In reply to Original Source for Dan X. Solo's "Potsdam Initials":
Thanks again for your replies. I haven't dared to try the first three suggestions from your first post because I can hardly read/write German. I also checked G. Helzel's and the Klingspor Museum's sites to no effect. However, from the first hint in my second post and from information digged from Luc Devroy's site and from F. Bauer's "Chronik der Schriftgießereien in Deutschland und den deutschsprachigen Nachbarländern" (set into PDF by H. Reichardt in 2011), I discovered that one Friedrich Schoch (FS) designed around 1840 a typeface ("Schochisch") on which the 1900's "Neudeutschen Schriften" seem to have been based. Solo's "Potsam Initials" fit perfectly with those typefaces, so joining everything together it is my (possibly wild) guess that those initials were originally designed by the "Schriftschneiderei und -gießerei Friedrich Schoch" ca. 1840. I'm afraid I can't go further, so any evidence or oppinion supporting/rejecting this guess will be mostly appreciated.