The rug has a golden cast that does not appear to be patina from age. It will be interesting to see what KAD and Sharafi say.

There are two ways to check - part the pile from the front of the rug in lighter areas to see if the roots may be more brilliant. If that does not work, the next best way to check is to extract a knot from the reverse of the rug. What you will look for is lack of gold tint on the areas of hard compression, such as where the knot wraps around the warps and is packed down by the wefts. These are tight, deep areas of the rug that the washing process pigment often will not fully permeate.

On a very fine rug like this which may normally have high-end or collector appeal, a golden wash will often detract from the value.

Results from my testing for "gold" wash:
1. I undid two tight knots of the fringe. The part of the fringe that had been buried was exactly the same colour as the part of the fringe that would have been exposed to any washing process.
2. I bent the pile over so that I could see to the root of the pile. There was no gradual lightening or darkening of the pile throughout its length. However, when looking at the pile from above, viz. by looking at the ends of the pile head on, it is obviously darker than looking at the pile along its length. But the colour of both views were the same. The difference in brightness is more than likely caused by a difference in the reflective properties of the two different angles.
3. I compared the back of the carpet to the front. The back seems to have a slight grayish cast while the front was darker and had a slight golden hue. Again, some (or all) of this can be accounted for by the difference in the reflective qualities of the hard verses the soft texture. However, not having had the experience of comparing a "washed" with an "unwashed" carpet of the same colour, I'm not sure at this point whether mine has or has not been "washed." I'm including some additional photos that my shed some light on this discussion.

Does look like it has had some form of light wash. The yellow tinge shouldn't be there just based on its age.

the rug was made in the late 1980´s up to end 1990´s. It even my have been new when purchased (time from finishing the rug, trading within Iran, export and so on may take some time). It has a wash that is not comparable to tea or herbal wash - it is a chemical wash that was popular at that time. Worldwide most famous company for these "antique" washs is Kiskan Process in Hamburg, Germany and Migro in Vienna, Austria. Some washing facilities in Iran come very close to the washing quality in Germany. I think this wash was made in Tehran.