Here is my analysis of the advertisements in the July 1939 issue: out of 212 advertisements (of all sizes and kinds from classified postings to full pages), 10 were set entirely in blackletter, 27 in blackletter combined with either roman or sans serif, and 165 in roman or sans serif or scripts. In the March 1939 issue there was a five-page advertisement by Rolf Heyne offering items to celebrate Adolf Hitler’s 50th birthday. Blackletter (a schaftstiefelgrotesk) was used for 16 of the subheads and five of the items for sale, but nowhere else!
In the May 1939 issue there is a two-page article about a gift for the Führer’s 50th birthday, a handbound calligraphic text, which is set (as was usual with Gebrauchsgraphik) in Futura. (This indicates that, contrary to some assertions, that Futura was banned by the Nazis after Paul Renner was removed from his post at the Meisterschule für Deutschlands Buchdrucker in Munich, Futura was still available and in use.)
None of the mastheads of the twelve issues is set or lettered in blackletter.
I hope to analyze other issues of Gebrauchsgraphik in the near future. Stay tuned.