Stamp Giveaway, Series 2, #37 [solved]

Arab Maghreb Union (Morocco, souvenir sheet)

WHO (Liberia, souvenir sheet)

ICAO (Barbuda, overprinted set and souvenir sheet of Antigua and Barbuda)

Lions Intl (Philippines souvenir sheet)

What printing process was used within the German Empire for postage stamps for the first time in the world?

The winner will be the sender of the first correct response sent at or before 7 AM, Nov. 12, 2022, eastern US time. If no correct response is received, the first response will win. My decision of winner will be final. Participation is open to anyone who wishes to enter.

Good luck!

Will 

Photogravure was used in 1914 Bavaria 

Congrats, waisaacs! I thought maybe use of German Empire might throw participants off for awhile but you weren't sidetracked. I hope you like the stamps.

Will

Thanks!  I pretty quickly found a resource that talked about the different printing processes that have been used for stamps, and from there it was tracking down the history of each of them.  I always learn stuff from your contest questions, thanks again.