Basic information about textile analysis

Magdalena Wo┼║niak
January 4, 2019

What is a textile?

From a technical point of view, a textile is composed of flexible fibres, intercrossing rectilinearly. The longitudinal threads are called the warp, the transversal ones, the weft. (CIETA definition)

This definition applies to a finished product, but the making of a fabric implies minimum preparative steps: you need to get raw fibres (plant or animal), which must be then transformed into yarn (this is called spinning) and only at that stage, when a sufficient amount of yarn is obtained, it can be set on the loom and the intercrossing process (that is weaving) can start.
The whole process is called chaîne opératoire.

However, beyond its material construction, a textile is a multi-layer product, reflecting the interaction between resources, technology, and society. This definition, proposed by Eva Andersson Strand and her colleagues in a now anthological paper
“Old Textiles - New Possibilities” published in the European Journal of Archaeology in 2010, was stressed by the authors in this simple but how speaking figure:

oldtextiles2.jpeg (714 KB)

This scheme resumes the multiplicity of data you can study in a piece of fabric – regarding resources and technology, the information is intrinsically carried by the textile in its structure (fibre, weave). At this level, it reflects also the degree of work organization (agriculture, animal husbandry, trade) and technical skills (fibre transformation, weaving, dyeing, tailoring) available at a certain moment in society. In addition, when replaced in context, a fabric evidences textile consumption in various social practices.

That’s why it is so important to study textiles found in archaeological excavations! Even tiny fragments can inform us about the raw material available to produce fabrics. The numerous tools, especially spindle-whorls, found on almost every settlement site in medieval Nubia, attest to the importance of textile production on the domestic level. For medieval Nubia, where we lack so much written documents, these are precious data for the investigation of the local economy.
 

Textile analysis - Some tips to start with your material

When you find yourself in front of a textile fragment, depending on its state of preservation, you can observe various things: its size (big, small, difficult to estimate when agglomerated with mud and dirt, ...), its condition (usually crumpled, but sometimes it can be flat, ragged, tailored …), and sometimes its colour (usually brownish, especially when stuck in mud and dirt, but in Sudan, the colours are often well preserved so you can also easily see blue, red, or yellow). So how sort these data? Where to begin?

Textile analysis consists in the examination of the structure of a fabric. You need to identify:
The weave - The density of the fabric -  The twisting direction of the yarn -  The fibre.
As you maybe noticed, we start from a finished product, so our analysis proceeds in the inverse order of the chaîne opératoire.

You might need a magnifying glass, a pair of laboratory tongs or tweezers, and some pins. Also, if you are working on material "fresh from the field", you might find it useful to be equipped with a surgical face mask and maybe gloves :)

 
comptefils.jpg (3.45 MB)toolbox.jpg (489 KB)











WEAVE


The process of intercrossing the warp and the weft to make the textile is named weaving. The weaving of a textile requires the use of a loom. (CIETA definition)
There are three main weaves: tabby (also named taffetas, plain or open weave), twill, and satin.

The simplest weave is tabby. The two faces of the fabric are the same.
"Tabby weave is based on a unit of two ends [=warp threads] and two picks [=weft threads], in which each end passes over one and under one pick, the points of the binding being set over one end on successive picks. If, in the weave unit, two or more ends or picks move together as one, the term extended tabby is used." (CIETA Vocabulary of technical terms, 2006, 36).
For example, you can have 2 warps and 1 weft, or 1 warp and 2 wefts, or 2 warps and 2 wefts, but the double yarns always work as a single unit and follow the simple rhythm one over, one under. It is written: extended tabby 2/1, 1/2 or 2/2 (in the notation system, the first number refers always to the warps and the second to the wefts).

SNM18096tabby.jpg (2.39 MB)MAPLP30tabby2.1.jpg (914 KB)MAPLP28linentabby2.2.jpg (881 KB)
                      











                        Tabby                                   Extended tabby 1/2                 Extended tabby 2/2
                   SNM 18096                                MAP 2010:75/14                      MAP 2010:75/15

The tabby weave declines also into two common variants: the warps-faced tabby and the weft-faced tabby. In the warp-faced tabby, the warp threads are more numerous and then more densely packed, so they cover the wefts. Inversely, in a weft-faced tabby, it is the weft threads which are more tightly packed and cover the warp threads.

