My name is Jennifer Weardon and I'm a textile curator in the Department of Furniture, Textiles and Fashion in the Victoria & Albert Museum. For the last twenty years I've been responsible for the Museum's collection of oriental carpets.

I'll be using fragments from the Museum's collection to show you how to examine the structure of a hand-knotted carpet.

When you're looking at a hand knotted carpet, there are three things to look at regarding structure: the warp, the weft and the knotted pile.

If you have an understanding of how a carpet is woven and you can look at the structure and you can identify the different elements, it will help you to understand the circumstances under which your carpet was woven, whether it was from a commercial workshop or possibly from the loom of a nomadic tribe. It may help you to date the carpet. It would certainly increase your appreciation of what it is you have.

The first element to look at is the warp. These are the long threads of a carpet which run the length of the carpet. If your carpet is complete, they'll probably form a fringe at the top and at the bottom.

I'm showing you a fragment of a carpet because it's the easiest way to see the structure, especially if, like this one, it is worn in places. So here the pile has actually worn away completely. And it enables us to see the pale coloured warp threads and the dark brown weft threads which form the structure of the carpet.

Some people, when they look at a carpet like this, think that the knots have been added once the warp and the weft have been woven. But it isn't true. The knots are actually tied as the carpet is being woven.

The weft in this carpet is dark brown wool, which you can see here. It isn't as tightly spun as the warp threads because it doesn't have to bear as much of the weight of the carpet. After every row of knots - and here is a row of red knots - several threads of dark brown wool have been inserted. They've been interlaced with the warp threads - going over one warp thread and then under the subsequent one. They form a plain weave structure which is what's holding the carpet together. If you actually pulled out every single knot in a carpet, you would end up with a piece of plain woven fabric that is still stable, still very secure. All the pile does is add colour and pattern and a certain degree of thickness so the fabric becomes more durable because if you are puting it on the floor, it has to be hard wearing.

The first thing to look at is the warp.  These are the threads which run the length of a carpet from the top to the bottom and if you have a complete carpet they probably form the fringe at the top and at the bottom. The warp threads have to be very strong because they take the weight of the carpet when it is on the loom. So they are tightly spun. They are usually not dyed because they are completely concealed by the knotted pile so they are usually undyed cotton which would be white colour or undyed wool which is usually a dark brown. The second thing to look at are the knots,and the knots are tied around the warp threads. Each individual knot is tied around two warp treads,and the weaver will complete one whole row of knots and then insert the third  element of the the structure, which are the weft threads, and the weft threads go from side to side across your carpet.  In this one it is brown wool and you can see because this is a fragment how its unravelling  so here you have the warp threads, the knots and then after every row of knots some shoots of weft are taken across.

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Most oriental carpets were woven on a vertical loom so there is a top and a bottom to the carpet. The bottom of the carpet is the end at which weaving began. It's very easy for you to find out which is the top and which is the bottom by simply stroking your hand over the pile of the carpet. The pile of a carpet is like the fur on the back of a cat. If you go from the head to the tail it's very smooth, you're stroking your hand with the fur. If you go in the other direction from the tail to the head, it's difficult because you're going against the fur. It's the same with a carpet. With this carpet, as I move my hand in this direction it's very smooth, I'm going with the pile and my finger is moving towards the bottom of the carpet where the weaving started. If I move in the other direction, I'm meeting resistance, I'm going against the pile and my finger is moving towards the top of the carpet which is where the weavers finished.

If the knots were taken to the very edge of the carpet the sides would curl under and it wouldn't lie flat. To prevent that from happening, the end warp threads have no knots on them.

When this carpet was taken from the loom a needle and thread were used to oversew the sides to create a flat and very firm edge.  A different method was used to secure the edge of this carpet. Instead of it being oversewn once it had been cut from the loom a red woollen thread has been looped around the unknotted warp threads along the side during the weaving process.

