RB1

Is this a silk thread in the circle? Also it is green and not intetermediate(grayish) correct?
Thanks Newby

The silk paper on this issue is very obvious, with many threads visible. This stamp should have a watermark.

The stamp is RB11a, the silk paper variety. And, no, there is no watermark.

The distinctions of violet, intermediate, and green papers applied to RB1, not RB11. To be sure you should have a reference set of the three papers for comparison. Scott does not give a separate catalog number for the intermediate paper. With used stamps, especially those which show staining, as your example, these distinctions are sometimes difficult. Nevertheless, a set of reference copies remains the key to proper identification. Again, those distinctions do not apply to your stamp.

This is not a question of intermediate papers, this is a question of being either silk (RB11a)or watermarked paper (RB11b). Both are very common, so catalog value is not an issue.
In general, the silk paper threads are numerous and are easily found on all the values of this issue. It is possible to have a silk paper stamp with only one thread, but it is unlikely. It is much more likely that it is simply a thread from the papermaking process on a watermarked stamp. The surface staining on the front does not sufficiently stain the reverse to make it difficult to see properly.

Here is an RB11a that someone is selling on ebay which includes an image of the back. The silk is very obvious.

http://www.ebay.com/itm/Scott-RB11a...AOSwJcZWciKM

And a 2 cent:

http://www.ebay.com/itm/Scott-RB12a...AOSwZ1lWciMg

Nice stamp to me. I never seen one until now.

Thanks revenuermd and you to revcollector for the information. I had read somewhere maybe here I don't know that sometimes you only find one fiber imprinted in the stamp but by looking at the ones on ebay that you informed me about the fibers are quite noticeable.
Could it be as revenuermd stated a RB11a and not b? I did the a fluid test on the stamp and could not see any evidence of a water mark 191R. The only mark I could see or even tell was the cancel mark on the front.
Ok, I was reading as I am typing and I found this in Scotts==Silk refers to two types of paper found by stamp collectors. One type has one or more threads of silk embedded in the substance of the paper extending across the stamp which is designated as "with silk threads."
The other type used to print many U.S. revenue stamps has short silk fibers strewn over it and impressed into it during manufacturing. This is simply called "silk paper".
So, that is why I am a little confused and being a Newby doesn't help matters neither.

Thanks Newby

First issue silk paper has very few threads, often only one or two on a stamp. The same with the experimental silk paper Match & Medicines. For all other revenue silk papers the threads are pretty obvious.
In your stamp it is possible that the watermark is on the edges of the stamp and is therefore difficult to see. I really doubt that it is silk paper, but as I said earlier it is possible.

After viewing the ones on ebay and it being the same type I am beleiving like you that it is not so, I will put in the book as watermark paper.

Thanks for the help again.
Newby