threads per cm by 40 cm.
The number of portées on a lame therefore allows us to determine the number of threads it has, and therefore gives us the density of the warp.
It is a way of establishing the density of the warp specific to the Creuse territory.
With these data, it is now easy to calculate the number of threads per cm that we will have on a lame depending on the size of the warp.
Process :
Example for a warp of :
- 13 portées : 13 x 12 (portées) = 156 (threads): 40 cm = 3,9 threads per cm.
- 16 portées : 16 x 12 (portées) = 192 (threads) : 40 cm = 4,8 threads per cm.
- 18 portées : 18 x 12 (portées)= 216 (threads) : 40 cm = 5,4 threads per cm.
- 10 portées : 10 x 12 (portées)= 120 (threads): 40 cm = 3 threads per cm.
-
-
-
The warp :
In the Creuse region, the tapestry warp is generally made of cotton (unlike the Gobelins factories which use wool).
The most commonly used warp thread is mouliné cotton : it is made up of several slightly twisted strands, and its calibration is expressed by two numbers according to the European Spinners convention.
Example :
13 portées = 10/11
- The first number, 10 in the example, indicates the titration of the thread. Its lengths per kilogram is obtained by multiplying it by 1000.
- The second number, 11 in the example, indicates the amount of strands which forms the warp thread.
This 10/11 cotton therefore consists of 11 strands of an initial thread which measures 10 000 meters per kilogram.
This thread “13 portées” therefore measures :
(10 x 1000) : 11 = 909,09 per kilogram.
Calibration
Number of portées
20/4
30
20/7
22
20/8
20
20/10
18
20/13
16
10/11
13
12/18
.
.
.
.
11
.
.
.
.
The wool :
The titration of wool is the opposite of that of cotton. The wool most commonly used in the Creuse region is a combed wool, thin and very resistant, it is wool 2/20 (two twisted ends of an initial thread which measures 20 000 meters per kilogram). This wool allows subtle assemblies of threads on the shuttle (flûte), called “marled fabric” (chiné) and piqué : chiné is a mix of colour tones of similar values, while piqué is an assembly of colour tones of opposite values that gives a special effect of fabric – for example piqué black and white.
The 2/20 wool allows combinations with other wools or other fabrics.
There is also wool 3/8, 2/8, 3/12, 3/18, 4/7…
Example : 2/20
- The first number, 2 in the example, indicates the number of strands.
- The second number, 20 in the example, indicates its length per kilogram. It is obtained by multiplying it by 1000.
This wool therefore consists of 2 strands of wool.
20 x 1000 = 20 000 : 2 = 10 000 meters/kg.
The same for each calibration.
Warp-to-weft ratio table
Titration of the warp
Number of portées
Number of threads for 10 cm
Number of ends in 2/20
Country wool 3/8
20/7
22
66
2
20/10
18
54
3
20/13
16
48
4
1
10/11
13
39
6
1+2 ends of 2/20
12/18
.
.
.
10
.
.
.
33
.
.
.
8 to 9
.
.
.
2
.
.
.
Exercises
For each row of this table, we can ask to explain how to calculate the number of threads per cm.
Give calibrations :
- Calculate the lengths and sort them in ascending or descending order.
- Calculate the number of threads per cm by calibration.
Then, considering a tapestry measuring 3,20 m by 2 m, how much does it measure in m2 ?
If we weave it in 3,20m, how many lames do we need ?
And knowing that we must add 1.50m of saut (that is, the remaining length of warp between the end of the tapestry and the rear roller of the loom), how much cotton (in kg), will we need to weave this tapestry in 13 portées, i.e. 10/11 ? Etc…
-
-
3. The basics in order to calculate the quantity of weft thread required per square meter for a tapestry
-
Let a woven square of 10 x 10 cm = 100 cm2.
Concerning the weft, a passée uses 40% more thread than the requested warp width.
Calculation : 10 cm + 40% = 14 cm of weft (for a width-a passée).
If the weft is made up of 6 strands of wool, and we need 14 cm of wool (weft) to cover 10 cm of warp : 14 cm x 6 strands = 84 cm.
For the height of our square, the number of duite will vary depending on the size of the warp and the weaver’s way of weaving.
We will therefore take a warp of 13 portées (average size used for the first exercises). We will estimate an average 60 duites (that is, 120 passes - passées) necessary to complete the weaving on a height of 10 cm.
There will need 10 080 cm of wool :
120 (passes) x 84 cm (14 cm x 6 strands) = 10 080 cm (that is, 100,80 m) of wool length per 100 cm2.
How much wool will be needed for 1 m2 of weaving in 13 portées ?
-