I love it when people post really good quality images as you have done. It makes things a whole lot easier!
While I'm still suspect of the fiber used, it doesn't change the other facts about this rug. This is a hand knotted carpet. The rug appears to be a Pakistani weaving, probably something like 20 years old or so. What you mentioned as a cotton backing is actually what is best described as a cotton "warp". The warp simply put is what the rug is woven upon, or the skeleton of the rug. It runs vertically like harp stings spanning the entire length of the piece. Where you see the pile of the rug revert to the flat woven area (white cotton) is could loosely be considered a "kilim" The rug uses a symmetrical knot with no offset, and appears to be a double ply yarn used. The type of knot as mentioned is often confusing to some: it's not unusual for people to count both sides of the knot as separate entities, sometimes doubling the knot count by accident. Take a look at
this post, and see the Ghiordes Knot (back view) picture. I also doctored your photo a little for an example of this knot.
Very interesting piece, I haven't seen one like it. While I cant decipher the signature, it may help attribute country of origin, which again, going by other characteristics of the rug seems to point to Pakistan. The signature does not necessarily add value, and might not even be a signature at all. That is to say, a fair amount of these inscriptions translate to gibberish.
Without a burn test on the wool, I'm a little suspect of the fiber. Part of the problem with valuing a rug online is determining fibers used. It could possibly be a wool pile subjected to a lemon wash, which gives wool fiber a high luster, and silk-like feel, or it could even be a mercerized cotton, although the close up photographs don't seem indicative of the latter.
Before giving a ballpark value, I just have a couple other questions for you:
1: The rug appears to be in good condition: Are there any stains, repairs, or dry areas which should be noted?
2: Could you
count the knots for me? Try taking a look at this example of how to do so, remember you're looking at two sides of one single knot!
3: What sort of value are you looking to assign to this piece? There are several types; insurance, private party resale, retail showroom....
4: Finally, what is the exact size of the rug, excluding fringe?
RugPro attached the following image(s):