But since around 1970 the paper industry seems to have adopted the tendency to have walls painted with structurized paint or wall paper instead of flat ones....
How exactly this structure was applied in stamp paper is not known yet as so far no philatelist has been bothered to pay attention to it - let alone wirte about!
I started to write about a very typical paper surface once noticed in the Mexico Exportas but later on also in the German commemoratives since 1975! But at least the German collectors were not pleased to find out they had to pay more atttention to their contemporary stamps
Still a paper surface with no or hardly any additional structure!?
With some structure:
Typical here is the rather hollow shape or width of the grooves!
Or with quite some grooves:
