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Often, hand spun wool results in slight pile color variances. You may also observe abrash or inconsistencies of wool gauge with hand spun wool. Hand spun wool is created by throwing the yarn resulting in a twist which varies in thickness creating different knot diameters. This is different from mill spun wool which results in much less variation in thickness but may strip the wool of its natural, stain resistant properties (lanolin.)
Both hand spun and twisted wool create a depth in a rug. Mill spun has more consistency in coloration but tends to give a rug a flat appearance. New rugs are mostly mill spun. None of these techniques necessarily add or subtract value from your carpet.
Hand Spun Wool
The best way to determine if your rug has hand spun wool is by looking at the knot thickness on the reverse side of the rug. Carefully see if the knots are uneven in height on the face of the rug. This is a fairly good indication that hand spun wool was used. Hand spun wool is often single ply.
The photograph below shows a nest of very high quality hand spun wool. Note how the wool twists up upon itself in certain areas. The yarn gauge varies significantly between strands in sections pointed out by the green arrows.
To see how this translates into a woven piece, take a look at the reverse side of your rug (as pictured below). Notice how the thickness of each knot varies significantly across the line as demonstrated by the green arrows. This carpet has both single ply, and varying thickness of yarn; a good indication that the wool is hand spun.
hard twisted Wool
To create a lustrous effect, and to add a greater dimension to the pile of a rug, weavers (primarily in India) have produced a technique of a "hard twist." The wool fiber is spun vigorously during milling to produce a tightly curling yarn. This yarn is usually a single ply. Another characteristic of this curly yarn is a speckled effect. This is created by two factors which can be used to assess if your rug has a hard twist. First, the yarn is spun so hard, it sometimes curls back into the face of the pile and avoids clipping. It is not unusual after a period of use for these fibers to straighten, creating what appears to be a "pull." (Click here to see how to treat this.) On the face of the pile a hard twist yarn can curl back into the pile exposing the side of the strand which reflects light more, and in turn, creates a speckled appearance in the pile. Secondly, due to the nature of hard twisting, dyes are often unable to penetrate the center of the yarn which also creates inconsistencies which also contribute to this speckled appearance.
The amount of dye which the yarn absorbs in any given place depends upon how hard the yarn as been thrown. If the yarn has an exceptionally hard twist in one area, it is less likely to absorb the dyes as thoroughly as in an area which has loosely thrown twist. Shearing of the pile will show that the tips of the wool have a denser color on the outside which slowly lightens going inward. These two factors yield a "speckled
" appearance to the face of the rug. Other notable characteristics of a hard twisted wool: knot thickness varies on the reverse side of the rug, twisted wool is usually single ply, and knots appear diagonal (not perfectly parallel or perpendicular to warp or weft) on the reverse side.
As you can see by the image below, this rug has a hard twisted wool.
Upon closer inspection, you can see the green arrows pointing to the circular shape of the fibers which also reflect more light. The blue arrows identify single strands of yarn where the dyes have not fully saturated (deep reds on the outside and whiter in the center.)
The image below is the same rug in a different section. Again, the green arrows point to the circular curls. The curls show higher luster, and often turn back into the face of the rug. Note the blue arrow, showing how the dyes have not fully penetrated the yarn. For purposes of the rug estimator Tool, select "Yes" to "Hand spun / Hard Twist."
Below is the reverse side of the same rug. Notice how the knots on the back are also twisted, and sit at varying angles. They are not all parallel or perpendicular. You can also identify a rug made with hard twist by feeling the reverse side of the rug. Hard twisted wool is somewhat slippery. When an individual knot is pulled through the face of the rug, some twists do not entirely pass the warp. This sometimes leaves a "nubby" feel to the hand. Also note how the height of each knot varies significantly.
For additional information or one on one assistance please refer to our Rug Forum.