The stamp I am looking at has no visible watermark and is perf 12. On orange paper it looks gray compared to other stamps on normal paper. It shows specks and dark fibers on the back when viewed under a scope. On the edges I see black or very dark fibers extending from the edges of the torn perfs, something I don't believe I have ever seen on any other stamps.
Scott list only 3 varieties of this denomination and design, all are either single line or double line watermarks. Sc 364 is blueish gray variety.
My question is it possible that a watermark can fade over time or not b visible on a stamp with this color and age, or do unwatermarked examples exist of the 3 varieties?
I added pics of a 1c Washington perf 10 for comparison purposes, knowing my cam and monitors may distort the colors.