The watermark on this stamp is easy to see.

Very interesting.
What surprises me is the color that appears on the back of the stamp and the watermark that appears generated by a darker shade of color.
Here you need the opinions of experienced members (I heard about watermarks drawn but have not met so far)
I like this site because I can learn from the experience of other members.
PostmasterGS and vayolene-I would be very happy if you could explain to me why you eliminated the possibility of being the non-perforated variety (I guess there are many clues on the face of the stamp that no longer require checking the watermark)
I "played" with a similar stamp but I couldn't notice anything different.

What do you think about it:

cut teeth
postal stationery cutout
non-perforated variety
photo processing