  WpTROM3526.JPG (2.07 MB)    WfTSNM18121.JPG (7.37 MB)
 











  Warp-faced tabby. ROM 973.243526          Weft-faced tabby. SNM 18121

When you look at a textile fragment, observe its edges: if there is one preserved (a selvedge, a starting border, or even a tiny fringe), it will help you to determine which yarns are the warps and which are the wefts. You will find a complete typology in I. Bergman, Late Nubian Textiles [=SJE vol. 8], Lund, 1975.
Here are pictures of edges preserved in some of the textiles I had the opportunity to examine during the project:

borderROM3417.bmp (3.52 MB)     








                                            
 
Corded edge with looped warps, type A7
(
ROM 973.24.3417)

frangesnoninv.SNM.jpg (947 KB)
Edge with unlooped warps (fringes), type B1
(SNM no inv. num.)

SNM18129reinforcedborder.JPG (7.66 MB)










Reinforced selvedge, type C2
(
SNM 18129)

If you cannot find any trace of a border (which is often the case), you can decide arbitrarily which threads you will consider to be warps and which ones the wefts. Sometimes, close observation of the degree of undulation of the yarns (depending of course of the state of preservation of your fragment) may also help you: the more undulated ones are most probably the warps, the less undulated ones are the weft.


Twill is easy to identify because of the oblique ribs created on the fabric's surface - have a closer look at your blue jeans :)
"Twill weave is based on a unit of three or more ends [=warp threads] and three or more picks [=weft threads], in which each end passes over two or more adjacent picks and under the next one or more, or under two or more adjacent picks and over the next one or more. The points of binding are set over by one end, always in the same direction, on successive picks forming diagonal lines. The repeat of a twill may be expressed as a numerical ration, the first figure indicating the number of picks over which an end passes, and the second the number of picks under which it passes. Thus, 1/3 twill indicates a binding system in which, on the face considered, the ends pass over one pick and under the next three picks."(CIETA Vocabulary of technical terms, 2006, 39).

ROM3552twill1sur2directionZzoom.bmp (3.52 MB)
Twill 1/2: 1 warp passes over 2 wefts and under the next one.
ROM 973.24.3552

Satin weave appears so far only in imported textiles.
"Satin weave is based on a unit of five or more ends [= warp threads], and a number of picks [=weft threads] equal to, or a multiple of, the number of ends. Each end either passes over four or more adjacent picks and under the next one, or passes under four or more adjacent picks and over the next one. The points of binding are set over two or more ends on successive picks.
Satins are called regular or irregular according to the regular or irregular spacing of the points of binding. A regular satin may be defined by the number of ends in the weave unit and by the interruption, e.g. 8-end satin, interruption 2. An irregular satin may be defined by the number of ends in the weave unit and by the interruption but, as the latter is variable, it must be expressed at length, e.g. 6-end satin, interruption 1.2.3.3.2.1." (CIETA Vocabulary of technical terms, 2006, 32).

ROM3480.2satinde5.bmp (3.52 MB)
5-end satin.
ROM 973.24.3480.2


DENSITY

In other words, thread counting. The idea is to estimate the number of warps and wefts in 1 square centimetre. The density is easy to observe by the naked eye (you see if the fabric is loosely woven or rather tightly packed), but counting will give you objective numbers to use for your analysis. A magnifying glass with a scale  1cmx1cm is very useful at this stage.

Dngfield.jpg (1.37 MB) ROM2898.JPG (1.72 MB)
 Woollen tabby 9 wp x 4 wf /cm2 and Linen tabby 24 wp x 20 wf /cm2 (
ROM 973.24.2898)
                                              

If you work with a very fragile material, I recommend the use of an electronic microscope (for example Dinolite) which will allow you to observe your fragment without touching it. You can take pictures directly on your computer and count your threads on the screen, which is much more comfortable for your eyes and your neck :)

Of course, archaeological textiles are often worn, threads are dry and broken. Try to find the best-preserved part, it will give you an idea of the original density. If you check the density in various places of a larger size fabric, you will find some variations: in one place 10 warps, in other 11 or 12. Same for the wefts. In that case, you can choose to report "10-12 warps" or to write an average number, e.g. "11 warps", or to keep the greater number, here "12 warps". The three choices imply various interpretations:
"10-12 warps" means that the warping was rather regular, but probably set with threads of variable thickness so the density can slightly vary depending on the series of warps.
"11 warps" indicates an average density which gives a general idea of a medium-quality cloth. It implies all the warps were similar in thickness.
"12 warps" presumes of the original density of the fabric, which became looser as the fabric was used.
All three options have pros and cons. The important thing is to be systematic - so when you chose an option, keep it throughout your study.

 

TWISTING DIRECTION

Before installing the threads on the loom to weave a fabric, the yarns need to be spun. They are processed from raw fibres. In the Nubian textile production, two types of fibres were used: plant fibres (cotton, linen) and animal fibres (wool from dromedary, sheep and goat).

