Common postal stationery from the 1900s becomes anything but “common” if you collect printed backs. And a fertile source of printed-back stationery is the correspondence of the early notaries. Unfortunately, stamp show judges criticize exhibitors who include printed backs in their exhibits saying that only government-printed text is relevant. This short-sighted view fails to take into account the relevance of understanding how postal stationery was used and who used it. Stamp dealers are a lot smarter than the show judges—most of them charge a premium for any card that has anything printed on the back.
Consider Dalheim. These were Dalheim’s early notaries:
1842-1881 Louis Eugene Majerus
1880-1913 Francois Edouard Velter
1914-1920 Adolf Gantenbein
1920-1929 Paul Cravat
And here is an example of Adolf Gantenbein’s printed-back postal stationery:
1 Aug 1918
Peppange [post: Bettembourg II],
1 Aug 1918
Domestic Postal Card Rate = 7 1/2c
1 Jul 1918—12 Apr 1920
The complete list of Luxembourg’s notaries is here: http://wiltgen.roots.lu/Notaires.pdf
You can put together a “topical” collection of printed backs by choosing those from a particular category of professionals or merchants. This is a much overlooked aspect of Luxembourg postal stationery collecting.