I will be as brief as possible. Apologies if this is in the wrong place.
I have uploaded a load of pictures to the testing area here.
https://goscf.com/t/60964.I have a stamp that could possibly be a new watermark variety. C in CA reversed.
In my T2 Signoscope it looks pretty clear to me, but could be an optical illusion.
As far as I know the ink is highly fugitive, so will not put the stamp anywhere near any kind of liquid.
My phone camera is useless and these are the best pictures I can get. Could someone please do their magic, and see if they can make the watermark clearer.
Scroll to the bottom of the test post to see the stamp and a picture of how the watermark should look.
If it looks possible, I will start a new post for opinions.