The process to transform raw fibre into a thread is called spinning. It consists of drawing out and twisting the loose fibres together to form the yarn. The simplest form of spinning is by hand. Other methods include the use of a spindle, which is a wooden stick, on which the thread is wound. The spindle can also be weighted with a whorl -  symmetrical and usually round object - which increases the speed of the work.

TRCspindle2014.0739.JPG (1.39 MB)
Spindle, spindle-whorl and spun cotton thread.
TRC 2014.0739

Depending on the spinner's ability and the destination of the thread, the quality of the spun yarn varies from very fine to coarse. There are two spinning directions: clockwise and counterclockwise. Spinning into a clockwise direction will produce a thread twisted from lower left to upper right - it is also described as Z-twist. Inversely, a yarn spun into a counterclockwise direction will produce a thread in which fibres are twisted from upper left to lower right or S-spun.


YarntwistSLeftZRightwikicommons.jpg (14 KB)
    Spinning directions illustrated (source: Wiki Commons)


SNM18119Sspunwool.bmp (3.52 MB)SNM18135Zspunwool.bmp (3.52 MB)
Two weft-faced woollen tabbies, decorated with blue and red bands.
SNM 18119 with S spun threads (left) and SNM 18135 with Z spun threads (right).
 
The spinning direction in Sudan seems to remain the same from Antiquity to the Middle Ages, which is counterclockwise. It means both spindle and spindle-whorl turn counterclockwise when seen from above. The thread is S-spun.


FIBRE

Fibre identification is not easy when you start. But with some practice, you will be able to distinguish wool, cotton, linen and silk by the naked eye - depending of course of the degree of preservation of your material. For example,
woollen textiles leave many dry fibres on your desk :) under a magnifying glass, you will observe that woollen fibres are long, thick and shiny.  Inversely, cotton has short fibres which ends often "escape" from the thread, creating a kind of "fluffy" texture.

The most secure method to identify a fibre is a microscopic examination.
You can examine a fibre on a longitudinal view or in cross-section, but the mounting process of the cross-section sample requires specific material and some training. The preparation of a sample for a longitudinal view is much simpler and you need only basic equipment: microscope slides, microscope cover glasses, a mounting medium (for temporary slides water works fine), drop pipet, tweezers and small scissors.
You can find a very good description of sampling and mounting process here: https://www.canada.ca/en/conservation-institute/services/conservation-preservation-publications/canadian-conservation-institute-notes/identification-natural-fibres.html

Vegetal fibres are composed of a tube (named lumen) surrounded by fibrils which form primary and secondary walls; animal fibres are composed of a cortex surrounded by a cuticle layer. The observation of the shape and size of these elements leads to the identification of a specific fibre.


Here are some pictures of the main fibres observed at various magnification
.


COTTON: the first two images show its various colour, condition and texture.
Mummycotton5020818.JPG (7.32 MB)Mummycotton5020819.JPG (7.13 MB)
This picture was taken at a magnification x20,
microexampleofcottontabbyfrommummysample6.bmp (3.52 MB)
and this one at magnification x230 (when the fibre dries, the thin walls collapse and create a flat ribbon with numerous twists).
microexampleofcottonfibresfromsample6.bmp (3.52 MB)




LINEN: under low magnification, linen appears as a bundle of fibres,
bastfibersudan2019.jpg (7.50 MB)bastfibresudanmikro171110062.jpg (6.58 MB)  
while under a microscope you can observe nodes, that is transversal lines on the fibre's length.
linenelar1inv.20.08.09.jpg (619 KB)



WOOL:
woolsudanmikro171110055.jpg (7.55 MB)woolsudanmikro171110058.jpg (7.75 MB)
Under high magnification, the most characteristic element is the cuticle, which is covered with scales (visible in the upper right angle). Their size and disposition vary depending on the species. In archaeological fibres, the cuticle is not always well preserved. Another interesting feature to observe is the presence of a central medulla (that is a hollow space in the cortex - visible on the first plan of the picture) which appears in hair: the coarser the hair, the more important the medulla. In the fine wool, the medulla is absent. The absence or the presence of this element is informative about the wool selection process before spinning, such as carding. These features may be more difficult to observe on dyed fibres.
woolSNAP1331190009.jpg (688 KB)



SILK: under magnifying glass the threads appear usually straight and glossy.
SILKROM3420.9A32220171114213004.bmp (3.52 MB)
Under higher magnification (here x230) we can observe a continuous fibre, which looks like a smooth and flat ribbon, with bulges.
SILKROM3420.9A00720200923160132.bmp (3.75 MB)SILKROM3420.9A00420200923160034.bmp (3.75 MB)