This rug has been treated with a "Sun Finish" wash. This wash includes not only the actual cleaning of the carpet but also its processing (ennobling) through the effect of being exposed to the sun which represents an increased value to the rug. Often after the production of a carpet the colors still seem "loud". Through this sun wash the colors become softer and sometimes get an antique look to it which of course depends on the duration of the exposure to the sun.
The special wool with which this Oriental rug has been made is called "Kork" wool. The Persian word "Kork" means "soft down". This expression is used for particularly fine and soft wool for very high quality rugs, especially for expensive rugs made in esteemed manufactures like e. g. in Kashan. It is common to add the word "Kork" to the provenance name as in e. g. "Kashan Kork".
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