If we turn the carpet over we can see that the red wool which loops around the unknotted warp threads along the side is actually woven into the body of the carpet and this makes an incredibly strong edge.

Most oriental carpets have a band of plain weaving at the top and the bottom. In this carpet it’s quite a broad band and several colours have been used to create a pattern.

These bands of plain weaving create a very firm and very stable edge to the carpet. When this carpet was cut from the loom, lengths of warp thread remained. These have been grouped together and knotted to form a fringe.  It creates both a decorative effect and it also stops the weaving from unravelling.

Patterns knotted with a symmetrical knot tend to be geometric and bold and powerful because of the bulky nature of the knot. If you look at carpet books published about twenty years ago you may find that the symmetrical knot was called a turkish knot. The problem with that name is that it implies that Turkish knots were only used in Turkish carpets and that's not true. Turkish knots like these were used in European carpets, Turkish carpets of course, some Central Asian carpets, some Persian carpets and some Chinese carpets. So the name symmetrical is better and it is called symmetrical because those threads used to tie the knot go in front of two warp threads, round the back of them and then the ends of the knot come out between the two warp threads and it is symmetrical when you look at it.

In order to count the number of knots, I'm going to turn the carpet over and work from the back. In order to assess the fineness of a carpet, we need to find out how many knots there are in a square inch. So I'm working from the back - this is the back of the carpet. It's much easier to see the individual knots because there is no pile in the way. So I'm going to work in this area here. What I'm going to do first is count the number of knots that are horizontal ... so across the carpet. Each knot is tied around two warp threads so it forms two little bumps on the back of a carpet. So I'm going to count how many bumps there are ... one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve - so there are twelve bumps in that one inch. If each knot forms two bumps, I simply divide twelve by two and I can say there are six knots in an inch across the carpet. I then do the same, finding out how many knots there are vertically. There's one, two, three, four, five, six - So there are six knots horizontally, six knots, vertically, multiply the two of them together - 36 knots per square inch in this carpet, which is a fairly coarse carpet.

This is an example of a carpet from the Museum's collection. It dates to the second half of the 16th century.

Simply looking at the design enables me to identify the type of knot used in it with a fair degree of confidence.

Look at these birds, here. Look how beautifully the head curves and the back. And then look at the leg, the separate toes - very natural looking design. This enables me to say with confidence that the knot used in this carpet is probably an asymmetrical knot.

If you look at books on carpets published about twenty years ago, you may find the asymmetrical knot called a Persian knot. The problem with calling it that is the implication that Persian knots are only used in Persian carpets and that isn't true. A Persian knot like this can be found in some Turkish carpets. Some carpets from Central Asia, Persian carpets of course and carpets from India. Asymmetrical is a much better term for it.

It's called asymmetrical because the thread used in the knot completely encircles one warp thread but only goes behind the second one. It's a very fine knot because of this. Because it only encircles one warp thread and it's possible to fit many of them into a given area. As a consequence, designs knotted with a Persian asymmetrical knot are very fine. You can get fine lines like the black outline here, beautiful curving lines and detail as well - the speckling on the bird's breast. So when you see a natural looking design of flowers, birds or even human beings, knotted in pile on a carpet the chances are it was knotted with an asymmetrical knot.

This is the back of the carpet and in order to calculate the knot density, I need to count how many knots there are in an inch in this direction and then in an inch in this direction. Because this carpet is very fine, I can only see one bump at the back per knot So I'm going to count them ... one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen. So there are 16 knots in one inch in that direction. And in this direction there are one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen. Fourteen multiplied by sixteen is 224. So there are 224 knots in a square inch in this carpet. This is quite a fine carpet, but for a really, really fine carpet
you may get more than one thousand knots per square inch.

This mottled effect in this carpet where two shades of pink have been used - a light pink and a dark pink - is often called 'abrash' which means cloudy. It happens when the weaver has used wool from two different dye batches. It's usually done accidently, but occasionally it can be done on purpose, just to create interest.